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SENSORS, PIPELINES, AND INTELLIGENT DECISION MAKING PROGRESS OF THE SMARTPIPE PROJECT
Martin Pendlebury
A thesis submitted in conformity with the requirernents for the degree of Master of Applied Science Graduate Department of Civil Engineering
Universiv of Toronto
O Copyright by Martin Pendlebury 1998
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ABSTRACT
Pendlebury, Martin, 1998. Sensars, pipelines, and intelligent decision making: progress of the SmartPipe
project. A thesis submitted in confomity with the requirements for the degree of Master of Applied
Science, Graduate Department of Civil Engineering, University of Toronto.
A colIaborative project was conducted behireen the University of Toronto and IPEX Inc. to develop the
SmartPipe concept. A SmartPipe is a fluid-conveying pipe with instrumentation for the determination of
parameten describing the hydraulics and chernical nature of the fluid. Provisions are also made for collecting
and transmitting this information to a central monitoring station. The aim of this research is to conduct
preliminary stages of development for the SrnartPipe. To this end, a pipeline was constnicted at IPEX to test
systern components, and subsequently preliminary designs for a SrnartConnector (to house the instrumentation)
were produced. Concurrent to the work at IPEX. the author has investigated the present state of water supply
and the impact that the SrnartPipe rnay have on its funire. The goal of the SrnartPipe concept is to liak not only
data but also a physical mode1 of system performance. That is, tying data directiy into questions of calibration,
design, and performance. Current systems do not generally incorporate this feature since their data sets are not
sufficiently dense.
ACKNOWLEDGEMENTS
The completion of this M.A.Sc. degree and thesis represents a tremendous personai achievement, and 1
certainly would not have accomplished it without the encouragement and support of a number of individuals.
Foremost, 1 would like to thank my supervisor Dr. Bryan W. Karney for his continuous and enthusiastic
assistance and encouragement throughout my studies at the University of Toronto. In addition, 1 must thank
Dr. Jiyang Chen for his patience and understanding in answering my questions and helping to guide my
research. The work cornpleted in this thesis could also not exist without the efforts of Mr. Kai Wah Tang, who
developed the data acquisition system and software for the SmanPipe. 1 would also like to thank Dr. Barry J.
Adams for his insightfi.11 cornments. and his fair evaluation of the thesis as the second reader.
At IPEX Inc.. special thanks must go io Mr. Veso Sobot (National Marketing and Product Development
Manager), Mr. Suresh Shah (Quality Control Supervisor), and Mr. Wayne Petenon (Plant Manager) for their
support and hard work. They have been more than generous with both their time and resources. Also, Mr.
Edward Loftus and Mr. Peter Melichar (Maintenance Personnel at IPEX) have helped to construct the test
pipeline, and the instalIation of the sensors.
This work was generously funded with assistance from the Natural Sciences and Engineering Research Council
of Canada (NSERC) and IPEX Inc.. through the NSERC Indumial Postgraduate Scholarship. This program
teams a mident and an educational institution with a Company in industry. with the intention of coilaborathg on
a research project of muhial interest.
Additional gratitude is extended to those friends and acquaintances who showed interest in rny work and who
gave me encouragement when 1 most needed it. Finally. 1 would like to thank rny parents for thek unfailhg
support and patience. Thank you.
CONTENTS
A b m c t
Acknowledgernents
List of Tables
List of Figures
List of Appendices
List of Abbreviations
CHAPTER 1 INTRODUCTION
PART 1 WATER MSTRIBUTION SYSTEMS
CHAPTER 2 DEVELOPMENT AM) DESIGN
2 1 History of Water SuppIy 2.2 Water Supply in the Twentieth Century
2.2. Basic System Design 2.2.2 Types of Distribution Systems 2.2.3 Operating Conditions
2.3 Summary
.- 11
iii
viii
Contents
CHAPTER 3 OPERATION AND MAINTENANCE
3.1 Organizing a Water Utility 3.2 Operation of a Distribution System
3.2.1 Optimal Control 3.22 Day to Day Operation 3.2.3 Cost of Operation
3.3 Maintenance of a Distribution System 3.3.1 Unscheduled Maintenance 3.3.2 Scheduled Maintenance 3.3.3 Record Keep ing 3.3.4 Personnel Training 3.3.5 Equipment
3.4 Monitoring and Control Systems 3.5 Surnmary
PART II THE SMARTPIPE
CHAPTER 4 THE SMARTPIPE CONCEPT
4.1 Histoncal Context 4.1.1 Telemetry 4.1.2 SCADA Systems 4.1.3 Sensors 4.1.4 The SmartPipe
4.2 Objectives of Monitoring Programs 4.3 Types of Data
4.3.1 Hydraulic 4.3.2 Water Quality 4.3.3 Stnictural
4.4 Key Components of a SmartPipe Systern 4.4.1 Sensors 4.42 Housing for the Sensors 4.4.3 Data Acquisition Systern 4.4.4 Hardware and Software Requirernents 4.4.5 Structural Requirements
4.5 Surnmary
Contents
CHAPTER 5 IMPACT ON WATER DISTRIBUTION
5.1 Benefits of the SmartPipe to a Water Utility 5.2 Applications of the SmanPipe
5.2.1 Computer Modelling 5.2.2 Operation 5.2.3 Maintenance and Repair 5.2.4 Case Studies
5.3 Leak Detection 5.3.1 Methods of Leak Detection 5.33 Dynamic Leak Detection and the SmartPipe
5.4 Summary
CHAPTER 6 DESIGN OF THE SMARTPIPE SYSTEM
6.1 Design Critena 6.2 System Configuration
6.2.1 The Access Charnber 6.2.2 Data Acquisition and Transmission 6.2.3 The SmartConnector
6.3 Choice of Sensors 6.3.1 Pressure 6.3.2 Flow Rate 6.3.3 pH 6 -3 -4 Temperature 6.3.5 Chlorine Residual
6.4 Design of the SmartConnector 6.4.1 SmartConnector Requirements 6.4.2 Details o f the Design 6.4.3 Sampling Port
6.5 Maintaining the System 6.6 Summary
Contents
PART III THE PROJECT
CHAPTER 7 PROGRESS OF THE SMARTPIPE PROJECT
7.1 Stage 1 : Feasibility Study 7.2 Stage 2: Test Pipeline
7.2.1 Putpose 7.2.2 Design 7.2.3 Construction 7.2.4 Data Acquisition System 7.2.5 The Sensors 7.2.6 Installation of the Sensors 7.2.7 Calibration of Sensors 7.2.8 Operation of the Test Pipeline
7.3 Stage3:MovingTowardslntegntion 7.3.1 Data Acquisition Sy stem 7.3.2 Sensors 7.3.3 SmartConnector 7.3.4 Market Studies 7.3.5 Software Development
7.4 Surnmary
CHAPTER 8 FUTURE WORK AND CONCLUDING REMARKS
8.1 Future Research 8.2 Key Problems to be Addressed 8.3 Finished Product
References
B ibliography
Appendices
vii
LIST OF TABLES
Table Description Page
The funetional elements of public water supply systems
Characteristics of other scheduled maintenance programs
Maintenance task schedu le
Types of data of interest for the SmartPipe
Benefits of the SmartPipe to the water utility
Possible applications of physical data for water distribution systems
Possible applications of water quality data for water distribution systems
Possible applications of structural data for water distribution systems
Ctassification of flow meters
Maintenance and calibration requirements of a typical pH meter
Maintenance and calibration requirements for the total chlorine analyser
Arrangement of senson in the SmartConnector
Parts list for the SmartConnector
List of sensors installed in the test pipeline
Problems and questions to be addresseci during development of the SmartPipe concept
LIST OF FIGURES
Figure
2.1
2.2
2.3
3.1
4.1
4.2
S. 1
5.2
5.3
5.4
5.5
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
7.1
7 2
7.3
7.4
Description
Typical components of a water distribution system
Configuration of distribution systems
Typicai arrangement of water and sewer services on a residential Street
Organization of a typical water utility: pubiicly or privately owned
Schematic of a simple SCADA system
Schematic of the SmartPipe system
Determining the hydraulic conductivity of a pipeline
Conducting fire flow tests
Acoustic leak detection
The method OC characteristics and the solution procedure
Wave propagation and computations in the x-t plane
Design of the access chamber
Mechanical pressure eiements
Transmissive sonic flow rneter
Schematic of a typical pH sensor
The amperomebic ce11
Schematic of the amperometric total chlorine residuai analyzer
The use of double containment pipe for the SmartConnector
Chosen design for the SrnartConnector
Configuration of test pipeline
Details of the pipeline inlet
Details of the pipeline outlet
Data acquisition system for the SmartPipe test pipeline
Page
9
9
10
14
34
46
57
60
72
76
77
83
85
88
89
91
92
97
I O0
1 O9
110
11 1
116
LIST OF APPENDICES
APPENDLX A: DETAILS OF THE TEST PIPELINE A. 1 Design Drawings A.2 Parts Lists
A.2.I Bill of Materials A.2.2 List of Sensors A.2.3 Description of Sensors Installed
A.3 Design Ca[culations A.3.1 Detemination of Required Support Spacing A.3.2 Catculation of Espectrd Head Loss Through the Pipeline
APPENDIX B: DETAILS OF THE SMARTCONNECTOR
B. 1 Design Drawings B.2 PartsLists
APPElrDlX C: SUPPLIER INFORMATION
APPENDIX D: INFORMATION ABOUT IPEX INC.
LIST OF ABBREVIATIONS
A/D
AM
ASCE
AWWA
BDCM
BF
CF
CIS
CS A
DBCM
DBP
DC
DIA
DS
DR
EBMUD
ESWTR
FM
FM
GAC
GIS
HAA
K R
MCL
NOM
analog/digital converter
automated mapping
American Society of Civil Engineers
American Water Works Association
bromodich!orornethane
bromofom
chlorofom
customer information system
Canadian Standards Association
dibromochloromethane
disinfection by-product
direct curren t
Denver hternational Airport
distribution system
dimension ratio
East Bay h.lunicipa1 L'tility District
Enhanced Surface Water Treatment Rule
Factory Mutual
Oemen t facilities mana,
granular activated carbon
geographic information system
haloacetic acid
Information Collection Rule
maximum concentration leve!
natural organic matter
List of Abbrwiations
NSERC
NSF
NTU
NWW
OPS
psi
PE
PVC
RCS
RSU
SCADA
SDWA
S m
THM
m UL
USEPA
Natural Sciences and Engineering Research Council
Nationai Sanitation Foundation
nephelometric turbidity unit
North West Warer
Ontario Provincial Standards
pounds per square inch
polyethy lene
polyvinyl ch loride
remote chernical sensor
remote sensing unit
supervisory conirol and data acquisition
Safe Drinking Water Act
Surface Water Treatrnent Rule
trihalomethane
total trihalometliane
Underwriters' Lrtboratory
United States Environmental Protection Agency
CHAPTER 1
Introduction
In the water industry it is understood that each distribution system has unique characteristics that often de@
simple classification. Modem networks are a patchwork of many different types of pipes, pumps, valves, and
storage reservoirs. Larson (1966) describes a distribution system as "a sensitive, dynarnic, Iiving individual
with its own peculiar characteristics, not just a network of tubes joined together." Traditionally, operators of
distribution systems have needed to gain experience with a specifk system to effectively solve operathg and
maintenance problems. However, fiequent staff changes can soon negate this advantage. Today, new tools and
new techniques are being made available to operators so that they may better understand and operate their
systems, regardless of how much experience they may have with a particular system.
In recent years "smart" systems have been used in applications ranging from concrete bridge decks CO
automobile engines, for the purposes of monitoring parameters and controlling components. It seems inevitable
that "srnart" systerns should be considered for use in water distribution systems, where the timely supply of
relevant data cm lead to Iarge savings in operating and maintenance costs, and an improvement of service to
customers.
To take advantage of the capabilities of "smart" systems, the SmartPipe concept is cumntly being developed
through a joint effort between the University of Toronto and IPEX Inc. A SmartPipe is a fiuid-conveying pipe
with instrumentation for the determination of parameters describing the hydraulics and chernical nature of the
fluid (Kamey and Laine 1997). Provisions are also made for collecting and transmitting this information to a
central location. A change in the data obtained fiom the SmartPipe aierts an operator to the possibility that
conditions within the network have changed, thus allowing a remedy to be implemented on a real-time bais ,
and the system to be returned to normal operation as quickly as possible.
Water supply and distribution is an essential service in any populated area In Canada, approximately 2,500
cornmunities have water supply utilities, with an estimated two billion dollars spent annually on improvements
and expansion of these systems (Chen 1997). A disruption of service caused by a pipe break or leak can be
costly to a utility, and the lack of detailed information conceming conditions within a distribution system makes
operation, maintenance, and repair more diffcult and ultimately more costly. The use of instrumentation to
collect data is valuable to utilities when carrying out these functions: although at present they are used on a
Limited basis. SmartPipes, installed at numerous locations within a distribution system, could meet the
increasing dernand for instrumentation, and provide the operator with much more information than is currentiy
available.
There are two principal reasons for the need to improve the effîciency of water supply through the use of
instrumentation. First, the high distribution losses that have been common in the past can no longer be ignored.
The industry is under pressure fkom environmenta1 lobby groups whenever an attempt is made to develop new
land-hungry sources. Second, there is additional pressure from the Government for greater operational
efficiency and to obtain the maximum benefits fiom existing facilities (Brandon 1984). Utilities will be hard
pressed to improve efficiency in these m a s without increasing their reliance on instrumentation for monitoring
and automation.
Before the attributes of the SmartPipe are discussed, it is important to look at the environment in which they
will be used. The next two chapten focus on water distribution systems; their development and design, and
how they are managed by utilities. The SmartPipe concept is introduced in Chapter 4, with a discussion of its
history, objectives, and the various components needed for a complete system. Chapter 5 extends this
discussion to consider how the SrnartPipe can be used to improve the operation and maintenance of disnibution
systems. Consideration is given to computer modelling, operation, and maintenance. A detailed discussion of
leak detection is also presented, focussing on the dynamic leak detection mode1 and its applicability to the
SmartPipe. Chapter 6 discusses the design requirements for some the SrnartPipe components, and describes in
detail the prelirninary design stage of the SmartCo~ector. Emphasis is placed on the construction of the
SrnartConnector using polyvinyl chloride (PVC) injection molding, which is used by IPEX to produce its Iine
of Blue Brute fittings'. The various stages of the SrnartPipe project are discussed in Chapten 7 and 8, fiom the
' Pmducing PVC fînings using injection molding involves forcing the f w d PVC hto a mold cavity in which the inner surfaces defined by the core and the outer surfaces by the inner walls of the cavity (Uni-Bell PVC Pipe Association 199 1).
Introduction
genesis of the idea through to the present stage, as well as expected future research. A detailed discussion of
the design and construction of the test pipeline for Stage 2 of the project is also included.
Throughout the preparation of this thesis, the author has had a number of intentions for the purpose of the
wrîtten report:
Reporting on curent operation and maintenance practices of water utilities;
Discussing the benefits and limitations of the SmartPipe concept;
Investigating the integration of the SrnartPipe with a distribution system; and
Reporting on the past, present, and future stages of the SmartPipe project.
The broad scope of the research has meant that the information contained is this report has a similarly broad
scope. However, despite the breadth of coverage, effort has been made to improve its cohesiveness.
PART 1
WATER DISTRIBUTION SYSTEMS
Development and Design
Before the concept of the SmartPipe is discussed in more detail, it is usefil to look at the current state of water
distribution systems, and the operation and maintenance practices used by utilities. This chapter discusses the
development of water supply and its peculiarities in the twentieth century. Chapter 3 focusses more on the
operation and maintenance aspects of water distribution.
2.1 HISTORY OF WATER SUPPLY
Since the dawn of civilization, the hurnan race has been concerned with the adequate supply of dnnking water
to urban populations. Evidence of water distribution systems dates back to the earliest known civilizations.
Ceramic pipes for water supply have been found in houses in the Indus valley dating fiom 3000 B.C.. and
aqueducts and pressure conduits have been discovered in Syria and Cyprus from 1000 B.C. (Rouse and Ince
1963). It was known, at least as early as Greek times, that pure water is an essential ingredient for a healthy life
(Hill 1996). As centres of population grew, the local supply of water became polluted and inadequate, and the
construction of aqueducts was necessary to convey water to cities fiom distant sources. These aqueducts were
the fo remers of today's distribution systems, although they were only able to supply water to cities at central
locations (Martini 1976).
However, due to the decline of shuctured society in Europe afier the fa11 of the Western Roman Empire in the
fifth century, the sophistication of water supply systems did not advance beyond that of the classical world until
the seventeenth century. Throughout the middle ages periodic efforts were made to irnprove the state of water
supply, but it was not until the end of the Renaissance that successful attempts were made to irnprove the
supply of water to European cities (Hill 1996). Modem disîribution systems. with pressurized pipes, were not
properly introduced until the middle of the seventeenth cenniry, and even these early systems were rather crude.
Water Distribution S'stem: Development and Design
Pipes were made of wood, clay or lead, and were usually laid at grade. As yet, water could not feasibly be
delivered to individual residences. However, by the early nineteenth century inexpensive cast iron pipes had
been developed, and the introduction of steam-dnven purnps rneant that for the first time in history it was
feasible for water to be delivered to individual residences (McGhee 199 1).
Treatrnent of drinking water supplies has unfortunately lagged behind developrnents in distribution techniques.
Certain types of treatment, such as coagulation and filtration, were used on a limited bais as long ago as 2000
B.C. by established civilizations such as ancient Egypt and Mesopotarnia. However, their effective use in
municipal water treatment was not common until this century (McGhee 1991). Even after the introduction of
widespread treatment of drinking water, water quality was always of l e s concem than hydraulics. Water
reaching the customer was assumed to have the same quality as that Ieaving the treatment plant. Larson (1966)
was one of the fmt to identiQ the need for water quality analysis in distribution systems. He suggested the
analysis of chemical reactions in both the water and on the pipe wall, microbial problems, corrosion,
tuberculation, erosion, and teaks. Today, a great deal of study has been conducted to understand the effects of
these processes on the quality of drinking water in distribution systems.
2.2 WATER SWPLY IN THE TWENTIETH CENTURY
Water supply systems Vary substantially, but share certain components, and can be divided into two parts. The
first part is the conveyance of water fiom its source, t h u g h a trunk main, to a service reservoir with some
form of treatment carried out en route. The second part is the distribution of water fiom that reservoir to
individual customets (Pipeline Industries Guild t 984).
The modem distribution system is an agglorneration of different stnicturai and mechanicd components, and can
be considered an interface between the customer's faucet and the remainder of the system (Reh 1975).
Although it has a definite physicai form and a clear purpose, impressions of the distribution system and its
purpose vary depending on the observer. To the water industry professionai a dimibution system is a complex
network comprised of water mains, storage resewoirs, pumping systems, vaives, hydrants, and various other
components. To the customer it is merely the piece of water main in front of their home to which theu meter is
comected and through which water fiows. The custorner judges the performance of the entire water supply
system by the quality of product that emerges nom their faucet (Reh 1975); whether it is clean, aestheticaily
Water Distribution Systems: Development und Design
pleasing, and supplied at an adequate pressure and quantity. This view of the system is understandable, since a
customer pays taxes and utility rates to ensure a reliable supply of water to their home. Customers only notice
the physical manifestation of the distribution system when a problem occun. A person living in a developed
counrry spends a very small fraction of their life worrying about the safety and reliability of their water supply,
even though it is the most pncious nsource each of uses every day of our lives. Although customen do not
regularly concem themselves with the management of water supply and distribution systems, public awxeness
of the issues faced by the water industry ha grown (Thompson 1975). Because customers today are more
informed, they are also more demanding of adequate service than in the past, and therefore the standards by
which we evaluate water supply systems are changing.
TABLE 2. t ï h e functional elements of public water supply systems (Linsley et al. 1992)
Functional element
Principal concerns in facility design (primary/secondary) Description
Source(s) of supply Quan titylquality Surface water sources of supply such as rivers, lakes, reservoirs, or groundwater
Storage Quantitylqual ity Facilities used for the storage of surface water, usually located at or near the source of supply
Transmission Quantitylquaiity Facilities used to transport water fiom storage to treatment facilities
Treatment Quality/quantity Facilities used to irnprove or alter the quaiity of water
Transmission Quantity/quality Fétcilities used to transport treated water and storage to intermediate storage facilities and to
one or more points for distribution
Distribution Quantitylquality Faciiities used to distribute water to the individual user comected to the system
Water Diktr ib ut ion Systems: Deveiopment and Design
Water supply and distribution systems are constructed, operated, and maintained by water utilities. It is the
function of these utilities to obtain water fiom a source, treat that water to an acceptable quality, and deliver the
desired quantity of fmished water at a sufficient pressure to the appropnate place at the required tirne (Walski
1984). Management of a distribution system comes under the broader heading of municipal engineering, which
also inchdes land development, service systems, and environmental systems for an urban area. Service
systems for a city include wastewater handling, solid waste handling, local transportation, recreational systems,
and water supply and distribution. Municipal water systems are comprised of a number of functional elements,
as described in Table 2.1.
2.2.1 Basic System Design
Distribution facilities, as show in Figure 2.1, consist of pumping stations, distribution storage, and distribution
piping, each of which has a nurnber of purposes (Mays and Tung 1992). Pipes are used to transport water
under pressure to the customer and to protect that water from contamination. Valves are used to regulate flow
and pressure and to protect the system fiom unusual operating conditions (Le., transient evenu). Storage
reservoin are used to maintain sufficient quantities of water for fire protection, provide adequate quantities of
water to customers, provide emergency norage in the event of pump failure, and allow pumps to operate at a
more constant rate despite variable demand throughout the day (Bhave 1981). Municipal water distribution
systems have two primary purposes. The fust is to deliver water to points of consumption for domestic,
commercial and industrial uses, and the second is to supply water for tire protection and street flushing, or other
public uses (Walski 1984).
Distribution systems are modelled on three basic types: tree feeder, ring feeder, and loop feeder. The loop
structure is the most economical in its use of pipe material. However, in practice the Gridiron system. a
combination of ring and ioop structures, is preferable (Figure 2.2). The configuration is dependent on the street
layout, topography, degree and type of development, and location of treatment and storage facilities. The
Gridiron configuration solves the problem of dead ends as demand at any point in the system is supplied from
more than one direction (Linsley et al. 1992). Water mains are generally located within municipal road
allowances so as to be accessible for maintenance. For temperate climates in the Northern Hemisphere,
hstallation on the north and east sides of m e t s (the wamer sides) is preferred. Pipes must be laid at a
sufficient depth to be safe from trafic loads, and aiso below the fiost level (one to three metea) (Henry and
Heinke 1996). Figure 2.3 shows a typical arrangement of water and sewer senrices on a residential Street,
Water Distribution Systems: DeveIopment and Design
FIGURE 2.1 Typical components o f a water distribution system (Mays and Tung 1992)
distriiution wurrlt I l war I
FIGURE 2.2 Configuration of distribution systems (a) Gridiron system (b) Branched system (Harnmer and Harnmer 1996)
Water Disnibution Systems: Deveiopment and Design
FIGURE 2.3 Typical arrangement of water and sewer services on a residential street (Henry and Heinke 1996)
Ropny Ropny i inc Muihola(cuay IW rn 2 Lia8
I or u rrgiind) I I I I
1 : S i d d k I ; b ; l I ; l ; l I I I 1 I I I I t 1 I l 1 t 1 cs ni 1 (s A) 1 1 1 I t
Designing distribution systems is an iterative process intended to achieve predetermined standards. Such
standards are usually considered absolute, and factors of safety are used to guarantee that shortfalls in
performance do not combine to violate these standards (Brandon 1984). Failure to make field measurements of
an existing system when designing expansions often leads to either a system with hadequate capacity or
needless expenditure caused by overdesign (Walski 1984). Today, with the move towards pnvaîization, and
the need for cost justification in the public sector, utilities are taking a hard look at the design practices of
yesterday (Westerhoff and Lane 1996). In the past engineers lacked the necessary tools to perform accurate
analyses of dimibution networks. Today, with the advent of faster and more powerful cornputen these same
analyses can be performed in a fiaction of the tirne, allowing more cost-effective designs.
Water Distribution Systems: Development and Design
23.2 Types of Distribution Systems
Water distribution systems operate by gravity, by pumps alone, or by pumps in conjunction with on-Iine
storage. In a gravity system, water is supplied or pumped to service resenioirs, and is then allowed to feed into
the distribution network through gravity. This type of system is only possible when the water supply is located
at an elevation substantiaIly above that of the city.
In a pumped system with on-line storage, water is put directly into supply and service reservoir storage, which
is either contained within the system or is on the far side of the distribution systern to the input. A reiiable
supply of water is achieved in a pumped system without storage by providing standby generation and duplicate
supply mains. This type of system is the les t desirable since it relies entirely on pumps to provide system
pressure. Pumps are expensive to operate, are not entirely reliable. and no reserve flow is provided in the event
of a power failure (McGhee 1991). However, it is unlikely that a systern will be able to operate reliably without
the use of pumps in some capacity. Furthemore, the cost of building a gravity system (Le., water towers) may
be prohibitively high, and it rnay be more economicaI to supplernent system pressure using pumps. Generally,
distribution systems utilize a combination of the pump and gravity systems. In such systems, the service
reservoir holds two main purposes:
1. To balance high and low demands during the day; and
2. To protect customers from a temporary failure of the source water, treatrnent, pumps, or the mnk
main.
The quantity of water demand at peak times rnay be two or three times the average daily rate. Therefore, the
service reservoir is used to balance the demands, leading to savings in both capital and operating corn of
incoming ûunk mains and other "upstrem" components (Pipeline Industries Guild 1984).
Excessive elevation changes over an area can cause excessive pressure on water mains in low-lying areas and
insufficient pressure at higher elevations. An excessiveIy high pipe pressure can cause increased leakage, while
low pressure is inconvenient, and can result in contamination of water mains and inadequate f i e protection.
The solution adopted by water utilities is to divide networks into separate pressure zones with reservoirs and
pumphg stations in each zone that are fed directly by high pressure feeder mains fiom the water treatment plant
or main reservoir (Henry and Heinke 1996).
Water Distribution Systems: Development and Design
2.23 Operathg Conditions
Water distribution systems must operate adequately under a variety of loading conditions. A loading condition
can be defmed as a unique pattern of nodal demands, where nodes are connections where water is either
removed fiom or fed into the system. Loading conditions include fire demand, peak daily demand, a series of
patterns varying throughout the day, or a critical load when one or more pipes are broken. When a system can
operate weil under a variety of Ioading conditions it is considered a reliable system (Mays and Tung 1992).
Water distribution systems are designed to meet estimates of user demand. They must be able to supply either
the maximum hourly flow or the maximum daily demand plus fire requirernent (whichever is most severe) to
any point in the municipality. In residential areas, mains of at Ieast six inches in diameter are necessary to
achieve this level of supply (Henry and Heinke 1996). However, in general distribution pipes are sized on the
basis on fire flow requirements rather than on customer needs (Cesario 1995).
The pressure in municipal water systems ranges fiom 20 to 40 psi (14 to 28 metres of water) in residential
districts, with structures of four stories or less, to 60 to 75 psi (42 to 53 metres of water) in commercial districts.
The Amencan Water Works Association (AWWA) recommends a normal static pressure of 60 to 75 psi
throughout a distribution system. A pressure in this range is suficient to supply ordinary uses in buildings of
up to ten stones in height, sprinkler systems in buildings of four or five stories. usehil fue flow without pumper
trucks, and a relatively large margin of safety to offset sudden high demand or isolation of part of the system
(Frornan 1975; McGhee 1991). Buildings of more than ten stories are required to provide their own booster
pumps to supply adequate pressure to the upper floors.
Now that the subject of water distribution systems has been introduced, Chapter 3 look at procedures that
utilities use for operation and maintenance. Before the attributes of the SmanPipe are discussed, it is important
to look at the environment in which they will be used. In the later chapters, the reader should keep in mind the
basic goals of water supply discussed here, aamely: consistently delivering a high quality water suppiy to al1
customers at the desired quantity and pressure.
CHAPTER 3
Operation and Maintenance
nie primary goal of a water utility is "to provide good quality water, in adequate amounts, at reasonable
pressures, to al1 usea, at al1 times, and at the lowest cost possible under the economic and other constraints
which exist at any specific tirne" (Reh 1975). A water utility rnust use the existing distribution systern to
accompiish this goal, whiie at the same tirne meeting demand for emergency situations, and carrying out their
own operational strategies. The manager of a water utility has many activities to administer and many
important decisions to make, such as (Reh 1975):
Deterrnining the quantity of water being used at present, and estirnating future water requirernents;
Establishing the conditions of service, and submitting the utility to regular public evaluation;
Exarnining the responsibility for service to several classifications of users;
Determinhg the definition of "good water", with a definite responsibility for maintaining standards;
E v a l u a ~ g new technologies, and monitoring system effectiveness;
Financing operation and maintenance, and ensunng that ernployees are well trained; and
Keeping the public infonned of operating policies and emergency situations.
When searching for ways to improve service, one m u t look at operation and maintenance fiom a global
perspective, considering ail of the above points.
3.1 ORGANIZING A WATER UTILITY
The organization of each water utility is subject to unique nquuements. The organuational strategy will
depend on the size and complexity of the utility, the number of customers being serviceci, and the location of
the utility. However, it is unial for utilities to share four functional units: operations, engineering, financial,
and administration. These divisions are accountab1e to the managing head of the utility.
Water Distribution Systems: Operation a d Maintenance
FIGURE 3.1 Organization of a typical water utility: publicly or privateiy owned (Stacha and Coustillas 1983)
Shanholdas or Public w
G e n d Manager, Cornmissioncr, CE0 or Director of Warcnvorks
Administration O pcrat ion D Engineering u Accounling ud inonid audit
Dnoibuiion a d purnping + I Finurial phnning and
budget m a n a p c n i 1
Water Distribution Systems: Operution and Maintenance
Any water utility must have an organizational structure that allows it to meet its overall plans and objectives,
and exhibits dynarnic and flexible characteristics to respond to the changing needs of customen and
organizations. This characteristic is mie of publicly or pnvately operated utilities. A schematic of the
organizational structure of a typical water utility is shown in Figure 3.1. Most water utilities, whether privately
or publicly owned, must report, respectively, to either shareholders or the public. The governing body exists to
make decisions, ratified by the shareholders or the public, concerning policies and finances (Stacha and
Coustillas 1983; Korbitz 198 1).
3.2 OPERATION OF A DISTRIBUTION SYSTEM
Operational conwl of a water dismbution system ranges between simple monitoring and complete automatic
control. This range can be divided into three basic stages (in order of increasing control): system monitoring,
remote supervisory control, and automatic control. AI1 control systems available today have evolved from
systems for monitoring field variables (Cesario 1995).
Effective control of dismbution systems is only possible given a sound understanding of its hydraulic
peculiarities (Goodwin 1988). System operators eventually become familiar enough with a system to make
reasonabIy infonned decisions, but fiequent staff changes can negate this advantage. Sometirnes, even if
operators have experience with a particular system, problems can occur that are not irnmediately identifiable.
As systems age valves stick, blockages occur, meters Wear out, pipes break, and control systems rnalfwiction.
This sub-par performance becornes accepted by operators as normal, and therefore no concem is exhibited or
investigation initiated.
3.2.1 Optimal Control
Optimal control generally refen to the scheduling of purnp operation to minimize the cost for a given set of
operating conditions. The minirnization of pumping corn over a planning horizon m u t be accomplished in the
presence of system constraints, bound constraints on decision variables, and other constraints that reflect
operator preferences or system limitations. Optimal control also incorporates a broader defmition including
planning, design, and operation of water distribution systems. Planning involves the selection of sources,
facilities, and the layout of nunk mains. Sizing of these components as welI as pipes is considered system
Water Disiribution Systems: Operation and Mainremnce
design, and operation involves the selection of operating policies for 'typical" or "criticai" conditions. Pump
scheduling falls under this third category of optimal control. The three problems of planning, design, and
operation are interrelated and should be considered jointly. However, the pracîical difficulties of this approach
requires these problems to be treated separately (Mays 1997).
Pump operation is one of the means by which pressure is supplied to a distribution system. Water is either
pumped fiorn a storage reservoir directly to the distribution system, or it is pumped to an elevated reservoir or
holding tank and then to the distribution network. The purpose of the elevated reservoir is to ensure adequate
water supply and pressure during times of peak demand. Pump operation for distribution systems has four
main functions:
i. Damp short term (hourly) variations in demand;
ii. Supply fire demand;
iii. Supply water during minor shutdowns; and
iv. Maintain uniform pressure throughout the system at a11 times.
Detennining pumping scliedules to meet these requirements, white at the same time maximizing eficiency, is
not a simple task. To get the maximum eficiency fiom pumps, one must consider mon than simply the
purnping schedule. Other reasons why pumping stations do not operate efkiently include (Omsbee and
Lansey 1994):
Pumps that are incorrectly selected or have wom out;
Leaks in the distribution system;
Limited storage capacity, and limited capacity in the transmission and distribution systems;
Inefficient operation of pressure (hydropneumatic) tanks;
Inadequate or inaccurate telemetry equiprnent;
Inability to automaticalIy or remotely control pumps and valves;
Penalties due to tirne-of4ay or seasonal energy pricing;
Lack of undemanding of demand or capacity power charges;
Operator error; and
Suboptimal control strategies.
in many cases, monitoring of distribution systern conditions cannot alleviate these pmblems. If a pump has
been incorredy selected or become worn the best course of action is to have it replaced or repaired. Similarly,
physicai limitations of the dimibution system cannot be directly altered, except by =habilitation or replacement
Water Distribution System: Operation and Maintenance
of these components. However, there are cases where improved monitoring of a distribution system may
increase purnp effïciency and decrease operating costs.
As an example, the East Bay Municipal Utility District (EBMUD) in Oakland, California, conducted a study of
its operations and found that although its operations were adequate, improvements could be realized in a
number of areas (Hendl and Linville 1992). The following recommendations were made following the study:
i. AnaIyze electric rate schedules to obtain the most cost effective rate schedule for each pumping plant;
ii. Fine tune operating procedures to ensure pumping occurs as much as possible during off-peak hours;
iii. Investigate the feasibility of changing plant rates at the treatment plants to minimize energy costs;
iv. Investigate the use of diesei-driven emergency standby generators at key pumping plants; and
v. Investigate the feasibility of using diesel-driven pumps during hot spells to avoid eIectrical on-peak
period pumping.
M a t the study did not recomrnend directly was a monitoring and control system. However, to achieve the
study recommendations the utility would have to investigate the use of monitoring and control to some extent.
When distribution system components are being operated inefficiently due to an inadequate operating policy,
changes can be made to this policy to improve eficiency, but the utility must still meet the requirements of
adequate service to the customer. As demand increases, pumps are turned on to maintain adequate pressure,
tank levels are maintained to ensure adequate pressure and emergency supply, and valves are operated to route
water to desired areas. There are many ways to operate these various components in tandem to achieve the
desired result: the question of which combination is most efficient remains. Historically, operational criteria
evolved over time as system operators gained experience with a given system. With the advent of computers,
modelling of operational procedures has become cornmonplace.
3.2.2 Day to Day Operation
Generally, day-to-day operation of a water distribution system involves regular maintenance, emergency
maintenance, and deaiing with situations liable to cause custorner cornplaints Maintenance operations are
discussed in Section 3 -3. The normal state of system operation is discussed here.
Water Distribution Systems: Operation and Maintenance
An acceptable drinking water should be free fiom al1 chemical, biological, physical, and radiological substances
which may have a public health effect or may cause customen to use an altemate, less desirable, or unsafe
source of drinking water (McPherson 1975). Utilities are pnmarily concerned with controlling biological,
chemical and radiological substances. On a secondary basis, utilities are interested in solving taste and odour
problems. Engineers are constantly concemed with these two aspects of water supply in both design and
operation of water utilities.
Distribution systems must be designed, constructed, maintained, and operated to assure not only quality and
quantity, but pressure. A minimum pressure of 20 to 30 psi (14 to 21 metres of water) under al1 flow conditions
at the highest elevation in the system, and adequate flow and pressure for fire fighting needs, must be supplied.
Continuous engineering reviews, personnel training, cooperation of federal and provincial govements, and
cooperation of water utilities and universitics are necessary to maintain a water uti1ityJs capability of meeting
these needs. Too often, the focus of investigations is limited to water treatment plants. Historicaily, water
quality was not a big concem; system hydraulics gamered most of the attention. The water reaching the
customer was assumed to have the same quality as that leaving the treatment plant. it was Lanon (1966) who
first identified the need for water quality analysis in distribution systems, encompassing chemical reactions in
both the water and on the pipe wall, microbial problems, corrosion, tuberculation, erosion, and le*. In a well
managed system, an operating plan should encompass al1 aspects of water supply and distribution, including
watenhed management, distribution system operation and maintenance. water treatment plant operation, and
water transmission systems. At al1 stages operators should consider both quantity and quality issues.
Normal daily operations are canied out by a superintendent, with a number of district inspecton and operators
working alone or in teams of two or three. The duties of the staff will Vary, but usually constitute some
combination of the above tasks. The detailed knowledge and ernpirical understanding of inspectors conceming
the behaviour and operation of the system they administer is usually excellent (Goodwin 1988). hspectors
spend mucb of theu time dealing with consumer inquiries and reports of Ieaks, but are also responsible for
valve operation. They must therefore have a varie^ of skills, h m an understanding of hydraulics to
sophisticated interpersonal skills.
Water Distribution Systems: Operation and Maintenance
3.23 Cost of Operation
Operating costs for water utilities can be divided into two main categones: treatment plant operation and
pumping. Both costs are reasonabiy large. but could be iowered if mon information about the system is
known. Treatment cos& are controlled by the amount and type of chemicafs used in the various treatment
processes, and the power costs associated with pumps and flocculators. Collecting information about the water
in the distribution system cculd improve these treatment processes, reducing the overall cost of water treatment.
Pumping costs are often much higher than necessary. The cost of pumping is largely affected by switching
pumps on or off depending on the power cost rate structure. Many utilities take advantage of elevated storage
reservoirs to provide adequate pressure during the day when demand and power costs are high, while pumping
water to replenish these reservoirs at night when demand and power costs are low. UtiIities spend a lot of time
and money developing elaborate pumping schedules to minimize the cost of pumping. However, to effectively
minimize pumping costs utilities need real-the data describing system performance so that a cost-effective
pumping schedule can be developed; one that is not static, but rather one that changes to reflect changing
conditions within the distribution systern.
Supplying and distributhg water to the public is an energy-intensive endeavour for municipal water utilities.
Nearly seven percent of electricity consumption in the United States is by the water industry (Orrnsbee et al.
1989). More than 95 percent of this electricity is used for pumping (Clingenpeel 1983; Cams et al. 1992). The
production of this electricity has both economic and envuonmental impacts on society; impacts that could be
lessened if demand for potable water could be reduced. Changing people's attitudes towards water
consumption could reduce demand, but there are other ways that water demand can more effectiveiy be
reduced. A significant percentage of the water that is treated and released into the distribution system is Iost
due to leaks or other sources of unaccounted for water. Unaccounted for water includes water lost through
physical leaks and water used but not accounted for through metering or estimates. For well-established
synems, levels of unaccounted for 80w less than eight percent of total production are considered acceptable
(Zipparro et al. 1993). However, in meny cities with older pipe networks the fi-action is much higher
(Skjervheim 1984). Leak detection devices and water accountability strategies ushg approaches such as the
SmartPipe could allow utilities to reduce the percentage of unaccounted for water, thereby reducing the overall
quantity of water that would need to be treated and purnped Consequently, the overdl cost of water supply
Water Distribution Systems: Operut ion and Maintenance
would be significantly reduced, and the strain on raw water sources would be similarly reduced. Of course, it is
generally impractical to account for every litre of potable water in a distri'bution system.
3.3 MAINTENANCE OF A DISTRIBUTION SYSTEM
While a water utility must allocate its resources among a variety of components in the overall water supply
industry, the distribution system generally demands the largest share of these resources. Because of its size,
complexity, and importance in the conveyance of potable water, the distribution system requires regular
maintenaxe to ensure its safe and reliable operation. The goal of a maintenance program is to preserve the
system's proper operating condition, with the ultimate goal being the most efficient operation in relation to
minimum cost, until deptetion of its economically usable life (Tinkey 1975).
In the U.K. half of the water supply pipes are over 40 years old, while one-sixth are over 80 years old. Yet the
majority remain in good condition, and so the annual expenditure on pipeline maintenance is less than 0.5
percent of the replacement value. However, some maintenance is essential to pmerve hydraulic performance
and rninimize problems that give rise to customer complaints.
Even the most carefully designed and constnicted systern will eventually deteriorate. For this reason, water
utilities require an adequate maintenance program to arrest this deterioration. If distribution systems are
negkcted, they cm develop a variety of potentially serious problems (Ministry of the Environment 1980):
Fire hydrana that will not produce the necessary volumes and pressures, nibsequently causing an
increase in f re insurance rates in the affected area;
Undesirable tastes and odoun caused by dead water, rerouting of water, or lack of a routine flushing
p rogram ;
Leak repair or maintenance work requirïng shutdown;
Reduced water flow caused by encrustation or bio-film lining the mains; and
O Frequent water main breaks resulting from fieezing of lines and services.
Tberefore, every utility m u t develop a cornprehensive maintenance program. The three simple seps of
organization, planning, and training will help a utility to achieve an effective maintenance program, which is a
cnticai cornponent of a utility's success (Flynn 1996).
Water Disrribution Systems: Operation and Maintenance
n ie maintenance manager should be knowledgeable, skiIlfil, and able in administrative, financial, supervisory,
and technical areas. However, they must be given the necessary time, support, and assistance required to
perfonn their tasks. It is important for the manager to direct maintenance work toward preventative md
predictive maintenance in order to extend equipment life and reduce the nurnber of breakdowns. In 1870,
Rudolf Virchow coined the phrase "prevention is better than cure" (Bwke 1996). He was refemng to public
health, but his comment applies equally well to water distribution systems.
There are five major categories under the heading of system maintenance: unscheduled maintenance, scheduled
maintenance, record keeping, personnel training, and equipment. A comprehensive maintenance program
should encornpass all of these categories.
3.3.1 Unscheduled Maintenance
Unscheduled maintenance is a utility's response to emergencies. When a pipe breaks unexpectedly or a valve
refuses to close, maintenance personnel must act quickIy and effectively to remedy the situation. Unscheduled
maintenance is the largest single problem faced by water utilities, but it cannot be eliminated. Even in a well-
managed system practicing preventative maintenance, pipes will still break without warning, but with suficient
planning and foresight, repair work can be streamlined.
a. Main Breaks
A main break is caused by hadequate or poor design, improper installation, surges or water hammer, extemal
srress, intemal or extemal corrosion, differential sealement, temperature differentials, manufacturing defects, or
other construction work interferhg with the distribution systern. The first three factors are the most important,
as they are most prevalent in a water distribution systern. Obviously, a system must be designed to meet the
imposed consumer demands, and pipes must be able to withstand the operating pressures. However, conditions
within a distribution system periodically exceed design limitations, usually without the foreknowledge of
system operators. Damage due to surges and water hammer can be limited by Uicorporating protective devices
such as surge tanks and pressure-relief valves in the design. For example, thrust blocks are instailed near
fittings and hydrants to withstand the thncit associated with the rnomenntm of fiowing water (Uni-Bell PVC
Pipe Association 199 1).
Water Distribution Systents: Operation and Maintenance
Extemal stress, caused by ground movement and impact loads. will generally not be a problern if pipe materials
are used correctly and are not expected to exceed their design limitations. Similarly, the effects of intemal and
extemal corrosion, and the effects of temperature differentials, can be reduced by intelligent use of pipe
matenals, proper use of pipe trench bedding, water treatment, and pipe wall coatings. Finally, rnanufacwing
defects are today only a small annoyance due to improvements in quality control procedures during the
manufacnuing process. Consequently, very few water mains fail as a result of poor workmanship.
Water mains are ofien damaged when people, not connected with the water utility, begin digging in the ground
without knowing where the pipes are located. Keeping contractors, the public, and other utilities informed is
the only solution to this problem. Information cm be made available by maintainhg adequate system records,
and establishing effective communication with the parties involved.
The five types of main breaks are circumferential, longitudinal, "blow-out", fitting "blow-off', and breaks
caused by human error. Each type is caused by different conditions, and each type requires different strategies
for repair. A more detailed discussion of repaMng main breaks can be found in Tinkey (1975).
b. Leak Detection and Repair
The presence of a leak is not as serious as a main break, although prompt action can reduce the time and cost of
repair. The biggest difficulties associated with leaks are detection, location, and isolation. Only a mal1
quantity of water may be lost, and so it does not always surface at the point of the le&. Detection equipment is
available, but accurate detection of leaks requires an operator experienced with the specific system. Generally,
Ieaks do not require shutting d o m the main since they can be repaired quite easily with the pipe under pressure.
Chapter 5 presents a more detailed discussion of leak detection.
c. Other Emergencies
Water distribution systems may also experience other emergencies that do nor fa11 under the categories of main
breaks or leaks. These emergencies include broken service lines, fiozen mains, broken hydrants, and frozen
meten. Each situation requires a slightly different method of repair. which the maintenance personnel mus be
able to handle at a moment's notice.
Water Distribution Systems: Operaiion and Mainienance
A further class of emergencies can be tenned catastrophes, which Uiclude earthquakes, tomadoes, hurricanes,
and ice storms. Every utility should have a plan of action in event of such catastrophes, and al1 employees
shouId be trained in its implementation.
3.3.2 Scheduied Maintenance
Scheduled maintenance is of great importance to the smooth operation of a water distribution system. Tinkey
(1975) states that scheduled maintenance is the second most important aspect of a good maintenance program,
helping to prevent serious problems before they develop. One might argue that it is equally important as
unscheduled maintenance since it solves problems more conveniently before they occur. A preventative
maintenance program consists of system sampling, valve operation, leak surveys, hydrant inspection and
maintenance, tank inspection and maintenance, meter maintenance, critical point surveys, excavation repairs,
main flushing, property maintenance, and pressure tests.
a. Valve Operation and Maintenance
Valves are used in distribution systems to isolate small areas and to control flow and pressure during
emergencies. Although great care is usually taken in the selection and installation of valves, they often suf5er
more from a lack of operation rather than fkom excessive Wear. Since vaives are operated infiequently, valve
operation should be part of any comprehensive maintenance program, to ensure that valves will work properly
when needed in an emergency. A valve operation program should include:
Operation of valves in both directions (opening and closing);
Counting the turns each way and noting the direction of opening and closing;
A check of the valve box for alignrnent;
A check that valve blockages are properly flushed;
A check that al1 valves operate in the same direction;
A check that the exact location of every valve in the system is recorded; and
A check that al1 valves are closed and opened at least once a year.
The information gathered fiom routine checks of this nature should be recorded and stored for friture reference
( T i e y 1975).
Water Diktribution Systems: Operation and Maintenance
b. Systern Sampling
Today it is well known by industry oficials that water quality in distribution systems is rarely as high as in the
treatment plant. Nevertheless, the utility must consistently provide high quality water to the public regardless
of conditions in the distribution system. A continuous sarnpling program is necessary to ensure ttiat the quality
of water reaching the consumer meets the standards set by the government. The number of sampling ports
necessary and the duration of sampling will depend on the size of the system, the stability of the water, and the
sophistication of the monitoring program desired. Parameters of interest for a sampling program include
chlorine residual, pH, dissolved oxygen, turbidity, and conductivity.
TABLE 3.1 Characteristics of other schedu Ied maintenance programs (Tinkey 1975)
-
Program Description
Le& survey
Fire hydrant inspection
Survey of critical points
Meter maintenance
Maintenance excavation
Should be camied out any tirne the quantity of accounted-for water shows a noticeable decline
Should be inspected periodically, including a check of the drain, and pressure
Should be conduaed on a routine bais and can be incorporated with valve operation, leak surveys, or fue hydrant inspection PWrams
Very important aspect of overall maintenance since revenues are based on water sales that are registered using these meters Errors in registration can be costly, and may create a public relations probiem
An aspect of system maintenance that generaies more il1 will toward a utility than any other single cause Expedient and proper excavation repair is a necessary public relations tool
Wafer Distribution Systems: Operation and Maintenance
c. Other Maintenance Programs
Other preventative maintenance programs that are regularly carried out by water utilities include leak surveys,
fire hydrant inspections, surveys of critical points, pressure maintenance, meter maintenance, and maintenance
repair excavations. Table 3.1 lists these programs and provides a brief description of their characteristics.
3.33 Record Keeping
Another important etement of a comprehensive maintenance program is record keeping. A utility must
maintain accurate and up-to-date records in order for its maintenance personnel to perform their work
effectively. The physical elements of a water distribution system are found almost wholly underground, and so
records are the only way of locating pipes and fittings. Record keeping has many benefits for the water utility:
e
O
O
O
O
O
O
O
O
a
Despite
Assisting the operator in soIving plant problems, and providing evidence that the plant is meeting
water quality objectives;
Providing a bais for handling complaints;
Determining the equipment, plant, and unit process performance standards;
Planning equipment replacement schcdules, design changes, and plant expansions;
EstabIishing a cost base, and predicting maintenance costs so that they can be financed;
Reducing the number and severity of main breaks, and determining weaknesses in the systern;
Projecting the required matenal needs, and estimating manpower needs;
Helping to meet present and fiiture operating requirements;
Providing means of ensunng proper maintenance schedules are adhered to;
Providing basis for justiQing plant expenses; and
Providing information by which design changes can be instituted.
il1 of these benefits, the purpose and objectives of a record keeping program m u t be clearly defmed. e
Othewise, keeping records is a waste of t h e , labour, and resources.
A record system should be as simple as possible, with the fom and extent of the records carefùlly planned, and
procedures established to ensure continuity of the desired records. Detailed and extensive information wilI be
no benefit to a utility if it is not organized in a logical and coherent manner that makes the information
accessible to the people who need it. Records for a water utility can be divided into plant operational records,
source records, pumping station records, distribution system records, and accounting records.
Water Distribution Sysîems: Operation and Maintenance
There are several database theories that can be applied to systern records. The first is to have a master database
containing information required for al1 applications. Data for each application is simple extracted and Uiserted
into the appropriate application. Such a database would be enormous, would require continual revisions to
ensure its relevance, and wouId require a substantial computer memory. The data extraction routines would
have to sort through al1 of the data to Find that of interest: a time consuming and not very practical procedure.
The second theory is based on the idea of having separate databases for each software package (i.e.,
AMIFWGIS, CIS, network modelling, SCADA). Each package would have a stand-alone system with limited
data sharing with other packages using a data transfer routine called a "link". Such a database system would
involve significant redundancy of data, Whiie the speed with which data is accessed would be increased, the
data storage requirements would be sipificantly increased. The third theory is a hybrid of the first two,
compromising between the speed of retrieval and the data storage requirements. A primas, database would
contain much of the information required by other systems. Each software package would utilize data fiom the
primary database, as well as fiom its own resident database. Cument research in database design focusses on
this third type of organization (Cesario 1995).
3.3.4 Personnel Training
Effective training of personnel is also a very important part of the overall maintenance pmgram. Training of
personnel should cover:
The overall goals of good maintenance;
Proper maintenance methods;
Proper and safe use of tools and equipment;
General pubIic and employee safety;
Public relations; and
rn The public heaith aspects of maintenance.
Employees must understand what is expected of them and what are the expectations of the depamnent. Due to
the public's increaxd interest in water utility operations, managers need to ensure that each employee acts as a
public relations person for the utility (Tinkey 1975). Each dimibution system will develop its own style of
maintenance program. However, it is rexommended that training meetings not be formal. Rather they shouid
be short, informal meetings held once or twice a month on the job site. Informai meetings of this sort are more
iikely to induce suggestions tiom ernployees (Cesario 1995).
Water Distribution Systems: Operation and Maintenance
3.3.5 Equipment
The success of a comprehensive maintenance program for a water utility is dependent on keeping equipment
well maintained. The traditional philosophy of "if it ain't broke, don? fix it" will result in equipment
breakdowns and the associated high costs of overtime, replacement, and disruptions to service (Flynn 1996).
Related to what was said previously, a master listing of equipment to be maintained should be kept current.
Types of equipment chat should be included in the database are pumps, rnotors, control valves, generators,
electrical systems, electronics, chernical feed systems, HVAC systems, and buildings and grounds (Flynn
1996). TabIe 3.2 indicates the maintenance tasks that should be addressed and the Frequency with which they
should be carried out.
3.4 MONITORING AND CONTROL SYSTEMS
Reliable information is the key to proper management of distribution systems (Goodwin 1988). Telemetry
systems monitor parameters such as flow and pressure at the source and within the distribution system, as well
as providing a certain amount of control. A system such as this can be coupled with a radio system to contact
mobile staff and a telephone system to contact site-based staff and receive calls fiom the public. Such a system
has rnany potential applications.
Control systems can also rnonitor the number and type of customer report incidents, the time taken for
inspectors to respond, and the time taken to complete a job of a particular type. Control systems with this
capability cm be said to have four main purposes: monitoring staff performance, maintainhg standards of
service, job costing for future planning and budgeting, and identifjing areas with system deficiencies (Cesario
1995). Further discussion on the development of monitoring and automated control systems for water
distribution systems is provided in the next chapter.
Water Distribution Systerns: Operation ami Maintenance
TABLE 3.2 Maintenance task schedule (Flynn 1996)
Equipmen t Task Frequency
Pump maintenance Inspection, oil change and lube, disassemble and rebuild, vibration analysis
Weekl y inspection, sem i- annual lube, annual teardown
Motor maintenance Inspection weekly, oil change and lube, test and rebuild, vibration analysis
Weekly inspection, semi- annual lube, 5-year rebuild cycle
Chemical feed pumps inspect, change oils, rebuild heads, PRVs, and back psi valves
Daily inspection, semi-annual oil change and rebuilds
Control valves. PRVs, altitude valves
Inspection, m ine r and filters, pilot rebuilds, valve rebuilds
Inspect and clean sûainers monthly, pilots quorterly, rebuild annually
Electrical maintenance Inspection, clean, adjust al1 high- and low-voltage switchgear
k p e c t quarterly. annual preventive maintenance by OEM service representative
Standby engines and generator sets
Inspect and test mn, PM as per OEM manuals
Test run and inspect weekly, annual PM by OEM service representative
Chlotinators, booster pumps, and controls
Flow, level, and Pressure transmitters
HVAC equipment
Inspect, rotate out of service, and rebuild
Daily inspection, semiannual rebuild
Inspect, test, and calibrate Inspect quarterly, test and calibrate annually
Inspect and PM as per manufacturer manuals
Inspect monthly, spring and fa11 preventive maintenance
Storage tanks Inspection, vent screens, flappers, ladders, and coatings
Water Distribution Systems: Operation and Maintenance
Telemetry has become an essential tool in the effective operation and control of distribution systems. It enables
automation of source works and a reduction of storage levels without afTecting security of supply. However, a
possible drawback to telemetry is the overabundance of information. If not properly handled, too much
information can create as many problems as too M e . Consequently, considerable thought must be given to the
necessary format of the coilected data, and the ease with which current and past data is obtained.
The nibject of operation and maintenance of water distribution systems has been introduced in this chapter.
The pnmary aim of this discussion is to outline the techniques and components of sound operation and
maintenance. Therefore, the discussion in this chapter has been fairly broad in scope. However, another aim
has been to demonstrate that aithough there are certain operational procedures cornrnon to ail water utilities,
each utility has unique needs. Consequently, operational strategies must be defined for a specific utility's
situation.
The second part of this report, beginning in the next chapter, discusses the concept of the SmartPipe, and its
potential impact on the operating and maintenance practices that have been discussed here. As water utilities
move into the next cenntry, the trends towards pnvatization and increased efEciency of operation wiIl no doubt
continue. To accomplish the goal of improved performance at iower expenditure a utility must employ
innovative techniques and technologies, such as monitoring and control systems.
PART II
THE SMARTPIPE
CHAPTER 4
The SmartPipe Concept
As the name suggests, a SmartPipe is a fluid-conveying pipe with instrumentation for the determination of
parameters describing the hydraulics and chemical nature of the fluid. In addition, it has the ability to colIect
and transmit this information to a central computer for monitoring, optimization, and control (Chen 1997). A
SmartPipe can also be defined as a pipe that incorporates, at the time of manufacture, data transmission lines,
instrumentation, and access ports for monitoring equipment (Karney and Laine 1997).
A SrnartPipe may be used for a number of appIications in a variety of fluid-conveying systems, such as sewers,
irrigation pipelines, and storm water systems. However, it is recognized that developing the concept for water
distribution systems might prove less problernatic. Since distribution systems convey clean drinking water,
many of the problems associated with more cornplex fluids will be avoided. Neveitheless, it is clear that
developing the SmartPipe for water distribution systems will present a variety of problerns in the areas of
marketing, design, construction, implernentation, and operation.
While there are many applications for the SmartPipe in water distribution systems, there are really two main
issues to be considered (Karney 1998):
i. Reducing the overalI cost of operating and maintainhg the system.
ii. improving service to the consumer by increasing the reliability of pressure and flow, and improving
water quality.
A balance must be smck between these conflicting issues; one that must be reached by the utility. The
SmartPipe simply provides the fîexibility needed to rnake this decision.
The SmarrPipe: The SmmtPipe Concept
The SmarrPipe aims to reduce operating costs by optimizing pumping schedules and minimizing water lost
through leaks. It is intended to impmve the quality of service to consumers by increasing reliability and
irnproving water quality. However, the utility must be able to cover the cost of implementing and operating the
SrnartPipe system without sacrificing hinire resources. Integrating SrnartPipe components will increase the
manufacturing costs of the pipe, but it is expected that the added coa of consmiction will be at least partially
offset by a reduction in operating and maintenance cos& (Karney and Laine 1997).
4.1 HISTORICAL CONTEXT
Traditionally, engineers have been primarily interested in maintaining the quality of potable water produced by
treatment plants, with not much thought given to the degradation of water quality in the distribution system.
This oversight was made more acute due to the poor materials used in the production of pipes and fittings.
However, over t h e industry professionab have begun to realize that treatment of drinking water does not end
when the water exits the treatment plant. Today, utilities look at water supply and distribution frorn a more
global perspective, taking into account al1 elements of the system. from the water source to the consumer's
faucet. There is a realization chat although the water produced by treatment plants may meet industry
standards, deterioration of the water as it passes through the distribution system is a real and potentially
troublesome problem. Physical, chernical, and biological interactions between the water and the pipe material
may compromise water quality, which could be hazardous to the health of consumers.
Remote monitoring systems had their genesis in the earIy 1950s, as the United States responded to the
unexpected detonation of a Russian atomic bomb, in August 1949. The govemment designed and built the fim
cornputer-linked chah of defense radar, to track aircrafi movements and feed the information to the National
Defense Command Center in Colorado. This innovation soon led to cornputer-linked systems far akline
reservations (Burke 1996), and eventually for water distribution systems.
Prior to the 1960s, essentiaily al1 cornponents of a water distribution system required manuai operation, and the
use of suge tanks or reservoirs to maintain a pipeline system in balance. Surge tanks were used in long
pipelines with multiple pump stations to receive excess flow or to make up a deficiency. To reduce the need for
The SmariPipe: The Srniutpipe Concept
surge tanks, automatic control of system components was necessary (McAllister 1989). Over the pan few
decades developments in sensor and computer technology have allowed the development of more sophisticated
monitoring and control systems to improve the operation of distribution systems, as well as the water that
ernerges at the faucet.
Many tems have been used to describe the process of acquiring and compiling data for a water distribution
system. In the 1970s the b m d name rneromezer was used to describe a very simple monitoring system. Later
in the 1970s and the early 1980s, telemetry was the term used to describe this type of technology, and is still in
Iimited use today. The first telemetry systems were limited in their capabilities, and were extremely expensive
by today's standards. The prirnary function of telemetry was to monitor system operations, and therefore
communication was limited to one-way data collection (Cesario 1995).
4.1.2 SCADA Systems
Until 1980 the development of telemetry for water distribution systems was slow and ponderous (Brandon
1984). Since 1980 the Pace of development has increased significantly, and by the mid- 1980s tefemetry had
evolved to encornpass a new capability. Supervisory Control and Data Acquisition (SCADA) systems, are
more accurate, sophisticated, versatile, and cost-effective than their predecessors. The purpose of a SCADA
system is to compile data about the operation of a distribution system and to allow automated control of system
components (Jentgen and Wehmeyer 1994). The term "supervisory" irnplies that a person is supervising the
operation and making decisions about when and how to operate facilities. In this way, SCADA systems are a
two-way communication system (Cesario 1995). Figure 4.1 shows a schematic of a simple SCADA system.
Efforts to link SCADA and network modeiling began in the late 1980s and early 1990s (Cesario 1995). The
DuPage Water Commission of Eimhurst, Illinois cornmissioned a successfÙI SCADA system in 1989. The
system incorporated data transfer, modelling for planning and operations, problem solving, and naining of
water system operaton (Schulte and M a h 1993). Today, SCADA systems can be found in applications such
as municipal water and wastewater monitoring, cryogenic storage tank monitoring, gas and oil pipeline leak
detection, irrigation control, and environmental monitoring.
The SmartPipe: The SrnartPipe Concept
FIGURE 4.1 Schematic of a simple SCADA system
HefRARCHY IN FORMATION TRANSFER
LEVU 3
4.1.3 Sensors
There has been significant development in sensor technology in recent years, and senson related to
measurement of fluid flow and water quality have experienced a particulariy strong development (Considine
1993; Coulbeck 1993a-b; Liptak 1995; Omega Engineering Inc. 199%-e; Skrentner 1988). The interfacing of
new digital instrumentation with smaller and more powerftl computers h s led to a quiet but rapid revolution in
pipeline monitoring and control (McAllister 1989). From the point of view of a water distribution synern,
sensors can be divided into on-line and off-line analyzen. The dificulty, from the standpoint of the SmartPipe
system, is that there are so many types of sensors available, tiom such a wide selection of manufacturers, that
the process of selecting appropriate sensors is complicated.
Parameters of interest include flow rate, pressure, temperature, pH, chlorine residual, turbidity, and
conductivity. Each parameter can be measured in a variety of ways using senson obtained f?om a variety of
suppliers. Essentially, one must decide which parameters are important, which of these c m feasibly be
The SmartPipe: The SrnortPbe Concept
measured, which method should be used for measurement, and from which supplier the sensor should be
obtained. To rnake this process even more dificult, sensor technology is constantly improving. Active
research and development of sensor technology is being conducted in many laboratones and companies around
the world. in the fùture sensors will become smaller, more accurate, more reIiabIe, easier to use, and less
expensive (Low et al. 1997). For this reason, provisions must be made for new sensors to be integrated into the
system after the initial installation. The SmartPipe may well end up being similar to computer products,
evolving over time as new technologies are made available.
An example of an emerging technology in sensor design is fibre optics. Fibre optic sensors measure chemical
parameters using synthetic dyes that undergo sensitive colour changes upon interaction with chemical species
(Wolfbeis 1997). Sensors of this type are presently in the development stage and will not be ready for use in an
application such as the SmartPipe for a number of years. One problem with these sensors is the difficulty in
using this hi@-precision technology outside the laboratory. Another probtem is the high cost of the sensors
(Crossley 1997). However, one should not be discouraged since there are many other types of senson available
that should be suitable for the SmartPipe.
The sensors that are chosen for the SmartPipe must have high accuracy, have high repeatability, be capable of
rneasuring small concentrations accurately, have simple maintenance and calibration requirements, and be
inexpensive. Many sensoa available on the market meet these requirements. Chapter 6 discusses the types of
senson that can be used to measure each parameter. It may eventually be necessary to approach a sensor
manufacturer and work with them to develop sensors specifically for the SmartPipe.
4.1.4 The SmartPipe
In the 1990s, many water utilities understand the need for continuous and controlled monitoring of distriiution
systems to provide better quality water at a reduced cost However, the execution of monitoring programs often
falls short of expectations and requirements. The inadequacy of monitoring programs stems from the fan that
each utility atternpts to irnplement its own monitoring system with little collaboration with other utilities or
researchea. Consequently, past work tends to be repeated in funve endeavours. instead of building on previous
successes. The financial resources of the utility often allows the system to be devised and built, but on a lhited
scale. They often do not have the chance to see the many usehl things that can be accomplished with extensive
The SmariPipe: The SrnartPipe Concept
monitoring. The SmartPipe is expected to change this situation, allowing for a standardized but flexible
monitoring system that can meet the needs of the utility within a shon time and within a limited budget.
The SmartPipe project underway at the University of Toronto and IPEX Inc. is in its third stage, and a lot of
work remains to produce a working system that can be integrated into a distribution network. Initially, the
SmartPipe rnay only have the ability to rnonitor certain hydraulic and water quality parameters. When the
SmartPipe system has been improved, it will be advantageous to link it with a SCADA system to allow for real-
t h e control of valves, pumps, and other distribution system components.
4.2 OBJECTIVES OF MONITORING PROGRAMS
Monitoring and control systems serve four ptimary functions for utilities operating their water distribution
systems (Mair 1992):
i. Collecting and transmitting data;
ii. Presenting data to users;
iii. Executing control logic; and
iv. Manipulating and storing data.
Monitoring of water system operations is an essential tool to help them understand what is happening within the
distribution network. Many different components in a distribution system require monitoring, such as
reservoirs, pumps, valves, and pipes. Monitoring of equipment in the field involves rnoni to~g local conditions
and sending results to a central location. Alarrns can be set to alert an operator when equiprnent is operathg
outside of the normal range. Control of components negates the need for manual operation, and automatic
changes cm be achieved by a computer program using minimum and maximum values or set points. Finally,
the continuous compilation of data is usefûl from a varîety of standpoints. The data can be collected and
summarized to produce values for different periods. However, too rnuch information can often cause greater
problems than too linle information: a case of not seeing the forest for the trees.
Also, there is a growhg concem about drinking water quality in distribution systems. Total chlorine residual,
disinfection by-products (DBPs), turbidity, taste and odour, pH, and temperature are important parameters of
concem to water utilities. Conditions within a distribution system such as a low chlorine residual, a long
residence time, bio-film growth, leaks, and mkbg of water fiom different sources, can have a negative effect
The SmartPipe: The SmartPipe Concepr
on water quality. Operaton could be alerted to potentially harmhil conditions with the use of a monitoring
program*
4.3 TYPES OF DATA
A SrnartPipe is usehil for rnany different applications and should therefore have the ability to collect a wide
variety of data. Applications of a SmartPipe include:
Coltecting infornation to u n d e m d hydraulic and water quality processes;
Monitoring parameters related to hydraulics and water quality;
Diagnostics of the state of the pipe, and detection of leaks and breaks;
Calibration of hydraulic and water quality models;
Optimization of system operation; and
Real-tirne control of the systern.
This list is far fiom exhaustive, but a general idea is gained as to the multitude of applications available. A
more detaiIed discussion of these applications is presented in the next chapter.
TABLE 4.1 Types of data of interest for the SmartPipe
H ydraulic Pressure, flow rate
Water Quality Chlorine residual, pH, temperature, conductivity, dissolved oxygen, ammonia, calcium, magnesium, heavy metais, chloride, turb idity
Structurai S train, stress, de formation
The SmartPlpe: The SmarîPipe Concept
The data that is desirable to obtain using a SmartPipe is divisible into three main groups (Table 4.1). Hydraulic
data includes parameters such as water pressure, and flow rate. Water quality data includes a wide range of
parameters such as pH, chlorine residual, temperature, turbidity, and conductivity. The third group consists of
data concerning the structura1 integrity of pipes and fittings.
4.3.1 Hydraulic
Hydraulic data, including pressure and flow rate, is of great importance to water utilities for a variety of
purposes. Except at a few locations, utilities are often unaware of hydraulic conditions within a distribution
system .
a. Pressure
Pressure measurements can be absolute, differential, or gauge. although in piping systems they are most
commonly gauge. Absolute pressure (psia), such as barometric pressure, is measured with respect to a perfect
vacuum. Differential pressure (psid) is the relative difference between two pressure levels. Gauge pressure
(psig) is the pressure that a hansducer rneasures. it can also be considered a differential pressure where
amiospheric pressure is used as a reference (Karney et al. 1997). For example, normal atrnospheric pressure at
sea level is 14.7 psia, but can be wrinen as O psig. For water distribution systems, one is usually interested in
gauge pressure, but for certain investigations, such as when one analyzes cavitation, absolute pressure
measurements are required.
As discussed in Chapter 2, maintaining distribution system pressure within a specified range is essential for
water utilities. An excessively high pipe pressure can cause increased leakage, while low pressure is
inconvenient, and can result in contamination of water mains and inadequate fue protection. A normal
operating pressure of between 60 and 75 psi (42 to 53 metres of water) is recomrnended by the AWWA,
aithough some variation outside this range is common (McGhee 1991). Water utilities m u s monitor their
system for pressure to ensure that it is adequate to meet these guidelines.
The SrnartPipe: The SmmtPipe Concept
b. Flow Rate
Flow rate data is important for water utilities when analyzing a distribution system. It can be used to analyze
the temporal and spatial distribution of flow and demand. Traditionally, the steady state flow conditions were
roughly known, but this information was often insufficient. In addition, very little was known about transient
conditions within a pipe network. Today, the importance of transient events is better appreciated.
4.3.2 Water Quality
An acceptable drinking water shouId be free from al1 chernical, physical, biological, and radiological substances
which may have a negative public health effect or may cause consumers to use an altemate, less desirable, or
unsafe source of drinking water (Thompson 1975). Although dnnking water regulations are fairly strict today
and will likely be more so in the future, water utilities often have little idea how the water within their
distribution systems is behaving. It used to be assumed that the water that cornes out of the consumer's faucet is
of the same high quality as the water that exits the treatment plant. Today this assumption is not taken for
granted, and many individuak and organizations are beginning to question its vaiidity.
The AWWA Policy and Position Statements on drinking water quality suggest that utilities should strive to
meet, or preferabIy exceed, current enforceable regulations or the recommended operating level. Every
reasonable effort, încluding back-flow prevention, should be made to protect water from degradation. Water
utilities should conduct adequate monitoring and periodic smitary surveys to ensure that water quality
objectives are met on a continuous basis (Karney et al. 1997). The SmartPipe is a perfect example of a tool that
utilities could use to rneet these guidelines.
Today, on-line analyzers are used throughout the water industry to monitor rain water, potable water, and
sewage treatment processes. There is a wide range of instrumentation available from various suppliers
(Crompton 1991). The purpose of the SmartPipe is to provide a standardized housing in which a number of
sensors can be instailed to provide on-line data from remote locations in a distribution system. Current systems
simply install sensoa at strategic locations, not gaining a clear picture of system conditions. This section is
intended to introduce sorne of the major water quality issues facing utilities.
The SmartPipe: The SmartPipe Concept
a. Total Chlorine Residual
In 188 1 Robert Koch first demonstrated that chtorine could kill or inactivate bacteria. However, not until 1905
was chlorine f i t used to disinfect a public water supply in London, England (Sawyer et al. 1994). Today
chlorine is the most common primary and secondary disinfectant used by water treatment plants in North
Arnerica (LinsIey et al. 1992). Chlorine is an excellent oxidant and serves well as a disinfectant. However, the
disinfection capabilities of chlorine are highly dependent on the temperature, pH, and organic content of the
water (Montgomery 1985). It is important for these parameters to be monitored within the distribution system
so interactions beniveen them can be observed and better understood.
The main purpose of disinfecting public water suppIies is to prevent the spread of waterborne diseases.
Disinfection to inactivate or kill microorganisms occurs by four mechanisms: damage to the ce11 wall, alteration
of cell permeability, alteration of the colloidal nature of the protoplasm. and inhibition of enzyme activity
(Metcalf and Eddy 1991). himary disinfection by water treatment plants is applied to achieve a desired level
of microorganism inactivation, while secondary disinfection is used to maintain a residual concentration in the
distribution system to prevent subsequent micmbial growth (Montgomery 1985). This residual chlorine
concentration should be monitored to ensure that it is sufficient for its purpose.
The AWWA suggests a minimum detectable chlorine residual of 1.0 m a at al1 locations in a distribution
system. Periodic changes in the characteristics of raw water (Le., seasonal variations in chlorine demand) can
have an important effect on the disinfection process. It is important for utilities to continuously monitor
chlorine residual in order to identiQ those times when chlorine demand suddenly increases, and take steps to
ensure a detectable residual in the distribution system.
The pH of water is a measure of the hydrogen-ion concentration. As the hydrogen-ion concentration Uicreases,
the pH decreases according to the following logarithmic relationship:
The SmartPipe: The SmartPipe Concept
Pure water at 24°C is balanced with respect to hydrogen and hydroxyl ions, containing 10" moVL of each.
Therefore, the pH of neutral water is 7 (Linsley et al. 1992). The hydrogen-ion concentration in water is
closely connected with the extent to which molecules dissociatc. Water will dissociate into hydrogen and
hydroxyl ions as follows (Metcalf and Eddy 199 1):
Water must be electrically neutral, and therefore in pure watet the positive hydrogen ions must balance the
negative hydroxide ions (Tchobanoglous and Schroeder 1985). When contaminants dissolve in water, ionizable
hydrogen and hydroxide groups shifi the equilibrium, and therefore the pH. As the water becomes more acidic
the pH decreases, while if the water becomes more basic the pH increases.
The hydrogen-ion concentration of water is of great importance because it affects chemical reactions,
equilibrium relationships, water treatment processes. and biological systems. In water supply systems, a tight
reign must be kept on pH levels to ensure that water quality is not affected.
Temperature is an important parameter that has implications for rnany physical, chemical, and biological
interactions. One of the most important chemical processes is the interaction of chlonne with impurities in the
water. When gaseous chlonne (Cl3 is added to water it rapidly hydrolyses to hypochlorous acid (HOCI):
CI, + H,O a HOCI + H* + Ci-
Hypochlorous acid reacts M e r , depending on the pH and temperature of the water:
HOC1 - OCI' + H' (4-4)
This reaction is heavily dependent on pH, but temperature also has a noticeable effen Assuming a constant pH
of 7. at a temperature of 20°C, as much as eighty percent of the &ee chlorine in solution is present as HOCl
while twenty percent is in the OCl* fonn. At a temperature of O°C, as much as eighty-seven percent of the
C ~ I O M ~ is in the HOC1 fom. In terms of pathogen inactivation. HOC1 is as much as 40 to 80 t h e s more
The SmartPipe: The SmurîPipe Concept
effective than OCI-, so a lower temperature is desirable. However, a low temperature rnay cause other
problems. Either way, it benefits the utility to have information about the temperature of water within the
distribution system.
d. Turbidity
Turbidity is a measure of the abundance of finely divided impurities that cause a reduction in the clarity of
water. Common irnpurities that contribute to turbidity include clay, silt, soit, and other colloida1 particles. The
degree of turbidity depends on the fineness of the particles and their concentration. Turbidity in drinking water
is undesirable, and so the AWWA recommends that turbidity of drinking water not exceed 0.2 nephelometric
turbidity units (N'ïü). A discussion of how turbidity is measured using sensors is included in Chapter 6.
e. Disinfection By-Products (DBPs)
Disinfection by-products (DBPs) are formed when surface water or ground water is treated with a disinfectant.
Traditionally, the most common disinfectant used in municipal water treatment is chlorine. Chlotine reacts
with precursors (humic or tiilvic acids) in the water to form DBPs such as Trihalomethanes (THMs) and
Haloacetic Acids (HAAs), which are known or suspected carcinogens (Viessman and Hammer 1993). The
most comrnon THMs formed by the reaction of chlorine with humic and fùlvic substances are chloroform (CF)
and bromodichloromethane (BDCM), although the formation of bromoform (BF) and dibromochlorornethane
(DBCM) is also observed. DBP formation is a function of disinfectant type and concentration, precursor type
and concentration, oxidant to precursor ratio, pH, contact t h e , and the temperature of the water. Chlorine
reacts easily with precursors to fom THMs and other halogenated and non-halogenated compounds. However,
monochloramine dissociates slowly in water and generally only results in the formation of trace amounts of
halogenated compounds (Montgomery 1985).
Since DBPs have a serious health risk associated with hem, methods of reducing their fonnation during
disinfection are needed One solution is to use an alternative disinfectant such as ozone that produces fewer
DBPs than chlorine (McGhee 199 t). However, ozone is a much more expensive disinfectant, and has other
problems associated with its use. Additionally, it is often impractical to change the type of disinfectant used at
a water treatment plant, so the rnost effective solution is to remove the precursoa in the water prior to
chlorination. This solution can be accomplished by changing the location of the disinfection process, or by
The Smartf ipe: The SmartPipe Concept
achially removing the precursors using a granular activated carbon (GAC) process, or enhanced coagulation. A
third solution that has been considered in the past is to remove the DBPs afier formation. It is important to
understand that this is not a desirable solution to the problem (Viessman and Hammer 1993). Rernoving DBPs
fiom water is dificult and costly, and it is uniikely that such a process would achieve the strict water quality
guidelines that are expected in the near future.
Utilities m u t show compliance with the new govemment dnnking water regulations such as the Enhanced
Surface Water Treatment Rule (ESWTR) and the Information Collection Rule (KR). The ICR, which was
promulgated on February 10, 1994 and will be introduced in the near future, wiII require more extensive
monitoring of drinking water quaIity by U.S. water utilities. Microbial and DBP monitoring will be required
for al1 systems supplying water to more than ten thousand persons (Owen 1995). These monitoring
requirements will probably not be met by on-line analyzers but by providing a sampling pon in the SmartPipe.
Samples of water may be obtained and experiments conducted on the sarnples using either a portable measuring
kit or by transporthg the sample to the laboratory. Although these strict regulations apply exclusively to the
United States, history has shown that Canadian regulations usually adopt many of these recommendations about
ten year later. Presently the Canadian regulations limit total trihalomethanes (TTHMs) in dnnking water to 100
pg/L based on a yearly average of quarterly sampling. However, utilities would be wise to aim to meet the
American regulations in preparation for future tightening of the regulations in Canada.
f. Bacteriological Quality
Maintainhg a measurable and stable chlorine residual is the most effective way of Iimiting microbial growth
within the distribution system. However, events may occur that reduce or eliminate this residual, or certain
microorganisms may be immune to the effects of chlorine. Therefore, it is important to monitor drinking water
for pathogenic microorganisms.
John Snow's reasoning that sewage-contarninated drinking water was the primary cause of the 1854 cholera
epidemic in London, England (Craun et al. 1996) was one of the fm steps on the road to understanding and
preventing epidemics caused by waterborne diseases. Today many of the classic waterbome diseases, such as
typhoid fever, dysentery and choiera, have been reduced to minor significance in developed nations, but
waterbome and water-related diseases are ail1 arnong the most serious health problems in the world today. Up
The SmartPipe: The S m d i p e Concept
to 35 percent of the potential pmductivity of many developing nations is lost because of these diseases
(Tchobanoglous and Schroeder 1985).
Although waterbome diseases are not as prevalent in developed nations. intermittent outbreaks of some of the
more troublesome diseases are reported. Two of the most difficult pathogens to remove from drinking water
are Giardia lamblia and Cryptosporidium parvum. Treatment methods to rernove or inactivate these protozoa
have met with some success, but at tirnes treatment failures allow outbreaks of Giardiasis (Beaver Fever) or
Cryptosporidiosis in the drinking water of an isolated area. Examples include the 1993 Cryptosporidium
outbreak in Milwaukee where 400,000 people were affected (Fox and Lytle 1996), or the recent outbreak in
Sydney, Australia.
Due to the complex and costly nature of bacteriological testing, continuous monitoring of microorganisms is
infeasible. A more practical system would be to obtain samples From various points in the distribution system
for analysis on-site or in a laboratory. A SmartPipe could facilitate easy attainment of representative samples of
drinking water for analysis. In addition, a fibre optic camera inserted into a special port on the SmartPipe could
allow for interna1 inspection of the pipeline to detemine if microbial growth is occumng on the pipe walls.
4.3.3 Structural
Water system operators are also interested in information concerning the state of pipes and fittings in the
distribution system. The condition of distribution piping should be monitored so that a proactive style of
maintenance can be applied: it is much more desirable to repair a pipe before it fails than after. Parameters of
interest rnay include stress, strain, and deformation. A fibre optic camera might also be usefùl for inspecting
the interior of pipes for possible corrosion damage, or build-up on pipe walls.
ïhere are two types of tools commonly used for monitoring the structural integrity of pipes. One is based on
magnetic sensors to detect metal loss, while the second is based on ultrasonic phenornena to sense defects and
cracks in pipe waIIs+ Used together, these tools provide a comprehensive picture of the structural srate of the
pipe. This type of data may not be necessary on a continuous basis, but may supplement on-line measurements.
A pipeline may be inspected regularly, changes identifie4 and possible trouble spots isolated. This data can
provide a usefil historical record, as well as a tool to plan maintenance work (McAllister 1989).
The SrnartPipe: The SmartPbe Concept
One of the most promising types of stnictural data is strain, which is used to measure the amount of
deformation a pipe has undergone. Strain is defined as the ratio of the change in length to the initial unstressed
nfennce length. A m i n gauge is an element that senses this change and convem it into an electrical signal.
Sûain data can also be converted to stress using Young's Modulus of Elasticity. For a pipeline, the axial strain,
E , and circumferential m i n , E, are of primary interest, rather than the bending or moment m i n , E,, (Kamey et
al. 1997). Fwtfier discussion on the measurernent of strain is included in Chapter 6.
Stress and smin gauges could be installed to ûack the long-tenn performance of a pipe to ensure that any
deterioration would be detected eariy and appropriate measures taken before a catastrophic failure were to
occur. Impacts of external Ioads and their associated deformations could also be monitored to provide valuable
insights into the amal forces to which a pipe is exposed. The rneasurernent of strain along a pipe can also help
in the understanding of deformation characteristics of the pipe due to settlemenf flow pressure, temperature
effects, and corrosion. However, main can also be used to determine the fiequency, distribution, and location
of pipe breaks and leaks. Unfortunately, strain gauges need to be placed in a dense pattern to obtain a good
picture of the deformations occumng. In the case of the water distribution system, the number of m i n gauges
necessary to adequately cover a11 of the pipe surfaces would be enormous (Kamey et al. 1997). A discussion of
this type of leak detection method is presented in Chapter 5.
Intemal inspection of a pipe could also prove valuable. Access ports for a fibre optic camera could be installed
so that the intemal condition of a pipe could be detemineci, including assessment of bio-film growth, carbonate
encrustation, and corrosion of the pipe wall.
4.4 KEY COMPONENTS OF THE SMARTPIPE SYSTEM
A SrnartPipe system is comprised of senson, a housing for the senson, the data acquisition systern, and the
hardware and software necessary for data processing, optimization, and control. Also of importance are the
peripheral needs such as the structural requirements for the SmartPipe system. These components are discussed
briefly in this section and are expanded upon in Chapter 6 where the design of the SmanPipe system is
discussed. Figure 4 2 shows a schematic of how the SmartPipe systern may be configured.
The SmarrPipe: The SmartPipe Concept
Not al1 elements of a complex monitoring system will be required for every application of the SmartPipe. For
example, a complex systern may include on-site display of parameters for checking the fidelity of instrument
response and the possibility of instrument malfunction at individual sensor sites. This feature can be very
expensive and is not even available for sorne instruments. If on-site variable display is not useci, instruments
can be checked by maintenance personnel using auxiliary communication with the monitoring centre. A less
complex system such as this may have only data logging, visual display charting, and warning and a l m
displays, even though they may be perfectly sufficient for the needs of that utility.
FIGURE 4.2 Schematic of the SmartPipe systern
The SmartPipe: The SmartPipe Concept
4.4.1 Sensors
The sensing system consists of a variety of different instruments for measunng physical, water quality, and
smictwal parameten. For the moment the parameten have been limited to flow rate, pressure, pH, and
temperature. More parameten may be investigated later as appropnate senson become available. For
example, chlorine residual. turbidity, dissolved oxygen, m i n , and conductivity are parameten that may be of
great interest, and which are considered later.
4.4.2 Housing for the Sensors
To make the SmartPipe a uxful and pmblem-fkee device, a standardized housing for the senson will need to be
developed. This will require a more concrete decision about which senson will be used and what parameten
will be measured. Extensive discussion among the colIeagues at the University of Toronto has produced a
unanimous decision to develop a SmartConnector to incorporate the sensor housing. A SmartConnector is a
pipe, with special provisions made for sensor installation, which can be inserted into a network at a desired
location to connect two reguiar pipes (Karney et al. 1997). As envisioned, ihe SrnartConnector will be molded
fiom PVC by IPEX Inc. using their extensive expenence with producing PVC fittings using injection molding.
The SmartCo~ector can be rnanufactured to virtually any size without affecthg the installation of the sensors.
Although it will be designed for use with PVC pipe, its design will allow compatibility with most pipe materials
found in distribution systems. Further discussion on the requirements and design of the SmartCo~ector is
presented in Chapter 6.
4.43 Data Acquisition System
The communication system for the SmartPipe is a vital link that carries information from the remote monitoring
locations to a central location for information storage and record keeping. As with any such system it is only as
mong as its weakest link. The characteristics of a communication system should include at l em the Collowing
capabilities:
Have industrial quality components that communicate with the central computer using standard
protocols;
The SmartPipe: The SmariPipe Concept
Suppon point-to-point and diseibuted multi-point networks;
a Compatibility with personal computer workstation sothvare; and
Compatibility with most communication networks such as modems, and analog or digital telephone
lines.
The data acquisition system is used for collection, temporary storage, signal conditioning, and transmission of
data fiom the sensors to a centrai monitoring station, as well as graphical representations of monitored
parameters and analysis of the data.
A sensor measures a parameter of interest and converts the physical measurement into an analog signal of either
voltage or current. This output signal, which needs to be arnplified for some sensors, is tmsmitted by wire to
the data collection station, Other means of transmission are possible, such as radio waves and fibre optic
cables, but it is uncertain which method will be suitable for the SrnartPipe. The data acquisition system has a
number of important fundons (Karney et al. 1997):
Providing power supply or excitation voltage to a sensor if necessary;
Receiving output signals from sensors;
Amplifjhg output signals from senson if necessary, and transmining these signals to a central
coIlection station;
Convening the signals to the corresponding physical value of the parameter in question;
OrganiUng the data into files for future reference;
Controlling the measurement of each sensor by activating the process of data transmission for that
sensor; and
Displayhg the collected data graphically for monitoring and analysis purposes.
Requirements for data transmission can grow quite large as the number of parameters measured at each location
increases. Therefore, continuous measurement of a reasonable number of parameters at a reasonable number of
locations will provide a wealth of information, but requires a data acquisition system that is well organized to
handle the monitoring complexities.
Each sensor location is comeaed through a common bus-line to a centrai m o n i t o ~ g station. Each sensor at
each Iocation has a unique address, allowing the computer to activate the data transmission line to that sensor at
the appropriate moment. It also ailows the computer to keep track of where the sensors are and what they are
rneasuring (Karney et al. 1997).
The SmartPipe: The SmartPipe Concept
4.44 Hardware and Software Requirements
The hardware requirements for the SmartFipe will initially be quite modest. A laptop computer is al1 that is
needed to control the data acquisition system and to process the data. As the SmartPipe system becomes more
complicated, and we get closer to installing the system into an amal network, the hardware requirements will
no doubt increase.
SoAware for data collection and processing includes software for graphical display, monitoring, and record
keeping. Future software requirements may include the capability for modelling, optimization, and control.
These cornponents will continue to be devebped as the project progresses.
4.4.5 Structural Requirements
For the SmartPipe to be incorporated into an actual distribution system, a number of logistic probiems witl need
to be solved. The fact that water distribution pipes are buried a few feet underground is problematic. Easy
access to the SmartPipe afler installation will be essential for proper operation and maintenance of the system.
Therefore, for each SmartPipe in the system, an access charnber will need to be constnicted (see atso Chapter
6). Power will also need to be supplied to the remote monitoring Iocations, and a decision must be made as to
how the data will be transmitted to the central monitoring station. Options include telephone tines, radio
transmission, or a separate network of transmission Iines such as fibre optic cables.
The concept of remotely monitoring and controlling the operation and maintenance of water distribution
systems is not necessarily new. However, the SmartPipe system provides some unique features not found in
traditional monitoring and control systems. This chapter has introduced the concept and discussed some the
requirements and probable components of such a system. This discussion is continued in Chapter 6, where the
design of system components is discussed in more detail.
The SmartPipe: The SmartPipe Concept
As mentioned at the beginning of this chapter, there are hvo main issues associated with the application of the
SmartPipe to water distribution (Karney 1998):
i. Reducing the overall cost of operating and maintaining the system.
ii. Improving service to the consumer by incnasing the reliability of pressure and flow, and improving
water quality.
A balance must be stmck between these conflicting issues; one that must be reached by the utility. The
SmartPipe simply provides the flexibility needed to make this decision. The next chapter discusses how the
SrnartPipe can be used to improve the operation and maintenance of water distribution systems, briefly
mentioning a nurnber of specific applications. These discussions are intended to describe what the SmartPipe
system is capable of, rather than recommending specific applications for a specific uti tity.
CHAPTER 5
Impact on Water Distribution
The application of new techniques and emerging technologies to the operation and maintenance of water
distribution systems must be appropriate to each situation. Okun (1982) States that "the key requirement for an
appropriate solution is that it be selected in the light of local circumstances, with particular attention to the
human, material, and financial resources available for operation and maintenance." It is impractical for a small
utility to install an elaborate monitoring systern, since the expected reduction in operating and maintenance
costs is outweighed by the cost of irnplementation. The selection of equipment must be made carefûlly, taking
into account capital and maintenance cos& weighed against the cost of manual operation. However, even small
systems are required to meet minimum water quality standards, and so a certain amount of monitoring is
necessary .
It is important that the SmartPipe be applied responsibly. There must be clearly defmed objectives for the
instrumentation, with a fm understanding of how it will be installed, maintaineci, and financed, Installation of
any component in a distribution system without a clear undemanding of its purpose will not benefit the utility
or the customer, and may be detrimental due to the added cost and unnecessary complexity. There must aIso be
a clear understanding of how the technology will integrate with a utility's existing operating policies.
Consultants are often employed by utilities to fmd answers to the following questions (Mair 1992):
What should be automated?
How will the system be used?
How wil the system be maintained?
Informed decisions will help a utility to develop a monitoring and control system that is efficient, focussed, and
above ali, useful.
me SmwfPipe: Impact on Water Distribution
A visual, on-site inspection of distribution system components is oRen the most effective means of gathering
information, but it is also the most expensive. The role played by instrumentation rnay be limited to routine
control and pinpointing areas of interest. However, water utilities have unique requirements, and have their
own ideas of how monitoring and control systems should be used. Therefore, the designers of the SmartPipe
wiil need to adapt the system to the needs of each distribution system. There are many ways for the SmartPipe
to be used in operating and maintaining a water distribution system, while at the sarne tirne improving the
overall understanding of hydraulic, chernical, and biological processes.
Many innovations that prove to be useful are often considered necessities soon after they are introduced. Many
people who have lived without computers in the past can no longer imagine life today without them. It is hoped
that the SmartPipe will eventually become as indispensable to water utilities as the cornputer is to today's
society, although initially the concept of a SmartPipe may be difficult to sell. Utilities have managed to provide
the public with an adequate drinking water supply for many years without the use of monitoring and control
systems. For this reason, it could be dificult to persuade them that the SmartPipe is a worthwhile investment.
Nevertheiess, utilities are beginning to realize that today's public is more demanding of a high quality water
supply. This trend has caused a subsequent increase in the demand for monitoring of pipeline operations (Beal
1988). Govements have responded to this demand by increasing the level of regulatory control of drinking
water. The United States has introduced the Surface Water Treatment Rule (SWTR) and more recently the
Information Collection Rule (KR) to better regulate the quality of drinking water supplied to the public.
Traditionally, Canada's drinking water regulations Iag about 10 years behind those in the United States. It is
likely that Canada will eventually adopt many of the recommendations found in these guidelines, and utilities
must show that their operations comply with these regulations. The increase in operational and regdatory
requirements for water utilities means that a need for detailed information regarding the state of the distribution
system exists. The SmartPipe could be very useful in meeting this growing need.
The SmartPipe: Impact on Wam Distribution
5.1 BENEFITS OF THE SMARTPIPE TO A WATER UTILITY
The SmartPipe brings to a utility a variety of benefits for any monitoring program it may wish to establish.
Table 5.1 lists the econornic and service benefits associated with the SmartPipe, due to its adaptability,
accessibility, accuracy, repeatability, and durability.
Traditional monitoring and control operations, where operaton physically travel to sites throughout the
distribution system, have served utilities well in the past, but such a system has several shortcomings (Fiddick
et aI. 1991). First, due to delayed information transfer, there is no way for operators to deterrnine the status of
the entire system at any given moment. Instead, they rnust wait until operators return fiom their inspection and
information collection rounds. Second, control operations can only be performed a few times a day, requiring a
great deal of travel. In addition, real-time information is not available to make control decisions. Thirdly, the
cos of physically travelling to monitoring and control sites is relatively high. Finally, equipment problems may
take hours or even days to detect, subjecting residents, operators, and the distribution system to potential
hazards. In addition, physically travelling to monitoring and control locations during heavy trafic periods
exposes operators to additional dsks (Fiddick et al. 199 1). Centralized monitoring and conîrol eliminates or at
teast reduces many of these problems, whiIe at the same time providing additional benefits.
TABLE 5.1 Benefits of the SrnartPipe to the water utility
Economic Benefits Service Benefits
Reduced energy costs Improved system performance Deferred system improvernents Reduced pressure surges and fewer water outages Deferred capital expenditures Improved water quality Reduced capital expenditures Improved quaiity assurance and preventive maintenance Reduced future capital Quicker emergency response expenditures Automated report generation
hprovement of operating conditions and operaîing efficiency Eliminating repetitive and tiresome tasks
The S r n d i p e : [mpact on Water Distribution
5.2 APPLICATIONS OF TRE SMARTPIPE
Applications of the SmartPipe can be divided into categories based on the type of data or the application.
Tables 5.2, 5.3, and 5.4 Iist the variow applications of SmartPipe data, based on whether the data used for the
application is hydraulic, water quality, or structural. It should be understood that the applications listed in these
tables are just a few of the areas in which monitoring and control could provide benefits to the water industry.
However, it should also be understood that not al1 applications are suitable for every utility. The intention of
this chapter is simpIy to illustrate the flexibility of the SmartPipe. The remainder of this chapter discusses the
applications of the SmartPipe based on the area of application: cornputer rnodelling, operation, and maintenance
and repair.
TABLE 5.2 Possible applications of hydraulic data for water distribution systems
Physical data: pressure, flow rate
Computer mode11 ing
0
O
Operation O
O
Maintenance and repair a
Compiling data to better understand hydraulic processes Verifying and calibrating hydraulic models Obtaining accurate estirnates of hydraulic conductivity Sirnulating system operation for emergency shutdoww, energy management, and feedback to operators on costs and benefits of system component
1
1
SimpliQing fie flow tests
Optimizing of pump scheduling and valve operation Locating low-flow areas in the distribution network Prioritizing capital improvement projects through identification of system constraints to eftïcientiy operate the distribution system to rneet required performance leveis Controllhg distribution system components on a real-time bais Water demand prediction
IdentiQing locations of leaks and breaks Performing water audits
The SmartPipe: Impact on Water Distribution
TABLE 5.3 Possible applications of water quality data for water distribution systerns
Water quality data: pH, chiorine rsidual, temperature, conductivity, turbidity
Computer Compiling data to better understand chemical and biological processes modelling Verifjhg and calibtating water quality models
Simulating effects of maintenance operations (Le., main flushing) Predicting occurrence of substances used for treatment, substances derived fiom pipe and plant matenal and contaminants originating at any point in the network
Operation Monitoring water quatity to ensure that regulations are being achieved Water treatment monitoring and control Improving treatment processes
Maintenance Monitoring potential for intemal corrosion of pipes and repair Planning network operation and investigating abnormal events
TABLE 5.4 Possible applications of structural data for water distribution systems
Structural data: strain, stress, vibration, deformation
Operation Monitoring the status of system components
Maintenance Inspecting pipes for corrosion, encrustation, and bio-film growth and repair identifying location of Ieaks and breaks
Tracking long-term performance of pipes Monitoring effects of extemal Ioads or internai transient conditions on the pipes Give insight into kinds of loads pipes are exposed to and conditions under which they must operate
The SmartPipe: Impact on Water Distribution
5.2.1 Computer Modelüng
Currently, to analyze a distribution system or to calibrate a cornputer model, a specially designed field test is
nonally used to collect the required data. These fields tests are usuaIly limited to a few strategic locations in
the system, or along a selected pipeline profile. Rarely does one have the richness of data needed for proper
calibration. The state of on-line monitoring of distribution systerns is improving, but slowly. Pressure
measunments are often made at pumping stations, and water level is monitored in reservoirs, but there is very
little data available for flow and water quality (Kamey et al. 1997). Applications of the SmartPipe for computer
modelling inciude determining hydraulic conductivity of pipes, calibrating hydraulic and water quality models,
and collecting data for real-time hydraulic models.
a. Determining Hydraulic Conductivity
Values of hydraulic conductivity of pipes in a distribution network are essential data for computer modelling,
and for calibration of hydraulic models. Hydraulic conductivity can also be used as a tool for investigating the
condition of intemal pipe walls; whether they are corroded. encrusted, or subject to bio-film growth.
To determine hydraulic conductivity one mus sirnultaneously rneasure the flow through and pressure drop
across a pipe reach of known length (Figure 5.1). The pipe section under consideration must be isoIated as
much as possible. Using these data, the coefficient of roughness can be computed fkom the Hazen-Williams
formula (Hammer and Hammer 1996). Currently, Tire hydrants are used as pressure taps and discharge meten,
but their use is problematic (Karney and Laine 1997). Their availabiiity is limited, and accurately determining
the distance between the connections and the supply line is difficult.
The SmariPipe: Impact on Water Dishibution
FIGURE 5.1 Detemining hydraulic conductivity of a pipeline. (a) schematic of a parallel hose C-value test installation; (6) schematic of a pressure gauge C-value test installation (Cesario 1995)
Length
( i,mlo ro 2,,000 A)
Flow rneasud widi h d - h d d pitot gaugc
Static hydraulic grade line
(6) Head bss Hydraulic grade Imc wiih flow
Pressure 1 -- Pipe elevation 1 ~ i p s e l m t i o n 2
4 Length
F (> 4,000 tt)
Comwt flow (mcruwcd with rnctcr a piiot md)
The SmarrPipe: Impact on Wafer Distribution
b. Calibration of Hydraulic and Water Quality Models
Mode1 calibration is "the process of cornparhg the results of the model with acrual conditions to determine if
the model is correct within a reasonabIe tolerance" (Walski et al. 1990). It is a logical and essential step in the
development of any cornputer model. If the accuracy of the model is found to be lacking, the cause of the
inaccuracy should be identified and corrected. If retiable data is not assured, the model is of Iimited use, and
since water quality models rely on accwate hydraulic models, they too are affected. Hydraulic models are olten
not very accurate due to a Iack of detailed information about a distribution system. Information of primary
importance includes pipe flow and pressure, boundary conditions, and pipe parameten such as the Darcy-
Weisbach friction factor,f; or the Hazen-Williams coefficient, C.
It is not uncommon for model calibration to be impractica1 or impossible. If the system is entirely new, or there
is insuficient time to check the model, calibration may be ignored. However, every effort should be made to
calibrate models since, in most cases, the benefits far outweigh any costs or delays. These benefits include
(Walski et al. 1990):
Locating errors in data collection and entry;
Providing training for model usen;
Providing the user with an appreciation of the sensitivity of mode1 results (and the real system) to
changes in input data;
HeIping to establish the credibility of the model; and
Providing people with an awareness of the weaknesses and shortcomings of the model.
c. Data for Real-Time Hydraulic Models
The applications of real-the models include training of personnel and simulation of system operation for
emergency shutdowns, energy management, and feedback to operators on costs and benetits of system
components. Other benefits include prioritizing capital improvements through identification of system
constraints, and efficiently operathg distribution systems to meet required performance Ievels (Gilbert and
Iacobs 1992). Essentidly, the goal of a real-tirne model is to provide water quantity and quality modelling
fiom the source to the customer's faucet This ability can be useful for tracking the chlorine residual through a
distribution system, in order to meet the requirements of indusny regdations such as the S m [CR, and the
EPA Disinfection Rule.
The SmartPipe: Impact on Water Distribution
d. Other Applications
Another application of the SmartPipe for water distribution is collecting information to better understand the
hydraulic, chernical, and biological processes occurring within the system. This knowledge can be used to
improve operation, develop cornputer models, and also when expanding a distribution system, or designing a
new system with similar characteristics. In such a situation, a comprehensive analysis of the existing system is
necessary. Finally, the SmartPipe can be used by itself, or in tandem with cornputer models, to simulate the
effects of maintenance operations, such as main flushing.
5.2.2 Operation
Operating a water distribution systern is a cornplex process, involving the optimization of pumps and valves to
provide a high Ievel of service at the lowest cost possible. The goal is to supply water at an adequate pressure
and flow rate to every customer at the desired place and tirne, and with the highest quality feasible. A great
deal of research focusses on how this goal can be accomplished emciently. This section discusses how
information collected using a monitoring system such as the SmartPipe can be used to improve the operation of
water distribution systems.
a. Pressure Measurement for Fire Flow Testing
Fire flow tests are conducted to determine if the required flow is available, to determine system performance
characteristics, and to aid in calibration of computer models. At l em hvo hydrants are required for a fue flow
test: one for pressure (static and residual) measurements, and the other for flow rneasurement. If adequate head
loss cannot be created by one flow hydrant, additional hydrants can be used. Conduaing a fire flow test is quite
simple, but consideration of the environment in which the hydrants are located can lead to dificulties in finding
suitable locations. If not careful, a tester may damage landscaping, roadways. and property, or may cause
injury (Cesario 1995).
Fire flow tests could be improved by ùistalling pressure sensors near fie hydrants. More extensive, and
possibly more accurate, results could be obtained (Karney et al. 1997). Removing the need to open tire
hydrants to test pressure and fIow would Uicrease the efficiency of testing, and have less impact on people
living near hydrants. However, it would rtill be necessary for maintenance personnel to occasionally open
The SmartPipe: Impact on Water Disrribution
hydrants to ensure that they are in satisfactory working condition. Another consideration is that the inability to
use the discharge hydrant for pressure measurement can cause difficulties regarding the availability of suitable
locations for pressure measurernents. The instalIation of pressure taps in the vicinity of a fire hydrant could
allow more realistic and extensive fire flow tests for a water distribution system (Karney and Laine 1997).
FIGURE 5.2 Conducting fire flow tests (Harnrner and Hamrner 1996; Cesario 1995)
Pressure Hydrant Flow
? Static pressure Residual pressure
Flow +
t Flow
Flow Hydrant
+ Flow
b. Optimization of Pumping Schedules
Optimization of pumping schedules refen to optimization of system operation to deliver the required quantity
of water at the desired location and t h e and at adequate pressure. With cenaalized control, it is possible to
iake advantage of the local power utility's load shedding program and timesf-day rate schedule. In addition,
efficient operation means that fewer pumps are running, hence reducing electricai demand, and extending the
life of purnps.
The SmartPipe: Impact on Water Dktribution
c. Locating Low-flow Areas
Pressure and flow rate measurements in a pipe network can easily be used to distinguish areas of low flow.
IdentiQing areas of low flow in a distribution system is important because of the negative effects of stagnant
and deoxygenated water on general water quality. In low flow areas, turbidity and iron settle out of the water,
and iron and sulfùr bactena are allowed to build up in the water mains, causing taste, odour, and colour
problems. A flushhg and foam-scnibbing pmgram can be of some help in conimlling these problems, but
problem areas must first be identified. If steps are not taken to rehabilitate the low flow area, the problems will
reoccur.
d. Information Feedback to improve Treatment Processes
Many water utilities now incorporate satellite re-chlorination stations at strategic points in their distribution
systems. They are not always operated, but they are there in case they are necded. However, detemining when
they are needed is a difficult task if timely information is not available. A utility needs to monitor chlorine
residual on-line throughout a distribution system to ensure that it is sufficient to inactivate pathogenic
microorganisms. However, it is currently expensive to monitor water quality on-iine due to the difficulties of
sampling. A water sample obtained on-line may not be representative of the bulk flow, and therefore the data
obtained from it is misleading. However, rnethods of analysis are improving, and the sophistication of on-line
process analyzers is increasing. Recently, the City of Denver, Colorado implemented a remote monitoring
program in its distribution system, monitoring for chlorine residual, pH, conductivity, temperature, and
turbidity (Onh et al. 1997). This midy is a good example of how a remote monitoring program cm be used by
a utility to ensure a high quality drinking water supply ta its customers. The application of this system is
discussed M e r in Section 5.2.4.
Water utilities must also operate their distribution systems to provide a water supply that meeu water quality
guidelines provided by the government. These guidelines have become increasingly stringent in recent years as
govemments respond to the growing demand fiom the public for high quality. Without remote sensing
technologies, utilities have very little information upon which to base their decisions about operating practices,
and find it difficult to demonstrate their compliance with regulations. With the use of continuous monitoring of
water quality parameten throughout a distribution system, operators can be alerted if conditions have changed.
Appropriate rneasures can then be taken to address the abnormal condition.
The SmartPipe: Impact on Water D&ribution
e. Control of System Components
Many components of a distribution system - such as wells, pumps. and valves - can be centnilly controlled
using a SCADA system. A system implemented in Phoenix, Arizona provided automatic control of wells and
booster pumps based on discharge pressure or remote storage facility levels (Fiddick et al. 199 1). To provide
real-time control of systern cornponents requires on-line infonnation to update control parameters. The
operator must know what the pressure in the systern is now to know how to openite pumps, valves and
reservoirs effectively. Knowing conditions in the system hours ago is not adequate.
System components may also be monitond for proper operation. Operators can be alened to equipment
malfunctions using alarms. Monitoring equipment in this way allows quicker identification of problems and a
quicker response time.
f. Pressure Zone Flow Optimization
Cornplex distribution systems generally have a number of pressure zones, and multiple sources of water.
Consequently, flow between zones occurs in a number of places. Water flow from higher zones to lower ones
occun through pressure reducing valves, whiie the opposite flow (fiom lower to higher) occun by aid of
booster pumps. According to Fiddick et al. (199 1). a computer based mode1 of the water system in the City of
Phoenix, Anmna indicates that at times, the m s f e r of water between zones occun by boosting it to a higher
zone only to bleed it down to another lower zone. Many distribution systems have no way of monitoring this
effect, which is one source of energy ineficiency. A monitoring and control system such as the SrnartPipe
could provide valuable information to a utility to reduce this inefficiency.
g. System Operation Management
"For even mal1 systems the operathg cos& due to electricity consumption for pumping, and chernical charges
for treatment, can be quite large. Consequently, cost minimization of water system operation is an important
feature in integrated control and scheduling systems." (Coulbeck 1993a). The effective control and scheduling
of systems requires the collection and üîmsmission of a significant amount of information and data. SrnartPipe
operators attempt to accomplish this control and scheduling in a pressurized system with a minimum of
complexity and cost. The main advantage of the SmartPipe is that it can provide detailed information about the
The SmartPipe: impact on Water Distribution
flow and quality of the water at only a marginal cost increase over a traditional system (Karney and Laine
1997). Due to improved information, existing facilities can serve greater demands, enabling the construction of
new facilities to be deferred. For example, the East Bay Municipal Utility District in OakIand, California was
able to m i se its reservoir design cnteria from 1.5 times maximum day demand to 1.0 (approximately 33
percent smaller), simply by obtaining more detailed information about system operation (Gilbert and Jacobs
19%).
Using remote monitoring and control, utilities can consider new policies for demand management such as time-
of-use, unit use, seasonal water supply considerations, and treatment or water quality irnprovements (Gilbert
and Jacobs 1992). In addition, a high level information system can assist managers in maintaining strategic
allocation of utility resources to manage performance, especially when prionties and goals are periodicalIy
adjusted for conditions such as:
Droughts and floods;
Narural disasters such as earthquakes, windstorms, hunicanes, fires, or electrical storms;
Financial problems; and
Changes in management or staff.
Utilities can also track the performance of the system against their short- and long-term goals. Finally, remote
monitoring and control can assist in prioritizing and routing personnel to critical and pIanned inspections. The
benefits of this application include improved performance, reduced costs, and automated sectionalizing of the
distribution system for field or remote control of valves. This benefit is usehl in preparing planned and
emergency shutdowns of the distribution system, in part or in whole.
b. Flow Metering
Flow metering is used to estimate customer demand rates such as peak daily demand, average daily demand,
and decreases, or in most cases increases, in demand over t h e . M e t e ~ g data can be used not only to
determine customer demand, but also to determine the quantity of water that is unaccounted for. lost throua
leaks and other unmetered connections.
The moa economical method of water metering is to h l 1 a pair of flow meten in custom-designed metering
mtions, monitoring the ratio of outputs to obtain a measure of Wear, or drift. The uncertainty in the meter
readings is relatively low if the outputs from the meters remain within preset Iimits. However, the
The SniartPipe: Impact on Water Distribution
disadvantages of such a metering system is that two meten mua be checked and maintained. In addition, if
faults develop, the pipeline may have to be shut down more frequently unless a by-pass loop is provided in the
design stage (McAllister 1989). For the SmartPipe, this disadvantage should be considered very senously.
i. Demonstrating Cornpliance With Drinking Water Regulations
Drinking water regulations in North America, and indeed in other developed countries around the world, are
becoming increasingly stringent. To satise these regulations, water utilities must continually improve their
water quality monitoring programs to demonmte to regulating bodies that the guidelines are being achieved.
Presently, the most frequently discussed water quality parameters are chlorine residual, bacteriological quality,
and the presence of disinfection by-products.
As an example, if routine bacteriological sarnpling shows a problem, the utility should immediately initiate an
intensive resampling program to trace the cause or origin of the problem. The operators should resample the
raw and treated water, resample the water at the location of the poor sample, and take samples on either side of
the poor sample. On-the-spot chlorination may even be necessary if interna1 contamination has occurred.
5.23 Maintenance and Repair
In North America, it is common for a water utility to lose about fifieen percent of its finished water due to leaks
and unmetered connections (AWWA Leak Detection and Water Accountability Cornmittee 1996). in a system
that is particularly well maintained this level may be as low as eight percent, but for a poorly-maintained system
it may be as high as forty to fi@ percent (Zipparro et al. 1993). Some utilities are unsure of how much water is
being lost because the system is not hlly metered. One might wonder why leaks in distribution synems are
important. After all, water that leaks into the environment is not hazardous. In fact, water lost due to leaks can
be a significant portion of the total water treated by a utility. As water is lost, more water must be treated and
pumped to replace it. Suppose that a community is experiencing a growth in population, and therefore has a
growing need for potable water. The utility anaiyzes the situation and decides that the construction of a new
treamient plant is necessary to meet the hcreasing demand. Now suppose that after the new treamient plant is
built, a study is conducted into the quantity of water lost through le&. The engineer finds that 30 percent of
the total water treated cannot be accounted for. The operating manager looks at the report and discovers that
the los water could have provided the utility with sufficient capacity to meet the increased demand, without
The SmartPiper Impact on Water Diriribution
constmcting a new treatment plant. This scenario is fictitious but it could easily apply to any one of the
thousands of water utilities in North America or around the world.
The move towards privatization of water utilities is demanding improvements in the eficiency of operation and
maintenance (Westerhoff'and Lane 1996). Accounting for a large percentage of the potable water in a system
is one way for these private utilities to reduce costs while continuing to provide the sanie level of service that
customen expect. Not only will utilities reduce their capital expenditure on new facilities, but they will also
reduce pumping costs. It is estimated that as much as seven percent of the total power usage in North Amenca
is used for pumping water (Omsbee et al. 1989). If sufficient potable water could be reclaimed from losses
and supplied to customers, power consumption by water utilities could be significantly reduced. This fact is of
paramount importance when one considers the arnount of power used in North America and the economic,
social, and environmental cos& associated with its production.
a. Detection of Leaks and Breaks
Potentially one of the most important applications of the SmartPipe is the detection of pipe breaks and leaks.
Utilities lose a significant percentage of their potable water through leaks, which has an important impact on the
cost of water supply. A detailed discussion of leak detection is presented in Section 5.4.
b. Interna1 Inspection of Pipes
Providing the SmanPipe with a fibre optic camera allows operaton to visually inspect the interior of a pipeline.
Traditional methods of inspecting the interior of a pipeline involved removing pipe sections, or using a pipeline
pigging apparatus, which is expensive and has the potential to lodge in the pipeline. A special access port could
be integrated with the SmartPipe to allow the insertion of this camera. Intemal inspection of a pipeline could
provide operators with information concerning intemal pipe wall corrosion, calcium carbonate encrustation,
and biofilm growth.
The SmartPipe: Impact on Water Distribution
c. Structural Condition of Pipes
M o n i t o ~ g the structural condition of pipes in a distribution system is important fiom the standpoint of system
maintenance. For example, pipe deformation due to extemal loads and interna1 transient conditions can be
investigated. Extemal loads are sornetirnes caused by heterogeneous soi1 senlement, impact loads, and stress
buildup due to the presence of tree roots. Determining the distribution of stress, and strain along a pipe helps
operaton to identify locations where pipe breaks and leaks are most likely to occur. It may also provide
utilities with a better understanding of why pipe breaks, and leaks occur, and the conditions that are most likely
to cause them.
d. Determining the Likelihood of Pipes Freezing
In most municipal water systems in Ontario, and the rest of Canada, fieeze-ups occur periodically. Therefore,
thawing crews are required during winter months to rernedy the situation. However, fteezing will not develop
if there is a favourable balance of heat maintained in the pipeline. For this reason, and the facts that there is less
water and longer periods of no motion, frozen service lines are more common than frozen mains. A common
remedy for pipeline fieezing is the use of insulation, or burying pipes below the fiost Iine (Ministry of the
Environment 1980).
It is advantageous for a water utility to monitor the water temperature throughout a distribution system. This
measure may not aHow a utility to prevent fieezing, but it wouId provide warnings of Lieeze-ups. However, if
sunicient waming is given, temperature monitoring may in fact alfow maintenance crews to prevent the water
fiom fieezing. This action may be accomplished by extemal heating, or by increasing the flow in an area where
stagnant water is a problem.
e. Keeping System Records
Al1 data obtained using the SmartPipe can be stored for fuaw use. The uses of these data must be agreed upon
by the individual utility, but suffice it to Say, there are many possible applications, as this chapter attests. The
types of records kept by a water utility include plant operational records, source records, purnping nation
records, distribution system records, and accounting records (Mhistry of the Environment 1980). The
SmartPipe may provide data for some or ail of these record types. Uses of system records include:
The SmartPipe: Impact on Water Distribution
Comparing existinq equipment;
Identijling major faults and problerns;
Evaluating the maintenance system;
Evaluathg maintenance and reliability of equipment as a bais for selection of funire equiprnent:
Measuring the performance and effectiveness of equipment and maintenance; and
Providing information feedback with supplies and the provisions of "feedback".
Accurate system records and integrated information databases are also necessary for many of the other
applications mentioned in this chapter.
5.2.4 Case Studies
Many water utilities around the world have already implemented monitoring and control schemes for their
water supply systems. These monitoring systems are as diverse as the utilities that initiated them. Some are
very simple systems for monitoring field variables, while others are integrated information control systems with
several levels of hierarchy. The purpose of this section is to illustrate how one water quality monitoring systern
was used by a utility to assist in the solution of certain unusual events.
The Denver Water Departnient recently integrated remote chemical sensors (RCS) into its distribution system.
Soon after impiementation of the RCS system, a large portion of the distribution system was expanded to
provide service to the Denver International Airport (DIA). The laboratory staff noticed elevated pH levels
during routine water monitoring near the DIA terminal. The elevated pH trend was observed using the on-line
moniton within the distribution system, and it was observed that the movement of increasing pH values
through the distribution system was characteristic of a tracer. The cleamess of the data and the speed with
which it was obtained allowed the utility to promptly Rush die conduit supplying water to the airpon. This
action reduced the pH to normal levels, maintainhg an acceptable water quality in this area (Orth et aI. 1997).
An elevated pH would have had an effect on the ability of the secondary disinfectant to inactivate pathogens.
At higher pH, more of the chlorine is present as OCI', which is 40 to 80 tirnes Iess effective than HOC1 as a
disinfectant (Snoey ink and Jenkins 1980).
The SmarrPipe: impact on Water Disiribution
Another example of the importance of on-line monitoring of water quality occurred on May 20, 1996 when a
forest fire occurred in the mountains to the south of the city of Denver. Following the fire, heavy rains
produced major flooding, depositing a high silt load to one of the city's raw water reservoin. On-line total
chlorine monitors in the distribution system detected a drop in the total chiorine residual of the drinking water,
implying that the chlorine dernand had increased. The drop in chlorine residual prompted the RCS to alert the
treatment plant. The chlorine residual Ieaving the plant was subsequently increased so that an adequate residual
was maintained in the system, even at the points farthest fiom the treatment plant. Later, the high chlorine
demand was linked to the high dissolved manganese leveis in the raw water due to the silt washed d o m fiom
the mountain. The high level of manganese in the siIt was due to the forest fire (Orth et al. 1997).
These examples show how remote monitoring can allow utilities to keep track of conditions within the
distribution system without the need to physically travel to each monitoring location. The information can be
gathered almost instantaneously, allowing prompt action to solve problems, with substantial savings in time and
labour due to the Iack of deployment (Orth et al. 1997). However, the use of automation cannot entirely replace
direct hurnan intervention in regulating the normal operation of a distribution systern, or to take appropriate
action when a malfunction is detected (Pipeline Industries Guild 1984).
In another case, the City of Phoenix, Arizona implernented a Iimited SCADA system for 10 RCS sites in its
distribution system. The initial success of this project led to more complex and encompassing systems. The
initial system provided the City with an indication of the potentiaI benefits of centralized monitoring and
control, and therefore operators were soon asking for more wide-ranging control capabilities (Fiddick et al.
1991). A number of lessons were leamed afier instaIlation of this initial s;lstern:
The level of accepuuice of the SCADA system was high, but operators soon found it lacking in its
capabilities;
The software was inflexible, and the remote terminal units (RTUs) could not be programmed;
Expanding the system to provide more information to operaton was dificult to achieve;
The City's maintenance personnel were not prepared or trained to repair and maintain the SCADA
equipment; and
Water Operations management soon recognized the value of the information the SCADA system
provided.
The SmartPipe: impact on Water Distribution
This example illustrates that developing and implementing a monitoring and control system for water supply
encompasses many areas of focus not directly related to the equipment itself Also, the transition of a utility
fiom non-SCADA to SCADA is a difficult one, and significant upheaval should be expected.
5.3 LEAK DETECTION
As discussed previously, a significant percentage of the water that is treated and reieased into a distribution
system is Iost due to Ieaks. Unaccounted for water includes water lost through physical leaks and water used
but not accounted for through metering or estimates. For well-established systems, levels of unaccounted for
flow less than 15 percent of total production are! considered acceptable (AWWA Le& Detection and
Accountability Committee 1996). However, in many cities the level of unaccounted for water may reach as
high as 27 percent (Fowles 1993). In particularly poor systems, this level may be substantially higher, such as
the municipal watenvorks in Bergen, Nonvay, where unaccounted for water ranges from 40 to 45 percent
(Skjervheim 1984).
Supplying and distributing water to the public is an energy-intensive endeavour for municipal water utilities.
Nearly seven percent of electricity consumption in the United States is by the water indusûy (Ormsbee et al.
1989). More than 95 percent of this electricity is used for purnping (Clingenpeel 1983; Carns et al. 1992). The
production of this electncity has both economic and environmental impacu on society, which could be lessened
if demand for potable water was reduced. Leak detection devices and water accountability strategies using
approaches such as the SmartPipe could allow utilities to reduce the percentage of unaccounted for water.
thereby reducing the overall quantity of water that would need to be treated and pumped. Consequen?ly, the
overalI cost of water supply would be significantly reduced, and the strain on raw water sources would be
similarly reduced. Active leakage control methods can significantly reduce the quantity of water 10% with flow
meters and pressure transducers playing important roles (Fowles 1993).
When investigating the extent of water loss through Ieaks, there are two major tasks to perfom. First, one must
determine if a leak exists, and its location. Second, one mua quantifi the amount of water lon These tasks are
not necessarily simple, and there are many difficulties inherent in detecting leaks (Makshovic et al. 1996): - Individual consumers are not metered regularly or not at d l ;
Many meters are unreliable, out of order, or not tùnctioning properly; and
The SmariPipe: Impact on Waier Distribution
Consurnption for fue fighting, street washing, and pipe flushing is not metered.
To combat the effects of leaks on water supply, utilities and water indu- organizations often make
recomrnendations for remedial action. For example, the Water Research Centre (WRC) made the following
recommendations to utilities in the U.K. (Brandon 1984):
i. Automated operational control and telemetry should be advanced arnong the water indusay;
ii. Al1 distribution systems should be subjected to network analysis and flow surveys;
iii. Pressure control should become a standard feature of distribution systems; and
iv. Where distribution systems are not fÙIly rnetered, the utility should make optional metering more
attractive to customers.
Other recommendations were made, but these four relate speciflcally to monitoring and controI of distribution
systems. These recommendations illustrate how the industry is beginning to recognize the importance of this
ability to remotely monitor and control the components of a distribution system.
5.3.1 Methods of Leak Detection
There are five main categories of leak detection methods used in pipeline systems, each relying on different
phenomena to detect the presence of a leak: fluid sensing methods, SCADA-based methods, acoustic methods,
pattern recognition meâhods, and model-based methods. Another leak detection method, conceptualized by
Karney et al. (1997), utilizes resistors to indicate the presence of a leak. The effectiveness of a leak detection
systern should be measured by its reliability, response rime, and the size of the smaI1er detectable leak (Liou an
Tian 1994).
a. Fluid-Sensing Methods
Fluid-sensing systems are not widely used in the water indumy, being more comrnon for oil and nanval gas
pipelines. Cables are laid underground next to the pipe. If a ieak occurs, the cable is exposed to the fluid,
changing its electrical properties and sending an alerting signal to a central monitoring station. n i e central
station then computes the location of the leak. A fluid-sensing leak detection system is capable of very high
sensitivity, but the cost of repairing the system is high since the cable must be laid next to the buricd pipe
(Whaley and Ellul 1994).
The SmartPIpe: impact on Water Dishibution
b. SCADA-based Methods
SCADA-based leak detection methods utilize SCADA equiprnent to provide flow and pressure data at regular
intervals throughout a distribution system. It is straightfonvard to compute balances of mass or volume across a
length of pipe using this detailed information. In the absence of iransient effects. any imbalanca cm
hypothetically be attributed to a le* in the system. A detection system of this type is economical and relatively
easy to implement (Whaley and Ellul 1994).
Normal transient events (i.e., valve closure, pump start-upkhut-dom, increased demand at a specific location)
can sometimes be mistaken for srnaIl leaks. Similarly, inaccurate rneasurements and calculations cm cause
discrepancies between the measured and calculated flow, and trigger a false alarm. To eliminate this problem.
SCADA-based leak detection methods usually integrate the calculated balances over time, thereby eliminating
the effects of transient events, which by nature are short-lived. However, the reduction in the frequency of false
aIarms is offset by the increase in the time required to detect a le&, which could be as long as 24 hours for very
small leaks (Whaley and Ellul 1994).
c. Acoustic Metbods
Acoustic leak detection systems are based on the distinctive acoustic signals generated by leaks. Theu
popularity for the past 15 years has been partially due to the speed of detection, which is equivalent to the speed
of sound in the fluid fiom the leak to the farthest detector. The detection system requires acoustic monitors that
are placed at each end of a pipeline segment. If a leak is present within a segment, it will generate a wave
travelling at the speed of sound towards the two moniton. By recording the time of arriva1 of the wave at each
monitor, the precise location of the leak can be detennined (Klein 1993). The le& position, D, is calculated
using the conelator, L:
L = 2D -t N = 2D + (velocity of sound x t,J (5- 1)
Where h = time deiay between the arriva1 time of the wave at each monitor.
The position of the Ieak dative to the monitor that fust receives the wave can be calculated as:
D = [t - (velocity of sound x a] / 2 (5-2)
The SmartPipe: fmpact on Water Distribution
if the wave is detected at both monitors at precisely the same instant, then the le* is located midway between
the sensors. However, if there is a time delay, b, between the arriva1 times, the leak is located doser to one
sensor than the other. Figure 5.3 shows how a leak is detected in this manner.
FIGURE 5.3 Acoustic le& detection (Fowles 1993)
Acouaic rarefaction waves propagate well through water, although attenuation cm occur due to constrictions or
expansions of the pipe. If the placing of acoustic monitors is not suniciently dense, the reduction in amplitude
of the acoustic signal fiom the leak can reduce the ability of the system to detect it (Whaley and Ellu1 1994).
d. Pattern Recognition Methods
niese methods, which rely on the recognition of a pattem or difference in a pattern, are gaining populanty.
The pressure signal at a location in a pipeline or pipe network is analyzed and a statistical pattern established.
The system cm oow identify and flag any deviation causeci by an unexpected dynamic event nich as a leak.
The SmartPipe: Impact on Water Distribution
The advantage of this method is that only one pressure transducer is required on each pipe segment. However,
the disadvantage is that no reliable way of differentiating between leaks and normal pipeline transients has been
found. Although, using information from flow meters can help to reduce the number of false alarms (Whaley
and Ellul 1994).
e. Model-based Methods
ModeI-based methods, also known as the dynamic leak detection model, are more sophisticated than most other
methods. niey comprise a mathematical model running in real-time using on-line data from the pipe network
as boundary conditions. Details of fluid flow throughout the pipe network are simulated from measurernents at
the ends of pipeline segments. Since the model is unaware of the presence of a possible Ieak, it is not
simulated, and therefore any discrepancy between the hydraulic values calculated by the model and those
measured in the pipe indicates the presence of a le&. Furthemore, analysis of leak profiles can yield estimates
of its location (Whaley and Ellul 1994; Wylie and Streeter 1993). The dynamic leak detection model is
discussed further in Section 5.3.2.
f. Leak Detection Using Resistors
Another method of detecting le& and pipe breaks involves wrapping a wire coi1 around the pipe
circumference, with each wire coil separated from those adjacent to it by a set distance. These coils are
c o ~ e c t e d in parallel to a common power supply and transmission wire. Each wire coil has a unique address to
identiQ the location of the coil along the pipe and in the distribution system. If the pipe breaks at a certain
location, the wire coils nearby are Iikely to break, cutting off the cumnt through those coils. The lack of
curent is deteaed by the monitoring station almost immediately and valves are closed to isolate the pipe while
a maintenance crew is sent to the site to repair the break ( b e y et al. 1997).
This systern can be improved if each wire coi1 is replaced with a resistor. With al1 other components as before,
the resiston remove the need for each coil to have a unique address. A pipe break creates a change in the total
resinance along the pipe. which is easily measured from the remote monitoring station. If the circuit in which
the ifi mistor is located is broken, the following equation can be used to determine the totai resistance Ri of
the remaining resistors in pipe i:
The SmartPipe: Impact on Water Dbtribution
where i is the pipe number, j is the resistor number, and Rv is the resistance of resistor j in pipe i. If Ril = Ri2 =
... = Rin= R, then the total resistance is:
which gives the location of the pipe break at the ith pipe and jth resistor location. Since the cost of a resistor is
very low and no addresses are needed, this method is preferred (Karney et al. 1997).
However, it is unlikety that a leak detection system of this design couId be incorporated with the SmartPipe
within the near future. Many potential problems exist with this systern, including:
the potential for increased corrosion of metal pipes,
the possibly prohibitive cost,
the tack of durability of system components, and
undesirable interactions of system components with the environment.
This method is put aside in favour of the dynamic leak detection model, which is discussed in more detail in the
next section.
5.3.2 Dyaamic Leak Detection and the SmartPipe
The data requirements for the dynamic leak detection model are more intensive than other methods. To detect
Ieaks in a pipe segment, one must obtain measured values for pressure and flow at al1 inlets and outlets. The
expected values of pressure and flow must then be calculated using a hydraulic model calibrated to the specific
system. For cornplex fluids, temperature is an important parameter that must also be taken into consideration
(Wylie and Streeter 1993).
The dynamic leak detection mode1 is abie to detect leaks rapidly compared with other methods. Leak detection
times are orders of magnitude shorter than most other methods. However, it is possible for benign transient
events to register as leaks, and fiequent false alarms cm be problematic (Whaley and Ellul 1994).
fie SmarrPipe: Impact on Water Distribution
A real-rime pipeline leak detection and location system consists of the numencal model describing tmsient
flow, two sets of pressure and flow measurement equipment for each pipeline segment, a central computer, and
a data acquisition system.
a. Description of How the Mode1 Works
The model is often referred to as deviation analysis since detection of a Ieak is based on detecting deviations
between transient model cornputed values and measurement values (Nicholas 19%). The following description
of how the method works is ftom Wylie and Streeter (1 993), and Liou and Tian (1 994).
The governing equations of motion and mass conxrvation are converted into a dimensionless form according
to Wylie and Streeter (1993). These equations are as follows:
where
Together with two boundary conditions, these equations completely define most transient flows. To detect
leaks, the boundary conditions are measured flow and pressure at the pipe inlet and outlet. Using the method of
characteristics, the above equations are transfonned into a pair of ordinary differential equations:
whicti are valid dong
The SmarrPlpe: Impact on Water Disrribufion
Since a is a constant, this equation defines two families of straight lines called characteristics on a distance x
versus tirne t coordinate plane. The Iines with dope Ila Xe called C+ characteristics and those with slope - I/a
are called C- characteristics. Figure 5.4 shows how the numerical procedures aIong the characteristics are
determined. For example, knowing the head and flow at points d and/; the head and flow at point e c m be
calculated as foltows:
FIGURE 5.4 The method of characteristics and the solution procedure (Liou and Tian 1994)
The SmartPipe: Impact on Water Dimibution
Figure 5.5 is a simple representation of a pipeline segment. The pressure and flow at the pipe ends are
measured in real-the at t l and 4 . Using the measured pressure and flow at the inlet between t l and 14, the
pressure and flow at the outlet between t2 and r3 cm be calculated. There are now two sets of data for pressure
and flow at the outlet between t2 and 13, one measured and one calculated. SimiIarly, there are two sets of
pressure and flow data at the inlet between t2 and r3.
FIGURE 5.5 Wave propagation and computations in the x-t plane (Liou and Tian 1994)
-- -- - -
in let outIet
The Srnaripipe: Impact on Water Distribution
In a perfectly closed system with accurate measurements and calculations, the calculated pressure and flow
çhould match the measured pressure and flow. If there is a discrepancy, either there is a leak in the pipeline, or
there are errors in the data. A le& creates its own transients, which cause a flow wave to propagate to the pipe
ends and imbues the measurements of pressure and flow with a Ieak signal. When the imprinted leak signal is
used in the calculations that assume no le&, the calcuiated pressure and flow at the pipe ends deviate fiom the
measured values. A discrepancy is considered a leak when the pattern is consistent with that of a Ieak.
b. Reducing False Alarms
With the dynamic Ieak detection model, it is possible for benign transient events to register as leaks under
certain conditions. A false alarm may also be the result of errors in the measurement of parameten, or in the
calculations. False alarms of this son can be troublesome for operators who must send out a maintenance crew
to investigate each alann that is sounded, wasting tirne, money, and resources if the leak does not exist.
Consequently, an effort should be made to reduce the fiequency of false alarms.
Errors in rneasurements or calculations are also calied uncertainties. In this case, uncertainties can exist in flow
balances, packing rates, pressure measurements, fluid propenies, rnodelling cornputations, temperatme
measurements, fiction factor eaimates, and total volume balances (Nicholas 1992). When detecting kaks in
water supply systems, operaton are not stnctly concemed with the fluid properties, as they are well established,
or the temperature, since this does not have a great effect on leak detection. Similarly, the pipeline packing rate
is not important fiom the standpoint of water suppIy.
One may decide to quantifi the probability of these erron and determine their magnitudes, in order to quantiQ
the probability of a false alarm. However, determinhg accurate leak detection esthates requires detailed
knowledge of al1 factors that may be important. Rarely is al1 of this data available to a water utility, so
estimates must be used. Unfomuiately, the esthates will not be entirely accurate (Liou et al. 1992). Although,
the use of monitoring can help a utility to quanti@ these parameters, thereby increasing the effectiveness of the
leak detection system.
The SmartPipe: Impact on Water Distribution
The possible applications of the SmartPipe for water distribution are numerous, as the size of this chapter
attesa. These applications have been divided into groups in two different ways. To list the applications in
tables, they have been categorized based on the type of data used to drive the application: physical, water
quality, or structural data. When discussed in more detail, the applications are divided into groups based on the
type of application: cornputer modelling, operation, or maintenance and repair.
Also discussed in this chapter are the benefits of the SmartPipe system to water utilities. These benefits are
divided into economic and service benefits. Econornic benefits include reduced energy costs, deferred system
improvements, and reduced capital expenditure, while service benefits include improved system performance,
improved water quality, and a quicker emergency response time.
Finally, this chapter discusses the detection of leaks, one the most important applications of the SmartPipe.
There are many methods proposed for finding leaks in pipelines and pipe networks, but many are unsuitable for
use in water distribution systems. One of the most promising methods is the Dynamic Leak Detection Model.
Although this method sometîmes suffen fiom fiequent false alarms, fûrther research and development could
address this problem and make it an integral part of the SmartPipe system.
CHAPTER 6
Design of the SmartPipe System
The SmartPipe is a revolutionary concept that could significantly affect the way utilities supply water. Over the
next few yean, a great deal of thought will have to be directed to how the SmartPipe system is configured and
how it will integrate with an existing distribution system. For example, disniptions to service caused by the
installation and maintenance of a monitoring system are not acceptable. Decisions must be made on rnany
aspects of system design:
The types of sensors to install;
The integration of the SrnartPipe system with the distribution network;
Transmission of data fiom the SmartPipe to the central monitoring station;
Calibration and maintenance of the sensors and other equipment; and
The means by which access to the SmartPipe will be achieved.
These cornplex problems require a great deal of thought to find adequate solutions that are feasible and
practicd.
6.1 DESIGN CRITERLA
The SmartPipe must be adaptable to a variety of situations to be of use to water utilities, and therefore it needs
to incorporate, among others, the following abilities:
Connection with existing pipes without difficulty despite the complications of different pipe rnaterials,
standards, pressure ratings, and sizes;
Relatively few design changes for di fferen t-shed pipes;
Removal andior maintenance of sensors without disrupting service;
Simple on-site calibration of sensors using a portable maintenance "kit";
Simple on-site testing of water samples for water qudity parameters not measured on-line;
The SmartPipe: Design of the SmariPipe System
An excess of sensor locations for future expansion of the monitoring program;
0 Protection of sensors from harsh conditions (i.e., humidity, temperature) and accidental damage;
Access to sensors, and simple installation and removal of the SmartPipe; and
Sensors must not have an impact on each other.
While the above points are directed to the details of the SrnartPipe design, there must be a clear definition of the
purpose of the SrnartPipe system, and procedures for implementation. McAllister (1993) suggests the
following system design guidelines for a utility considering implementing a monitoring pmgrarn:
Aims and requirements of a pipeline monitoring system should be outlined as fiilly, and as early, as
possible;
The system should be as simple as possible, as well as practicaI, but requirements shoufd not be under-
specified for the sake of simplicity;
Instrumentation and pipeline equipment should be selected based on performance and not economic
grounds (it is better to install a few high quality pieces than nurnerous poor ones);
Equipment compatibility is essential, and therefore standard communication protocols should be used;
Custom designed systems are more costly to develop and often cause frustration;
Develop a strict schedule for calibration and maintenance, and make sure it is adhered to;
Use computer software to check data to aid in identification of problems;
Install devices that are self-checking, self-diagnosing, or dual systems (the initial cost is higher, but
may be more economical considering performance); and
Seek independent references, user experiences or validation of equipment chosen (the performance of
most hardware is different for real applications to that specified under ideal conditions).
6.2 SYSTEM CONFIGURATION
Deciding how the SmartPipe system will be configured requins a great deal of thought. The reader is referred
to Figure 4.2 for a basic idea of how the SmartPipe system couId be organized, including components such as
the SmartCo~ector, the access chamber, the data acquisition system, and the central monitoring station. Each
component is discussed in a separate section below. The SmaRComector is discussed separateiy in Section 6.4
since it is the most fùlly developed component at present.
The SmartPipe: Design of the SmartPipe System
6.2.1 The Access Chamber
Since the majority of the pipes and fittings in a water distribution system are buned, the SmartPipe will need to
be installed below grade. However, the SmartPipe rnay not be capable of extended penods of operation without
servicing. It is conceivable that with the recent and expected advances in sensor technology, the SmanPipe
may be able to operate independently for as long as a year or two. However, it cannot be buried and forgotten
in the same way that a regular pipe cm. Therefore, a means of accessing the SmartPipe needs to be devised.
Perhaps the best way of accomplishing this is to construct access chambers that are simiIar to sewer system
appurtenances, or valve chambers in water distribution systems. The access chambers would generally not need
to be as deep as those used in sewer systems, since water mains are buried at a lesser depth than sewer pipes.
Figure 6.1 shows a possible design for a SrnartPipe access charnber. Construction of the access chamber could
be achieved using precast concrete annular rings or, in the case of chambers with special requirements, cast in
concrete. A space would need to be provided for standing to one or botb sides of the pipe, and an area reserved
for equipment and tools.
The cost of constructing a large number of concrete accew chambers thnughout a distribution system to
accommodate the SmartPipe would be prohibitively hi&. Pipe networks for new subdivisions could integrate
the SrnartPipe at little extra cost, but systems already in operation present a problem. One solution is to install
the access chamber while pipes are being replaced, such as when a pipe break occurs. n i e utility could instaii
the access chamber at the same tirne that the pipe is being repaired. Since excavation is the single most
expensive part of maintenance and repair, considerable swings could be achieved.
6.23 Data Acquisition and Transmission
The purpose of the data acquisition system is to collect, temporarily store, condition, and transmit data obtained
fiom the senson to a centrai monitoring nation. The monitoring station should allow for graphical
representation of parameters as well as andysis of the data This component has been discussed in detail
elsewhere and will not be elaborated upon here. The final physicd fom that the dam acquisition system will
take is unknown. Signals may be transmitted over telephone Iines, radio waves, microwaves, or a dedicated
system may be constructed using fibre optics.
The SmartPipe: Design of the SmmtPipe System
FIGURE 6.1 Design of the access chamber
Stcp irons
S M rings
Mass comoc
Chamkr rings
Wata main
Dnin to scwer
6.23 The SmartConnector
The SmartCo~ector is the length of pipe in which various sensors are installed, as well as the power supply
and certain cornponents of the data acquisition system. A detailed discussion conceming the requirements and
design of the SmartComector is presented in Section 64.
6.3 CHOICE OF SENSORS
Sensor technology is contiming to develop, making it dificult to senle on definite sensor types or models at
this the. The experience gained in Stage 2 of the project may allow us to narrow the choices. However, it is
not the a i . at this stage to make £inal decisions on specific sensor models. The SrnartPipe may be like
The SmurtPipe: Design of the SmartPip Sysîem
cornputer software and hardware, continually developing with many updated venions incorporating the latest
advances and techniques. The first generation SmartPipe will be the most difficult to produce, while the second
generation should begin to give the desired performance. The biggest problem that is foreseen is the
development of standard protocols to facilitate communication between instruments. At present, many
interface boxes scattered throughout the system are needed to facilitate "talking" between components (Karney
et al. 1997).
This section provides a general discussion of sensor types for some of the more important panmeters, such as
pressure, flow rate, pH, temperature, and chlorine residual. A description of the senson used in Stage 2 of the
project is included in the next chapter. Selection of senson should be based on cost, ease of installation and
replacement, dependability, reliability, accuracy, stability, and repeatability. Data rnay be required on both an
intermittent and continuous basis. Intermittent data is obtained by means of discrete samples or the use of on-
line analyzers. Continuous data can only be obtained by on-line analyzers. The data may be obtained by a
variety of methods, each preferable in a certain situation. One method is to insen probes directly into a smam.
Alternately, one may use sampiing ports to coliect sarnpies (either rnanually or using an automatic sampler) for
analysis at a laboratory. n i e sample may also be ttansported to a specially designed shelter containing on-line
anaIyzers.
6.3.1 Pressure
Pressure measurernents are usefil for a number of applications, such as network modelling, calibtating
hydraulic models, providing data on system performance, operations problem solving, and indicating the level
of service provided to the customer. Many different types of pressure sensors are available, including Bourdon
tube gauges, manometers, and electronic devices. Regardless of the type of meter, accurate elevation data are
required to obtain accurate hydraulic grade Iine calculations (Cesario 1995).
The three most common elernents used to measure pressure are Bourdon tubes, bellows, and diaphragms.
Schernatics of each type are shown in Figure 6.2. The pressure in the system causes the mechanical element to
move proportionally. This movement is then arnplifîed by a mechanical Iinkage to a scale or by electronics to a
voltage curent signal (Skrentner 1988).
The SmartPipe: Design of the SmartPipe Sysrem
The Bourdon tube utilizes a curved tube, sealed at the tip, which straightens as pressure increases. The
deflection is transferred to a dial indicator by a mechanical linkage. nie configuration is similar to a standard
thermostat. Bellows, metal cylinden that are corrugated and sealed at one end, expand as pressure is applied.
This expansion causes the nnoring springs to cornpress. which ~ansfers the amount of expansion to a dia1
indicator. Finally, diaphragms are metal disks. which expand outward as pressure is applied frorn one side.
Again, this expansion is transferred to a dia1 indicator using a mechanical or electronic linkage (Skrentner
1988).
FIGURE 6.2 Mechanical pressure elements (a) Bellows, (b) Diaphragms, (c) Bourdon tubes (S krentner 1 988)
I C-T
The SmartPipe: Design of the SmartP@e Systern
Another type of pressure transducer is the vibrating wire sensor, which uses a hmgsten wire encapsulated inside
a ce11 and vibrating at its naîural fiequency. As pressure is applied to the silicon bamier diaphragms, the tension
in the wire changes, altering the resonant fiequency. This change is identified and amplified by the msducer,
subject to pressure and temperature compensation within the cell. This type of meter is very attractive because
it is much smaller and less expensive than typical pressure transducers. while at the rame tirne provides
excellent pressure measurements (McAllister 1993).
6.3.2 Flow Rate
Measurement of fiow is one of the most important process variables in the operation and control of water
distribution systems. Unfortunately, the measurernent of flow rate in a pressurized pipe cm be rather complex
and costly. There are many different types of flow meters on the market, each relying on a different principle
of operation, and each suitable for a different application. These types include magnetic, sonic and ultrasonic,
mechanical (turbine and position displacement), diflerential pressure, and vortex shedding. Although flow
rneters operate under many different principles, al1 flow meten c m be classified into three groups (full bore,
insert, and clamp-on) based on how the rneter is mounted to the pipe. The full-bore rneter is placed directly
into the pipe, and is therefore not easily removed once installed. The insertion meter is inserted into the pipe
through a tap in the pipe wall. The easiest type of meter to remove once installed is the clampon rneter, which
is fmed to the outside of the pipe. Table 6.1 indicates the different classes of flow meters and the different
principles of operation that can be incorporated into each type (Skrentner 1988).
For the case of water flow in pressurized pipes, the orifice meter and pitot tube are of limited use. Orifice plates
and turbines create a high head loss and have a limited rangeability, while pitot tubes have poor accuracy and
repeatability, and have a tendency to cIog. Other types of meters are ideai for water metering, such as the
positive displacement meter. This type of meter is very accurate, with wide rangeability, although it is a
totalizing type meter and is not suitable for providing fiow rate data (Skrentner 1988). The most promising
flow meters for use with the SmartPipe seem to be the sonic and ultrasonic meters, the turbine meter, and the
ventun tube meter.
The SmartPipe: Design of the SmartPl'pe System
TABLE 6.1 Classification of flow meters (Skrentner 1988)
- -- - . . ---p. - -. -- - - -
Meter Full bore Insertion Clampon Suitabiiity
Orifice plates Venturi tubes Magnetic Turbines Positive displacement Vortex shedding Sonic Ultrasonic Pitot tubes Tar get
low medium low medium low medium high high low medium
The ideal flow meter is one that is installed on the ouüide of the pipe but yields a performance equaling the best
flow meters hstalled on the inside. An example of this type of fiow meter is the ulûasonic timeof-flight meter.
There are two types of this meter: the Doppler meter. and the transit-time meter. The Doppler meter is
relatively crude. with an error of 15 percent. However, modem clamp-on transit-time meters, also called
tansmissive sonic meten, can indicate flow to k2 percent or better. The main advantages of this type of meter
are the negligible head loss involved. and the ability to install other portable or dedicated systems without
disniptions to service (McAIlister 1989). Figure 6.3 shows how the msrnissive sonic meter operates.
The tmsmissive sonic flow meter measures fluid velocity by determining the difference in the tirne requued
for a sonic pulse to travel a specific distance throuph the fluid in the same general direction as fluid flow, and
the time required for a sonic pulse to travel the sarne distance in the opposite direction. The t h e difference is
proportional to the tluid velocity. and an output signal linearly proportional to the flow rate is prduced in the
meter transmitter (Skrentner 1 988: Cesario 1995).
The S m d i p e : Design of the SmmtPipe System
This type of flow meter is sensitive to flow-disturbing piping obstructions located too near the meter inlet.
Valves, elbows and tees, pumps, and severe reducers and expanders may add up to 10 percent error to the
measured flow rate. These obstructions should be located no less than seven to ten pipe diameters fiom the
meter inkt, and five pipe diameters frorn the outlet. Calibration of this type of flow meter should be carried out
every two months (Skrentner 1988).
The problem with al1 flow meters is that they are affected by the fluid they are metering. To obtain the least
uncertainty, a flow meter should be calibrated on-line under actual operating conditions. Traditionally,
calibration was accomplished using large and expensive hardware called bal1 provers. The large size was
necessary to provide adequate volume within the calibrated section of pipe to ensure suffkient resolution and
accuracy for the flow rneter. More recently, compact provers have been developed that are not only smaller,
but perform bener (McAllister 1989).
FIGURE 6.3 Transmissive sonic flow meter (Skrentner 1988)
r"l Procas piping w M a r flangc
Fiow
The SmarrPipe: Design of the SmrarPipe System
The pH of dnnking water is considered one of the most important pieces information when detenining the
quality of water. AI1 pH sensors on the market use a glas membrane electrode to develop an electrical
potential that varies with the pH of the water. Figure 6.4 shows a schematic of a typical pH sensor. The
reference electrode is used to measure the potential generated across the g las elec~ode. The measured
potential is then amplified by an electronic signal conditioner (Skrenmer 1988).
The combined accuracy (electrode and signal trammitter) of a pH meter ranges fiom 0.02 to 0.2 pH units. The
effects of temperature on pH measurements are negligible (additional error of 0.002 pH per degree centigrade
difference from the calibration temperature), but most pH meters include automatic temperature compensation
regardless. Repeatability ranges fiom 0.02 to 0.04 pH units, and stability ranges fiom 0.002 to 0.2 pH units per
week. The level of stability of a pH rneter indicates the requind fiequency of ncalibration (Skrentner 1988).
The maintenance and calibration requirements of a typical pH meter, assuming normal operating conditions, are
listed in Table 6.2.
FIGURE 6.4 Schematic of a typical pH sensor (Skrentner 1988)
The SmartPipe: Design of the SmorrPipe System
TABLE 6.2 Maintenance and calibration requirements of a typical pH meter (Skrentner 1988)
Tas k Frequency
Clean efectrodes MonthIy
Add reference electrode fluid Weekty Add as necessary ( fiee- flow ing type electrode)
Replace reference electrode As dictated by operating experience (non-flowing gel type electrode)
Weekly after initial installation Reduce to once per month if justified by expenence
Transm itter calibration Every six months
63.4 Temperature
Mesurernent of water temperature in a distribution system is important since many of the physical, chernical,
and biologicai pmcesses that may be occumng in the water are temperature dependent. Shce sensoa used to
measure chlorine and pH require temperature compensation, it is possible that data on the temperature in the
distribution system could be obtained fiom this source. However, it may be advantageous to have an
independent rneasurernent of temperature for cornparison purposes. Many types of temperature senson are
available corn a variety of manufacturen, and they are relatively inexpensive.
6.3.5 C hiorine Residual
Together with pH, chlorine can be considered one of the two most important water quality parameters for water
dimibution systems. Chlorine is added in various foms to the water at the treatment plant in a process cailed
chlorination. The chlorine acts as an agent to destroy or inactivate pathogenic microorganisrns. in order to
The SmurtPipe: Design of the SmarîPipe System
ensure a safe water supply to the customer a measurable level of chlorine residuai must be maintained within
the distribution system at al1 t h e s and at al1 locations.
There are several methods available for measuring chlorine residual such as c o l o ~ e û i c . amperometric, and
polarographic techniques. While al1 three are useful, the amperometric technique is rnost ofkn used for
measuring the total chlorine residual in tinished water. The amperometric meter requires the use of two
dissimilar metals held in a solution called an electrolyte. The two metais act as opposite electrodes when a
voltage is applied. The voltage potential causes electrons to flow fiom the cathode to the anode generating a
current that is proportional to the chlorine concentration of the solution. A schematic figure of the
amperometric cell is show in Figure 6.5 (Skrentner 1988).
FIGURE 6.5 The amperornetric ce11 (Skrentner 1988)
I I
A L I F
Current. 1, is pmportional to the chbrinc concentration
œ + Elcctrolyte
The SrnartPipe: Design of the SmwtPip System
The arnperometric chionne midual analyzer consist. of an inlet sample tank and flow regulator, reagent
solutions with metering pumps, a measurement cell, and an electronic signal converter. Chlorine is able to exist
in many different forms in water, and so the sample is conditioned so that sll of the chlorine present in the
sample will be detected. The sample is then passed through the measurement ceil where it acts as the
electrolyte. The current that is generated will be proportional to the total chlorine concentration in the
electrolyte. Since the measurement process is sensitive to variations in temperature, automatic temperature
compensation is required. This compensation is accomplished by installing a temperature sensor in the
measurement cell providing continuous temperature feedback to the electronic converter. The feedback is used
to modiS, the output From the measurement cell to account for variations in temperature. Figure 6.6 shows a
schematic of the arnperometric total chlorine analyzer with automatic temperature compensation.
FIGURE 6.6 Schematic of the amperometric total chlorine analyzer (Skrentner 1988)
Buffet sduoon Ip)i 4)
The SmarfPipe: Design of the S r n d b e System
The accuracy of the analyzer depends on the operating range. which is available from 0-1 mg/L to 0-20 mg/L.
Depending on the range chosen the measurement error could range fiom 0.03-0.6 mgL. Cenerally, the
accuracy of the amperomeeic analyzer is about i 3 percent of full scale. Repeatability for the analyzer is quite
good at k 1 percent of hl1 scale. Due to the use of automatic temperature compensation, this accuracy and
repeatability should be stable over a sample temperature range of O-SOOC (Skrentner 1988).
TABLE 6.3 Maintenance and calibration requirements for the total chlorine analyzer (Skrentner 1988)
Tas k Frequency
- - - - - - -
Check reagent supply Check analyzer cal ibration Daily Check sample flow through analyzer Check reagent flow to sample line Calibrate analyzer Replace tubing on reagent pumps Backflush sarnple line Clean analyzer drain lines Clean ceIl electrodes
Daily
Daily Daily When need is indicated by calibration check Monthly WeekIy Weekfy Monthly
Maintenance and caiibration of the chlorine anaiyzer should be canied out on a routine basis. However, the
analyzer is a compIex instrument with many different parts, each with different maintenance and calibration
requirements. Table 6.3 shows the maintenance and calibration requirements for each part of the analyzer. A
glance at this list indicates that the amperometric chlonne analyzer requires ftequent maintenance of its many
elernents.
Although the amperometric chlorine analyzer is quite common, some agencies have encountered problems with
it. The Denver Water Department has recently begun a program of remote chernical m o n i t o ~ g of its
distribution systern. As part of this program, they instailed a nurnber of amperometric chlorine analyzen with a
membrane and e1ectroIyte system. The sensor in question was the EIT mode1 5251 total chlorine monitor
me SmartPipe: Design of the SmarîPipe System
which is designed to work unassisted for three months. In practice, the Denver Water Department found that
over time, weekly total chlorine calibrations became necessary. The amperometric analyzer was chosen shce it
does not require the use of chemical reagents, which are needed for colorimetric monitors. However, the
reduction in cost was partially negated by the need for more frequent maintenance of the analyzers (Orth et al.
1997).
It was found that any foreign material or film present on the surface of the membrane would cause a decrease in
the interaction between the membrane and the electrolyte. A decrease in the sensitivity of the receiving
platinum and silver electrodes was also observed. The conclusion was that for water distribution, the rernote
chemical sensors would need to be more tolerant of deposition. The colorimetric analyzer, although it requires
the use of chemical reagents, may be more appropriate for water distribution systems. The Hach CL 17 total
chlorine analyzer provides automatic zero on the water prior to the addition of colour. The chernical reagents
need to be replaced every thirty days during routine cleaning and calibration activities (Orth et al. 1997).
The conclusion that can be drawn fiom this example is that while there are a number of types of chlorine
analyzers available, no one type is ideal for water distribution systems. For the SrnartPipe, the measurement of
chlorine residual is a very attractive ability, but no decision has been made conceming the type of chlorine
meter that is suitable. The expense of chlorine meters has made the process of selecting an appropriate sensor
both more important and more dificult.
6.4 DESIGN OF THE SMARTCONNECTOR
A SmatCo~ector is a pipe, with special provisions made for sensor installation, that can be inserted iato a
pipeline or network at a desired location to c o ~ e c t two regular pipes. The size of the SmartComector can be
altered without senously affecting the installation of the sensors. Although it will be designed for use with
PVC pipe, the connecter should be compatible with other common pipe rnaterials.
A mdardized housing for the sensors, power supply, and part of the data acquisition system is the mon
promising method for integrating the SmartPipe with the disttliution system. The SmartConnector could be
rnass-produced using PVC injection molding. The collaboration between the University of Toronto and iPEX
inc. on this project makes the use of PVC almost inevitable. However, the cornmitment to use PVC is not
The Srnari Pipe: Design of the SmartPipe System
entirely due to the involvement with IPEX Inc. PVC has many advantages over traditional pipe materials (Uni-
Bell PVC Association 199 1 ; Matthews 1996):
Its wide use in industry today, and its ever increasing importance in modem pipeline systems;
Its ease of handling, being very light compared with the same sized pipe made of cast iron;
Its high strength to weight ratio;
The ease with which it can be molded into various shapes;
Its exceptional durability and resitience; and
The fact that it is essentially inert when exposed to a variety of chemical compounds.
This thennoplastic construction material has been proven, through experimental analysis, to be inert with
respect to most fonns of acids, alkalis, and corrosives.
IPEX Inc. produces a nuinber of Blue Brute fittings conforming to AWWA C-907 to accompany its range of
AWWA C-900 CIass 100 @R25) and Class 150 (DR18) Blue Brute pipe. These fittings are manufactured to a
very high standard, undergoing dimensional tests, material tests, burst pressure tests, fusion tests, and
qualification tests before they are deemed suitable for use in a pressurized potable water system. After passing
these rigorous tests, Blue Brute fittings made by IPEX meet the following standards (IPEX 1993):
AWWA C-907 "Polyvinyl Chloride (PVC) Pressure Fittings for Water (Cinch to &inch);
Certified to CSA B 137.2 "PVC Injection Molded Gasketed Fittings for Pressure Applications";
Underwriters' Labotatories (UL) Inc. listed;
Factory Mutual (FM) approved;
Ontario FVovincial Standards (OPS) Specification 70 1 .OSOS; and
The compound is listed with the National Sanitation Foundation (MF) for potable water service.
Blue Bnite fittings are a high quality product and are accepted as such by utilities and contractors. In many
cases, the product far exceeds the above standards. It is hoped that the SmartConnector will be rnanufactured
by IPEX to meet the same high standards.
The problem with the SmartComector at this stage is financial. It costs IPEX between one and two hundred
thousand dollars to create the injection mold for a new fitting. It is therefore impractical to test different
designrj for the SmartCo~ector using injection molding. A more feasible method is to pmduce a "mock-up" of
the proposed fitting which would cost on the order of a couple of hundred dollars. Alterations to the design
could be made to this prototype at littie extra cost. IPEX can then create the mold for the fiaing when the
The SmatPipe: Design of the SrnartPipe Systern
design is finalized and there is less chance of unforeseen problems. The purpose of this section is to provide a
few ideas as to how the SmartConnector could be configured and how it will funaion.
6.4.1 SmartConnector Requirements
Designing a SmartConnector to house on-tine sensors is not a simple task. Al1 requirements for the fitting must
be met while at the same time ensuring that service is not affected. Problems such as cavitation, leakage, or
significant head loss must also be prevented. Experience with the test pipeline, constructed at the IPEX
manufacturing plant in Scarborough, has shown that installing sensors in a pressurized pipe presents a number
of problems.
A standardized system is required for installing the sensors, housing the power supply and data acquisition
system, and containing shutoff valves to isolate the flow to the sensors. It is essential to allow for calibration or
replacement of the sensors while maintaining water flow through the pipe so that regular service is not
disrupted. By-pass lines were constmcted for the test pipeline to solve this problem'. However, flow
conditions in the by-pass are not the same as in the main pipe, so the condition of the water is not representative
of the whole. In other words, measurements of water quality parameters would not be accurate. Also, the flow
meter cannot be mounted in the by-pass; the nature of flow rate measurement requires that the meter be
mounted in the main pipe. Finally, by-pass lines have the probIem of added complexity. Therefore, it has been
decided that for the next stage of the project, a new method of mounting the sensors will have to be found.
The fundamental requirement of the SmartComector - that sensors may be removed without the need for
disrupting service - is a difficult problem to solve. The use of double containment pipe as a solution has been
investigated (Ziu 1995). Flow to the sensors, which would be installed in the outer pipe. could be suspended
while service continued through the inner pipe (Figure 6.7). However, such a configuration is too complex at
tbis stage. Isolating flow through one path is very difficult to achieve, and a satisfactory solution cannot be
foreseen at this t he . For the present, designers will have to make do with a less sophisticated arrangement.
'See Chapter 7 (Section 72.5) for a discussion of the by-pass lines.
The SmartPipe: Design of the SrnartPipe System
FIGURE 6.7 The use of double-containment pipe for the SmartConnector
[
Most sensors availabte fiom manufacturers have male-threaded ends to facilitate their insertion into female-
threaded holes. The SmartConnector will need to have a nurnber of threaded holes along its length to
accommodate these senson. The wall thickness of standard PVC pipe is too thin to accommodate threaded
holes. Therefore, it will be necessary to mode1 the SmartConnector on the tapped coupling produced by IPEX.
which has a greater wall thickness in the area surrounding the tapped hole.
The types of sensors that will ultimately be used have not been finalized at this stage. As discussed above, there
are an enormous variety of sensor types available from a variety of sensor manufacturers, making the selecrion
of sensors diEcult. During the second stage of the project, ten sensors of various types were installed in the
test pipeline. From this installation, much has been learned about the problems inherent in inserting sensors
into a pressurized pipe.
Perhaps the best way of ensuring the SmartConnector can accommodate different numbers and types of sensors
is to provide more holes than initially required, which can be plugged if not needed. These holes should also be
made Iarger than the typicd diameter of the senson so that reducer bushing can be used with a variety of sizes
The SmuttPipe: Design of the SmarrPipe System
to accommodate a variety of sensors. Unfortunately, the flow meters that we have had experience with do not
have male-threaded ends. It is anticipated that the flow rneter may cause more trouble than the other sensors.
However, there may be other types of flow meten available fiom manufactures that will integrate more easily
with the SmartConnector concept.
The pararneters that have been measured using the test pipeline are flow rate, pressure, pH, and temperature.
Apart fiom fiow rate, measurement of these parameters is straightforward. However, expansion of the project
to include other pararneters such as chlorine residual could be problematic. As discussed in Section 6.3, there
are doubts about the accuracy and repeatability of the amperometric chlorine analyzer, and the colorimetric
method requires the use of chemical reagents that must be restocked periodically. Nevertheless, chlorine is a
very important parameter for water distribution systems, and every effort should be made to incorporate it into
the SrnartPipe.
Orth et al. (1997) used a standardized vertical manifold for positioning the daily remote chemical sensors
(RCS). The manifold was designed for a laboratory sample spigot to accept chemical sensor implants along the
height of the unit. The fint sidearm of the manifold was used as a laboratory sarnple tap with a running tap
flow of 1 .O Umin. The outlet for the total chlorine analyzer was positioned directly above (i.e., downsîream)
from the sample tap. The chemical sensors were then installed downstream of the chlorine analyzer in the
following order: conductivity, pH. temperature. and turbidity. These sensors were positioned directly in the
manifold's water Stream. A similar design may be usefùl for the SmartPipe system.
Another consideration in the design of the SmaxtConnector is the type of distribution system. Although many
new distribution systems exclusively use PVC pipe, some do not, and existing systems are a patchwork of many
different pipe materials ( L a o n 1966). For maximum flexibility, the SmartCo~ector will need to be adaptable
to many different pipe materials.
PEX Inc. has developed an excellent joint system for its pressurized pipes using mbber gaskets. Once
lubncated, the spigot end of a pipe can be hserted into the bel1 end of the adjoining pipe to facilitate a tight
joint that can withstand two and a half times its pressure rating without leakage (Shah 1997). However, for the
SmariPipe this joint has a couple of disadvantages. Fim, the gasket joint is only compatible with pipes made of
PVC. Second, installation of the SmartComector should be simple, and once installed it should not be too
difficult to remove. The gasketed joint does not allow simple insertion or removal of a length of pipe since pipe
The Srnaripipe: Design of the SmartPipe Sysiem
sections are "locked" together. Altematively, a flanged connection is probably more suitable. In this way the
SmartConnector could simply be dropped into position, and bolted to adjacent pipes. Removal of the
SmartCo~ector is also simplified using this type of joint. However, for the present it is recommended that the
gasketed joint be uxd since the test pipeline is built entirely using PVC pipes and fittings.
6.4.2 Details of the Design
At this stage in the development of the SmartConnector, simplicity is the primary goal. The design is based
closely on the configuration of the Blue Brute tapped coupling that is manufactured by IPEX. It is recognized
that at least six holes are required to accommodate the sensors. The six holes have been divided into three rows
of ovo holes each. On each row the two holes are positioned at angles of 45 degrees above the horizontal, on
opposite sides of the pipe. In other words, there is a ful l 90 degms of arc between the holes. At present there
are 7.5 inches (for the six-inch nominal diameter fitting) separating adjacent rows. This distance can be
increased or decreased as required. Changing this dimension would also change the overaIl length of the
SmartConnector that now stands at 30 inches (for the six-inch nominal diarneter fitting), including the belb at
both ends. h c h of the six holes in the SrnartConnector has been allotted a different purpose. Table 6.4
describes how each hole will be used. Table 6.5 lists the parts chat will be required to assemble one
SmartConnector.
The reducer bushings that will be installed in each hole will not need to be removed unless the type of sensor
for that hole changes. This configuration will maintah the integrity of the thread in the PVC fitting, reducing
the chance of leakage. The primary advantage of reducer bushings is that they corne in a variety of sizes so that
if the type of sensor changes, the reducer bushing can be replaced with one of a different size.
The StnartPipe: Design of the SmartPipe System
FIGURE 6.8 Chosen design for the SmartConnector. (a) Longitudinal cross-section showing sensor mounting using reducer bushings; (b) Axial cross-section showing holes offset at 45 degrees to the vertical
ïIre S m P i p e : Design of lhe Srnapipe Systern
TABLE 6.4 Arrangement of sensors in the SmartConnector
Hole Sensor type S b of tapped-hole Fitting type
1 Pressure msducer 20 mm (W') %" x W' reducer bushing, accornmodating a W male- threaded pressure transducer
2 Ternpenture sensor 20 mm (%") %" x !4" reducer bushing, accommodating a %" maie- threaded tempenture sensor
3 pH sensor 25 mm (1") 1" x MW reducer bushing, accommodating a f/4" housing for the pH sensor
4 Flow meter 40 mm (1 Yi") 1 !4" x 1 L/4( reducer bushing, accommodating a 1 %" housing for the flow meter
5 Sample line 20 mm (56") ?/1" x %" reducer bushing, accommodating a %" stopcock with a %" rubber hose attached
6 Expansion hole 20 mm (%") Yi'' plug Available for future use
The size of the prototype SmartConnector has not yet been decided. A four-inch nominal diameter would be
ideal, as this would fit nicely with the test pipeline. However, Suresh Shah suggests that a four-inch fitting may
not be strong enough to support s k holes in the fashion discussed. He recornmends that we use a six-inch
fining. If a six-inch Tirting is used with the test pipeline, reducing adapters will be needed to change frorn the
four-inch pipe to the six-inch fittin;. However, the sudden expansion frorn four inches to six inches may cause
excessive head loss and turbulence near the sensors, giving enoneous results.
The SmartPipe: Design of the SmurtPipe System
TABLE 6.5 Parts list for the SmartConnector
Part Name and specifications Quantity Material
1 SrnartConnector (see Figure 6.6 for details)
2 Reducer bushings 2a W' x !4" reducer bushing 2b I/r" x %" reducer bushing 2c 1" x f/4" reducer bushing 26 1 %" x 1 1/41' reducer bushing
?4" plug
4 %" stopcock
6 Reducing adaptor - spigot x bel1 (6" x 4" nominal diameter)
PVC
C.I. C.I. C.I. M.I.
C.I.
Brass
Rubber
PVC
The sire of the fitting must allow installation of senson as the manufacturer recornmends. For example. the
flow meter must be positioned deep enough so that the blades of the rotor enter the flow fully, but not so deep
that the flow is intempted. Similarly, the end of the pressure transducer should be flush with the inside pipe
wall to obtain accurate readings. Although it is necessary to strengthen the pipe wdl around each tapped hole,
we would like to keep the thickness of each boss to a minimum. In addition, it is questionable whether the
bosses on the inside of the fitting opposite the tapped holes are necessary. These questions will have to be
Iooked into fiirther before the fitting is constnicted.
Before an actual fitting is fabricated according to the above specifications, some modifications will be
necessary. To test the design, we intend to i d 1 Blue Brute double-tapped couplings to the test pipeline.
Each fiaing has two tapped holes (one on each side), and by cornbining three of these fitthgs in series, we cm
approximate the above design.
The SmcuiPipe: Design czfthe S m d i p e System
6.43 Sampling Port
The importance of obtaining a sample that is spatially and temporally representative cannot be oventated. It is
expected that one of the tapped holes in the SmartConnector might be used as a sarnpling port. A stopcock with
a short length of hose rnight be appropriate, but whether this would provide a representative sample is not
known. A potential problem with the sarnpling port is clogging of the sample Iine. Although potabIe water is
usually clean, impurities do exist and over tirne residue may build up in a sample Iine. An impuIse line with a
purge valve may rectiS, this potential problem.
6.5 MAINTAINMG THE SMARTPIPE SYSTEM
Once a SmartPipe system has been commissioned by a water utility, provisions wiH have to be made for the
maintenance of the system. According to Mair (1992), maintenance of a monitoring and conaol system such as
the SmartPipe should include:
changing the configuration of the system ro accommodate changes to the utility's operational
strategies,
r adding enhancements to the system to provide greater benefits,
expanding the system's scope to cover additional facilities, and
r ensuring the compatibility of new facilities that may be connected to the system.
Maintenance of the SmartPipe system will not be lirnited to simply repainng it when it breaks. It will also
include keeping the system up to date with changes in operational strategies, and changes in the technological
capabilities of monitoring and control components: in other words, maintainhg the systern's relevance to a
utility's operation.
The SmartPipe: Design of the SmartPipe @stem
This chapter has focussed exclusively on the design the SrnartPipe system. discussing general design criteria as
well as specific designs of individual system components such as the access charnber and the SmartConnector.
Al1 of the designs included in this chapter should be considered as suggestions only. Further development is
required to improve their suitability.
Choosing sensors for the SmartPipe is a dificult process due to variety of sensor types and rnanufacturers
available. The discussion in this chapter focusses on the more important parameten: pressure, flow rate, pH,
temperature, and chlorine midual. The principles of analysis of different sensors an discussed, as well as the
problems associated with each type, and the fiequency of calibration and maintenance required. This 1s t
consideration is important since the sensors rnust be installed underground. The need for fiequent maintenance
of sensors negates the purpose of remote monitoring.
The last part of the chapter concerns the detailed design of the SmartConnector. Although a great deal of
thought has gone into designing this component, more development is required. The SmartConnector design
proposed here is simplistic. The main problem is that it does not allow for the removal of sensors without
suspending service. This ability is critical to the success of the SmartPipe system. Consideration has been
given to double containment pipe to solve this problem, but problems exist with this design as well.
THE PROJECT
CHAPTER 7
Progress of the SmartPipe Project
The SmartPipe is a multidisciplinary project requiring a team with a variety of skilis and expertise. The main
objective of this project is to develop the various components of the SmartPipe system. These components
include a comprehensive sensing system, a SmartConnector to accommodate the sensors, a data acquisition and
transmission system, and the hardware and software for data processing, monitoring, modelling, optimization,
and control of a pipe nework. A potential secondary goal is to strengthen ties between the University of
Toronto and IPEX Inc., and more generally between the academic community and industry. It is hoped that the
research will eventually allow for the provision of a standardized system for the monitoring of parameters in
distribution systems. For the long-term, it is hoped that water utilities wil1 adopt the SmartPipe to provide
solutions to operational problems that go beyond the traditional methods of operating a water system by the
"han& on" approach (Carns et al. 1992).
7.1 STAGE 1 : FEASIBILITY STUDY
Karney and Laine (1997) prepared a feasibility study for IPEX Inc. to investigate the usefùlness of the
SmartPipe for water distribution. This feasibility study focussed on the engineering feasibility of the SrnartPipe
concept. Consideration was given to the types of data that could be monitored, the applications for which the
SmartPipe could be used, the requirements of the system for a variety of specific applications, and
recommended future work to develop the idea.
The midy mentioned economics only briefly since the cos6 and benefits associated with the SmartPipe cannot
be reliably quantified at this stage. Similarly, the fuiancial feasibility - the ability of water utilities to pay the
cos6 of nart-up and operation of the SmanPipe system - cannot be analyzed until costs have been detemine&
and the willingness of utilities to pay these costs is gauged.
The Project: Progress of the SmartPipe Project
7.2 STAGE 2: TEST PIPELINE
The second stage of the project involves constructing a test pipeline to develop the various cornponents of the
SmartPipe systern. The goals of this stage of the project include:
Obtaining preliminary information about the behaviour and accuracy of sensors;
Investigating the feasibility of the SmartPipe concept;
Constmcting a working monitoring system;
lnvestigating the applicability of the SrnartPipe to water distribution; and
Aiding in the selection of appropriate hardware and software for future stages of the project.
One of the prirnary purposes of the second stage of the project was to search for commercially available sensors
suitable for the SmartPipe. The test pipeline was constmcted to test the usefulness of a variety of different
senson. The work done with the test pipeline indicates that the SmartPipe is a viable idea, and that many of the
sensors used in this stage can be considered for h u r e use.
7.2.1 Purpose
One of the aims of this stage is to construct a controll ivironment in which to test the practicality of
installing sensors into a PVC pipe to mesure various parameten such as pressure. flow rate. pH, and
temperature. Experirnents will be conducted using the test pipeline to detemine the accuracy and usefùlness of
the sensors.
The pipeline will also be used to solve any problems that are encountered with the SrnartPipe concept. For
example, we are interested in determining the best method of mounting and housing the sensors. how the cables
for power supply, conaol, and information transmission will be attached, and how the electronic components
will be configured. These electronic components include the address generator, conaol units, A/D converter,
and persona1 computer. Finally, the sothvare for controlling the data collection and monitoring m u t be wrîtten
and modified to suit the application. We are also interested in determining the compatibility of the individual
components such as the sensors and the data acquisition system.
The Project: Progress of the SmmrPipe Project
The test pipeline will be built for long-tem use, so that in the future more complex applications may be
incorporated. A very exciting and usehl type of information that could be gathered with a SmartPipe is water
quality data. Chlorine measurements would be a good starting point, but the sensors for testing water quality
are expensive. Therefore, it has been decided to collect only physical data at this stage, so problems with the
system may be solved without excessive expenditures. At a later stage the system may include measurements
of water quality. In addition, transient analysis rnay also be possible using this system.
7.2.2 Design
The first consideration in the design of the test pipeline is location. The location of the apparatus will affect al1
aspects of the design. The decision was made to build the system at the IPEX manufacturing plant in
Scarborough. Building the pipeline at the university would have been convenient in some ways, however the
IPEX plant is better equipped with materials, had more available space, has a large volume of water readily
avaiiable, and has an estabfished supply network that will be needed to obtain parts.
It was decided to build the system on the north wall of the main manufachuing floor, beside production line
one. Along this wall there are a number of areas that are relatively free of pipes, wires, and other obstacles.
The most ideal location, just to the West of the door to the chilling room, is close to the water supply. This
location was also chosen because:
There is an accessible power supply nearby;
There is an area of wall space Free of pipes, wires, machinery, etc. (approxirnately 18 feet (5.5 metres)
long by 8.5 feet (2.6 metres) high); and
There are two holes (about four inches in diameter) in the wall that could allow access for the four-
inch PVC hose.
One minor problem with the Iocation is the presence of a supporthg column along the wall. This column
makes it necessary to build the pipeline about 1.5 feet (0.46 metres) out fiom the wall. However, this is not a
serious problem since the pipes do not corne out from tfic xalI much more than the column. There will still be
a fairly wide aisle space for trafic to pass by the apparatru. Another more serious drawback to this Iocation is
the high level of noise. IPEX will supply ear protection to each person working with the system, but the noise
makes communicaîion dificuit,
The Project: Progress of the SmwtPipe Project
FIGURE 7.1 Configuration of the test pipeline (Kamey et al. 1997)
The basic requirement of the pipeline is to have a significant lengh of a single pipe in which measurements of
flow rate, pressure, and a number of other parameters can be taken. In order for the measurernents to be
meaningfiil, the pipeline will need to be fairly long. The only feasible way of accornplishing this is to bend the
pipeline back on itself several times, Constructing the pipeline is this manner, makes possible a length of pipe
in excess of 80 feet within an area of wall space chat is only 15 feet (4.6 metres) long by 9 feet (2.7 metres)
high. Figure 7.1 shows how the pipeline is configured.
a. Pipes
The same type of pipîng that is oAen used in water distribution systems (i.e. C-900 DR 18, W C pipe) is used to
consma the pipeline. Ideally, we would like to use a six-inch diameter pipe. but the use of larger diameter
pipe creates a number of problems:
Heavier pipe to work with, including a greater flow of water;
Difficuity in obtaining a 50 psi (35 metres of water) and 20 Us flow;
A water supply pipe that is only four inches in diameter;
Difficulty in obtaining a hose with a suficientiy small bend radius; and
A lack of space at the chosen location for larger diarneter pipe.
The Project: Progress of the SmartPipe Project
The choice of C-900 pipe for this project means that thrust restraints are required at the locations of the 90-
degree elbows to ensure that the elbows do not disengage from the pipes. If this system were to be consûucted
underground, concrete blocki would be used for this purpose. However, in this case it is necessary to use steel
straps and cast iron clamps to keep the elbows and pipes in position (Uni-Bell PVC Association 1991; Shah
1997).
b. Valves
A number of valves are required in order for this pipeline to perform correctly. A regulating valve is necessary
at the upstream end to control the flow of water through the system. Also, since the pipeline discharges water
to the atmosphere, a restricting valve is required at the downstrearn end to reserict the flow of water and achieve
the desired operating pressure of 50 psi. After discussing these requirements with the supplier a decision was
made to use four-inch gate valves for the regulating and restricting valves. The characteristics of a gate valve
allow it to be left partially open, which is necessary when attempting to control or restrict the flow.
Drainage for the system is achieved by attaching a one-inch rubber hose to a fitting near the regulating valve.
This drainage line will require a shutoff valve in the fom of a one-inch bal1 valve. A bal1 valve is usually
operated in either a fùliy open or fùlly closed capacity, making it an ideal choice for this application.
FIGURE 7.2 Details of the pipeline inlet
v From pippîy
The Project: Progress of the SmartPipe Project
FIGURE 7.3 Details of the pipeline outlet
__I_, To dmin
Finally, a pressure-relief valve is an essentiai safety device for any pressurized system. Although the operating
pressure is expected to be about 50 psi (35 rnetres of water), and the supply pressure is at moa 70 psi (49
rnetres of water), it is good practice to have a pressure-relief valve. This valve is located at the top of the
system near the restricting valve. The PVC pipe was tapped and a special fitting instaI1ed. The valve may also
be used os an air relief valve to bleed off the air that may get trapped in the system dunng the initial filling
stage. Also attached to this fining is a pressure gauge, which is used to monitor pressure in the system
independently of the pressure transducers (Shah 1997). Detaib of the valves and other fittings, and how they
are connected, are show in Figures 7.3 and 7.3.
c. Frame and Support
It was decided that the best way of mounting the pipes to the wall is to constmct a m e . The chosen location
has a structural column along the wall, and therefore the pipes cannot be placed close to the wall, and it is
necessary to build the fraaie so that the pipes cm be mounted horizontalIy at about 18 inches (0.46 metres)
Corn the wall. This problem is not serious since the corridor is fairly wide and the apparatus does not block
trafic.
The Project: Progress of the SmarrPipe Project
The fi-ame is constnicted fiom steel members such as structural tees, angles, and flat bars, as shown in
Appendix A. After some quick calculations (Appendix A) it was determined that three supports an requued
dong the length of each 15-foot pipe. Therefore, the frarne consists of three "uprights", each of which is
essentially a rectangular frame of steel eight feet high and 1.5 feet (0.46 metres) wide. These uprighrs art
spaced at equal intervals dong the length of the wall and are connected to each other with a number of flat bars,
To increase the stability of the m e , the uprights are welded to large 18-inch channel sections, To provide
additional support the uprights are bolted to the wall with threaded rods that are bolted on both sides. A total of
three rods per upright should be suficient to provide the necessary strength and stability.
7.2.3 Construction
Construction of the test pipeline was completed by the author with the essential assistance of Edward Loftus
and Peter Melichar, who are maintenance personnel at the IPEX plant. The consmiaion can be divided into
three main parts: construction of the frame, mounting of the pipes to the fiame, and construction of supports for
the valves. Outlined below is a general overview of the construction process:
r Construct the frame;
r Mount the pipes to the frame and connection of PVC pipes to PVC fittings; - Assemble the valves and fitting, and lay out the PVC hose;
m C o ~ e c t the flanges to the PVC pipes;
m Construct suppon for regulating and restricting valves; - Tap a hole in PVC pipe for pressure-relief valve;
a DriIl a five-inch hole in the wall for the four-inch PVC hose;
ir Attach a four-inch PVC hose to supply pipe;
ir Attach a four-inch PVC hose each gate valve; and
m Attach the one-inch rubber hose to bali valve.
a. Bi11 of Materials
included in Appendix A is a bill of materials showing al1 of the parts required in the construction of the test
pipeline. This list includes the name, specifications, and quantity of each part, but does not show the costs. It
should be noted that while a complete bill of materials was prepared before construction, certain changes were
The Project: Progtas of the SmarrPipe Projecf
made to the design during construction. This list reflects these changes and shows exactly what materials were
used in the construction.
b. Frame
The frame was the fim part of the system to be consuucted and ultimately the most cime consurning. It was
difficult to know exactly how strong the frame would need to be since the use of the system is not precisely
defined. Therefore, the h e was over-designed to ensure that it wouId not fail. The main components of the
hime are the three uprights and the beams that connect these uprights together and provide rigidity to the
hune.
Each upright was consûucted by first welding two eight foot long structural tees to the opposite flanges of an
18-inch channel section. Then a flat piece of steel was welded to the other end the smicturaI tees to tie them
together. Finally, fûrther steel ties were welded to the structural tees to provide additional rigidity. The
finished uprights were then moved into position along the wall. Tiiree holes were drilled through the brick wall
(for each upright) at the desind locations. Threaded rods were inserted into these holes so that the uprights
could be bolted to the wall securely with bolts on both sides.
Once the uprights were bolted into position. a number of steel beams were cut and welded to the uprights to tie
them together. These pieces provided the fiame with added strength and rigidity. Finally, to complete the
M e , steel struts (guides for the steel straps) were welded to each of the three uprights.
c. Mounting the Pipes to the Frame
This stage of construction was comparatively simple once a system had been worked out The mounting of the
pipes took less than a day once expenence with connecring the elbows to the pipes was gained. The five
horizontai pipes were mounted so that there is a gap of about 12 inches (0.30 metres) between any two adjacent
pipes. This spacing was done so that there would be suficient room to instalI the sensors. To ensure that the
pipes were mily horizontal, we cut some pieces of wood to the desired spacing and inserted them between two
adjacent pipes. By working up fiom the ground we ensured that the pipes would be Ievel.
The Project: Progras of the SmarrPipe Project
It was found that the easiest method of construction was to connect the elbows to the horizontal pipes before the
pipe is mounted on the frame. Once the horizontal pipe is mounted with the elbows, the short section of
vertical pipe can easily be inserted into the elbow. Then an elbow with the next horizontal pipe already
attached can be inserted into the ftee end of the vertical pipe. This method can be repeated until al1 of the pipes
have been attached.
Two types of support for the pipes and elbows are required: support to mount the pipes to the h e , and
support to prevent the elbows and pipes From disengaging. To attach the pipes to the h e a standard method
using steel straps and stmts was used. When properly installed these straps not only mount the pipes to the
fiame but also provide sorne thrust restraint for the elbows. Due to the large force of water in the pipes, thrust
restraint is required for the elbows. Cast iron clamps are attached to the elbows and pipes to keep them
together.
The cast iron clamps were added after the initial construction, in response to movement of the elbows with
respect to the pipes, In one case, a steel strap was not adequately tightened and this led to one of the eIbows
disengaghg from a pipe. It is supposed that this accident, which occurred at a pressure of 25 psi (18 metres of
water), was due to air trapped in the system. Following this incident, the cast iron ciamps were attached to hold
the elbows and pipes together. Since then the system has performed well under pressures as high as 50 psi (35
metres of water).
d. Construction of Support for the Valves
The final stage of construction consisted of the support for the valves. The one-inch bal1 valve for drainage is
not a problem, but the four-inch gate valves for reguIating and restricting the flow are quite heavy and therefore
must be supported by some means other than their attachent to the PVC pipe. The regulating valve with the
drainage line attached is at the boaom of the pipdine, and is quite simple to support. Being dose to the floor, a
steel frame bolted to the floor was adequate. The restrkting valve was the more difficult to support since it is at
the top of the system, eight feet above the floor. After some discussion, a triangular steel bracket bolted to the
wall and bolted to the flange was selected as the sirnplest way of providing the necessary support.
The Project: Progress of the SmcutPipe Project
7.2.4 Data Acquisition System
A data acquisition system has been developed for the test pipeline by Kai Wah Tang (Figure 7.6). AI1
measurements, transmissions, and conditionings are controlled by a central computer. Each sensor in the
system is identified by a unique address number, specific to the sensor type and its location. At each location
there is a power supply unit which receives a signal from the computer to activate the data acquisition process
for a given sensor (Karney et al. 1997).
The software used for data acquisition is primitive at this stage. The software is able to pe~orm graphical
representation of the data, monitoring, and data archiving. However, the data acquisition system is not able to
perfonn complex tasks such as modelling, optimization, and control. The development of the data acquisitior.
system is ongoing and these features will be introduced at a Iater stage.
Data acquisition is achieved by connecting senson to dedicated analog to digital (AID) converters that are fully
controlled by a common address bus. A laptop computer with special software is used to contra1 and facilitate
data management. n ie A/D converter changes the analog signal from the sensor into a digital signal that
consists of an on or off signal represented by five volts and zero vola DC respectively. The five and zero volt
reference points are defined as Tn logic levels used in the cornputer's binary language of ones and zeros. The
actual analog signal is represented by a serial strearn of ones (5 volts) and zeros (O volts). Once encoded, the
computer can readily accept and manipulate the digital signal (Karney et al. 1997).
The digital data can be transmitted to the computer in a number of ways. In the present system the data is
transmitted directly to the cornputer's parallel (pinter) port through the SmartPipe Command Centre. The
Command Centre moniton and connols al1 of the sensoa in the system. At present up to eight sensors can be
monitored sirnultaneously, although the computer is capable of monitoring a much larger number of sensors.
Sensors can be individually activated (addressed) and programmed to transmit on one of the eight data lines
(Kamey et al. 1997).
The Project: Progress of the SrnartPipe P roject
FIGURE 7.4 Data acquisition system for the SmartPipe test pipeline (Karney et al. 1997)
7.2.5 The Sensors
The chosen sensors have been obtained from various rnanufacturers, and even those fiom the same
manufacturer have different characteristics that make a standard installation difficult. The sensors have
different sizes, lengths, shapes, and threads; some have no threads at all. To make this process more difficult,
the sensors must be removable for caiibration and replacement. Another consideration is the ability to remove
sensors without having to drain the system. AIso, each sensor should be partiaiiy immersed in the water
without senously disturbing the flow.
A total of ten senson are installed in the test pipeline: four pressure tramducers, two flow meten, nuo pH
meters, and two temperature sensors. With the exception of the temperature sensors, these sensors were
obtained from either OMEGA Engineering Inc. or Cole-Parmer Instrument Comp. The temperature sensors
were built by Kai Wah Tang. Detailed specifications for the sensors are presented in Appendix A- A list of the
sensors is given below in Table 7.1.
The Projecr: Progress of the SmartPbe Project
TABLE 7.1 List of sensors installed in the test pipeline
Sensor Number Quantity Manufacturer
Pressure transducer PX.203-200GSV 3 OMEGA Engineering
Pressure transducer H-68845-68 I Cole-Parmer
Flow meter FP-700 1 1 OMEGA Engineering
Flow meter E-325-00-02 I Cole-Parmer
pH eiectrode PHE-5460 1 OMEGA Engineering
pH electrode E-27003-00 I Cole-Parmer
Temperature sensor NIA 2 Kai Wah Tang
7,2,6 Installation of the Sensors
The problem of mounting the senson becarne the most time consumhg aspect of construction. AAer carrful
consideration, it war decided that the ben solutios would be to construct thne bypass lines in which to install
the senson (Figures AS, A.6, and A.7 in Appendix A). This configuration would solve a nurnber of problems,
but is by no means an ideal solution. Each bypass consists of a length of 1.25-inch galvanized steel pipe, male-
threaded on both ends. Bal1 valves are attached on both ends, and these bal1 valves are co~ected to elbow
fittings, which are then co~ected to saddles that are attached to the main PVC pipe. Therefore. two 1.25-inch
holes need to be drilled in the PVC pipe where the saddles are located. Holes of different size are drilled in the
steel pipe to allow insertion of the sensoa. The pressure and temperature sensors present no problems since
they are threaded and have a fairly small diameter. n i e pH sensors can aiso be attached to the bypasses, but the
hole needs to be larger than for the pressure sensoa. As expected, this larger hole caused a pmblem with leaks.
To repair the leaks, the steel housing for the sensor was welded to the steel pipe. This configuration still allows
for rernoval of the pH senson.
The Project: Progras of the SmartPipe Projecf
One of the problems with the bypass configuration is that it cannot accommodate the flow sensors. The
housing for these sensors are made of PVC and the diameter is quite large. Therefon, they cannot be installed
into the bypass lines, and must be installed directly into the main PVC pipe, using custom-built sensor
housings. Because of the relatively thin pipe wall and the relatively large size of the tapped hole, excessive
leaking occurred when pressure was applied to the system. Temporarily, the flow sensors were removed and
saddles were used to close off the holes. To solve the problem it was necessary to use a PVC weld to join the
sensor housing to the main PVC pipe. Despite this seemingly complex arrangement, the fiow sensors are still
removable.
The by-pass will allow the flow to be shut off so that the sensors cm be removed or repIaced without the need
to drain the entire system. Unfominately, since the flow meters need to be installed directly into the main PVC
pipe, these sensors cannot be removed without draining the system. Although the by-pass lines work well for
sensor installation at this stage in the project, a different configuration will have to be devised for the
SmartConnector.
7.2.7 Caiibration of the Sensors
Calibration of the pH sensors was conducted by Kai Wah Tang and Jiyang Chen in the Environmental
Engineering Laboratory at the University of Toronto. Before calibration of each pH rneter, the electrode must
be immersed in tap water and then immened in a commercially available standard solution of known pH. The
output voltage signal of this solution of known pH cm be read using a voltmeter (Standard Methods 1995).
Calibration of the pressure transducers was conducted using readings of the independent pressure gauge in the
test pipeline. The results of this calibration can subsequently be used to determine whether the sensor
rneasurements have drifled fiom the original. For a more detailed discussion of the calibration of these sensors,
the reader is referred to the report by Kamey et al. (1 997).
The Project: Progress of the S m d i p e Project
7.2.8 Operation of the Test Pipeline
Since the test pipeline draws its water supply From the plant's main supply, which is also used for
manufacauing, it is recommended that care be taken during operation. Experience has show that operating the
systern at a high pressure and flow rate significantly reduces the supply of water to the nearest production line.
The goal is to avoid interfenng with production at the plant and so care is required.
Avoiding entrapped air in the system is also important. Air trapped in the system can cause pipe blowouts,
excessive leakage, pipe breaks, and darnage to sensors. To avoid trapping air in the system, it is recommended
that the process of filling the pipe be done gradually by opening the valve on the supply line. While the system
is filling up, both the control valve and the resûicting valve should be in the fùlly open position. The pressure
relief valve can be used to bleed off air in the system periodically as the restricting valve is slowIy closed to
build pressure. Controlling the flow rate cm be done using either the control valve or the butterfiy valve on the
supply line. In either case, the operator should be carefil not to increase the flow rate without opening the
restricting valve to offset the increase in pressure. Several tests have been conducted using the pipeline. These
tests indicate that the various components of the SmartPipe system (water circulation, sensors, data acquisition
system, control software) are working properly and are interacting as expected. The test pipeline will remain at
the IPEX manufacturing plant in Scarborough, allowing fùrther tests as they are needed.
7.3 STAGE 3: MOVING TOWARDS INTEGRATION
The third stage of development for the SmartPipe project will include a number of sub-projects, each essential
to the success of the whole. A version of the SmartConnector will have to be designed and built, market studies
will have to be performed to identify uses for the SmartPipe, software specific to the SmartPipe system will
have to be developed, and the search for appropriate sensors will need to continue.
Market studies should focus on the information needs of water distribution systems, so that the SmartPipe can
be geared towards the appropriate information. One must also determine the density of SmartPipes necessary in
a distriiution network. This last consideration is of great importance since it will have a significant effect on
the cost of a SmartPipe monitoring system.
The P roject: Progress of the SmartPipe Project
73.1 Data Acquisition System
The next stage in the development of the data acquisition system involves the development of a sophisticated
and user-fiiendly program that both controls and interprets the signals fiom the sensors. The software is
responsible for generating the addressing signals that switch on the appropnate sensors at the appropriate times.
Once the sensors are switched on, their corresponding converted digital signal is connected to the common data
bus lines. The program collects the digital signal, processes the information, and presents the results on the
screen. The data can dso be recorded in data files for fiinire analysis.
Further consideration must be given to what data to rneasure, how often the data should be coHected, and how it
should be stored in data tiles. The needs of water utilities in the operation and maintenance of their dismbution
systems must be considered. Monitoring of certain parameters should be conducted on a continuous basis
whiIe other parameters may require only periodic monitoring. Furthemore, detailed data with a fuie time
resolution are required for analysis of transient events. If a parameter can be considered to be in a quasi-steady
state, values averaged over a defined time interval can be kept in data files as opposed to al1 of the data
collected. Process optimization and sensor comparison/calibration studies can benefit fiom data collected at a
rate of once per minute. Long-terrn process trends can get by with ten-minute or hourly readings for sirnilar
purposes (Karney et al. 1997).
The data acquisition system developed for the test pipeline by Kai Wah Tang is a good begiming. Funher
developrnent and simpIification of this systern must be canied out to make it suitable for field conditions. For
example, distributed data collection centres would be usefbl in a more cornplex system to collect data fkom
sensor locations and transmit the data to a central cornputer. Essentially, these distribution centres would act as
intemiediate nodes to simplify the configuration of the system. Also, a decision must be made concerning the
bea method of data transmission over long distances. Ideas may be gained by looking at how cumnt SCADA
systems are configured.
The Project: Progress of the SmarrPipe Project
7.3.2 Sensors
Searching for more viable senson for the SmartPipe is an important focus of the third stage. Arnperometric
sensors for residual chlorine concentration, and dissolved oxygen sensors might be incorporated at this stage.
One potential problem is that the amperometric senson require signal conditionen to function properly. This
can become costly, and so modification of the senson will be necessary before they are used. The use of tibre
optic senson with the SmartPipe may be feasible. Advances in this field are being made every day, meaning
that accuracy and reliability are increasing while costs are decreasing. A variety of fibre optic sensors are
available ffom manufacturers to measure various parameters such as tiow rate, pressure, pH, chemical
concentration, and strain.
By the end of the third stage there should be some finn decisions made conceming what types of sensors to be
included. Otherwise, production of a proper SmartConnector will not be possible. To create the molding for
PVC fittings, IPEX must spend on the order of a couple of hundred thousand dollars. Therefore, problems with
the SrnartConnector must be worked out in this stage of the project using the "mock-up" prototype.
Special ernphasis should be given to tinding an appropriate chlorine residual analyzer, dissolved oxygen meter,
and strain gauges. Also, the type of flow meter we use needs to be examined carefully. There are many types
on the market but most are not suitable for our purposes. Unfominately, it is doubtfùl whether the fïow rneters
used in stage two will be of use in stage three.
Further investigation rnay indicate that in order to produce a simple and inexpensive SmartPipe we may have to
develop sensors specificatly for use with the SrnartPipe. Coilaboration with a sensor manufacturer could be
investigated to determine the viability of this option. Advantages of such collaboration hclude a decrease in
the tirne required to obtain, calibrate, and install sensors, better and more appropnate senson can be developeci,
and the c o s of senson may be drarnatically reduced. In addition. it is easier to limit or avoid the use of signal-
conditioners.
The Project: Progress of the SmurtPipe Project
An initial concept for the SmartConnector is curently being designed at the University of Toronto. Details of
this design are presented in chapter 6. This housing for the senson must allow for simple, qui& and economic
installation of sensors into the pipe. Developing a SmartConnector with these characteristics wil: be
fundamental to the success of the SrnartPipe system.
It is expected that IPEX Inc. will be able to create a prototype "mock-up" of the connector for a cost of a few
hundred dollars. This prototype can be used to test and modib the design before a proper fitting, costing
hundreds of thousands of dollars, can be manufactured.
7.3.4 Market Studies
This thesis is an initial attempt to detennine uses for the SmartPipe in the context of the operation and
maintenance of water dimibution systems. Curent operation and maintenance procedures for water
distribution systems are discussed in Chapter 3 and a number of possible applications have been discussed in
detail in Chapter 5 .
Only so much cm be discussed about the application of a SmartPipe without defming a specific distribution
system. Each system will have unique requirements, and the SmartPipe needs the ability to adapt.
Requirements for data will Vary, such as the type of data, frequency of measurement, and how the data it is
stored and used for analysis.
Further research is required to prepare a comprehensive document to hand to water utility managers to convince
them of the usefriiness of the SmartPipe. Such a document exceeds the scope of this repoh and will not be
required until the SmartPipe is ready to be installed. However, it cannot hurt to aiert managers to the existence
of the Sinartpipe in the development stage to allow them time to become used to the idea, and also tune to
identifi some of their potential needs. As water utilities must have a good public relations program, we must
have a useful information campaign to keep water utilities abreast of advancemenu in the SrnartPipe project.
The Project: Progress of the SrnartPipe Project
7.3.5 Software Development
Software developrnent is another essential component of the SmartPipe project. Further development of
soRware for data acquisition must take place, focussing on a user-fnendly interface and improvements in the
software for control of data transmission. The expected expansion of the SmartPipe system will require the
development of database systems to manage the enormous amounts of data that will be collected. Funhemore,
linking the SmartPipe with a SCADA system will require codes and utilities for process optimization and
control in a water distribution system. An expert system will also be necessary, with typical operation measures
of a water utility, including the integration of available cornputer programs for analysis of hydraulics and water
quality. Finally, the integration of the SmartPipe concept with inverse transient analysis is expected to
continue.
The development of the SmartPipe is an ongoing project, and does not end here. The project has been carried
out in stages so far. The first stage, conducted by Dr. Kamey and Dari Laine, involved the preparation of a
feasibility study for IPEX Inc. The second stage, coordinated by Dr. Chen, involved the construction a simple
monitoring systern. The bulk of this chapter focusses on the design, construction, and operation of the test
pipeline used for this monitoring systern.
The project is currently in the third stage. where al1 system componenü are undergoing f i e r development.
The fast part of this chapter briefly discusses some of the work being done on these components. It aiso
mentions the need for market midies, and the basics of patent protection. It is envisioned that the next stage of
the project will involve installhg the SmartPipe system into a working water distribution system. Most likely,
the dîstriiution system will be small in scale, such as an irrigation network.
CHAPTER 8
Future Work and Concluding Remarks
Throughout this report, the author has atternpted to introduce the concept of the SmartPipe, and discuss its
application to the water indusûy. The developrnent of the SmartPipe is in its infancy, and a great deal of
research remains to produce an effective monitoring and control system. Sensors must be chosen, the data
acquisition system must be hrther developed, sothvare must be written, and the sensor housing must be
designed and constructed. The test pipeline that has been constnicted at IPEX Inc. will continue to benefit the
project, allowing the team to test the various components of the SmartPipe system. Eventually, the project will
outgrow this apparatus. The operators of an irrigation system have expressed an interest in the SmartPipe
concept, and so perhaps this venue will serve as a testing ground for a SmartPipe prototype.
Even when the technology of a monitoring and control system is fiilly developed and ready for installation,
careful planning is necessary to ensure proper support for the systern and to ensure successful implementation.
Mair (1992) suggests the following steps for the implementaiion of a monitoring and control system:
i. Planning;
ii. Auditing - pre-design stage;
iii. Final design stage;
iv, Construction stage;
v. Commissioning; and
vi. Maintaining.
The SmartPipe project is presently in the planning and pre-design stages. The equipment for the system wiii
soon reach the stage where it may be instailed into a distribution system in a limited capacity to test some of its
capabilities. However, M e r design is needed after this initial test before construction of a fuli-scale system
can be considered.
The Project: Future Work und Conciuding Remurks
The work that has been conducted to date serves as a solid foundation for future development. Many lessons
have been leamed with respect to sensor installation. sensor types, data acquisition, and system applications.
The experience gained during these first stages will be invahable as the project progresses.
8.1 FUTURE RESEARCH
By the time the project has progressed beyond the third stage, it is hoped that a complete package is ready to
install into a firnctional distribution system. The hardware and software components of the data acquisition
system will need to mature sufficiently to allow access to monitored data and the integration of hydraulic and
water quality rnodelling. Also, the configuration of the SmartConnector should be finalized, and the types of
data to be monitored should be known. However, certain aspects of the SmartPipe system, such as the method
of data transmission, and the design of the access chamber, may not yet be finalized at this later stage. When
the SmartPipe is installed in a distribution system, extensive testing and verification of the system will need to
take place.
At present, the central computer is used for controlled rneasurement, data collection, data processing, and
graphical display. In the future, it is hoped that the information collected by the computer may be used for
optimization and on-line control of system components by incorporating a SCADA system with the SmartPipe
system. Indeed, the SmartPipe systern wiI1 need to be integrated with other information systems used by water
utilities, such as automated mapping systems, automatic control systems, customer information systems (CIS),
materials management information systems (MMIS), water consumption information systems (WCIS), work
management systems (WMS), and large meter maintenance (LMM) (Giibert and Jacobs 1992).
ûther areas for research and development that will bring about benefits of irnproved water service and lower
power, labour, and capital costs include (Cam et al. 1992):
Additional cntical gradient measurements;
Single phase electric power detection relays;
Treamient plant process control;
Set point control of flow rate controt valves;
Expansion of Data Acquisition Radio multiple address system; and
Data transfer to the relational database at the mainframe computer.
The Projecl: Future Work and Concfuding R e m a h
It is important to have integrated information systems available to al1 those responsible for operation of the
water utility. Unfortunately, there is a tendency to allow each operating unit to develop independent
applications for their individual responsibiIities. Such an arrangement will satisv immediate needs but not the
overall needs of the distribution system (Carns et al. 1992). It is also important for the SmartPipe system to
have a high degree of standardization, which aids in troubleshooting system components. It also increases the
on-line capability for remote locations. To ensure a standardized system, a minimum number and type of
materials should be used in construction (Orth et al. 1997).
Finally, a great deal of study should focus on the types of senson suitable for the SmartPipe. Sensor
technology is continually being updated, and so the team will need to keep abreast of these changes. The
selection of appropriate senson should be conducted using the following criteria: cosr e u e of installation and
replacement, ease of calibration, dependability, reliability, accumcy, stability. and repeatability. As mentioned
previously, fibre optic sensors are an exciting field of study, and these sensors may be of use for SmartPipe
applications. Of course, the cost of these senson will have to corne down substantially before their use can be
seriousiy considered.
8.2 KEY PROBLEMS TO BE ADDRESSED
Although a great deal of work has already been done by a number of individuals to conceptualize and realize
the SrnartPipe concept, many probIems or questions stiil remain in a number of areas. Table 8.1 lists some of
these problems or questions, categorized according to the stage of development: design, implementation. and
operation.
The integration of the SmartPipe with a distribution system is an important problem that requires creative
solutions. One difficulty stems from the fact that distribution networks are located aimost exclusively
underground. Either the SrnartPipe will have to be underground also. or a branch line cm be constructed to
bring the water to the surface. However. the latter arrangement is problematic since the SrnanPipe components
would be more susceptible to environmental conditions. In addition, the conditions in a branch Iine may not be
the same as those in the main pipe. Since the purpose of the SmartPipe is to obtain accurate and reliable data on
distriiution system operating conditions, this consideration is very important.
The Project: Future Work and Concluding Rem&
TABLE 8.1 Problems and questions to be addressed during development of the SmartPipe concept
Design
How will access to the SmartPipe be achieved afler implementation for operation and maintenance How will components be protected from harsh environmental conditions (i.e., temperature and humidity) How are costs defined (Le, design, manufacturing, implementation, operation, maintenance) What operational and regulatory requirements are changing that will affect the SmartPipe How will the instrumentation and its configuration change depending on the size of the pipe, its use, its location in the network. and unique characteristics of a particular distribution system How wilI data be retrieved from the remote monitoring location and transmitted to the central monitoring station How will sarnpling ports be designed to ensure a representative sarnpting is obtained How much consideration should be given to the durability of the sensors that are chosen How will a fibre optic camera (for intemal inspection of pipes) be integrated into the SmartPipe
lm plementation
What percentage of pipes in a distribution system require SmartPipe capabilities How should they be distributed in a network to yield the maximum benefit How will data transmission lines be installed and maintained Tests should be perfomed to determine the extent to which sensors impact each other How wiIl power be supplied to the remote monitoring locations How wiI1 the SrnartPipe system change depending on its complexity
a The remote monitoring Iocations should be uniquely defined by a catalogue number that denotes its purpose and characteristics, size, date installed, type of pipe connection, and sensor types
Operation
How wiil the sensors be calibrated and recdibrated How ofien will calibration and/or replacement of sensors be necessary Problems may arise with fouling and phgging of equipment and smpling ports due to particdate matter in the water
The Project: Future Work and Concluding Rernarkis
If the SmartPipe is installed underground, an access chamber will need to be built so that maintenance
personnel can access the SmartPipe to calibrate or replace senson. restock chernical reagents, and otherwise
ensure the smooth running of the system. The excavation cost of installing access chambers throughout a
distribution system is very high. To reduce this cost, a utility may install sorne access chambers concurrent
with other maintenance work, such as main rehabilitation or replacement. When possible, the utility should try
to install the SmartPipe in the shallowest parts of the distribution network to Ciirther reduce excavation costs.
Finally, the actual SmartConnector should be relatively easy to install and remove; perhaps using flanged
connections with adjoining pipes.
Periodically, a water system somewhere in the world will suffer problems due to pathogenic microorganisms
that have somehow eluded the treatment process. The most notorious pathogens are the protozoa Giwdia and
Cryptosporidium, which are very difficult to kill or inactivate. Often the first indication of a problem is the
outbreak of widespread sickness in the population, such as the 1993 Crypmsporidium outbreak in Milwaukee
where 400,000 people were affected (Fox and Lytle 1996), or the recent outbreak in Sydney, Australia. The
water industry has decided that waiting for problerns of this magnitude to manifest, is inadequate. However,
monitoring potable water for Giardia and Cryptosporidium is dificult and costly, although new techniques of
detection are k ing researched. It is hoped that the SmartPipe may assist utilities to detect these pathogens by
supplying representative sarnptes of potable water for analysis in a Iaboratory.
The Project: Fume Work and Concluding Rem&
8.3 FINISHED PRODUCT
Development of the SmartPipe needs to continue to produce a commercially available product. A good suvt
has been made by the University of Toronto and IPEX Inc. The ultimate goal of the SmartPipe project is to
develop a product chat a water utility can install in a distribution system with relative ease that will provide a
range of data for a variety of applications. It is intended that utilities will use this information to improve their
maintenance and repair prograrns, improve operations, and gain a better understanding of their distribution
systems. In the end, the goal is to help utilities to improve the quality and reliabiiity of their water supply to
customers, while at the sarne time reduce expenditures.
It is hoped that the SmartPipe will hetp to improve, and indeed change, the current situation of water supply in a
profound way. This change will be accomplished using the information collected by the SmartPipe system to
provide a cornprehensive analysis of hydraulics and water quality in the system. The problem with many
monitoring systems today is the Iack of integration with the existing distribution network. The aim of this
project is to develop a system that is fùlly integrated. The SrnartPipe will link a SCADA system with a
hyâraulic mode1 of the network for calibration and performance evaluation. Existing SCADA systems do not
incorporate this feature, and do not have the density of data required for such analyses.
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Mays, L. W. "Water distribution system infrastructure analysis." Wat. Resources Updaie, No. 86. 199 1.
pp. 20-22
Ministry of the Environment. Wafer Distribution ~vsrm Operation and Maintenance. Her Majesty the Queen
in Right of Ontario as Represented by the Minister of the Environment, 1979.
Vercruyssen, P., K. G. Culley, G. O. Cosgriff, M. F. Prior, C. Nagura and T. Ihara. "Remote Reading of
Water Meters." Water Supply, Vol. 9, No. 314, 199 1. pp. SS 14- 1 - SS 14-5
Von Radar, J. E. "Telemetric control of water distribution systems." J. A WWA, Vol. 75. No. 1 1, 1983.
pp. 542-549
Walski, T. M., G. Iohannes and J. W. Sjostrom. Water Distribution Systems: Simulation and Sbing. Lewis
Publishers, Inc.: Chelsea, Michigan, 1990.
APPENDICES
APPENDM A
Details of the Test Pipeline
A.l DESIGN DRAWTNGS
A detailed description of the design and construction of the test pipeline is presented in Chapter 7. Included
below are a number of detail drawings of the test pipeline, showing elevation. plan, schematic, and details of
the sensor mountings. A list of these figures with a description of their content is included in Table A. 1.
TABLE A.l List of figures describing the test pipeline
Figure Description Page
A. 1 Schematic of the test pipeline A.2 Details of the inlet of the pipeline A .3 Details of the outlet of the pipeline A.4 Schematic of the data acquisition system AS Detail drawing of sensor location 1 A.6 Detail drawing of sensor location 2 A.7 Detail drawing of sensor location 3
Details of the Test Pipeline
FIGURE A. 1 Schematic of the test pipeline
FIGURE A.2 Details of the inlet of the pipeline
- Fmm ntppiy
1- 90 Dyrer d b w b- To d m n
1" bbba h o r
Details of the Test Pipeline
FIGURE A.3 Details of the outlet of the pipeline
4" WC Hot
W C A ~ r Fluip
FIGURE A.4 Schematic of the data acquisition system
(a) S a d i q commamis m unnie S a w r A m y *I (b) Rccriving sgnib fiom Saaor Aaay Ul
REVOTE SEMOR UNI'IS I
I
COMMAND CENTRE
Detaiis of the Tkst Pipe fine
FIGURE A.5 Detail drawing of sensor location I (pipeline in let)
FIGURE A.6 Detail drawing of sensor location 2 (middle of pipeline)
Details of the Test Pipeline
FIGURE A.7 Detail drawing of sensor location 3 (pipeline outlet)
Details ofthe Test Pipeline
A.2 PARTS LISTS
A.2.1 Bill of Materials
n ie bill of materials (Table A.2) accompanies the above design drawings. Listed are al1 parts requhd in the
construction of the test pipeline, including the name, specitications, and quantity of each part, but without the
costs. It should be noted that whiIe a complete bill of materials was prepared before construction began, certain
changes were made to the design of the apparatus during construction, particularly for the support of the pipes
and elbows. This tist reflects these changes, showing exactly what materials were used in the construction.
A.2.2 List of Sensors
Table A.3 lists the sensors installed in the test pipeline, while Table A.4 is a list of the approximate costs of the
sensors and certain other apparatus related to the data acquisition system. Finally, Table A.5 lists the parts
required to mount the sensors to the PVC pipe.
Details of the Test Pipeline
TABLE A.2 Bill of Materials
Part Name S peci fications QtY* Mati.
Pipes and Hose:
1 4" PVC pipe
2 4" PVC pipe
3 4" 90' elbow
4 4" PVC hose
5 1" mbber hose
PVC PVC pressure pipe. A WWA C-900 class 150 (DR1 8) Length = 15 feet (chamfered at both ends)
As per part 1, length = 1'2"
Blue Brute Fining A WWA C-907 class 150 (DR1 8 )
Hose Cat. No. FB-03-064.2 sections inlet hose = 35 feet, outlet hose = 24 feet
Length = 35 feet 1 Ru bber
PVC
PVC
PVC
Connections:
6 Flange
7 Flange adaptor
8 Special adaptor
9 4" Nipple
10 1" Nipple
1 1 1" 90" elbow
4" Met/Outlet pipe To connect flange adaptor to vaIves and fittings
To connect 4" PVC pipe to flange
To connect 4" PVC hose to 4" PVC supply pipe
C.I.
PVC
PVC
Steel
1
Male-threaded one end, female-threaded one end 1
(Table A.2 continued on next page)
Steel
C.I.
Details of the Tesi Pipeline
TABLE A.2 (continued from previous page)
Part Name Specifications QtY- Matf.
Valves and Fittings:
12 4" Gate valve Regulating valve, restricting valve - 3 B rass
13 1 " Bali valve Drainage valve 1 Brass
14 Relief valve Relief pressure = 1 50 psi 1 Bras
15 Pressure gauge 1 -
16 Tee fitting 4 " x 4 " x 1" 1 C.I.
Frame:
17 Base plate Designation MC460 x 86, length = 1 .O foot 3 Steel (depth = 18". width = 4.2", thickness = 0.25")
18 Structural tee Designation WT65 x 12, length = 8 feet 6 Steel (width of fianges = 2 9 , thickness = 0.25")
19 Stnictural tie (width = 2.5". thickness = 0.25"). length = 1.5 feet 12 Steel
20 Structural tie As per part 17. length = 6.5 feet 8 Steel
21 Stnit Guide for straps (length = 8 feet). depth = 1 2 ' 2 Steel
22 Strut As per part 18, depth = Y4" 1 Steel
23 Strap Hoop diameter - 5.625 inches 10 Steel
24 Strap Hoop diameter = 4.0 inches 5 Steel
25 CIampUsed to hold pipes and eibows together 16 C.L
26 Bracket 1 For support of the regulating valve 1 Steel
27 Bracket 2 For support of the restricting valve 1 Steel
28 Threaded rod Diameter = 38". length = 15" 17 Steel
(Table A 2 continued on next page)
Detaiis ofthe Test Pipeline
TABLE A.2 (continued from previous page)
Part Name Speci fica tions QtY- Mat!. - - -
By-passes:
29 1%'' Bal1 valve Used to shut off flow to the sensors in the by-pass 6 Brass
30 1%'' Saddle 6 Brass
3 1 1 !4" Steel pipe Threaded at both ends. length = 0.36 metre 3 Steel
32 1%'' Union 6 Steel
33 1 W 90" elbow Male threaded at both ends 6 Steel
TABLE A 3 List of sensors installed
Sensor Type Location Notes
Pressure PH Flow Temperature Pressure Pressure Pressure PH Flow Temperature
Near pipe inlet With pressure snubber P S 4 E New pipe idet Near pipe inIet Near pipe inlet Same hoIefthread as pressure snubber Mid-pipe With pressure snubber PS4E Mid-pipe With pressure snubber 68800-82 Near pipe outlet With pressure snubber PS4E Near pipe outlet Near pipe outlet Near pipe outlet Same hole/thread as pressure snubber
Details ofthe Test Pipeline
TABLE A.4 Estimated cost of sensors and additional material
Item Reference No. PriceAJnit (US%) Quantity Cost (Um
Pressure transducer Pressure msducer Flow sensor FIow sensor pH electrode pH electrode Temperature sensor A/D Converter Cable Addressor Module switch Additional software Miscellaneous Power supply
#OM EGA-P-2 #Co leparmer-P- 1 #ColeParmer-Q- 1 #OMEGA-Q- 1 #ColeParmer-pH- 1 #OMEGA-pH- 1 #Kai Wah-T- 1 #Kai Wah-ND- 1 #Kai Wah-Cable- l #Kai Wah-DAS-AG M a i Wah-DAS-MS #Kai Wah-DAS-SW #Kai Wah-MS #Kai Wah-PS-B
TOTAL US!§2,132
Details ofihe Test Pipeline
TABLE A S Lia of parts required for installation of sensors
Part Quantity
E-27003-00 (pH) ?4" female threaded coupling l/r" male and femaie threaded snubber w plug %" NPT holes in pipe
PHE-5460 (pH) 'A" pIug
E-325-00-02 (Flo W)
1 'A" fernale coupling 1 W' to W' male to fernale reducer 1 'A" pipe 1 W NPT plug I W NPT hole in pipe
PX203-200G5V, H-688 45-68 (Pressure) 1 !4" NPT plug 11/41? NPT hole in pipe
FP-7001 (Flow) Specia! fitting ordered from OMEGA
Defails ofthe Tèst Pipeline
A.23 Description of Sensors Installed
The sensors instdled in the test pipeline were obtained from OMEGA Engineering Inc. and Cole Parmer Inc. A
detailed description of the sensors follows:
Table A.6: OMEGA thin film voltage output pressure sensor
TabIe A.7: Cole-Pmer industrial pressure transmitter
TabIe A.8: OMEGA paddle-wheel flow sensor
TabIe A.9: Cole-Pmer rotor-X paddle-wheel flow sensor
Table A. 10: OMEGA industrial pH electrode
TabIe A. 1 1 : Cole-Parmer gel-filled pH electrode
The temperature sensors used for the test pipeline were designed and built by Kai Wah Tang. The sensor
consists of a thermistor (a temperature-sensitive resistor) and an electronic circuit. The electronic circuit, in
conjunction with the thermistor. converts the varying resistance signal of the themistor to an equivalent DC
voltage. The output voltage signal of the temperature sensor can be transrnitted to a measuring device. The
relationship between resistance and temperature is linear, as is the relationship between output voltage and
temperature. The body of the temperature sensor is a male-threaded %" NPT cap in which the thermistor and
the circuit and embedded (Karney et al. 1997).
TABLE A.6 OMEGA thin film voltage output pressure sensor
Model number Range Excitation Accuracy output Zero balance Span Etecûicai connections Operating temperature Response time Dimensions Price WUing
PX203-200GV O to 200 psi 24 Vdc @ 15 mA (12 to 36 Vdc) 0.25% FS 0.5 to 5.5 Vdc 5 Vdc + 75 mV 5 Vdc 2 75 mV 36" shielded konductor cable -20 to 85°C l msec 3.87" length, 1.07" diameter $239 + % 10 for PS4E pressure snubber for water +EXC RedPin 1; COMMON BlackIPin 2 + OUT White/Pin 3
Details of the Test Pipeline
TABLE A.7 Cole-Parmer Industrial Pressure Transmitter
Mode1 number Range Power Accuracy Output Dimensions Temperature range Price
H-68845-68 O O to 200 psig
10 to 32 Vdc 2 5% BFSL
O 1 to 5 V (Transmitters) m 3 W length, IV diameter 0 -18 to 71°C O $292 + $8 for pressure snubber H-68800-82
TABLE A.8 OMEGA Paddle-wheel Flow Sensor
Mode1 number Accuracy Connections
Power Wetted materials
Restrictions Frequency output
Cable length
r, FP700 1 œ 2 2 % r Black = GROUND (both pulse output and C power input)
Red = 5 to 18 Vdc (power input) White = Frequency signal output (high) Green = No connection 5 to 18 Vdc@ 10 mA maximum
r Polypropylene body (PVDF) and PVDP paddle, Viton O-ring, 3 16SS shaft
rn For PVC fittings, do not exceed 100 psig @ 38°C Nominal 1 Hz/fps (amplitude of open collecter pulse = output power)
rn 2.4 rn
Detaifs of the Test P@elline
TABLE A.9 Cole-Parmer Rotor-X Paddle-wheel Flow Sensor
Mode1 number H-056 18- 1 1 for 5 to 8" pipes Flow range 1 to 20 fps Maximum temperature 100°C Maximum pressure 180 psi '2j! 20°C Signal r 1 V peak-to-peak per Ws. nominal fiequency of 6 Hz per fps Price $235
TABLE A.10 OMEGA Industrial pH Electrode
Mode1 number 9 PHE-54GO Materials - CPVC. gel-fiIled, double junction combination PH range - O c 0 14 Temperature range 10 to 100°C Maximum pressure O 1 O0 psi :g 76°C Irnpedance Less than 300 megaohrns @ 25°C
TABLE A.l l Cole-Parmer Gel-filled pH Electrode
Mode1 number E-2701 1-10 Temperature range o -3 to 100°C Maximum pressure 0 130 psi Output -100 to JO0 mV (pH I to 13) Price - $ 1 17 (with a 10' cable and BNC connecter)
Derails of the Test Pipeline
A.4 DESIGN CALCULATIONS
For the design of the test pipeline, cenain calculations were necessary. The calculations described below were
performed as suggested in the Handbook ofP VC Pipe: Design and Construction (3rd edirion), published by the
Uni-Bell PVC Pipe Association ( 1 99 1). The following criteria are known or are assurned about the system:
4-inch nominal pipe diameter. A WWA (2-900, DR 18
a Temperature = 73.J°F (23°C)
Given this information the required support spacing for the horizontal pipes can be determined. Also, the
expected head loss in the pipeline should be estimated to ensure that it is large enough to measure.
A.4.1 Determination of Required Support Spacing
Given the above information. and the data in Table 8.6 (Uni-Bell PVC Pipe Association 1991), the maximum
PVC pipe suppon spacing allowed under these conditions is 7.8 feet (2.3 meten). However. we require
supports secured to the PVC pipe on both sides of the pipe joints with the interval between support and joint not
exceeding two feet. The supports should have n jmooth bearing surface that conforms to the bottom half of the
pipe, and which is greater than two inches wide. Also, the supports should permit longitudinal pipe movement,
and should be rigid to prevent lateral or vertical pipe movement perpendicular to the longitudinal axis.
Additionally, any changes in pipeIine size or direction should be adequately anchored
For the test pipeline, the horizontal sections of pipe are 15 feet (4.6 metres) in Iengrh. To provide adequate
Nppon three anchoa are required along the length of each section. with the approxirnate distance between
supports of 6.5 feet (2.0 metres).
a. Calculation of Vertical Displücement with this Support
If the horizontal pipes are supported at each end and in the middle. with the distance between two adjacent
supports not exceeding 6.5 feet (3.0 metres). the maximum vertical displacernent can be calculated as follows:
(Equation 8.27 corn Uni-Bell 1991)
Details of the Test Pipeline
where y, = mid-span vertical pipe displacement (in.) w = weight of pipe filled with water (lbdin.) L = support spacing (in.) E = modulus of elasticity (psi) I = moment of inertia (in.")
(Equation 8.30 fiorn Uni-Bell 1991)
where Do = average outside diameter (in.) Di = average inside diameter (in.) and the speci tic gravities are assumed as (SGpvc = 1.40, SG,, = 1.00).
From Table 8.2 (Uni-Bell 1991): Do = 4.80 in., Di = 4.234 in.
L = 6.5 fl. = 78 in. E = 400,000 psi
y2 = 0.0054(0.7087!b~/in.)(78in.)~ = 0.034 in. (400000psi)( 1 O . Z ~ I . ~ )
Percent of span length = (0.034'78) .u 100% = 0.044 % < 0.2 % Therefore, OK.
Since the vertical displacement is less than 0.2 percent of the length of the span. then this design is adequate.
Three supports along the length of each horizontal pipe are necessary.
b. Calculation of Maximum Bending Stress witb this Support
Similarty, the maximum bending stress can be calculated as foliows:
where Sb = bending stress (psi) M = bending moment (in-lb.) Do = average outside diameter (in.) I = moment of inertia (in.")
(Equation 8.3 1 from Uni-Bell 199 1)
(Equation 8.32 fiom Uni-Bell 1991)
Details of the Test Pipeline
w = load (Ib/in.) L = support spacing (in.)
substituting:
Sb = 1 .273wL2D, (Equation 8.33 from Uni-Bell 199 1) (D; - D;) -
&, = 1.273(0.70871b/in.)(78in. )'(4.80in.) = 125.8 IWin.' (psi) < 800 psi Therefore, OK. [(4.80in.)" - (4234in.)"]
Since the maximum bending stress imposed on the pipe is considerably tess than 800 psi (564 metres of water),
the design is adequate. Therefore, three supports are required along the length of each pipe.
A.4.2 Calculation of Expected Head Loss Through the Pipeline
Calculation of the expected head loss through the pipeline was carried out to ensure that a rneasurable drop in
pressure would exist. The approximate distance of 60 feet ( 1 8.3 rnetres) between the fint and last pressure
sensors shouId provide suficient head loss to be detectable by the sensors.
a. Head Loss Calculation Using Hazen-Williams
(Equation 9.4 from Uni-Bell 1991)
where Q = flow rate = 20 L/s = 3 17 gprn Di = interior diameter of pipe = 4.234 in. C = 150 (consemative estirnate)
When converted to pounds per square inch. the pressure drop can be written as 1.593 psi per 100 feet of pipe.
if there is only 60 feet of pipe between the pressure senson. then the expected headloss would be sixty percent
of this value, or 0.956 psi per 100 feet (0.022 1 rnetres of water per metre of pipe). This calculated pressure
drop does not consider the pipe ben&.
APPENDIX B
Details of the SmartConnector
B.l DESIGN DRAWINGS
The design for the SmanConnector included in this appendix (Figure B. 1 ) is a preliminary design only. Further
refinement of this design wilî be necessary before an actual prototype is constnicted. A detailed discussion of
the design process is inciuded in Chapter 6.
B.2 PARTS LISTS
Table B.l shows how the six holes of the SmartConnector would be utilised, with four senson, a sarnple Iine,
and an extra hole to instal! a chlorine analyser at a future date. Table 8.2 is a list of the parts needed to
constntct a single SmartConnector according to the prehinary design presented in this report,
Detuils of the Smartconnector
FIGURE B.l Chosen design for the SrnanConnector. (a) Longitudinal cross-section showing sensor mounting using reducer bushings; (b ) Axial cross-section showing holes offset at 45 degrees to the vertical
Details of the SmartConnector
TABLE B.l Arrangement of sensors
Location Sensor S u e of Hole Fitting
1 Pressure transducer 20 mm (M") %" x W bushing accornrnodating a W' rnale-threaded pressure transducer
2 Temperature sensor 30 mm (%") %" x !4" bushing accommodating a %" male-threaded temperature sensor
pH sensor
Flow meter
Sample Iine
25 mm (1") 1" x ?A" bushing accornmodating a ?4" housing for the pH sensor
40 mm ( 1 %") 1 !/t" x 1 W bushing accommodating a 1 Yi" housing for the flow rneter
20 mm (%") %" x W' bushing accommodating a !hW stopcock
6 Expansion location 30 mm (Yi") ?A" plug Hole will be available for future use
Details of the SmmConnecror
TABLE B.2 Parts list for the SmartConnector
Part Name and Specifications Req. Matl.
1 SmartConnector (sec Figure D. 1 ) 1 PVC
2 Bushing 2- 1 (%" x %'') 2-2 (%" x y?") 2-3 ( 1 " x 'h") 2-4 ( 1 %" x l 'A")
Plug (W)
C.I. C.I. C.1 C.I.
1 C.I.
4 Stopcock (%") 1 Brass
5 Hose (W x 3 feet ) 1 Rubber
6 Reducing adaptor - Spigot x Bell (6" x 4") 2 PVC
APPENDIX C
Supplier Information
The addresses of some manufacturers and their main products related to the SmartPipe are presented below.
This information is provided for future reference, in the event that someone working on the project is interested
in contacting one of these sensor rnanufacturers.
Automation Controls, Inc. 200 Main Street, Newport News, VA 2360 1 Tel: (757) 599-6884 Product: SCADA systems
Control Microsystems 28 Steacie Drive, Kanata, Ontario. K2K 2A9 Tel: (613) 591-1943, Fax: (613) 591-1022 Product: SCADA systems
Dr. A. Kuntze GMBH Viersener Str. 1-1 1 P.O. Box I 1 06 45. D-40506 Duesseldorf Fax: (2 1 1) 508- 1 150 Products: Instrumentation for water and wastewater applications.
Eisag Bailey (Canada) Inc. 134 Norfinch Dive Downsview, ON Canada M3N 1 X7 Tek (4 16) 667-9800 Fax: (4 16) 667-8469 Website: www.bailey.ca
Hach Company P.O. Box 608, Loveland, Colorado 80539-0608 Tel: (970) 669-3050, Fax: (970) 669-2932 Products: Instrumentation for water and wastewater applications. Senson and electrodes for measurernent of pH, dissolved oxygen, chlorine, ozone. conductivity, and peroxide.
Information Concerning lPEX Inc.
Fryston Canada, Inc. (Representatives of Hach Company in Canada) 7370 Bramalea Road, Suite 30, Mississauga, Ontario L5S 1N6 Tel: (905) 6 12-0566, l-SOO-~87-7SO3, Fm: (905) 6 13-0575
Kyowa Electronie Instruments Co. Ltd. Overseas Department, 1-22- 14. Tonnomon. Minato-Ku, Tokyo. 1 O5 lapan Tel: (03) 3502-3553, Fax: (03) 3502-3678 Products: Strain gauges, pressure transducen, data acquisition systems
Omnitronix (Representative of Kyowa Etectronic Instruments Co., Ltd. in Canada) #1-2 180 Dunwin Dr.. Mississauga. Ontario L5L lC7 Tel: (905) 828-622 i , Fa,: ( 905) 828-6408
Lakewood Systems Ltd. Remote Data Recording Products, Canadian Corporate Eieadquarters 9258-34A Avenue, Edmonton, Alberta T6E 5P4 Tel: (403) 462-9 1 10, Fax: (403) 450-3 867 Products: Pressure transducers, data loggers, remote data recording products
OMEGA Engineering, Inc. P.O. Box 4047, Stamford, CT 06907-0047 Products: Smin gauges, pressure tnnsducers. pH electrodes, flow sensors, temperature sensors, data acquisition system
Omega Engineering, Inc. 976 Bergar Street, Laval, Quebec H7L 5A1 Tel: (5 14) 856-6928. F a : ( 5 1-1) 856-6886
Prairie Digital, Inc. 846 Seventeenth Street, industrial Park. Prairie du Sac. Wisconsin 53578 Tel: (608) 643-8599, Fax: (608) 643-6754 Products: Economic data acquisition sy stems
Rosemount Analytical, Inc. Uniloc Division. 2400 Bananca Pkiv?.. Irvine, CA 937 14 Tel: (714) 863-1 181 Products: Sensors for continuous on-line analysis of pH, conductivity, dissolved oxygen, ozone, chlorine, and turbidity.
Sewer Depot, Inc, 3045 Southcreek Road, Units 42 and 43. Mississauga, Ontario L4X 2x7 Tel: (905) 206-9939. Fax: (905) 206-96 1 1 Products: instrumentation of composite video systems for pipeline inspection.
Smart Pipeline Services, Ltd. 430,700 - 4th Avenue SW, Calgary. Alberta T2P 354 Tel: (403) 237-0093, Fax: (403) 237-6255 Products: in-Iine inspection tools.
APPENDM D
Information Concerning IPEX Inc.
IPEX Inc. is the largest Canadian manufacturer of plastic piping systems for the municipal, industrial,
plumbing, and electrical markets. lPEX has been manufacturing nonmetallic pipe and fittings since 1951,
formulating their own compounds. and maintaining strict quality controls during production. They market and
distribute their products from regional branches throughout Canada. Consequently, they can offer a complete
line of piping, fittings, valves, and cusrorn- fabricated items.
IPEX is a leader in the plastic pipe industry. and has a commitment to continually develop new products,
modernise manufacturing equipment. and acquire inventive process technology. Their staff takes pride in their
work, offering extensive industry knowledge and fieid experience with thermopIastic matenals to their
customers. Products available from IPEX include pressure pipe and fittings for water distribution, flexible
xwer pipe, ngid PVC conduit and tittings. polyethylene pipe for a variety of applications, pipe for dua work,
eiectrical boxes and fuctures, and elrçtrical nonrnetallic tubing and fittings. For fùnher information or specific
deuils about IPEX products, contact tlieir custorner service department.
The Company was Uivolved with the '-Chelsea Lake Lung", a pioneering effort in lake rernediation, by the
partners, Fnends of Chelsey Lake. Ontario Ministry of Environment and Energy (MOEE) and PEX Inc. It will
dramaîically raise oxygen levels and virtually stop bluegreen algae pollution which has traditionally closed
many lakes throughout the province.
IPEX serves customers in Ontario. Atlantic Canada. Quebec. Western Canada. U.S. Northeast, U.S. West, U.S.
Midwest, U.S. South, Caribbean. Pacitïc Rim. and Latin America, and is interested in expanding to serve the
growing African market.
Information Concerning IPEX Inc.
Contact Veso Sobot, Director o f Sales and National Marketing and Product Development Manager at
[email protected], IPEX also has a website Iocated at www.ipexinc.com.
Vancouver 20460 Duncan Way, Langley, British Columbia V3A 7A3
(604) 534-863 1 TOLL FREE (800) 663-5864 FAX (604) 534-76 16
Calgary 77 10 - 40" Street S.E., Calgary. Albcw T2C 3S4 e (403) 236-8333 FAX (403) 279-8445
Edmonton 4225 - 92* Avenue, Edmonton. Alberta T6B 3 ~ 1 7
(403) 468-4444 FAX (403) 465-56 17
Saskatoon 61 1 -47"' Street East, Saskatoon. Saskatchewan S7K SG5
(306) 933-4664 FAX (306) 924-2020
Winnipeg 208 1 Logan Avenue West, Winnipeg. Manitoba E R OJ 1 le (204) 633-3 1 1 I FAX (204 633-3075
Toronto 68 10 Invader Crescent, Mississauga. On tririo L 5T ZB6 f (905) 670-7676 TOLL FREE ( 800) 363-4343 FAX (905) 670-5295
Montreal 6665 Chemin St. Francois, St. Laurent. Quebec H4S 1 B6 f (5 14) 33 7-2624 TOLL FREE I QOO) 363-4343 FAX (5 14) 337-7886
Saint John P.O. Box 127, Grandview Industrial Park. Saint John. New Brunswick E2L 3x8 n (506) 633-7473 (PIPE) roLL FREE (800 j 56 1-7473 (PIPE) FAX (506) 633-8720
SC. John's P.O. Box 13247, Station A, St. John's. New foundland A 1 0 JAS 4 (709) 747-7473 (PIPE) F.-IS (709) 365-9 I 1 1
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