Pipeline Toolbox Liquid - Technical Toolboxes · Accidental Release from Liquid Hydrocarbon Pipeline ... Pipeline Toolbox Liquid 2013 2 ... relates to steel pipelines installed using

Pipeline Toolbox Liquid

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Table of Contents

API - 1117 Movement of In-Service Pipelines ............................................................................... 1

API 1102 - PC PISCES ................................................................................................................... 5

API 1104 - Appendix A: Weld Imperfection Assessment ............................................................ 23

API 2540 - Volume Correction Factors ........................................................................................ 25

ASTM 2161 cSt/Saybolt Viscosity API/Baume/Specific Gravity Conversion ............................ 27

Accidental Release from Liquid Hydrocarbon Pipeline ............................................................... 29

Adiabatic Bulk Modulus for Hydrocarbons .................................................................................. 31

How to Export Report in Adobe Acrobat? ................................................................................... 33

Buoyancy Analysis and Concrete Coating Thickness .................................................................. 41

Buoyancy Analysis and Concrete Weights Spacing ..................................................................... 43

Cathodic Protection Attenuation Calculation ............................................................................... 45

Centrifugal Pump - Affinity Laws ................................................................................................ 49

Compressibility Factors for Hydrocarbons: 0-90 API .................................................................. 53

Darcy - Weisbach .......................................................................................................................... 57

Dead Load on PE Pipe - Prism, Marston and Combined Load .................................................... 59

Distributed Static Surcharge Load Directly over Buried PE Pipe ................................................ 63

Distributed Static Surcharge Load not over Buried PE Pipe ........................................................ 67

Document Management System ................................................................................................... 71

External Applications Integration ................................................................................................. 87

Flume Design ................................................................................................................................ 95

Design of Uncased Pipeline Crossings ....................................................................................... 109

HDD PE Pipe - ATL Allowable Tensile Load During Pull-In Installation ................................ 117

Pipeline Toolbox Liquid 2013

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PE Pipe - Post-Installation Stress Analysis ................................................................................. 119

PE Pipe - Pull Force and Installation Stress Analysis................................................................. 121

Installation of Pipelines by Horizontal Directional Drilling ....................................................... 141

Internal Design Pressure - Steel Pipe .......................................................................................... 143

Internal Pressure % SMYS ......................................................................................................... 145

Live Load: AASHTO H20 Load on Buried PE Pipe - 12" Thick Pavement .............................. 151

Live Load: AASHTO H20 Load on Buried PE Pipe - Flexible or no Pavement ....................... 155

Live Load: Aircraft Load on Buried PE Pipe ............................................................................. 159

Live Load: Cooper E-80 Railroad Load on Buried PE Pipe ....................................................... 163

Live Load: Distributed Surface Load on Buried PE Pipe - Unpaved Road Only (Timoshenko's

Equation) ..................................................................................................................................... 167

Live Load: Multiple Wheel not over Buried PE Pipe - Concentrated Point Load ..................... 171

Live Load: Multiple Wheel over Buried PE Pipe - Concentrated Point Load ............................ 175

Live Load: Single Wheel over Buried PE Pipe - Concentrated Point Load ............................... 179

Local Atmospheric Pressure ....................................................................................................... 183

Maximum Impact Load and Penetration Depth .......................................................................... 193

Modulus of Soil Reaction (E') - Average Values for Iowa Formula .......................................... 195

Modulus of Soil Reaction (E') - Values of E' for Pipe Embedment ........................................... 197

Nominal Wall Thickness Straight Steel Pipe .............................................................................. 201

How to Export Report in Microsoft Outlook Express? .............................................................. 205

Pack in Pipelines ......................................................................................................................... 207

Pipe Requirements for Horizontally Drilled Installation ............................................................ 213

Pipe Wall Compressive Stress (PE Pipe Crushing) .................................................................... 217

Pipeline Anchor Force Analysis ................................................................................................. 219

Table of Contents

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Pressure Wave Speed in Pipe ...................................................................................................... 243

Centrifugal Pump - Specific Speed ............................................................................................. 245

Pump Station Piping - Pipe Diameter and Velocity.................................................................... 247

Reciprocating Pump - Acceleration Head ................................................................................... 251

Reciprocating Pump - Displacement and Actual Capacity ......................................................... 253

Reciprocating Pump - Piston Rod Load...................................................................................... 255

Reinforcement of Welded Branch Connection ........................................................................... 259

Relief Valves - Reactive Force ................................................................................................... 271

Required Pump Horsepower ....................................................................................................... 275

Restrained Liquid Pipeline Stress Analysis - Steel Pipe ............................................................. 279

Sizing for Liquid Relief: Relief Valves Not Requiring Capacity Certification .......................... 291

Sizing for Liquid Relief: Relief Valves Requiring Liquid Capacity Certification ..................... 293

Spangler's Modified Iowa Formula for PE Pipe ......................................................................... 295

Suction Specific Speed ............................................................................................................... 303

Surge Analysis - Water Hammer ................................................................................................ 305

Technical References .................................................................................................................. 319

Temperature Rise Due to Piping ................................................................................................. 321

Track Load Analysis ................................................................................................................... 325

Unrestrained Liquid Pipeline Stress Analysis - Steel Pipe ......................................................... 333

Values of E'n - Native Soil Modules of Soil Reaction ............................................................... 335

ASTM D 341 - Viscosity Temperature Relations for Hydrocarbons ......................................... 337

Wheel Load Analysis .................................................................................................................. 339

How to Export Report to Microsoft Word? ................................................................................ 347


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1

API - 1117 Movement of In-Service Pipelines TOTAL LONGITUDINAL STRESS

The total longitudinal stress in the pipe can be estimated

With the following equation:

Where:

API 1117 Movement of In-Service Pipelines

LONGITUDINAL TENSILE STRESS DUE TO INTERNAL PRESSURE

The longitudinal tensile stress in the pipe due to internal pressure may be estimated with the following equation:

Where:

LONGITUDINAL TENSILE STRESS DUE TO TEMPERATURE CHANGE

The longitudinal tensile stress in the pipe due to a change

in the temperature may be estimated with following

equation:

Where:

If the pipe's temperature at installation time is not known, it should be reasonably estimated.


2

LONGITUDINAL FLEXURE STRESS DUE TO EXISTING ELASTIC CURVATURE

When a pipeline is laid to conform elastically to a given trench profile, the pipeline will experience induced flexural stress in amount proportional to its curvature. In hilly terain, where slopes are unstable, or where soils are subject to frost heave or liquefaction, the pipeline is likely to experience stress of unpredictable and varying magnitude. This stress

(S )can range from near-yield-strength levels in tension to near-bulking levels in compression. This existing stress should be considered prior to a movement operation. EXISTING LONGITUDINAL STRESS

The existing longitudinal stress in a pipeline will normally be in the range of-10,000 psi to 20,000 psi. In the flat or gently rolling terrain where soils are not subject to frost heave or liquefaction, the pipeline will experience only the longitudinal tensile stress due to internal pressure and temperature as discussed above. The existing longitudinal stress in the pipe may be estimated

With following equation:

Where:

S = longitudinal stress in the pipe due to existing elastic curvature, in psi. LONGITUDINAL STRESS DUE TO BENDING

The longitudinal stress in the pipe due to bending may be

estimated with following equation:

Where:

w = net uniformly distributed load required to achieve the desired mid-span vertical

deflection of the pipe [not full weight of the pipe and fluid], in pounds per inch.

L = minimum trench length required to reach the mid-span vertical deflection of the pipe

, in inches.

S = elastic section modulus of the pipe, in inches . LONGITUDINAL STRESS DUE TO ELONGATION

The longitudinal stress in the pipe due to elongation caused by the movement operation may be estimated with the following equation:

Where:

= mid-span deflection of the pipe, in feet.

L = minimum trench length required to reach the mid-span deflection of the pipe , in feet.

API - 1117 Movement of In-Service Pipelines

3

The effects of this stress may be offset by an elastic compressive stress existing in the pipeline prior to the moving because of slack. AVAILABLE LONGITUDINAL BENDING STRESS

The longitudinal stress available for bending may be estimated with the following equation:

Where:

S = longitudinal stress available for bending, psi.

F = design factor. SMYS = specified minimum yield strength of the pipe, in psi. TRENCH LENGTH

The minimum trench length required to achieve a particular mid-span deflection of the pipe without exceeding the longitudinal stress limit can be determined with the following

equation, based on elastic free deflection theory, which treats the pipe as a single-span beam that is fixed at both ends andthat has a uniformly distributed load:

L=

TRENCH (OR DISPLACEMENT) PROFILE

A profile for the moved portion of the pipeline should be designed to minimize induced bending stress concentrations. Therefore, to obtain acceptable longitudinal stress distribution due to bending, the deflection at any point along the trench profile can be determined with the following equation:

Where:

= vertical deflection of the pipe at distance x, in feet. x = distance along the length of the trench from the

starting point of the pipe deflection, in feet. SUPPORTING SPACING

Based on a four-span, uniformly loaded beam, the maximum free span between supports can be determined with the following equation:

L =

Where:

L = maximum free span between pipe supports, in feet. d = inside diameter of the pipe, in inches. Reference: API RP 1117 "Movement of In-Service Pipeline", Second Edition, August 1996 Technical Toolboxes, Inc.

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API 1102 - PC PISCES A.) PROGRAM SCOPE

API 1102 - PC PISCES (Personal Computer Pipeline Soil Crossing Evaluation System Liquids) program is based on the design methodology resulting from the research and has been implemented in the program to aid pipeline designers in analyzing existing uncased pipelines and designing new uncased pipelines that cross beneath railroads and highways. The details of the full design methodology can be found in “Technical Summary and Database for Guidelines for Pipelines Crossing Beneath Railroads and Highways” (GRI-91/0285, Final Report) and should have been read and understood. The design methodology used in program follows directly the approach given in API RP 1102. Concise summaries of the Cornell/GRI Guidelines are given in “Guidelines for Pipelines Crossing Beneath Highways” (Stewart, et al., 1991b) and “Guidelines for Pipelines Crossing Beneath Highways”. API RP 1102 should be available to the user for additional documentation and preferences, and supplement the information provided by the program help and graphical display of the design curves. This design methodology relates to steel pipelines installed using trenchless construction methods, in particular auger boring, with the crossing perpendicular to the railroad or highway. The design methodology used in the program is such the pipelines having diameters of D = 2 to 42 in. (51 to 1067 mm) can be analyzed. The wall thickness to diameter ratios must be within the range of tw/D = 0.01 to 0.08. Railroad crossings can be analyzed for depths of cover H = 6 to 14 ft (1.8 to 4.3 m). Highway crossings can be analyzed for depth of cover H = 4 to 10 ft (in accordance with API 1102) and H = 3 to 10 ft (PC-PISCES). The loading condition for railroads if based for four axel distributed to the track surface, and would develop from the trailing and leading axles sets form sequential cars. Highway loadings are based on both single and tandem-axle truck loading configurations. B.) LIST OF SYMBOLS/TERMS

Bd - Bored diameter of crossing

Be - Burial factor for circumferential stress from earth load

D - Pipe outside diameter

E - Longitudinal joint factor

E' - Modulus of soil reaction

Ee - Excavation factor for circumferential stress from earth load

Er - Resilient modulus of soil Es - Youngs modulus of steel F - Design factor

Fi - Impact factor

FS1- Factor of safety for Seff FS2 - Factor of safety for girth welds

FS3 - Factor of safety for longitudinal welds

GHh - Geometry factor for cyclic circumferential stress from highway vehicular load

GHr - Geometry factor for cyclic circumferential stress from rail load

GLh - Geometry factor for cyclic longitudinal stress from highway vehicular load

GLr - Geometry factor for cyclic longitudinal stress from rail load

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H - Depth to the top of the pipe

KHe - Stiffness factor for circumferential stress from earth load

KHh - Stiffness factor for cyclic circumferential stress from highway vehicular load

KHr - Stiffness factor for cyclic circumferential stress from rail load

KLh - Stiffness factor for cyclic longitudinal stress from highway vehicular load

KLr - Stiffness factor for cyclic longitudinal stress from rail load

L - Highway axle configuration factor

LG - Distance of girth weld from centerline

MAOP - Maximum allowable operating pressure

NH- Double track factor for cyclic circumferential stress

NL - Double track factor for cyclic longitudinal stress

Nt - Number of tracks at railroad crossing

Ps - Single axle wheel load

Pt - Tandem axle wheel load

P - Internal pipe pressure

R - Highway pavement type factor

RF - Longitudinal stress reduction factor for fatigue

Seff - Total effective stress

SFG - Fatigue resistance of girth weld

SFL - Fatigue resistance of longitudinal weld

SHe - Circumferential stress from earth load

SHi - Circumferential stress from internal pressure

SHiB - Circumferential stress from internal pressure calculated using the Barlow formula

S1 - Maximum circumferential stress

S2 - Maximum longitudinal stress

S3 - Maximum radial stress

SMYS - Specified minimum yield strength

T- Temperature derating factor

T1- Installation temperature

T2 - Operating temperature

tw- Pipe wall thickness

w - Applied design surface pressure

T - Coefficient of thermal expansion

r- Unit weight of soil SHh - Cyclic circumferential stress from highway vehicular load

SHr - Cyclic circumferential stress from rail load

SLh - Cyclic longitudinal stress from highway vehicular load

SLr - Cyclic longitudinal stress from rail load

s - Poissons ratio of steel C. PROGRAM AND VARIABLES LIMITATIONS

C.1.) DIAMETER. The diameter, D, is the outside pipe diameter, and has units of inches. The range of D is 2.0000 to 42.000 in. The default value is D = 12.750 in. C.2.) MAXIMUM ALLOWABLE OPERATING PRESSURE, MAOP

API 1102 - PC PISCES

7

The maximum allowable operating pressure, MAOP, is used as the design internal pressure for calculating circumferential stress due to internal pressurization, and has units of psi. The range for MAOP is 0000 to 5000 psig. C.3.) SPECIFIED MINIMUM YIELD STRENGTH, SMYS

The specified minimum yield strength, SMYS, has a range of allowable values covering steel grades A25 (SMYS = 25000 psi) to X-80 (SMYS = 80000 psi). The SMYS is also used to establish the girth and longitudinal weld fatigue endurance limits. C.4.) DESIGN FACTOR, F

Although 49 CFR 192 or 195, establishes a design factor, F, the user can input another F value. The range for F is from 0.10 to 1.00. The default design factor is F = 0.72. C.4.) LONGITUDINAL JOINT FACTOR, E

The longitudinal joint factor, E, depends on the type of pipe welds. The input screen limits E to either 0.60, 0.80, or 1.00, consistent with the values given in 49CFR192, Section 192.113. The default value is E = 1.00. C.5.) INSTALLATION TEMPERATURE, T1

The installation temperature, T1 is given in F . This value is used with T2 to determine thermal stress effects. The range of T1 is from -20 to 450 F. C.6.) OPERATING TEMPERATURE, T2

The operating temperature, T2 is give in F. The T2 value is used to determine the temperature derating factor, T. T2 also is used with T1 to determine thermal stress effects. The range for T2 is from -20 to 450 F. C.7.) WALL THICKNESS, tw

The pipe wall thickness, tw has units of inches. The wall thickness to diameter ratios must be within the range of tw/D = 0.01 to 0.08. C.8.) DEPTH OF CARRIER PIPE, H

The depth of the carrier pipe, H, given it ft, is measured from the top of tie to the pipeline crown for railroads and from the top of pavement to the pipeline crown for highways. The limits on H are: 6ft <= H <= 14 ft for railroads, and

H = 4 to 10 ft (in accordance with API 1102) and H = 3 to 10 ft (PC-PISCES) for highways. These are the depth limits for the live load design curves. The depth, H, also is used to establish the impact factor, Fi used in the design methodology. C.9.) BORED DIAMETER, Bd

The bored diameter, Bd (Bd in RP 1102), has units of inches. The minimum value is Bd = D, and the maximum value is Bd = D + 6 in. The default value is Bd = D + 2 in. C.10.) SOIL TYPE FOR THE EARTH LOAD

The soil type for the earth load calculations is either A or B. See Figure 4 in API RP 1102, C.11.) MODULUS OF SOIL REACTION. E' The modulus of soil reaction, E', has units of ksi. The minimum value allowed is E = 0.2 ksi, and the maximum recommended value for auger bored installations is E = 2.0 ksi. The maximum input value for E is 8.0 ksi. When an E value greater than 2.0 ksi is used, a warning will be displayed that the value is beyond the normal range of E' for auger bored installations. See details in API RP 1102. C.12.) SOIL RESILENT MODULUS, Er

The soil resilient modulus, Er has units of ksi. The minimum allowable value is Er = 5.00 ksi, and the maximum allowable value is Er = 20.0 ksi. These are the limits for the live load

8

design curves. See Table 3 in API RP 1102 or The default value is Er = 10.0 ksi, as recommended in API RP 1102. C.13.) SOIL UNIT WEIGHT, r

The soil unit weight, r, has units of pcf, and can range from 0 to 150 pcf. The default value is r = 120 pcf. C.14.) TYPE OF LONGITUDINAL WELD

The type of longitudinal weld is used with the SMYS to establish the longitudinal weld fatigue endurance limit, SFL. The choices for the type of longitudinal seam weld are SAW or ERW. See Table 3 in API RP 1102 for the influence of longitudinal weld type and SMYS on the seam weld fatigue endurance limits. The default type of longitudinal weld is SAW. C15.) GIRTH WELD DISTANCE, LG (RAILROAD ONLY) The girth weld distance, LG has units of ft and can range from 00 to 99 ft. The LG distance is used to determine the longitudinal stress reduction factor, RF , needed for the girth weld fatigue calculations. See Figure 18 A and 18 B in API RP 1102 for the RF values as dependent on LG, H, and D. When a double track crossing is being analyzed, the recommended value for LG is less than 5 ft. For LG less than 5 ft, longitudinal stress reduction factors are not used. C.16.) NUMBERS OF TRACKS, Nt (RAILROAD ONLY) The number of tracks, Nt is used to determine whether a single or double track railroad crossing will be analyzed. The Nt value determines the single or double track NH and NL factors for circumferential and longitudinal live load pipelines stresses, respectively. The default value is Nt = 1. C.17.) E - TYPE RAIL LOADING (RAILRAOD ONLY) The E - Type rail loading is used to determine the applied surface stress, w, for railroad crossings. The range for the E type lading is from E - 00 to E - 99. can also be entered, which causes the surface load, w, to be 1.0 psi. The default value is E - 80 loading, as recommended in API RP 1102. C.18.) DESIGN SINLE WHEEL LOAD, Ps (HIGHWAY ONLY) The design single wheel load, Ps , has units of kips, and can range from 0.00 to 20.0 kips. The pavement type, design wheel loads, diameter, and depth are used to establish the pavement type factor, R, and axle configuration factor, L. The default value is Ps = 12.0 kips, as recommended in API RP 1102. C.19.) DESIGN TANDEM WHEEL LOAD, Pt (HIGHWAY ONLY) The design tandem wheel load, Pt (, has units of kips, and can range from 0.00 to 20.0 kips. The pavement type, design wheel loads, diameter, and depth are used to establish the pavement type factor, R, and axle configuration factor, L. The default value is Ps = 10.0 kips, as recommended in API RP 1102. C.20.) PAVEMENT TYPE (HIGHWAY ONLY) The pavement type for highway crossings can be either flexible , none, or rigid . The pavement type, design wheel loads, diameter and depth are used to establish the pavement type factor, R, and axle configuration factor, L. The default pavement type is flexible. C.21.) YOUNGS MODULUS, Es

Youngs modulus of the steel carrier pipe, Es (Es in RP 1102), has units of ksi. The range is from 29 000 to 31 000 ksi. The default value is Es = 30 000 ksi. C.22.) POSSIONS RATIO, s


9

Possions ratio of the steel carrier pipe, s , is used to assess thermal and longitudinal stresses due to the circumferential earth load and internal pressure stresses. The allowable range is from 0.25 to 0.30. The default value is s = 0.30. C.23.) COEFFICIENT OF THERMAL EXPANSION, T

The coefficient of thermal expansion of the steel carrier pipe T , is given for temperature is F, and is used to assess longitudinal thermal stresses. The range is from 0.0000060 to 0.0000080 per F. The default value is T = 0.0000065 per F. D. DESIGN CURVES

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Technical Toolboxes, Inc.

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API 1104 - Appendix A: Weld Imperfection Assessment Please see API Standard 1104 Welding of Pipelines and Related Facilities, Appendix A, Option 2 for the background of the assessment procedure. Technical Toolboxes, Inc.

25

API 2540 - Volume Correction Factors This program module is developed in accordance with API standard 2540 Manual of Petroleum Measurement Standards, Chapter 11.1-Volume Correction Factors, Volume X - Background, Development, and Program Documentation. All number rounding and truncation in the program fully comply API 2540 standards requirements. Reference: API STANDARD 2540 (1980) FIRST EDITION, VOLUME X, AUGUST 1980

REAFFIRMED, OCTOBER 1993 Technical Toolboxes, Inc.

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ASTM 2161 cSt/Saybolt Viscosity API/Baume/Specific Gravity Conversion A. ASTM 2161 cSt/Saybolt Viscosity Conversion

SUS = 4.6234cSt +

SUS =

B. API/Specific Gravity Conversion

C. BAUME/Specific Gravity Conversion

References: ASTM 2161, Part I

"Hydraulics for Pipeliners",Second Edition, C.B. Lester Technical Toolboxes, Inc.

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Accidental Release from Liquid Hydrocarbon Pipeline Note: Spill volumes were calculated based on the leak rate and time to isolate pipeline section and release rate during free flow. It is important to note that this assessment adopts a very conservative approach to estimating spill volumes. It was assumed that gravitational effects were the sole mechanism for release after isolation siphoning effects, drain down procedures, and pipeline depressurization were not considered. PHASE 1: The discharge/release rate of liquid through the sharp edged orifice can be calculated as:

Calculation of Spray Zone

PHASE 2: Pressure differential during free flow phase:

30

References: - Handbook of Chemical Hazard Analysis Procedures, - Risk Management Program Guidance for Offsite Consequence

- API Recommended Practice 520, Sizing, Selection, and Installation of Pressure-Relieving - Devices in Refineries, Part I, American Petroleum Institute, - API Recommended Practice 521, Guide for Pressure-Relieving and Depressuring Systems, American Petroleum Institute, - Crane Limited, Flow of Fluids through Valves, Fittings, and Pipe, Technical Paper No. 410-C, Crane Engineering Division

- Bosch, C.J.H. van den and N.J. Duijm, The Netherlands Organization of Applied Scientific Research. Methods for the Calculation of Physical Effects, CPR 14E: Part (TNO

Yellow Book), - Ramskill, P.K., Discharge Rate Calculation Methods or Use in Plant Safety Assessments, Safety and Reliability Technical Toolboxes, Inc.

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Adiabatic Bulk Modulus for Hydrocarbons Wostl/ARCO Equation:

Ks Adiabatic Bulk Modulus

P = pressure, psig

A = API gravity at 60 F

T = temperature R = F + 460

Reference: Hydraulics For Pipeliners, C.B. Lester Technical Toolboxes, Inc.

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How to Export Report in Adobe Acrobat? Requirements: In order to export report to Adobe Acrobat, version 5.0 or 6.0 of Adobe Acrobat must be installed on your computer.

1. On the report toolbar

select and click on the “Print…” button.

2. On the printer selection screen select Adobe PDF (or Adobe Distiller) and click “Print” button

3. After you click “Print” button you will be prompted to save the file. Select the directory/folder, rename the file and click “Save” button.

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35

Bending Stress and Deflection in Pipelines

FIXED ENDS SUPPORTS

y = maximum deflection, feet

S = maximum bending stress, PSI

W= unit weight, pounds per foot

L = length, feet

E = modulus of elasticity, PSI

steel = 30,000,000

plastic(dupont) = 100,000

plastic(plexco) = 125,000

cast iron = 15,000,000

copper = 15,000,000

D = outside diameter, inches

d = inside diameter, inches

SIMPLE SUPPORTS y = 5 times y for fixed ends

S = 1.5 times S for fixed ends

CANTILEVER SUPPORT y = 48 times y for fixed ends

S = 6 times S for fixed ends

S and y on the schematics indicate the points of

MAXIMUM stress and deflection. Technical Toolboxes, Inc.

37

Blasting Analysis

SCOPE

This procedure describes the method for calculating the stresses caused by underground blasting

near an existing pipeline(s). The equations used follows guidelines set forth in CFR Title 49, Part

192.

BASIC CONSIDERATIONS

Blasting near an existing operating pipeline frequently occurs for a variety of reasons. Whenever

these underground explosion occur, they create circumferential and longitudinal stresses in

adjacent pipelines.

These stresses must be estimated to determine the possibility of damaging the pipelines.

This procedure describes the method for calculating the combined stresses on a pipeline in the

vicinity of blasting, those stresses being hoop stress due to internal pressure in the pipeline and

circumferential and longitudinal stresses due to blasting. In some instances, blasting may occur

near pipelines that are under the influence of circumferential and longitudinal stresses caused by

excessive backfill overburden (>10 Ft. of cover) or surface traffic. These situations require

special analysis and are not addressed in this standard procedure.

This procedure assumes that the blasting occurs at one location - a point charge. A blasting plan

may consists of a series of point charge blasts with a small delay between each blast. A biaxial

stress state exists when blasting occurs. These stresses are combined stress state.

Knowledge of soil (rock) conditions and construction methods is necessary to make sound

engineering judgements about each blasting situation. The following information is usually

required:

1. Description (trade name) of the explosive.

1. Method of detonation.

1. Delay time and weight of charge per delay.

1. Distance from pipeline.

1. Alignment Drawing No.and Survey Station or Mile Post.

1. Predominant rock type between the detonation point and the pipelines.

1. Diameter, wall thickness and SMYS of all pipelines in the vicinity of the blasting.

1. MAOP and the actual operating pressure of all pipelines in the vicinity of the blasting.

1. Class Location.

Frequently a series of blasts will be detonated with a small delay between each blast. It is

necessary to analyze the delay time with respect to seismic velocity to insure that each shock

wave arrives at the pipeline separately. In general, a minimum delay time of 25 milliseconds

(0.025 seconds) will assure that there is no compounding of shock waves. If seismic velocities

are low (1,000 - 2,500 ft./sec. ) a longer delay time may be required. Conversely, if delay times

38

are significantly less than 25 milliseconds, information about the expected seismic velocities

should be obtained.

II. EQUATIONS FOR CHARGE BLASTING ANALYSIS

The hoop stress due to internal pressure is calculated as follows:

The circuferential and longitudinal stresses caused by a point charge underground explosion are

calculated as follow:

The hoop stress and circumferential stress are combined as follows:

The combined stress level (S) is calculated as follow:

The longitudinal bending stress occurs in tension on the outside of the bend and in

compression on the inside of the bend. Tensile stress is represented with a positive value for ;

conversely, compressive stress takes a negative value for . The negative value for is used

when calculating the combined stress level (S). This will result in a larger ( more conservative)

combined stress level.

The allowable combined stress design factor (DFa) should be applied to the SMYS as follows:

S, psi < SMYS x DFa, where

Blasting Analysis

39

S = Combined stress level, psi

SMYS = Specified Minimun Yield Strength of pipe, psi

DFa =Allowable Combined Stress Design Factor

The calculated combined stress design factor (DFc) should be determined as follows:

An unsafe blasting condition may be rectified in several ways. They include increasing the

distance away from pipeline, using an explosive with a lower energy release ratio, or reducing

the pressure in the pipeline. It is normally impractical to reduce the pipeline pressure. Technical Toolboxes, Inc.

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Buoyancy Analysis and Concrete Coating Thickness

1. Determine bare pipe weight:

1. Determine total volume of pipe in air including corrosion and concrete coating:

1. Determine Volume of corrosion coating:

1. Determine volume of concrete coating:

1. Determine total weight of pipe in air, including weight of corrosion and concrete coating:

1. Determine weight of displaced water

42

1. Determine the difference :

1. Determine bulk specific gravity:


43

Buoyancy Analysis and Concrete Weights Spacing Buoyant Force

Weight of Steel Pipe in the Air

Weight of Pipe Coating in the Air

Weight of Product in the Pipe

Downward Force of the Pipe

Net Controlling Force

44

Downward Force of the Concrete Weight

Concrete Weight Spacing

Unit Weights:

Fresh water 62.42

Salt water 64.0

Concrete 140

Steel 490

PE Coating 59.30

FBE Coating 89.89

Wood lagging 26.84

Reference: “Pipeline Geo-Environmental Design and Geohazard Management”, ASME, 2008, Edited by Moness Rizkalla Technical Toolboxes, Inc.

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Cathodic Protection Attenuation Calculation

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For typical pipeline with multiple drain points (anodes) with uniform spacing of 2L The potential and current are given:

Reference:

1. Uhlig's Corrosion Handbook (2nd Edition) Edited by: Revie, R. Winston © 2000 John Wiley & Sons

2. ISO 15589-2 Petroleum and Natural gas Industries Cathodic Protection Pipeline Transportation Systems

3. Pipeline Corrosion and Cathodic Protection, Third Edition, Gulf Publishing Company


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Cathodic Protection

Cathodic Protection - Includes both single and multiple anode placement and resistance calculations with electric current and power consumption requirements.

Estimated Life of a Magnesium Anode Resistance to Earth of an Impressed Anode Ground Bed Rudenberg’s Formula for the Placement of a Close or Distributed Ground Bed Resistance to Earth of a Single Vertical Anode Resistance to Earth of Multiple Vertical Anodes Resistance to Earth of a Single Horizontal Anode Required Number of Anodes and Total Current Requirement Power Consumption of a Cathodic Protection Rectifier


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Centrifugal Pump - Affinity Laws A. Diameter Change Only

B. Speed Change Only

C. Diameter and Speed Change

Reference:

1. Engineering Data Book, Volume 1, Gas Processors Suppliers Association, Tenth Edition

2. Pump Handbook, Fourth Edition, McGraw-Hill Professional Technical Toolboxes, Inc.

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Colebrook - White Liquid Flow Equation

Friction factor is solved using Newton-Raphson method.

The Colebrook-White equation is recommended for use by those unfamiliar with pipeline flow equations, since it will produce the greatest consistency of accuracy

over the widest possible range of variables. This equation is recommended for use when the Reynolds number exceeds 4000. References:

"Flow of fluids", Technical Papers No.410, CRANE

"Hydraulics for Pipeliners", Volume I: Fundamentals, Second Edition, C.B. Lester

"Hydraulics of Pipeline Systems", Bruce E. Larock, Ronald W. Jeppson, Gary Z. Watters

"Pipeline Design for Hydrocarbons Gases and Liquids", ASCE, Commitee on Pipeline Planning

Nomenclature Technical Toolboxes, Inc.

53

Compressibility Factors for Hydrocarbons: 0-90 API The purpose of this program is to correct hydrocarbon volumes metered under pressure to the corresponding volumes at the equilibrium pressure for the metered temperature based on API standard. This standard define procedure for determination of compressibility factors related to meter temperature and API gravity (60 F) of metered liquid. The program fully comply with standards algorithm and required number rounding and truncation. The example from standard, the compressibility factor (F) is used in the normal manner for volume correction:

Where: Ve = volume at equilibrium (bubble point ) pressure, Pe. Vm = volume at the meter pressure, Pm. As an example, calculate the volume of 1000 barrels (Vm) of a 19.9 API (60F) fuel oil metered under a pressure of 500 pounds per square inch (Pm) and 100 F. Assume a Pe value of 0 pounds per square inch. The application first round API to the nearest 0.5 API, in this case 20.0 API and then perform calculations. The result produced by application is exact to the number taken form the API Compressibility tables. From the table: F factor is 0.448 divided by 100,000 is 0.00000448. Reference: API "Manual of Petroleum Measurement Standards", Chapter 11.2, "Compressibility Factor for Hydrocarbons: 0-90 API", First Edition, August 1984 Technical Toolboxes, Inc.

55

DOT & MMS Pipeline Regulations

DOT & MMS Pipeline Regulations - Contains both the(1) U.S.D.O.T. Federal Pipeline Safety Regulations with all inspection report templates and the (2) DOI-Minerals Management Service Offshore pipeline regulations (Subpart J). In hypertext format to permit easy key word/phrase searches

Pipeline Safety Laws

DOT Code PART 190, Pipeline Safety, Prescribed Procedure

DOT Code PART 191, Annual Reports, Incident Reports, and Safety Related Condition Reports

DOT Code PART 192, Transportation of Natural and Other Gas by Pipeline

DOT Code PART 193, Liquefied Natural Gas Facilities

DOT Code PART 194, Onshore Oil Pipelines

DOT Code PART 195, Transportation of Hazardous Liquids by Pipeline

MMS Regulations, SUBPART J, Offshore Pipelines and Pipeline Rights-of-Way

DOT Instructions for Annual Report for Gas Distribution System

DOT Instructions for Incident Report for Gas Distribution System

DOT Instructions for Annual Report for Gas Transmission and Gathering System

DOT Instructions for Incident Report for Gas Transmission and Gathering System

DOT Instructions for Accident Report - Hazardous Liquid Pipeline


57

Darcy - Weisbach

Friction factor is solved using Newton-Raphson method.

References: "Flow of fluids", Technical Papers No.410, CRANE


"Hydraulics of Pipeline Systems", Bruce E. Larock, Ronald W. Jeppson, Gary Z. Watters Technical Toolboxes, Inc.

59

Dead Load on PE Pipe - Prism, Marston and Combined Load A. Prism Load

B . Marston Load (ASCE Manual No.60)

Typical Value for

Soil Typical Value for

Saturated clay 0.110

Ordinary clay 0.130

Saturated top soil 0.150

Sand and gravel 0.165

Clean granular soil 0.192

C. Combined Prism and Marston Load

For flexible pipe, a more conservative method is to use a soil pressure load in between prism and Marston load:

60

Reference:

1. “Soil Engineering”, Third Edition, Spangler, M.G. and Handy, R.L., Intext Educational Press

2. “Structural Mechanics of Buried Pipes”, Watkins, R.K, and Loren, R, A, 3. “Polyethylene Pipe Handbook: Design of PE Piping Systems”, Second Edition,

Plastic Pipe Institute, Inc.


61

Design Pressure - Plastic Pipe

Design pressure for plastic pipe is determined in accordance with either of the following formulas :

Note :

For design limitations and definitions, see DOT Code 192 in the DOT & MMS Regulations Module ! Technical Toolboxes, Inc.

63

Distributed Static Surcharge Load Directly over Buried PE Pipe

1. Dead/Earth Load

A. Prism Load



64


2. Distributed Static Surchage Load

This method is using Boussinesq equation for pressure acting on pipe crown.

Influence coefficient is selected from the table below:

Distributed Static Surcharge Load Directly over Buried PE Pipe

65

3. Pipe Deflection is calculated using Spangler's Modified Iowa Formula:

4. Pipe Wall Compressive Stress

66

Reference:





67

Distributed Static Surcharge Load not over Buried PE Pipe

1. Dead/Earth Load

A. Prism Load



68


2. Distributed Static Surchage Load not over PE Pipe

This method is using Boussinesq equation for pressure acting on pipe crown.

Distributed Static Surcharge Load not over Buried PE Pipe

69

Influence coefficient is selected from the table below:


70


Reference:





71

Document Management System The purpose of the Document Management System (DMS) is to allow the user to customize his/her own Toolbox with commonly used documents such as Design Guidelines, Company Recommended Practice, etc... One sample document has been included in your Document Management System to get you started. Any document can be added to your Toolbox by simply clicking on the DMS icon to reveal the following screen:

Step 1

Click the Add Document button. The following screen will be revealed:

72

Step 2

Click the Find Document button. This will reveal a standard Windows common dialog box to allow the user to browse files anywhere on his/her PC or files available from the users network, CDs, etc. See below:

Step 3

Document Management System

73

Once you identify the document you wish to add to the DMS within your Toolbox simply click on the file to be added:

Step 4

Select from one of three (3) file types Microsoft Word (*.doc) Adobe (*.pdf) HTML (*.html) and retrieve the document

74

Step 5

At this stage you have the option to change the Document Name. The user can preview the document to ensure it is the correct document to be saved by clicking on the Preview button. If the document is not the correct one simply click the Cancel button and start the procedure from step 3. If the document is the correct one and you have selected the name of the document then simply click on the Save button at which stage the document is saved in the Toolbox DMS:

Document Management System

75

Step 6 (Optional) If the user wishes to remove a document from his/her DMS within the Toolbox simply click on the document you wish to delete then click the Delete Document button. Step 7

To confirm that your document has been added to the Toolbox DMS simply click on the document you wish to review and click on the Open Document button:

76


77

Electrical Resistance of a Conductor


79

Electrolyte Resistance from the Surface of an Electrode to any Distance


81

Engineering Drawing Board

The Engineering Drawing module is Visio Technical from Visio Corporation. It contains over 2000 SmartShapes with 150 Petroleum Engineering Templates. This drawing module is intuitive and easy to use and offers drag-and-drop functionality with links to calculations. It is AutoCAD compatible for both import and export. Technical Toolboxes, Inc.

83

Engineering Units Conversion

Units Conversion - The Units Conversion module provides the pipeline professional with a functional, easy to use and very comprehensive units conversion package. The package contains over 400 SI international and English energy-related conversions. Technical Toolboxes, Inc.

85

Estimated Life of a Magnesium Anode


87

External Applications Integration This feature provides the user with the capability to integrate external applications with the Pipeline Toolbox program suite. Applications can be added or deleted as determined by the individual user. Please see the Document Management System HELP for detailed procedures. The only file formats that can be integrated are spreadsheets (*.xls) and application executables (*.exe). Technical Toolboxes, Inc.

89

Fluid Database - Nomenclature

Type

1. Elements (e.g. H2,N2,He...)

2. Inorganic Compounds (e.g. CO2,H2S....)

3. Alkanes with up to 9 Carbon atoms ('Paraffins')

4. Alkanes with 10 - 40 Carbon atoms ('Paraffins')

5. Alkenes ('Olefins')

6. Alkynes & Dialkenes (e.g.Acetylene...)

7. Cycloalkanes ('Naphthenes')

8. Aromatic Single-Ring Hydrocarbons (e.g. Benzene)

9. Aromatic Multi-Ring Hydrocarbons (e.g. Naphthalene)

10. Organic Nitrogen & N/O Compounds (e.g. Ethanolamine)

11. Aliphatic Oxygen Compounds (e.g. Alcohols)

12. Aromatic Oxygen Compounds (e.g. Phenols)

13. Organic Sulfur Compounds (e.g. Odorants)

14. Organic Halogen Compounds (e.g. Refrigerants)

15. Radical Species (N.B. only use at high T, gas phase)

MW

Molecular Weight

Tc, Pc, Dc

Critical Temperature, Pressure and Density ( K, MPa, g/cm3)

W-fact

90

Acentric Factor

X-LRS, Y-LRS

British Gas LRS Equation X and Y Acentric Factors

Vap1-4

Wagner vapour pressure equation for the pure component :-

ln(VP/Pc) = ( Vap1*t + Vap2*t^1.5 + Vap3*t^A + Vap4*t^B )/ Tr

where Tr = T / Tc , t = ( 1 - Tr )

A=2.5 & B=5 or A=3 & B=6

(the 3, 6 form is indicated by a negative Vap1 when the first term is -Vap1*t)

Den1-4

ESDU equation for saturated liquid density :-

ln(D/Dc) = ln(Vc/V) = DEN1*q + DEN2*q^2 + DEN3*q^3 + DEN4*q^4

where q = ( 1 - T/Tc )^(1/3)

AN, BB, A0-3

Benedict-Webb-Rubin-Starling Coefficients

CV

Calorific Value (MJ/scm)

Bi, Fi

Z-Factor and Weaver Flame Speed Factor

ParaC

Parachor

LFL, UFL

Lower and Upper Flammability Limit

DipM

Dipole Moment

Pola

Fluid Database - Nomenclature

91

Polarizability

dHform, dGform

Entropy and Enthalpy of Formation (kJ/mol)

W-NBS

Ely-Hanley (National Bureau of Standards (NBS), now NIST) method

for transport properties :- W-Factor.


93

Fluids Properties (PVT)

GasVle Licensed From BG plc (British Gas) - An industry-leader in petroleum fluid PVT analysis,

GasVle™ computes the vapor-liquid equilibrium of hydrocarbons and the associated gas and oil

PVT properties of the mixture. GasVle™ calculates single phase (gas and liquid) properties, dew

and bubble points, critical points, two and three phase fluid equilibria, solid and hydrate

formation conditions. Calculations can be carried out at isenthalpic, isentropic, isochoric and

specified vapor fraction conditions. Properties calculated include compression factor, density,

heat capacities, speed of sound, viscosity, thermal conductivity, interfacial tension, calorific

values and theoretical air requirement, vapor and liquid mole fractions. Ten (10) equation of state

methods are available: AGA8, BWRS, GERG, GRC, IG, LRS, MCSP, PR, RKS and SW.

GasVle™ has a data-base over 200 'library' components. The user can also input user-defined

fractions. GasVle™ is integrated within the Toolbox and the Microsoft family of software, both

by use of DDE and OLE. The results of calculations and their inputs can be entered and viewed

by any other program that uses these standards. GasVle™ is also usable as a DLL function from

within Microsoft Excel, allowing complicated custom calculations to be set up by the user in

spreadsheet format. Technical Toolboxes, Inc.

95

Flume Design ESTIMATING ROUGHNESS COEFFICIENTS

This section describes a method for estimating the roughness coefficient n for use in hydraulic computations associated with natural streams, floodways, and excavated channels. The procedures applies to the estimation of n in Manning's formula . The coefficient of roughness n quantifies retardation of flow due to roughness of channel sides, bottom, and irregularities. Estimation of n requires the application subjective judgement to evaluate five primary factors: - Irregularity of the surfaces of the channel sides and bottom; - Variations in the shape and size of the channel cross sections; - Obstructions in the channel; - Vegetation in the channel; - Meandering of the channel. Procedure for estimating n

The procedure for estimating n involves selecting a basic value for a straight, uniform, smooth channel in the existing soil materials, then modifying that value with each of the five primary factors listed above. In selecting the modifying values, it is important that each factor be examined and considered independently. Step 1. Selection of basic value of n. Select a basic n value for straight, uniform, smooth channel in the natural materials involved. The conditions of straight alignment, uniform cross section, and smooth side and bottom surfaces without vegetation should be kept in mind. Thus, basic n varies only with the material that forms the sides and bottom of the channel. Select the basic n for natural or excavated channels from Table 8.04a. If the bottom and sides of a channel consist of different materials, select an intermediate value. Table 8.04a. Basic Value of Roughness Coefficient for Channel Materials

Soil Material Basic n

Channels in earth 0.02

Channels in fine gravel 0.024

Channels cut into rock 0.025

Channels in coarse gravel 0.028

Step 2.Selection of modifying value for surface irregularity. This factor is based on the degree of roughness or irregularity of the surfaces of the channel sides and bottom. Consider the actual surface irregularity, first in relations to the degree of surface smoothness obtainable with the natural materials involved, and second in relation to the depth of flow expected. If the surface irregularity is comparable to the best surface possible for the channel materials, assign a modifying value zero. Irregularity induces turbulence that calls for increased modifying values. Table 8.04b may be used as a guide to selection of these modifying values.

96

Table8.04b. Modifying Value for Roughness Coefficient Due to Surface Irregularity of Channels

Degree of Surface Comparable Modifying

Irregularity Value

Smooth The best obtainable for the material 0.000

Minor Well-dredged channels; slightly eroded

or scoured side slope of canals or

drainage channels 0.005

Moderate Fair to poorly dredged channels; moderately sloughed or eroded side

slopes of canals or drainage channels 0.010

Severe Badly sloughed banks of natural channels: badly eroded or sloughed sides of canals

or drainage channels; unshaped, jagged

and irregular surfaces of channels excavated

in rock 0.020

Source for Tables b-f: Estimating Hydraulic Roughness Coefficients

Step 3. Selection of modifying value for variations in the shape and size of cross sections. In considering this factor, judge the approximate magnitude of increase and decrease in successive cross sections as compared to the average. Gradual and uniform changes do not cause significant turbulence. Turbulence increases with the frequency and abruptness of alternation from large to small channel sections. Shape changes causing the greatest turbulence are those for which flow shifts from side to side in the channel. Select modifying values based on Table 8.04c. Table 8.04c. Modifying Value for Roughness Coefficient Due to Variations of Channel Cross Section

Character of Variation Modifying

Value

Changes in size or shape occurring

gradually 0.000

Large and small sections alternating

occasionally, or shape changes causing

occasional shift of main flow from side

to side 0.005

Large and small sections alternating

frequently, or shape changes causing

frequent shift of main flow from side

to side 0.010-0.015

Step 4. Selection of modifying value for obstructions. This factor is based on the presence and characteristics of obstructions such as debris deposits, stumps, exposed roots, boulders, and fallen and lodged logs. Take care that conditions considered in other steps not be double-counted in this step. In judging the relative effect of obstructions, consider the degree to which the obstructions reduce the average cross-sectional area at various depths and the characteristic of the obstructions. Shaped-edged or angular objects induce more

Flume Design

97

turbulence than curved, smooth-surfaced objects. Also consider the transverse and longitudinal position and spacing of obstruction in the reach. Select modifying value based on Table 8.04d. Table 8.04d. Modifying Value for Roughness Coefficient Due to Obstruction in the Channel Relative Effect Modifying

of Obstruction Value

Negligible 0.000

Minor 0.010 to 0.015

Appreciable 0.020 to 0.030

Severe 0.040 to 0.060

Step 5. Selection of modifying value for vegetation. The retarding effect of vegetation is due primarily to turbulence induced as the water flows around and between limbs, stems and foliage and secondarily to reduction in cross section. As depth and velocity increase, the force of flowing water tends to bend the vegetation. Therefore, the ability of vegetation to cause turbulence is related to its resistance to bending. Note that the amount and characteristics of foliage vary seasonally. In judging the retarding effect of vegetation, consider the following: height of vegetation in relation to depth of flow, its resistance to bending, the degree to which the cross section is occupied or blocked, and the transverse and longitudinal distribution of densities and height of vegetation in the reach. Use Table 8.04e as a guide. Table 8.04e. Modifying Value for Roughness Coefficient Due to Vegetation in the Channel Vegetation and Flow Conditions Range in Modifying Value

Comparable to: Low Effect 0.005 to 0.010

Dense growths of flexible turf grass or

weeds, such as Bermudagrass and Kentacky

bluegrass. Average depth of flow 2 to 3 times

the height of the vegetation. Medium Effect 0.010 to 0.025

Turf grasses where the average depth of flow

is 1 to 2 times the heigth of vegetation

Stemmy grasses, weeds or tree seedlings

with moderate cover where the average

depth of flow is 2 to 3 times the height of vegetation

Brushy growths, moderately dense, similar

to willow 1 to 2 years old, dormant season, along side slopes of channel with no significant

egetation along the channel bottom, where the

hydraulic radius is greater then 2 ft High Effect 0.025 to 0.050

98

Grasses where the average depth of flow is

about equal to the height of vegetation

Dormant seasons, willow or cottonwood

tree 8-10 year old, intergrown with some

weed and brush; hydraulic radius 2 to 4 ft

1. yr old, intergrown with some weeds in

full foliage along side slopes; no significant

egetation along channel bottom; hydraulic

radius 2 to 4 ft Grasses where average depth of flow is less

than one-half the height of vegetation

Very High Effect 0.050 to 0.100

Growing season, bushy willows about 1-yr

old, intergrown with weeds in full foliage

along side slopes; dense grown of cattails

or similar rooted vegetation along channel bottom; hydraulic radius greater than 4 ft Growing season, tree intergrown with weeds

and brush, all in full foliage; hydraulic radius

greater than 4ft

Step 6 Computation of n for the reach. The first estimate of roughness for the reach

n , is obtained by neglecting meandering and adding the basic n value obtained in step 1 and modifying value from steps 2 through 5.

Step 7. Meander. The modifying value for meandering is not independent of the

other modifying values. It is estimated from the n obtained in step 6, and the ratio of the meandering length to the straight length. The modifying value for meandering may be selected from Table 8.04f. Table 8.04f.Modifying Value for Roughness Coefficient Due to Meander of the Channel

Meander Ratio Degree of Modifying

Meandering Value

0.0 to 1.2 Minor 0.000

1. 2 to 1.5 Appropriable 0.15 n

1. 5 and greater Severe 0.30 n

Flume Design

99

Step 8. Computation of n for a channel reach with meandering. Add the modifying

value obtained in step 7, to n , obtained in step 6. The procedure for estimating roughness for an existing channel is illustrated in Sample Problem 8.04a. Sample Problem 8.04a. Estimation of roughness coefficient for an existing channel. Description of reach: Soil - Natural channel with lower part of banks and bottom yellowish gray

clay, upper part light silty clay. Side slopes - Fairly regular; bottom uneven and irregular. Cross section - Very little variation in the shape; moderate, gradual

ariation in size. Average cross section approximately trapezoidal with

side slopes about 1,5:1 and bottom width about 10 ft. At bankfull stage, the average depth is about 8.5 ft and the average top width is about 35 ft. Vegetation - Side slopes covered with heavy growth of poplar tree,

2. to 3 inches in diameter, large willows, and climbing vines; thick,

bottom growth of waterweed; summer condition with the vegetation

in full foliage. Alignment - Significant meandering; total length of meandering

channel, 1120 ft; straight line distance, 800 ft. Solution: Step Description

Number n Value

1. Soil materials indicate minimum basic n 0.02

Modification for:

2. Moderately irregular surface 0.01

3. Change in size and shape judged insignificant 0.00

4. No obstructions indicted 0.00

5. Dense vegetation 0.08

6. Straight channel subtotal, n = 0.11

7. Meandering appreciable,

meandering ratio: 1120/800 = 1.4

Select 0.15 from Table 8.04f

100

8. Modified value =(0.15)(0.11) = 0.0165 or 0.02

Total roughness coefficient n = 0.13

Out-of-Bank Condition Channel and Flood Plain Flow

Work with natural floodways and streams often requires consideration of a wide range of discharges. At high stages, both channel and overbank or flood plain flow may occur. Usually, the retardance of the flood plain differs significantly from that of the channel, and the hydraulic computations can be improved by subdividing the cross selection and assigning different n values for flow in the channel and the flood plain. If conditions warrant, the flood plain may be subdivided further. Do not average channel n with flood plane n. The n value for in-bank flow in the channel may be averaged. To compute a roughness coefficient for flood plain flow, consider all factors except meandering. Flood plain n values normally are greater than channel values, primarily due to shallower depths of flow. The two factors requiring most careful consideration in the flood plain are obstructions and vegetation. Many flood plains have fairly dense networks of obstructions to be evaluated. Vegetation should be judged on the basis of growing-season conditions. The overland flow portion of flow time may be determined from Figure 8.03a.The flow time (in minutes) in the channel can be estimated by calculating the average velocity in feet per minute and dividing the length (in feet) by the average velocity. Table 8.03a Value of Runoff Coefficient (C) for Rational Formula

Land Use C Land Use C

Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10

Neighborhood areas 0.50-0.70 Sandy soil, ave., 2-7% 0.10-0.15

Sandy soil, steep, 7% 0.15-0.20

Residential: Heavy soil, flat, 2% 0.13-0.17

Single-family areas 0.30-0.50 Heavy soil, ave., 2-7% 0.18-0.22

Multi units, detached 0.40-0.60 Heavy soil, steep, 7% 0.25-0.35

Multi units, attached 0.60-0.75

Suburban 0.25-0.40 Agricultural land: Bare packed soil Industrial: Smooth 0.30-0.60

Light areas 0.50-0.80 Rough 0.20-0.50

Heavy areas 0.60-0.90 Cultivated rows

Heavy soil no crop 0.30-0.60

Parks, cemeteries 0.10-0.25 Heavy soil with crop 0.20-0.50

Sandy soil no crop 0.20-0.40

Play grounds 0.20-0.35 Sandy soil with crop 0.10-0.25

Pasture

Railroad yards areas 0.20-0.40 Heavy soil 0.15-0.45

Sandy soil 0.05-0.25

Unimproved areas 0.10-0.30 Woodlands 0.05-0.25

Streets:

Flume Design

101

Asphalt 0.70-0.95

Concrete 0.80-0.95

Brick 0.70-0.85

Drives and walks 0.75-0.85

Roofs 0.75-0.85

NOTE: The designer must use judgment to select the appropriate C value within the range for the appropriate land use. Generally, large areas with permeable soils, flat slopes, and dense vegetation should have lowest C values. Smaller areas with slowly permeable soils, steep slopes, and sparse vegetation should be assigned highest V value. Sources: American Society of Civil Engineers

Step 4. Determine the rainfall intensity, frequency, and duration (Figure 8.03b through 8.03g - source: North Carolina State Highway Commission; Jan.1973). Select the chart for the locality closest to your location. Enter the "duration" axis

of the chart with the calculated time of concentration,. . More vertically until you intersect the curve of the appropriate design storm, then move horizontally to read the rainfall intensity factor, i, in inches per hour.

Step 5. Determine peak discharge, Q , by multiplying the previously determined factors using the rational formula (Sample Problem 8.03a) Sample Problem 8.03a Determination of peak runoff rate using the rational method. Q = CiA

Given: Drainage area: 20 acres

Graded areas: 12 acres

Woodland: 8 acres

Maximum slope length: 400 ft Average slope: 3% area bare

Location: Raleigh, NC

Find: Peak runoff rate from 10-yr frequency storm

Solution: (1) Drainage area: 20 acres (given) (1) Determine runoff coefficient, C. Calculate Weighted Average

Area C from Table 8.03a

Graded 12 x 0.45 = 5.4

Woodland 8 x 0.15 = 1.2

20 6.6

C = 6.6/20 = 0.33

1. Find the time of concentration, from Figure 8.03a using maximum

length of travel = 400ft and height of most remote point above outlet = 400 ft x 3% = 12 ft; assuming overland flow on bare earth.

102

= 3.2 minutes. NOTE: Any time of flow in channel should be added to the overland flow to

determine . (1) Determine the rainfall intensity factor, i. i = 8.0 inches/hr (from Figure 8.03e) using 10-yr storm, 5 min. duration. (1) Q = C(i)(A) Q = 0.33 (8.0)(20) = 52.8 cfs; Use 53 cfs

Table 8.05a

Maximum Allowable Design Velocity

For Vegetated Channels

Typical Soil Grass Lining Permissible Velocity

Channel Slope Characteristic for Established Grass

Application Lining (ft/sec) 0-5% Easily Erodible Bermudagrass 5.0

Non_plastic Tail fescue 4.5

(Sand & Silts) Bahiagrass 4.5

Kentucky bluegrass 4.5

Grass-legume mixture 3.5

Erosion Resistant Bermudagrass 6.0

Plastic Tall fescue 5.5

(Clay mixes) Bahiagrass 5.5



5-10% Easily Erodible Bermudagrass 4.5







(Clay Mixes) Bahiagrass 5.0



>10% Easily Erodible Bermudagrass 3.5






(Clay Mixes) Bahiagrass 3.5


Flume Design

103

Source: USDA-SCS Modified

NOTE:

Selecting Channel Cross-Section Geometry

To calculate the required size of an open channel, assume the design flow is uniform and does not vary with time. Since actual flow conditions change throughout the length of a channel, subdivide the channel into design reaches and design each reach to carry the appropriate capacity. The three most commonly used channel cross-section are "V"-shaped, parabolic, and trapezoidal. Figure 8.05b gives mathematical formulas for the area, hydraulic radius and top width of each of these shapes. Table 8.05b Manning's n for Structure Channel Linings

Channel Lining Recommended

n values

Asphaltic concrete, machine placed 0.012

Asphalt, exposed prefabricated 0.015

Concrete 0.015

Metal, corrugated 0.024

Plastic 0.013

Shotcrete 0.017

Gabion 0.030

Earth 0.020

Erosion Control Blankets 0.030

Source: American Society of Civil Engineers (modified) Design Procedure-Permissible Velocity

The following is a step-by-step procedure for designing a runoff conveyance channel using Manning's equation and the continuity equation: Step1. Determine the required flow capacity, Q, by estimating peak runoff rate for the design storm (Appendix 8.03). Step2. Determine the slope and select channel geometry and lining. Step3. Determine the permissible velocity for the lining selected, or the desired velocity, if paved. (see Table 8.05a,pg. 8.05.4) Step 4. Make an initial estimate of channel size - divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area. Then select a geometry, depth and top width to fit site conditions. Step 5. Calculate the hydraulic radius, R, from channel geometry (Figure 8.05b,pg.8.05.5). Step 6. Determine roughness coefficient n. Structural Lining - see Table 8.05, pg. 8.05.6

Grass Lining: . Determine retardance class for vegetation from Table 8.05c, pg.8.05.8

To meet stability requirement, use retardance for newly mowed condition

104

( generally C and D). To determine channel capacity, use at least one retardance class higher. . Determine n from Figure 8.05c, pg.8.05.7

. Step 7. Calculate the actual channel velocity and required, V, using Manning's equation (Figure 8.05a, pg. 8.05.3), and calculate channel capacity, Q, using the continuity equation. Step 8. Check results against permissible velocity and required design capacity to determine if design is acceptable. Step 9. If design is not acceptable, alter channel dimension as appropriate. For trapezoidal channels, this adjustment is usually made by changing the bottom width. Sample Problem 8.05a Design of a grass-lined channel Channel summary

Trapezoidal shape, Z = 3, B = 3 ft, d = 1,5 ft, grade = 2%

Note: In Sample Problem 8.05a the "n-value" is first choosen based on a permissible velocity and not a design velocity criteria. Therefore the use of table 8.05c may not be accurate as individual retardance class charts when a design velocity is the determining factor. Tractive Force Procedure

The design of riprap-lined channel and temporary channel linings is based on analysis of tractive force. NOTE: The procedure is for uniform flow in channels and is not to be used for design of deenergizing devices and may not be valid for larger channels. To calculated the required size of an open channel, assume the design flow is uniform and does not vary with time. Since actual flow conditions change through the length of a channel, subdivide the channel into design reaches as appropriate. PERMISSIBLE SHEAR STRESS

The permissible shear stress, , is the force required to initiate movement of the lining material. Permissible shear stress for the liner is not related to the erodibility of the underlying soil. However, if the lining is eroded or broken, the bed material will be exposed to the erosive force of the flow. COMPUTING NORMAL DEPTH

The first step in selecting an appropriate lining is to compute the design flow depth (the normal depth) and determine the shear stress. Normal depth can be calculated by Manning's equation as shown for trapezoidal channel in Figure 8.05d. Values of the Manning's roughness coefficient for different ranges of depth are provided in Table 8.05e for temporary lining and Table 8.05f for riprap. The coefficient of roughness generally decrease with increase flow depth. Table 8.05e Manning's Roughness Coefficient for Temporary Lining Materials

n value for Depth Ranges

0-0.5 ft 0.5-2.0 ft >2.0 ft Lining Type

Woven Paper Net 0.016 0.015 0.015

Flume Design

105

Jute Net 0.028 0.022 0.019

Fiberglass Roving 0.028 0.021 0.019

Straw with Net 0.065 0.033 0.025

Curled Wood Mat 0.066 0.035 0.028

Synthetic Mat 0.036 0.025 0.021

Adapted from: FHWA-HEC 15, pg.37-April 1988

Table 8.05f Manning's Roughness Coefficient n-value

n value for Depth Ranges

Lining Category Lining Type 0-0.5 ft 0.5-2.0 ft 2.0 ft (0-15 cm) (15-60cm) (>60cm) Rigid Concrete 0.015 0.013 0.013

Grouted Riprap 0.040 0.030 0.028

Stone Masonry 0.042 0.032 0.030

Soil Cement 0.025 0.022 0.020

Asphalt 0.018 0.016 0.016

Unlined Bare Soil 0.023 0.020 0.020

Rock Cut 0.045 0.035 0.025

Gravel Riprap 1-inch (2.5 cm) 0.044 0.033 0.030

2-inch (5-cm) 0.066 0.041 0.034

Rock Riprap 6-inch (15-cm) 0.104 0.069 0.035

12-inch (30-cm) -- 0.078 0.040

Note:Values listed are representative values for the respective depth ranges. Manner's roughness coefficient, n, vary with the flow depth. DETERMINING SHEAR STESS

Shear stress, T, at normal depth is computed for lining by the following equation: T = yds

= Permissible shear stress

where:

T = shear stress in

y = unit weight of water, 62.4

d = flow depth in ft s = channel gradient in ft/ft.

If the permissible shear stress, , given in Table 8.05g is greater than the computed shear stress, the riprap or temporary lining is considered acceptable. If a lining is unacceptable, select a lining with a higher permissible shear stress and repeat the calculations for normal depth and shear stress. In some cases it may be necessary to alter channel dimensions to reduce the shear stress. Computing tractive force around a channel bend requires special considerations because the change in flow direction imposes higher shear stress on the channel bottom and banks.

106

The maximum shear stress in a bend, , is given by the following equation:

where:

The value of is related to the radius of curvature of the channel at its center

line, , and the bottom width of the channel, B, Figure 8.05e. The length of

channel requiring protection downstream from a bend, , is a function of the roughness of the lining material and the hydraulic radius as shown in Figure 8.05f. Table 8.05g Permissible Shear Stresses for Riprap and Temporary Liners

Permissible Unit Shear Stress, T

Lining Category Lining Type

Temporary Woven Paper Net 0.15

Jute Net 0.45

Fiberglass Roving: Single 0.60

Double 0.85

Straw with Net 1.45

Curled Wood Mat 1.55

Synthetic Mat 2.00

Erosion Control Blankets 2.25

Gravel Riprap 1 0.33

2. 0.67

Rock Riprap 6 2.00

9 3.00

12 4.00

15 5.00

15 6.00

21 7.80

24 8.00

Adapted From FHWA, HEC-15, April 1983, pgs. 17 & 37. Design Procedure-Temporary Liners

The following is a step-by-step procedure for designing a temporary liner for a channel. Because temporary liners have a short period of service, the design Q may be reduced. For liners that are needed for six months or less, the 2-yr frequency storm is recommended.

Flume Design

107

Step 1. Select a liner material suitable for site conditions and application. Determine roughness coefficient from manufacturer's specifications or Table 8.05e, pg.8.05.10. Step 2. Calculate the normal flow depth using Manning's equation.Check to see that depth is consistent with that assumed for selection of Manning's in Figure 8.05d, pg.8.05.11.For smaller runoffs Figure 8.05d is not as clearly defined. Recommended solutions can be determined by using the Manning equation. Step 3. Calculate shear stress at normal depth. Step 4. Compare computed shear stress with the permissible shear stress for the liner. Step 5. If computed shear is greater than permissible shear, adjust channel dimension to reduce shear or select a more resistant lining and repeat step 1 through 4. Technical Toolboxes, Inc.

109

Design of Uncased Pipeline Crossings This method is proven and acceptable and can be used in the cases when the crossing conditions for design are out of the scope and the limitations of API RP 1102 and PC-PISCES.

Reference: GPTC Guide for Transmission and Distribution Systems, Appendix G-192-15, A.G.A. Technical Toolboxes, Inc.

111

Gas Pipeline Pressure Testing - Maximum Pressure Drop


113

Gas Pipeline Pressure Testing - Required Time


115

Gas Properties

Gas Properties - This module uses the American Gas Association AGA-8 equation for calculating the physical properties of the natural gas mixture input by the user. The user will enter amount (the decimal value -%) of the listed components present in the gas mixture, along with the temperature and pressure to calculate the resultant properties. Technical Toolboxes, Inc.

117

HDD PE Pipe - ATL Allowable Tensile Load During Pull-In Installation

Reference: ASTM F 1962 - 05 and ASTM F 1804 - 08 Technical Toolboxes, Inc.

119

PE Pipe - Post-Installation Stress Analysis External Earth Load

Earth Load Deflection

Buoyant Deflection

120

Reissner Effect

Reference: ASTM F 1962 - 05 Technical Toolboxes, Inc.

121

PE Pipe - Pull Force and Installation Stress Analysis Minimum Bend Radius

Local Radius of Curvature

Average Radius of Curvature and Horizontal Transition Distance

Unconstrained Collapse

122

Axial Bending Stress

Pulling Force

HDD PE Pipe - Pull Force and Installation Stress Analysis

123

Effective Weight of Empty Pipe

124

Upward Buoyant Force

Hydrokinetic Pressure

Axial Tensile Stress

HDD PE Pipe - Pull Force and Installation Stress Analysis

125

Reduced PE Collapse Strength

Reference: ASTM F 1962 05 Technical Toolboxes, Inc.

127

Liquid Pipeline Hydraulics - Hazen-Williams Equation

The Hazen-Williams equation was developed specifically for water, but is used for other liquids. Its chief drawback is that the Hazen-Williams coefficient is largely an experience factor which also depends on the viscosity of the product flowing. This equation may be used for values of Reynolds numbers in the range of:

References:


"Flow of fluids", Technical Papers No.410, CRANE




129

Liquid Pipeline Hydraulics - Heltzel Equation

The Heltzel equation is an older equation which is still being used for Reynolds values in the range from 4,000 to 57,600. References:





131

Hoop and Longitudinal Stress

Hoop stress is determined by Barlow's formula

Longitudinal stress


133

Hot Tap Sizing

Scope:

When a compressible fluid, such as natural gas or air, is passed through an orifice, the rate of

flow is determined by the area of the orifice opening; the absolute upstream pressure is P1; and

the absolute downstream pressure is P2: unless the ratio P2/P1 equals or is less than the critical

ratio. When P2/P1 equals or is less than the critical ratio downstream pressure no longer effects

rate of flow through the orifice, and flow velocity at the vene contracta is equal to the speed of

sound in that fluid under that set of condition. This is commonly referred to as critical or sonic

flow. Orifice equations are therefore classified as "sonic" or "subsonic" equations.

1. 0 Critical Ratio-The equations for the critical ratio of a compressible gas is based on

P1 and the ratio, k of the specific heats of the gas for constant pressure, , and

constant volume .(See Table I for values of k.)

For natural gas this ratio is 0.55.

2. 0 Subsonic Orifice Flow Equation-Subsonic flow conditions exist where

.

M = 28.964 G

3. 0 Sonic Orifice Flow Equation-Sonic flow conditions exist where

These flow graphs are to be used as an aide in selecting the size and number of taps necessary to

flow a given amount of gas as various pressure drops across a hot tap opening. Under normal

circumstances, a pressure drop of approximately 1 psi across the top is ideal. Pipeline pressure or

134

size limitations may not allow a drop of 1 psi across the hot tap. The flow charts will provide the

amount of flow possible given the actual pressure drop up to and including 8 psi.

There are certain parameters which must be met in order to obtain accurate results from these

graphs. For a hot tap opening, the orifice is in a curved surface (the side of the pipeline being

tapped) and flow through the orifice enters the pipeline flow perpendicularly. The orifice

coefficient decreases the calculated flow value to adjust for this geometry. To calculate flow

through an orifice with geometry that differs from a hot tap, the orifice coefficient should be

adjusted to reflect the differing geometry. If the pipeline pressure varies substantially from 800

psig, the orifice flow equation (utilizing the actual pipeline pressure) should be used to determine

the flow volume. In special circumstances, when much larger pressure drops across the orifice

are encountered (P2< .55 P1), sonic flow formulations must be used to determine the flow

volume. For more detailed explanation of the orifice flow equation, foe both sonic and subsonic

flow, reference the Onshore Pipeline design Catalog of TI-59 software and the Design Procedure

Manual.

Where: A = Orifice area, square inches

Qm = Flow, standard cubic ft. per minute

M = Molecular weight of flowing gas

T = Inlet temperature,

K = Orifice coefficient, use

Z = Compressibility factor for inlet conditions,

(see AGA Report NO. 3 for Fpv.) Technical Toolboxes, Inc.

135

Pipeline Operation & Design How-To

Purpose: The purpose of this "How To" help system is to provide you with guidelines on how to use the Pipeline Engineer’s Toolbox to obtain fast and accurate results. The procedures contained within this "How To" help system have been generated from industry accepted standards. Technical Toolboxes, Inc.

137

Pipeline Hydrostatic Testing

Volume of Water Required to Fill Test Section

Volume of Water Required at Test Pressure

Pressure Change

138

Reference: Pipeline Rules of Thumb Handbook, Third Edition, Gulf Publishing Company Technical Toolboxes, Inc.

139

Gas Pipeline Hydraulics - IGT Distribution Equation


141

Installation of Pipelines by Horizontal Directional Drilling The calculation procedure in this module is based on Pipeline Research Council International, Inc. (PRCI) report number PR-227-9424 “Installation of Pipelines by Horizontal Directional Drilling, an Engineering Design Guide”

Research report in electronic form is included for easy reference. In order to access report, please select and click on “PRCI Design Guide” button on the program screen. Technical Toolboxes, Inc.

143

Internal Design Pressure - Steel Pipe ( From DOT Code, Part 195 ) (a) Internal design pressure for the pipe in a pipeline is determined in accordance with the following formula:

P - Internal design pressure in pounds per square inch gauge. S - Yield strength in pounds per square inch determined in accordance with paragraph (b) of this section. t - Nominal wall thickness of the pipe in inches. If this is unknown, it is determined in accordance with paragraph (c) of this section. D - Nominal outside diameter of the pipe in inches. E Weld/Seam joint factor determined in accordance with paragraph (e) of this section. F - A design factor of 0.72, except that a design factor of 0.60 is used for pipe, including risers, on a platform located offshore or on a platform in inland navigable waters, and 0.54 is used for pipe that has been subjected to cold expansion to meet the specified minimum yield strength and is subsequently heated, other than by welding or stress relieving as a part of welding, to a temperature higher than 900° F(482° C) for any period of time or over 600° F(316° C) for more than 1 hour. (b) The yield strength to be used in determining the internal design pressure under paragraph (a) of this section is the specified minimum yield strength. If the specified minimum yield strength is not known, the yield strength to be used in the design formula is one of the following: (1) (i) The yield strength determined by performing all of the tensile tests of API Specification 5L on randomly selected specimens with the following number of tests: Pipe size Number of tests

Less than 168.3 mm (6 5/8 in) nominal outside diameter. One test for each 200 lengths. 168.3 through 323.8 mm (6 5/8 through 12 3/4 in) nominal outside diameter. One test for each 100 lengths. Larger than 323.8 mm (12 3/4 in) nominal outside diameter. One test for each 50 lengths. (ii) If the average yield-tensile ratio exceeds 0.85, the yield strength shall be taken as 165, 474 kPa (24,000 psi). If the average yield-tensile ratio is 0.85 or less, the yield strength of the pipe is taken as the lower of the following: (A) Eighty percent of the average yield strength determined by the tensile tests. (B) The lowest yield strength determined by the tensile tests. (2) If the pipe is not tensile tested as provided in paragraph (b) of this section, the yield strength shall be taken as 165,474 kPa (24,000 psi). (c) If the nominal wall thickness to be used in determining internal design pressure under paragraph (a) of this section is not known, it is determined by measuring the thickness of each piece of pipe at quarter points on one end. However, if the pipe is of uniform grade, size, and thickness, only 10 individual lengths or 5 percent of all lengths, whichever is greater, need be measured. The thickness of the lengths that are not measured must be verified by applying a gage set to the minimum thickness found by the measurement. The

144

nominal wall thickness to be used is the next wall thickness found in commercial specifications that is below the average of all the measurements taken. However, the nominal wall thickness may not be more than 1.14 times the smallest measurement taken on pipe that is less than 508 mm (20 in) nominal outside diameter, nor more than 1.11 times the smallest measurement taken on pipe that is 508 mm (20 in) or more in nominal outside diameter. (d) The minimum wall thickness of the pipe may not be less than 87.5 percent of the value used for nominal wall thickness in determining the internal design pressure under paragraph (a) of this section. In addition, the anticipated external loads and external pressures that are concurrent with internal pressure must be considered in accordance with §195.108 and 195.110 and, after determining the internal design pressure, the nominal wall thickness must be increased as necessary to compensate for these concurrent loads and pressures. (e) The seam joint factor used in paragraph (a) of this section is determined in accordance with the following table: The seam joint factor for pipe which is not covered by this paragraph must be approved by the Administrator. References: DOT Code, Part 195

ASME B31.4 - 1998 Edition "Pipeline Transportation Systems for Liquid Hydrocarbons and other Liquids", Art. 404.3.1(c) Technical Toolboxes, Inc.

145

Internal Pressure % SMYS


147

DETERMINATION OF MAXIMUM ALLOWABLE LONGITUDINAL EXTENT OF CORROSION - ANSI B.31.G - 1991

The depth of a corrosion pit may be expressed as a percent of nominal wall thickness of pipe by:

% pit depth = 100 (1)

where

d = measured maximum depth of the corroded area(inches).

t = nominal wall thickness of pipe(inches). Additional wall thickness required for concurrent

external loads shall not be included in the calculation.

A contiguous corroded area having a maximum depth of more then 10 % but less than 80 % of

the nominal wall thickness of the pipe should not extend along the longitudinal axis of the pipe

for a distance greater than that calculated from:

(2)

where

L = maximum allowable longitudinal extent of the corroded area(inches).

D = nominal outside diameter of the pipe(inches).

B = a value which may be determined from :

(3)

except that B may not exceed the value 4. If the corrosion depth is between 10% and 80%, use B

= 4.0 in Equation (2). Technical Toolboxes, Inc.

149

Liquid Pipeline Hydraulics

Liquid Pipeline Hydraulics - Includes 5 flow equations to determine flow rate, upstream and downstream pressure, internal pipe diameter, pressure drop and velocity.

Colebrook - White Hazen - Williams Heltzel T.R. Aude Shell / MIT


151

Live Load: AASHTO H20 Load on Buried PE Pipe - 12" Thick Pavement

1. Dead/Earth Load

A. Prism Load



152


2. Live Load: AASHTO Load on Buried PE Pipe - 12" Thick Pavement


Live Load: AASHTO H20 Load on Buried PE Pipe - 12" Thick Pavement

153


Reference:

154





155

Live Load: AASHTO H20 Load on Buried PE Pipe - Flexible or no Pavement

1. Dead/Earth Load

A. Prism Load



156


2. Live Load: AASHTO Load on Buried PE Pipe - Flexible or no Pavement


Live Load: AASHTO H20 Load on Buried PE Pipe - Flexible or no Pavement

157


Reference:

158





159

Live Load: Aircraft Load on Buried PE Pipe 1. Dead/Earth Load

A. Prism Load




160

2. Live Load: Aircraft Load on Buried PE Pipe


Live Load: Aircraft Load on Buried PE Pipe

161


Reference:

162





163

Live Load: Cooper E-80 Railroad Load on Buried PE Pipe

1. Dead/Earth Load

A. Prism Load



164


2. Live Load: Cooper E-80 Railroad Load on Buried PE Pipe


Live Load: Cooper E-80 Railroad Load on Buried PE Pipe

165


Reference:

166





167

Live Load: Distributed Surface Load on Buried PE Pipe - Unpaved Road Only (Timoshenko's Equation)

1. Dead/Earth Load

A. Prism Load


168



2. Live Load: Distributed Surface Load on Buried PE Pipe - Unpaved Road Only (Timoshenko's Equation)

The Timoshenko equation gives soil pressure at a point directly under a distributed surface load, neglecting any pavement. This conservative equation may be used for the vehicle that does not much AASHTO standard live loads such as off-road vehicles.

Impact factors for unpaved road are 2.0 and higher.


Live Load: Distributed Surface Load on Buried PE Pipe - Unpaved Road Only (Timoshenko's

Equation)

169


Reference:

170





171

Live Load: Multiple Wheel not over Buried PE Pipe - Concentrated Point Load

1. Dead/Earth Load

A. Prism Load



172


2. Live Load: Multiple Wheel not over Buried PE Pipe - Concentrated Point Load

This method is based on of Boussinesq equation for stress distribution in soil. It assumes that load is concentrated in the point.


Live Load: Multiple Wheel not over Buried PE Pipe - Concentrated Point Load

173


Reference:

174





175

Live Load: Multiple Wheel over Buried PE Pipe - Concentrated Point Load

1. Dead/Earth Load

A. Prism Load



176


2. Live Load: Multiple Wheel over Buried PE Pipe - Concentrated Point Load

This method is based on of Boussinesq equation for stress distribution in soil. It assumes that load is concentrated in the point.


Live Load: Multiple Wheel over Buried PE Pipe - Concentrated Point Load

177


Reference:

178





179

Live Load: Single Wheel over Buried PE Pipe - Concentrated Point Load

1. Dead/Earth Load

A. Prism Load



180


2. Live Load: Single Wheel over Buried PE Pipe - Concentrated Point Load

This method is based on Newmarks and Ho lls integration of Boussinesq equation for

stress distribution in soil. It assumes that load is concentrated in the point.

Load coefficient Choll is selected from the table below:

Live Load: Single Wheel over Buried PE Pipe - Concentrated Point Load

181


182


Reference:





183

Local Atmospheric Pressure The local atmospheric pressure may be calculated using Smithsonian Metrological Tables:

Reference: American Gas Association, Report No.3, A.G.A. Catalog No. XQ9210 Technical Toolboxes, Inc.

185

Longitudinal Stress


187

EVALUATION OF MAOP IN CORRODED AREAS - ANSI B.31.G -1991

Computation of A

If the measured maximum depth of the corroded area is greater than 10 % of the nominal wall

thickness, and the measured longitudinal extent of the corroded area is greater than the value

determined by Equation (2), calculate:

where

Lm = measured longitudinal extent of the corroded area(inches).


t = nominal wall thickness of the pipe, in. Additional wall thickness required

for concurrent external loads shall not be included in calculation.

COMPUTATION OF P’

(a) For values of Less Than or Equal to 4.0.

where

= the safe maximum pressure for the corroded area

d = measured maximum depth of corroded area, in.

may not exceed P

P = the greater of either the established MAOP or

Where

S = specified minimum yield strength (SMYS), psi

F = appropriate design factor from ASME B31.4, ASMEB31.8, or ASME B31.11

T = temperature derating factor from the appropriate B31 Code(if not listed, T = 1)


T = nominal wall thickness of the pipe(inches). Additional wall thickness required

for concurrent external loads shall not be included in the calculations.

(b) For Value of A Greater Than 4.0

MAOP and

If the established MAOP is equal to or less than , the corroded region may be used for service at

that MAOP. If the established MAOP is greater than , then a lower MAOP should be established

not to exceed , or the corroded region should be repaired or replaced.

Reference:

ASME B31G "Manual for Determining the Remaining Strength of Corroded Pipeline"

188


189

Math & Graphics Module

New comprehensive math/graphics calculator module designed to provide users of all levels with an easy, intuitive way to perform various simple and complex mathematical tasks as well as 2D/3D graphing, solving equations, etc. Users can input their own equations and variables and save them for recall. Technical Toolboxes, Inc.

191

Maximum Allowable Pipe Span Length

Step 1: Variables Definition D - Pipe Outside Diameter [in]

W - Weight [lb/ft], includes water weight if hydrostatic testing is specified

MOAP - Maximum Allowable Operating Pressure [psi],

MOP - Maximum Operating Pressure [psi],

t - Pipe Wall Thickness [in]

SMYS - Specified Minimum Yield Strength or Grade of Steel [psi] ,

E - Modulus of Elasticity ( 29000 ksi )

H - Hoop Stress, [psi]

B - Bending Stress [psi]

M - Bending Moment [ft-lb]

L - Span Length [ft]

d - Deflection [in]

Step 2: Calculate Hoop Stress

Where P = MOP

Step 3: Calculate Maximum Allowable Bending Stress Solve Von Mises Equation through Quadratic Equation, and than solve for

Bending Stress B

Step 4: Calculate Maximum Allowable Bending Moment

Step 5: Calculate Maximum Span Length L, due to bending

Step 6: Calculate Maximum Span Length L, due to deflection

Important Notes : Maximum Operating Pressure (MOP) Must Be Less Then Maximum Operating Pressure

(MAOP)

192

Maximum Allowable Operating Pressure is calculated in accordance to DOT Code Part 192

using design factors


193

Maximum Impact Load and Penetration Depth A. Maximum Impact Load

194

B. Penetration Depth

Reference: “Guidelines for the Design of Buried Steel Pipe” American Lifeline Alliance Technical Toolboxes, Inc.

195

Modulus of Soil Reaction (E') - Average Values for Iowa Formula

Reference: “Modulus of Soil Reaction Values for Buried Flexible Pipe”, Journal of the Geotechnical Engineering Division, ASCE, Vol. 103, No GT 1, Howard, A.K. Technical Toolboxes, Inc.

197

Modulus of Soil Reaction (E') - Values of E' for Pipe Embedment

Reference: “Evaluation of Modulus of Soil Reaction E and its Variation with Depth”, Report No. UCB/GT/82-02, Technical Toolboxes, Inc.

199

Resistance to Earth of Multiple Vertical Anodes in Parallel

R - Anode resistance to earth [ohm]

- Soil resistivity [ohm-cm]

L - Anode length [ft.]

d - Anode diameter [ft.]

N - Number of anodes in parallel

s - Anode spacing in feet

h - Earth surface - Anode [ft.]


201

Nominal Wall Thickness Straight Steel Pipe Nominal Wall Thickness Straight Pipe

Reference: ASME B31.4 - 1998 Edition "Pipeline Transportation Systems for Liquid Hydrocarbons and other Liquids", , Art. 404.1 Technical Toolboxes, Inc.

203

Ohm's Law for Corrosion Current


205

How to Export Report in Microsoft Outlook Express? Requirements: In order to export report to your email client such as Microsoft Outlook Express, the email software must be installed on your computer.


select and click on the “Copy” button.

2. Minimize application, open MS Outlook Express (or any other email client) select “Edit” and then click “Paste”

206

Note: The report should be exported page by page, to scroll through pages use following

buttons on the report toolbar. The imported report may need some additional editing. Technical Toolboxes, Inc.

207

Pack in Pipelines

Reference: DOT Inspector's Handbook Technical Toolboxes, Inc.

209

Physical Properties of Fluids

This module contains a comprehensive list of petroleum fluids and their physical properties. From the table of elements select the appropriate fluid and the related properties will appear in the windows. Technical Toolboxes, Inc.

211

Pipe Database

The Pipe Database contains multiple complete on-line databases containing all current steel and plastic pipe specifications for high and low pressure pipes, incorporating API & AGA standard pipe and non-standard pipe. All pipe data is available in English or metric measurements. Included is a custom database for users to enter custom or user-defined pipe specifications for storage and use. The available pipe data for users is listed below:

API 5L - For Nominal Sizes 1/8" through 80" API 5LX - For Nominal Sizes 2 3/8" through 64" AGA SDR/Wall Thickness - For Nominal Sizes 1/2" through 12" DRISCOPIPE Series 1000 - For Nominal Sizes 3/4" through 54" Custom Pipe Database - Empty database designed for user to enter custom pipe

specifications and data. All entered data will be saved or updated.


213

Pipe Requirements for Horizontally Drilled Installation

1. Determine Hoop Stress:

1. Determine Overburden Stress:

1. Determine Total Circumferential Stress:

1. Determine Bending Stress:

1. Determine Total Combined Stress and select max value:

214

1. Determine calculated design factor:

1. Determine maximum pull force:

1. Determine minimum bend radius - entry & exit at installation:

1. Maximum SMYS for hydrostatic pressure:

1. Determine maximum cantilever length

1. Determine maximum allowable hydrostatic test pressure:


215

Pipe Stress Analysis

CAESAR II Pipe stress analysis and design for a wide range of piping systems including static and dynamic

solutions and code compliance options. Caesar II produces results that completely describe the

system behavior based on guidelines and design limits from ASME B31, ASME section III &

VIII, WRC, API, NEMA, EJMA and others ensuring that your final solution is within code

specifications. Input and modeling capabilities include; structural steel modeling, buried pipe

modeling, automatic expansion joint modeling, multiple valve and flange databases, etc.

Caesar II begins a static analysis by recommending load cases necessary to meet code

compliance for the specified loads and piping code. In most cases, CAESAR’s default load cases

are desired, but you have the complete freedom to alter, add or delete load cases. This ability to

perform algebraic combinations of displacements, forces and stresses frees you to build your

own load cases to suit specific problems. Models composed of piping and structural elements can

be analyzed together, and the effect of the non-linear pipe/structure interaction can be observed

graphically and numerically.

A dynamic analysis in CAESAR II begins with the specification of the dynamic input data, such

as lumped masses, observed vibration, snubbers, and spectrum definitions. Spectra can be

defined by the user, or you can use the built-in shock spectra. The ability to handle "Force"

spectra makes the solution to impact loading, such as water hammer, slug flow, steam hammer

and relief valve firing problems, possible.

The output modules of CAESAR II provide you with still more interactive flexibility. Load case

and report selection, heading control and report annotation combine to give you a complete tool

for reviewing analysis results. You see what you want, and only what you want, when you want

it. The output graphics show displaced shapes, forces, moments, stresses and animated motions,

giving a comprehensive picture of the piping system behavior. The advanced interactive features

of Caesar II enable a piping system to be completely analyzed, modified and checked before a

single report is printed, saving time and money. Technical Toolboxes, Inc.

217

Pipe Wall Compressive Stress (PE Pipe Crushing)

Reference:

1. “Polyethylene Pipe Handbook: Design of PE Piping Systems”, Second Edition, Plastic Pipe Institute, Inc.


219

Pipeline Anchor Force Analysis

Tensile stress due to Poisson effect:

Compressive stress due to temperature change:

Net longitudinal stress at the beginning point ( A ) of the transition:

Net longitudinal stress at the end point ( B ) of transition:

Net strain at point B, will be:

Soil resistance force based on Wilburs formula for average soil:

Length of transition zone:

220

Total pipe movement at point B will be:

Anchor force:

Reference: "Pipe Line Industry", Wilbur, W.E., February 1963

"Theory of Elasticity", Timoshenko, s. Technical Toolboxes, Inc.

221

Pipeline Corrosion

Pipeline Corrosion - This module incorporates ASME B31G into calculations for MAOP and external corrosion limits plus various current and resistance calculations.

ASME B31G - Maximum Allowable Longitudinal Extent of Corrosion ASME B31G - Evaluation of MAOP in Corroded Areas Rate of Electrical Current Flow Through the Corrosion Cell Relationship Between Resistance and Resistivity Electrolyte Resistance from Surface of an Electrode to any Distance Ohm’s Law for Corrosion Current Electrical Resistance of a Conductor


223

Pipeline Toolbox

Pipeline Facilities

Gas Properties

Physical Properties of Fluids

Meter & Regulator Station Designer Gas Pipeline Hydraulics

Liquid Pipeline Hydraulics

Pipeline Stress Analysis

Pipeline Testing & Maintenance

Pipeline Corrosion

Cathodic Protection

Pipe Database

Engineering Units Conversion

Engineering Drawing Board

DOT & MMS Pipeline Regulations

Math & Graphics Module

Power Tools Technical Toolboxes, Inc.

225

Pipeline Facilities

Hot Tap Sizing

Regulator Station Sizing

Relief Valve Sizing

Reinforcement of Welding Branch Connection Technical Toolboxes, Inc.

227

Purging Calculations

Method "A"

1. Find flow rate through the blow-off valve by using the formula for critical velocity,

Q = K

where Q = flow rate, MSCFH

K = flow coefficient, MSCF/(h x psi absolute)

P2 = pressure just upstream of blow-off valve, psi

2. From rearranged Weymouth formula to find an estimate pressure value of necessary to

maintain this flow rate:

3. Recommended purge time is 2T. The minimum purge time in minute is

or

where D = inside diameter of pipe, in

L = length of purge section, mi

C

C = (0.0361)D (1-h Weymouth coefficient in MSCF/h x mi)

Pm = average pressure, psi absolute

P1 = pressure at upstream end of section, psi absolute

P 2= pressure at downstream end of section, psi absolute (just

upstream of blow-off valve)

K = 1-h blow-off coefficient for standard blow-off sizes,

MSCF/ ( h x psi absolute)

One-Hour-Blow-off Coefficient for Standard Blow-off Sizes: Blow-off size, in. K, MSCF /(h x psi absolute)

1 0.75

2 3.0

3 6.0

228

4 13.5

6 24.0

8 47.0

10 72.0

where c = conversion constant = 60/14.73 = 4.07

V = actual volume of pipe section purged, thousand ft , where

pipe section is assumed to be filed with air prior to purge

K = blow-off coefficient, MSCF /(h x psi absolute)


P1 = pressure at downstream end of section, psi absolute, just

upstream of blow-off valve

The volume of gas lost, MSCF, is

where V = actual volume of pipe action purged, thousand ft ,where

pipe section is assumed to be filled with air prior to purge;

equal to (0.028798)D , D in inches, L in miles


P2 = pressure at downstream end of section, psi absolute

( just upstream of blow-off valve)

C , with C = (0.0361)D , D in inches, L in miles

K = 1-hour blow-off coefficient for standard blow-off sizes,

MSCF/(h x psi absolute)

Method "B"

where V = actual volume of pipe purged, thousand ft , where

pipe section is assumed to be filled with air prior to purge;

equal to(0.028798)D L, D in inches, L in miles

P = pressure of downstream end of section, psi absolute

( just upstream of blow-off valve)

t = actual time of purge, minutes

K = 1-h blow-off coefficient for standard blow-off sizes,

MSCF/ (h x lb/in absolute) Technical Toolboxes, Inc.

229

Pipeline Testing & Maintenance

Testing & Maintenance - This module includes calculations for pipeline hydrostatic testing and pack in the pipeline. Also included are a complete series of calculations for blowdown and purging.

Pipeline Hydrostatic Testing Gas Pipeline Pressure Testing - Required Time Gas Pipeline Pressure Testing - Maximum Pressure Drop Gas Pipeline Blowdown - Time Gas Pipeline Blowdown - Volume Lost - Large Hole Gas Pipeline Blowdown - Volume Lost - Small Hole Gas Pipeline Purging - Required Time Gas Pipeline Purging - Volume Lost Pack In Pipeline


231

Piping Design & Drafting (CAD)

CADWorx/PIPE An AutoCAD based design and drafting piping package. Includes a two-way link to CAESAR II.

Generates automatic ISO’s, Ortho’s, 2D, 3D and more. CADWorx/PIPE works with AutoCAD

R12c3 (DOS, Windows 3.1, Windows 3.11 for Work Groups & Windows 95) and also with

AutCAD R13c4 (DOS, Windows 95 & Windows NT). For a two-way link with CAESAR II,

CADWorx/PIPE requires either Windows 95, Windows NT or DOS. Technical Toolboxes, Inc.

233

Gas Pipeline Hydraulics - Pittsburgh Equation

The Pittsburgh equation is used in low pressure pipelines within the following range:


235

Power Consumption of a Cathodic Protection Rectifier

Note : The formula is approximate, and based on 48% efficiency of rectifier. Technical Toolboxes, Inc.

237

POWER TOOLS

The "Power Tools" button has two (2) purposes:

1. To be used by you and your company to "customize" the product and allow you to "launch" your internal software applications through your local area network (LAN) or intranet. Technical Toolboxes, Inc. (TTI) can assist you in this effort, if required, as well as to provide it’s services to you to enhance and upgrade older internal "legacy" software to meet today’s software standards, i.e. Windows (3.X, 95, NT, etc.), OLE Automation, ActiveX, ODBC, etc. Click here for further information

2. The second purpose of the Power Tools icon is to offer optional advanced software applications from third party vendors to assist you and your company with solutions to special situation problems. Below you will find a list of the current "Power Tools" available from TTI. Click here for further information


239

Power Tools Menu

Please click on the appropriate hot spot for further detailed information on each of the available

"Power Tools":

Distribution Automation API 1102 Compliance Regulations & Standards Pipeline Modeling Piping Design & Drafting (CAD) Fluid Properties (PVT) Storage Tanks Pipe Stress Analysis Pressure Vessels


241

Pressure Vessels

PVElite Complete pressure vessel analysis and design including towers, per ASME Section VIII,

Division 1 & 2 codes and BS-5500 Head & Shell equations. PVElite includes the same

functionality as CodeCalc. PVElite Version 3.0 is a Windows 95 and Windows NT based

program.

PVElite’s powerful analysis engine is designed to provide computational capabilities ranging

from the most basic vessel component design to very complex complete vessel analysis. This

analysis engine provides the user with the tools to perform complete analysis of both horizontal

and vertical vessels in almost any configuration and under a variety of operating conditions. The

power of PVElite can quickly and reliably analyze conditions of internal and external pressure,

deadweight calculations (including erected weight, operating weight, and hydrostatic test

weight), live load calculations including wind and seismic, and other calculations required to

satisfy a host of governing specifications such as ASME VIII Divisions 1 and 2. PVElite features

multiple libraries which contain properties for over 3600 materials, including allowable stress

versus temperature, yield stress versus temperature, external pressure charts, UNS number, and

product form. These material properties are listed just as they appear in the ASME Code with the

added benefit of being sorted alphabetically. PVElite hosts a vast number of features and

capabilities including an extensive on-line help capability.

CodeCalc An engineering library of PC tools to assist in the design and analysis of the components

associated with pressure vessels, heat exchangers and piping systems. CodeCalc is a DOS based

program. Technical Toolboxes, Inc.

243

Pressure Wave Speed in Pipe Pressure wave in pipes for hydrocarbons

a = wave speed

K = adiabatic bulk modulus of fluid

= density of fluids

E = modulus of elasticity of pipe steel D = pipe diameter

t = pipe wall thickness

m = coefficient for kind of pipe support WOSTL equation for calculation of adiabatic bulk modulus for hydrocarbons

P = pressure, psig

A = API gravity at 60 F

T = temperature R = F + 460

Reference: "Hydraulics for Pipeliners", C. B. Lester Technical Toolboxes, Inc.

245

Centrifugal Pump - Specific Speed

Reference:



247

Pump Station Piping - Pipe Diameter and Velocity

Reference: API RP 14E Technical Toolboxes, Inc.

249

Rate of Electrical Current Flow Through the Corrosion Cell


251

Reciprocating Pump - Acceleration Head

Reference:



253

Reciprocating Pump - Displacement and Actual Capacity

Actual Capacity

Reference:



255

Reciprocating Pump - Piston Rod Load

Reference: The Reciprocating Pump; Theory, Design, and Use; Krieger Publishing Company Technical Toolboxes, Inc.

257

Regulations & Standards

DOT Gas Pipeline Regulation Amendments: Licensed from ViaData Corporation, the U.S. Department of Transportation (DOT) gas pipeline

Amendments to 49 CFR 190-198.

DOT Gas Pipeline Regulation Interpretations: Licensed from ViaData Corporation, the U.S. Department of Transportation (DOT) gas pipeline

Interpretations to 49 CFR 190-198 with AGA GPTC Guide.

DOT Liquid Pipeline Regulation Amendments: Licensed from ViaData Corporation, the U.S. Department of Transportation (DOT) Hazardous

Liquid Pipeline Amendments parts 49 CFR 190, 194, 195, 198 including printable report forms.

DOT Liquid Pipeline Regulation Interpretations: Licensed from ViaData Corporation, the U.S. Department of Transportation (DOT) Hazardous

Liquid Pipeline Interpretations parts 49 CFR 190, 194, 195, 198 including printable report forms.

DOT Drug & Alcohol Resting Regulations: Licensed from ViaData Corporation, the U.S. Department of Transportation (DOT)

Drug/Alcohol Testing - 49CFR 40, 199. Technical Toolboxes, Inc.

259

Reinforcement of Welded Branch Connection

ASME 31.4 Art. 404.3.1(c) - DESIGN CRITERIA FOR WELDED BRANCH CONNECTION

260

Reference: ASME B31.4 - 1998 Edition "Pipeline Transportation Systems for Liquid Hydrocarbons and other Liquids", Art. 404.3.1(c) Technical Toolboxes, Inc.

261

Relationship Between Resistance and Resistivity


263

Relief Valve Sizing for Gas or Vapor Relief

CRITICAL FLOW BEHAVIOR

If a compressible gas is expanded across a nozzle, an orifice, or the end of a pipe, its velocity and

specific volume increase with decreasing downstream pressure. For a given set of upstream

conditions (using the example of a nozzle), the mass rate of flow through the nozzle will increase

until a limiting velocity is reached in the throat .It can be shown that the limiting velocity is the

velocity of sound in the flowing media at that location. The flow rate that corresponds to the

limiting velocity is known as the critical flow rate.

The absolute pressure ratio of the pressure in the throat at sonic velocity to the inlet

pressure is called critical pressure ratio. is known as the critical flow pressure.

Under critical flow conditions, the actual pressure in the throat cannot fall below the critical flow

pressure even if a much lower pressure exists downstream. At critical flow, the expansion from

throat pressure to downstream pressure takes place irreversibly with energy dissipated in

turbulence into the surrounding fluid.

The critical flow pressure ratio in absolute units may be estimated using the ideal gas

relationship in Equation 1:

(1)

Where:

The sizing equations for pressure relief valves in vapor or gas service fall into two general

categories depending on whether the flow is critical or subcritical. If the pressure downstream of

the throat is less than or equal to the critical flow pressure, , then critical flow will occur, and

the procedures in SIZING FOR CRITICAL FLOW should be applied. (See Table 8 for typical

critical flow pressure ratio value.) If the downstream pressure exceeds the critical pressure, ,

then subcritical flow will occur, and procedure in SIZING FOR SUBCRITICAL FLOW

SHOULD BE APPLIED.

SIZING FOR CRITICAL FLOW

General

Pressure relief valves in gas or vapor service that operate under critical flow conditions (see

4.3.1) may be sized using Equations 2-4. Each of the equations may be used to calculate the

effective discharge area, A, required to achieve a required flow rate through a pressure relief

valve. A valve that has an effective discharge area equal to or greater than the calculated value of

A is then chosen for the application.

264

Where:

A = required effective discharge area of the valve, in square inches.

W = required flow through the valve, in pounds per hour.

C = coefficient determined from an expression of the ratio of the specific heats of the

gas or vapor at standard conditions. This can be obtained from Figure 26 or Table 9.

Note: See for applications that involve superimposed back pressure of a magnitude that will

cause critical flow.

T = relieving temperature of the inlet gas or vapor, in degrees Rankine

(degrees Fahrenheit + 460).

Z = compressibility factor for the deviation of the actual gas from a perfect gas,

a ratio evaluated at inlet conditions.

M = molecular weight of the gas or vapor. Various handbooks carry tables

of molecular weights of materials, but the composition of the flowing

gas or vapor is seldom the same as that listed in tables. This value should be

obtained from the process data. Table 8 lists values for same common fluids.

V = required flow through the valve, in standard cubic feet per minute at 14. 7

pounds per square inch absolute and .

G = specific gravity of gas referred to air = 1.00 for air at 14.7 pounds per square

inch absolute and .

The value of the coefficient C can be evaluated from the expression of the ratio of the specific

heats of the gas or vapor as shown in Figure 26.

The ratio of specific heats of any ideal gas and possibly the ratio of specific heats of a diatomic

actual gas can be found in any acceptable reference work.

Table 9 complements Figure 26 where When k cannot be determined, it is

suggested that C = 315.

Relief Valve Sizing

265

While ideal gas low behavior is generally acceptable for the majority of refinery applications,

Appendix E should be referred to for unusual situations in which deviation from ideal behavior is

significant.

Example:

In this example, the following relief requirements are given:

. Required hydrocarbon vapor flow, W, caused by an operational upset,

of 53,500 pounds per hour.

1. Molecular weight of hydrocarbon vapor [a mixture of butane ( )and

pentane ( )], M, of 65.

1. Relief temperature, T, of .

. Relief valve set at 75 pounds per square inch gauge, the design pressure

of the equipment.

. Basic pressure of 0 pounds per square inch gauge.

In this example, the following data are derived:

. Permitted accumulation of 10 percent.

1. Relieving pressure, P , of 75 x 1.1 + 14.7 = 97.2 pounds

per square inch absolute.

. Calculated compressibility, Z of 0.84 (If a calculated compressibility is not

available, Z = 1.0 should be used.)

. Critical back pressure (From table 8) of 97.2 x 0.59 = 57.3 pounds per

square inch absolute (42.6 pounds per square inch gauge).

Note: Since the back pressure (0 pounds per square inch gauge) is less than the critical back

pressure (42.6 pounds per square inch gauge), the relief valve setting is based on the critical flow

equation.

1. .

2. Capacity correction due to back pressure, , of 1.0.

The size of a single pressure relief valve is derived from Equation as follows:

See API Standard 526, which also provides a purchase specification sheet for flanged steel relief

valves.

Select "P" letter orifice size (6.38 square inches)

SIZING FOR SUBCRITICAL FLOW: GAS OR

266

VAPOR OTHER THAN STEAM

General

When the ratio of back pressure to inlet pressure exceeds the critical pressure ratio , the

flow through the pressure relief valve is subcritical . Equation 5 - 7 may be used to calculate the

required effective discharge area for a conventional relief valve that has its spring setting

adjusted to compensate for superimposed back pressure and for sizing a pilot-operated relief

valve.

Note: Balanced-bellows relief valves that operate in the subcritical region should be sized using

Equations 2-4. The back pressure correction factor for this application should be obtain from the

valve manufacturer.

Where:

A = required effective discharge area of the valve, in square inches.

W = required flow through the valve, in pounds per hour.

=

k = ratio of the specific heats.

r = ratio of back pressure to upstream relieving pressure, .

Z = compressibility factor for the deviation of the actual gas from a perfect gas,

a ratio evaluated at inlet conditions.

T = relieving temperature of the inlet gas or vapor, in degrees Rankine (degrees

Fahrenheit + 460).

M = molecular weight of the gas or vapor. Various handbooks carry tables of

molecular weights of materials, but the composition of the flowing gas or vapor is

seldom the same as that listed in tables. This value should be obtained from the

process data. Table 8 lists value for same common fluids.

V = required flow through the valve, in standard cubic feet per minute at 14.7 pounds

per square inch absolute and .

G = specific gravity of gas referred to air = 1.00 for air at 14.7 pounds per square inch

Relief Valve Sizing

267

absolute and .

Example






1. Relief temperature, T, of


of the equipment.

. Constant back pressure of 55 pounds per square inch gauge. The spring

setting of the valve should be adjusted according to the amount of constant back pressure

obtained.



1. Relieving pressure, P , of 75 x 1.1 + 14.7 = 97.2 pounds


. Calculated compressibility, Z = 0.84 (If a calculated compressibility is not




Note: Since the back pressure (55 pounds per square inch gauge) is greater than the critical back

pressure (42.6 pounds per square inch gauge), the relief valve setting is based on the subcritical

flow equation (see Equation 5).

. Permitted build-up back pressure of 0.10 x 75 = 7.5 pounds

per square inch.

. Total back pressure of 55 + 7.5 = 62.5 pounds per square

inch gauge.

1.

2. Coefficient of subcritical pressure flow, , of 0.86 (from Figure 29).

The size of a single pressure relief valve is derived from Equation as follows:

268

See API Standard 526, which also provides a purchase specification sheet for flanged steel relief

valves.

Select "P" letter orifice size (6.38 square inches)

.

ALTERNATIVE SIZING PROCEDURE FOR

SUBCRITICAL FLOW

General

Critical flow Equations 2-4 may be used to calculate the required discaharge area of a pressure

relief valve used in subcritical service. The area obtained using this sizing procedure is identical

to the area obtained using the subcritical flow equations. (The capacity correction factor due to

back pressure is derived by setting the subcritical flow equation equal to the critical flow

equation and algebraically solving for .) This alternate sizing procedure allows the designer

to use the familiar critical flow equation to calculate the same area obtained with the subcritical

flow equation. A graphical presentation of the capacity correction factor, , is given in Figure

30. It should be noted that this correction factor is used only for the sizing of conventional

(nonbalanced) relief valves that have their spring setting adjusted to compensate for the

superimposed back pressure. The correction factor should not be used to size balanced-type

valves.

Example






1. Relief temperature, T, of .


of the equipment.

. Constant back pressure of 55 pounds per square inch gauge. The spring

setting of the valve should be adjusted according to the amount of constant

back pressure obtained.



1. Relieving pressure, , of 75 x 1.1 + 14.7 = 97.2 pounds


Relief Valve Sizing

269

. Calculated compressibility, Z of 0.84 (If a calculated compressibility is not




Note: Since the back pressure (55 pounds per square inch gauge) is greater than the critical back

pressure (42.6 pounds per square inch gauge), the sizing of the relief valve is based on the

subcritical flow equation. The back pressure correction factor, , should be determined using

critical flow formulas.

. Build-up back pressure of 0.10 x 75 = 7.5 pounds

per square inch.

. Total back pressure of 55 + 7.5 + 14.7 = 77.2 pounds per

square inch absolute.

1. .

2. Back pressure correction factor, , of 0.88 (from Figure 30)

. Coefficient determined from an expression of the ratio of specific the

heat of the gas or vapor at standard conditions, C, of 326 ( form Table 9)

The size of the relief valve is derived from Equation 2 as follows:

Note: This area requirement is the same at that obtained using the subcritical flow equation.


271

Relief Valves - Reactive Force

Reference: Marks “Standard Handbook for Mechanical Engineers”, McGraw-Hill Technical Toolboxes, Inc.

273

Required Number of Anodes and Total Current Requirement


275

Required Pump Horsepower Hydraulic/Water Horsepower

Brake Horsepower

Reference:


2. Pump Handbook, Fourth Edition, McGraw-Hill Professional


277

Resistance to Earth of an Impressed Anode Ground Bed


279

Restrained Liquid Pipeline Stress Analysis - Steel Pipe Hoop Stress

Longitudinal Stress due to Thermal Expansion

Net Longitudinal Stress Restrained Pipe

Reference: ASME B31.4 - 2009 Technical Toolboxes, Inc.

281

Rudenberg Formula

Vx - Potential at x in volt caused by grounds anode current

I - Ground anode current in amperes

- Earth resistivity in ohm-centimeters

y - Length of anode in earth in feet

x - distance from ground anode in feet

If x greater then 10y then,


283

Bending Stress in Pipelines Caused by Fluid Flow Around Pipeline

S = bending stress, PSI

w = unit weight of fluid, pounds per cubic feet

@ 59 degree and 14.7 PSI:

air = 0.07651

water = 62.4

D =outside diameter of pipe, inches

d = inside diameter of pipe, inches

V = velocity of fluid, feet per second

L= length of pipe, feet

BENDING STRESS IN PILING

CAUSED BY FLUID FLOW

AROUND PILING

D = outside diameter of piling, inches Technical Toolboxes, Inc.

285

Liquid Pipeline Hydraulics Shell / MIT Equation

The Shell / MIT equation is used for calculating pressure drop and flow rates for pipelines. The equation uses a modified Reynolds number. When calculating FLOW RATE or INTERNAL PIPE DIAMETER, you have to enter an estimated modified Reynolds number (r) in the appropriate range indicated below. After the first calculation using the estimated modified Reynolds number, you must replace the estimated modified Reynolds number you initially entered with the resulting Calculated modified Reynolds number, and RECALCULATE until the modified Reynolds number is within acceptable tolerance of the Calculated modified Reynolds number.

References:

"Pipeline Rules of Thumb Handbook", Third Edition, E.W. McAllister



287

Single Horizontal Anode Resistance to Earth and Typical Installation








289

Single Vertical Anode Resistance to Earth and Typical Installation








291

Sizing for Liquid Relief: Relief Valves Not Requiring Capacity Certification Before the AMSE Code made provisions for capacity certification, valves were generally sized for liquid services using equation below. This method assumes a coefficient of discharge, Kd = 0.62, and 25 percent overpressure. An additional capacity correction factor, Kp, was obtained from Figure 33 for relieving pressures other than 25 percent overpressure. The sizing method may be used where capacity certification is not required.

Where: A = required effective discharge are, in square inches. Q= flow rate, in U.S. gallons per minute. Kd = effective coefficient of discharge that should be obtained from valve manufacturer. For a preliminary sizing estimation, a discharge coefficient of 0.62 can be used. Kw = correction factor due to back pressure. If back pressure is atmospheric, Kw = 1. Balanced - bellows valves in back - pressure services will require the correction factor. Conventional valves require no special correction. Kv = correction factor due to viscosity

Kp = correction factor due to overpressure. At 25 percent overpressure, Kp = 1.0. For overpressures other than 25 percent, Kp is determined from interactive graph, see example below

G = specific gravity of the liquid at the flowing temperature referred to water = 1.0 at 70F. p = set pressure, in pounds per square inch gauge. pb = total back pressure, in pounds per square inch gauge. Reference: API RP 520 Part I - Sizing and Selection, Sixth Edition, March 1993, Technical Toolboxes, Inc.

293

Sizing for Liquid Relief: Relief Valves Requiring Liquid Capacity Certification Section VIII, Division I, of the ASME Code requires that capacity certification be obtained for pressure relief valves designed for liquid services. The procedure for obtaining capacity certification includes determining the coefficient of discharge for the design of liquid relief valves at 10 percent overpressure. Valves that require a capacity in accordance with the ASME code may be sized using equation:

Where: A = required effective discharge area, in square inches. B = flow rate, in U.S. gallons per minute. Kd = effective coefficient of discharge that should be obtained from the valve manufactured. For a preliminary sizing estimation, a discharge coefficient of 0.65 can be used. Kw = correction factor due to back pressure. If the back pressure is atmospheric Kw = 1. Balanced-bellows valves in back pressure services will require the correction factor determined from the interactive graph. Conventional valves require no special corrections. Kv = correction factor due to viscosity as determined from interactive

G = specific gravity of the liquid at the flowing temperature referred to water = 1.0 at 70 F. P1 = upstream relieving pressure, in pounds per square inch gauge. This is the pressure plus allowable overpressure

P2 = total back pressure, in pounds per square inch gauge. When a relief valve is sized for viscous liquid services, it should first be sized as it was for nonviscous - type application so that a preliminary required discharge area, A, can be obtained. From manufacturer's standard orifice sizes, the next large orifice size should be used in determining the Reynold's number, R, from either of the following relationship:

Where: Q = flow rate at the flowing temperature, in U.S. gallons per minute. G = specific of the gravity of the liquid at the flowing temperature referred to water = 1.00 at 70F

n = absolute viscosity at the flowing temperature, in centipoises. A= effective discharge area, in square inches ( from manufacturer's standard orifice area).

294

U = viscosity at the flowing temperature, in Saybolt Universal seconds. Note: Equation is not recommended for viscosities less than 100 Salybolt Universal seconds. After the value of R is determined, the factor Kv is obtained from interactive graph. Kv is applied to correct the preliminary required discharge area. If the corrected area exceeds the chosen standard orifice area, the above calculations should be repeated using the next larger standard orifice size. Next larger standard orifice size is retrieved form the program database automatically. Example form API RP 520

In this example, the following relief requirement are given: Required crude-oil flow caused by blocked discharge, Q, of 1800 gallons per minute. Specific gravity, G, of 0.90 ( viscosity at the flowing temperature is 2000 Saybolt Universal seconds). Relief valve set at 250 pounds per square inch gauge, the design pressure of the equipment. Back pressure variable from 0 to 50 pounds per square inch gauge. In this example, the following data are derived: Overpressure of 10 percent. Relieving pressure, P1, of 1.10 * 250 = 275 pounds per square inch gauge. Back pressure of (50/250) * 100 = 20 percent. Balanced-bellows valve is indicated, since back pressure is variable. From interactive graph read Kw value by positiong cursor on the intersection curve-vertical line for 20% of back pressure. When you place the cursor on proper intersection just double click and Kw value will be automatically determined , Kw = 0.97. The manufacturer's effective coefficient of discharge K= 0.75. Step 1: Sizing first for no viscosity correction (Kv = 1.0), Program automatically retrieve next larger standard orifice "N" with area of 4.34 square inches

AR = required area without viscosity correction. In oreder to determine Kv value place cursor on curve for calculated Reynolds number and duble click, program will recalculate reqired discharge area and then select next larger orifice size, "N" orifice size is selected for relief valve, orifice area is 4.34 square inches. Reference: API RP 520 Part I - Sizing and Selection, Sixth Edition, March 1993, Technical Toolboxes, Inc.

295

Spangler's Modified Iowa Formula for PE Pipe

Reference:





297

Gas Pipeline Hydraulics - Spitzglass Equation

The Spitzglass equation is used with pipe diameters of 10" or less and with a range of pressure:


299

Storage Tanks

TANK Oil storage tank analysis and design according to the very latest API 650 and 653 codes. It

includes settlement calculations and nozzle loads. Design and analysis of supported cone roofs as

well as self supporting cone, dome and umbrella roofs. Thickness design and analysis using the

variable point method, one-foot method and API-650 Appendix A method. All material

adjustments, allowed fluid heights, seismic requirements, internal pressure, wind girder, shell

settlement evaluations, anchorage, wind overturning stability calculations and nozzle limiting

load interactions are all calculated in compliance with the appropriate API 650 and 653

appendix. TANK is currently a DOS based program. Technical Toolboxes, Inc.

301

Pipeline Stress Analysis

Stresses & Pressure - Contains calculations to determine design pressures for both steel and plastic pipe, internal pressure (%SMYS), hoop stress, and longitudinal stress. Also includes calculations for various bending and pipeline stresses due to external fluids, soil and vehicular loading, thermal pipe expansion and thrust. ASME B31.4 and ASME B31.8 have been incorporated into the calculations.

Design Pressure - Steel Pipe Design Pressure - Plastic Pipe (AGA Manual) Design Pressure - Plastic Pipe (SDR) Hoop Stress Longitudinal Stress Bending Stress & Deflection Bending Stress - Caused by Fluid Flowing Around Pipeline Bending Stress - Caused by Soil & Vehicular Load Linear Thermal Pipeline Expansion Thrust at Blow-off


303

Suction Specific Speed

Reference:



305

Surge Analysis - Water Hammer The program module/solution is based on the Method of characteristics. Calculation of pressure wave speed is specifically designed for liquid hydrocarbons. Mathematical Model Basic Equations: V- Instantaneous velocity

H- Instantaneous piezometric head

g - Acceleration of gravity

f - friction factor

x - Distance along pipe

t - time

306

Surge Analysis - Water Hammer

307

Boundary condition: Valve on the end of pipe. References: Streeter, V.L. and Wylie, E.B. (1967), Hydraulic Transients, McGraw-Hill, New York. Streeter, V.L. (1969), `Waterhammer analysis'. Jour. Hyd. Div., ASCE., Vol. 88, HY3, pp79-113 May. Streeter, V.L. (1972), `Unsteady flow calculations by numerical methods', Jour. Basic Eng.,

ASME., 94, pp457-466, June. J. P Tullis (1989), Hydraulic Pipelines, John Wiley & Sons Technical Toolboxes, Inc.

309

Liquid Pipeline Hydraulics - T.R. Aude Equation

The Aude equation has been reported to be accurate for Reynolds numbers in a range from: - 6,000 to 130,000 for 8" and 12" crude oil lines. - over 57,000 for 6" and 8" refined product lines. References:





311

313

Nomenclature

C - Constant for English or Metric (S.I.) units

D - Internal pipe diameter, inches or millimeters

e = 2.718… , natural logarithm base

E - Pipeline efficiency factor

F - Transmission factor, dimensionless

G - Gas specific gravity, relative to dry air ( relative density )

H - Elevation above some reference, feet or meters

h - Pressure,

k - Absolute roughness, inches or millimeters

L - Length of pipeline, miles, feet / kilometers, meters

, dimensionless

Q - Flow rate, standard cubic feet per day ( hour ) / standard cubic meter per day ( hour )

s - Gas density factor, dimensionless

Z - Compressibility factor at average flowing conditions, dimensionless

315

317

TTI Consulting Services

TTI Consulting Services offers a team of experienced software & network engineering and

marketing professionals for the following core expertise:

Legacy Code Enhancement & Conversion Windows interface design

Visual Basic / SQL Server / Visual C++

Integration of Software Applications Integration of proprietary applications

Integration of applications with Visio

Network Integration Services Network design & installation

Windows 95/NT network solutions

Applications Software Training Integrated applications training

Visio/Visio Technical training

Marketing & Distribution of Applications Software Domestic & International channels

Telemarketing & direct sales

Value-Managed Solutions For Engineering & Technology Firms Technical Toolboxes, Inc.

319

Technical References Pipeline Hydraulics

- A.G.A GEOP Series Book T-1 Pipeline Planning and Economics

- A.G.A Plastic Pipe Manual for Gas Service, 1989

- Petroleum Fluid Flow Systems, Boyd, CAMPBELL CPS Petroleum Series

- Pipeline Design for Hydrocarbon Gases and Liquids, American Society of Civil Engineers, 1975

- DOT Office of Pipeline Safety Handbook

- Hydraulics for Pipeliners, C.B. Lester, Gulf Publishing 1994

- Hydraulics of Pipeline Systems, Larock, Jeppson Watters, CRC 1999

Pipeline Design and Stress Analysis

- DOT Pipeline Safety Regulations

- ASME B31.8 Gas Transmission and Distribution Piping Systems

- DOT Office of Pipeline Safety, Handbook


- A.G.A Plastic Pipe Manual for Gas Service, 1989

- Gas Engineers Handbook, Industrial Press, 1965

- Introduction to Pipe Stress Analysis, Kannapann, Krieger Publishing Company

- Evaluation of Buried Pipe Encroachment, BATTELLE, Petroleum Technology Center, 1983

- Technical Summary and Database for Guidelines for Pipeline Crossings Railroads and Highways GRI 1991

Pipeline Testing and Miscellaneous

- DOT Pipeline Safety Regulations

- ASME B31.4 Pipeline Transportation System for Liquid Hydrocarbons and Liquids

- DOT Office of Pipeline Safety, Handbook


- Gas Engineers Handbook, Industrial Press, 1965

Corrosion Control - DOT Pipeline Safety Regulations

- Control of Pipeline Corrosion, A.W. Peabody, NACE International - Pipeline Corrosion and Cathodic Protection, Parker & Peatie,Gulf Publishing Company, 1984

- A.G.A GEOP Series Book TS-1 Corrosion Control/System Protection Technical Toolboxes, Inc.

321

Temperature Rise Due to Piping

Reference:



323

THERMAL EXPANSION OF PIPELINES - LINEAR

E = elongation, in.

C = coefficient of linear expansion, inches per in per degrees F

L = length, feet

MATERIAL COEFFICIENT

steel 6.80E - 06

cast iron 6.60E - 06

copper 9.00E - 06

plastic 9.0E - 05

water 1.15E - 04

LONGITUDINAL STRESS

DUE TO TEMPERATURE CHANGES

S = stress, psi

E = modulus of elasticity, psi

C = coefficient of linear expansion, inches per inch per degrees F


325

Track Load Analysis SCOPE: The Track Load Program was designed to calculate the overburden and track loads on buried pipe with a Single Layer System (soil only). The information used to design this program was taken from the Battelle Petroleum Technology Report on "Evaluation of Buried Pipe Encroachments" which considered the theoretical work done by M.G. Spangler on overburden and vehicle loads on buried pipe. REQUIRED INFORMATION:

1. Values for all of the following variables:

H - cover, vertical depth from the ground to the top of the pipe (ft.) B - trench width (ft.) Ds - weight per unit volume of backfill (lbs./ft.³) D - outside diameter of the pipe (in.) SMYS - specified minimum yield stress of the pipe (psi.) P - pipe internal pressure (psi.) T - pipe wall thickness (in.)

2. Values for the following information about the track:

Lt - operating weight of the object crossing the pipeline with tracks (lbs.) Tw - width of standard track shoe (in.) Tl - length of track on the ground (ft.) Tg - track gauge (ft.)

3. The Design Class of the pipeline being analyzed (1-3) which is used to find the Maximum Allowable Combined Stress (% SMYS), see 7.

4. The Soil Type which is used to find the friction force coefficients (Km), see Table II. 5. The Crossing Construction Type which is used to find the bedding constants for

buried pipe (Kb & Kz), see Table V & Figure 3.

326

REQUIRED INFORMATION IF LONGITUDINAL BENDING STRESS OCCURS:

6. All the above information along with values for the following variables:

X - longitudinal distance over which deflection occurs (ft.) Y - vertical deflection (in.)

7. Maximum Allowable Internal Stress of 72% for Max. Levels (Per Code) and for Target Leveles (Temporary Crossings).

Maximum Allowable Combined Stress of 90% for Max. Levels (Per Code) and 80% for Target Levels (Temporary Crossings) ASME B31.4 - 1998 allows effective stress due to internal pressure and external loads (including both live and dead loads) to be as high as 90% of specified minimum yield strength under highway and railroads. ( Sections 434.13.4 and 451.9) As a first estimate of the soil load on the pipe it could be assumed that the backfill soil slides down the trench walls without friction. Additionally assume that all soil above the pipe is supported by the pipe itself and that the backfill soil on either side of the pipe does not assist in this support. These assumptions are very conservative but they help a great deal in initial understanding of the method of solution. The assumptions yield a soil load on the pipe equal to the weight of the backfill soil above the pipe. This analysis provides an estimate of soil loads on the buried pipe if nothing else is known about the system. The basic analysis developed by M.G. Spangler follows similar arguments to that given above. In this analysis, Spangler includes frictional forces between the trench wall and the backfill. This permits the weight of the overburden to be partially carried by the surrounding soil and reduces the total soil load on the pipe. The resulting equations for calculating the pipe load due to overburden are as follows:

Track Load Analysis

327

Cd - trench coefficient. B - trench width (ft.). H - cover, vertical depth from the ground to the top of the pipe (ft.). Km - coefficient of friction force between the backfill soil and the trench wall. Cd determines how much load is carried by the pipe. If there is no soil friction Cd becomes equal to H/B and the entire backfill load must be supported by the pipeline. The term Km provides a coefficient of friction force between the backfill soil and the trench wall. A high value of Km implies that friction between the backfill and trench wall is high and the weight of the backfill is supported largely by the wall friction. A low value implies that there is little friction encountered and the backfill is allowed to settle more such that the weight must be supported by the pipe. Table II provides values of Km used in the program for five different soil types. Also in Table II are examples of values for Ds, the density which is the weight per unit of backfill, which may be used if an actual value is not known. Note: If a value for Ds is already given use that value instead of the one in Table II. Table II

Friction Force Coefficients For Various Soils

Soil Type Km Ds

(lbs/ft³) (1) Granular Materials without Cohesion 0.1924 90-100

(2) Sand and Gravel 0.165 110-120

(3) Saturated Top Soil 0.150 110-120

(4) Clay 0.130 110-120

(5) Saturated Clay 0.110 120-130

The soil types and coefficients given in this table represent the range that could normally be expected. Saturated clay has little internal friction so that it has the smallest value for Km. This implies that almost all of the soil load is carried by the pipe. Granular materials have a great deal more internal friction. Their value of Km is higher which leads us to the conclusion that the pipe carries less of the backfill load. Spangler, in his work, recommends using the value for clay in most instances. Higher values may be used when there is adequate evidence that the internal friction is higher and warrants a higher value of Km. Spangler's recommendation provides a conservative estimate for common buried pipe situations. Marsh and bog areas, however, have friction properties more similar to saturated clay such that a value for Km equal to 0.110 should be used in these areas.

Wc - load per unit length of the pipe due to overburden (lbs./in.). B - trench width (ft.). Ds - density which is the weight per unit of backfill (lbs./ft.³). H - cover, vertical depth from the ground to the top of the pipe (ft.). Km - coefficient of friction force between the backfill soil and the trench wall. The Impact Factor (I) for a track load calculation with a single layer system is always going to be 1.5. The reason for this is that the impact factor for soil is 1.5 and that is the only thing that separates the track from the pipe in a single layer system.

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Calculating track load is somewhat different from calculating a wheel load because the load of a track expands over a larger area rather than a single point as does the wheel load. The information needed from the track are the operating weight (Lt) of the object crossing the pipeline with tracks is measured in lbs., the width of the standard track shoe (Tw) measured in inches, the length of the track on the ground (Tl) measured in ft., and the track gauge (Tg) measured in ft . The weight of a track can be considered as a uniformly distributed load applied at the top of the soil over an area equal to the length of the track on the ground times the width of the standard track shoe. On the basis of this assumption, the unit pressure at a point on the top of the line pipe or casing pipe directly beneath the center of the area may be estimated by means on Newmarks Integration of Boussinesq equation. Newmark determined the pressure at a point in the undersoil at any elevation below one corner of the rectangular area over which unit loads are uniformly applied, and gave influence coefficients corresponding to the Influence Factor m and Influence Factor n.

H - cover, vertical depth from the ground to the top of the pipe (ft.). Tw - width of standard track shoe (in.).

H - cover, vertical depth from the ground to the top of the pipe (ft.). Tl - length of the track on the ground (ft.). These two factors are used by M.G. Spangler in the table called "Influence Coefficients for Solution of Holl's and Newmark's Integration of the Boussinesq Equation for Vertical Stress", see Table VI. Both of the influence factors will be rounded off to the nearest 0.01 in order to cross reference Table VI.

Track Load Analysis

329

Qd - maximum static pressure on the pipe directly under the center of the object with tracks

(lbs./ft.²). Ic - Influence Coefficient selected from Table VI. Lt - operating weight of the object crossing the pipeline with tracks (lbs.) Tl - length of the track on the ground (ft.). Tw - width of standard track shoe (in.). The equation for Qd is widely employed in structural work to estimate the unit pressure on a deep soil stratum below a foundation, it appears to be appropriate for this problem. The constant equal to 0.5 will be multiplied by Lt to get the operating load of one track.

Wt - total track load on the pipe (lbs./in.). D - outside diameter of the pipe (in.). I - impact factor of 1.5. Qd - calculated result from equation Qd (lbs./ft.²). Dividing the part of the equation (I * Qd) by twelve gives the load per linear inch of pipe. Dividing the outside diameter of the pipe by twelve converts D, which is measured in inches, into units of feet.

Sc - circumferential stress due to pipe wall deflection (PSI). D - outside diameter of the pipe (in.). E - pipe material modulus of elasticity (2.9 x 107). Kb - bending coefficient which is a function of the crossing construction types. Kz - deflection coefficient which is a function of the crossing construction types. P - pipe internal pressure (PSI). T - pipe wall thickness (in.). Wc - load per unit length of pipe due to overburden (lbs./in.). Wt - total track load on the pipe (lbs./in.). Note that the equation Sc includes pressure in the denominator so that bending stresses are reduced by increasing pressure. Equation Sc, as well as equation St, have two constants which depend upon the bedding material upon which the pipe is placed. This bedding material is based on the crossing construction type. When the pipe is placed on a rigid bedding such as an Open Cut-Rock, little soil deformation occurs so that the load application area on the bottom is very small. However if the pipe is placed on soil, the support conforms to the pipe somewhat and the load is distributed over a larger area (See Figure 3). The latter case produces less pipe stress and is preferable. Spangler's formulation includes both of these possibilities in order to provide a conservative estimate for the rigid bedding case without penalizing the soil bedding case. It does so by varying the constants Kb and Kz. Spangler's recommended values for the constants are provided in Table V.

330

Table V

Bedding Constants for Buried Pipe

Width of

Uniform Crossing

Soil Reaction Construction

(Degrees) _ Type Kz Kb

0 (1) Open Cut-Rock 0.110 0.294

30 (2) Open Cut 0.108 0.235

90 (3) Bored 0.096 0.157

Sh - hoop stress due to internal pressure (PSI). D - outside diameter of the pipe (in.). P - pipe internal pressure (PSI). T - pipe wall thickness (in.).

St is the total circumferential stress in the pipe wall due to pressure (hoop) stress and bending stresses resulting from circumferential flexure caused by external loads measured in PSI. The first term on the right hand side of the equation is the formula for hoop stress due to internal pressure (Sh) and the second term is the formula for circumferential stress due to pipe wall deflection (Sc). Longitudinal Bending Stress (Sb) is when the overburden and vehicle loads on buried pipelines will cause pipe settlement into the soil in the bottom of the trench. This settlement occurs because soil is not as stiff as the pipe and will deform easily as the pipe is "pushed" downward. Under uniform soil conditions and overburden loading, the pipe will settle evenly into the trench bottom along its entire length. Soil is not generally uniform, however, and regions of "softer" soil will occur adjacent to regions of stiff soil, so that the pipe will settle unevenly and hence bending will occur. A load that is applied on only one portion of a pipeline will cause the section of pipe under the load to settle more than the unloaded pipe, such that bending will also result. Longitudinal bending stress occurs in tension on the outside of the bend and in compression on the inside of the bend. Tensile stress is represented with a positive value for Sb; conversely, compressive stress takes a negative value for Sb. The longitudinal bending stress is calculated as follows:

Sb - longitudinal bending stress (PSI). D - outside diameter of the pipe (in.). E - pipe material modulus of elasticity (2.9 x 107). X - longitudinal distance over which deflection occurs (ft.). Y - vertical deflection (in.).

Track Load Analysis

331

A negative value will be used when calculating the total combined stress (S). This will result in a larger (more conservative) combined stress. Note: If longitudinal bending stress does occur, click onto the option box. If the box is not marked then the program will assume "0" for Sb.

S - total combined stress by Von Mises (PSI). Sb - longitudinal bending stress (PSI). St - total circumferential flexure caused by external loads (PSI) Note that if longitudinal bending stress is not present then the S will equal St. The final calculation is % SMYS. This is calculated to determine if the current conditions exceed the Maximum Allowable Combined Stress determined by Transcontinental Gas Pipe Line Corporation.

S - total combined stress by Von Mises (PSI). SMYS - specified minimum yield stress of the pipe (PSI). References: ASME B31.4 - 1998 Edition "Pipeline Transportation Systems for Liquid Hydrocarbons and other Liquids", Art. 404.3.1(c) "Evaluation of Buried Pipe Encroachments", BATTELLE, Petroleum Technology Center, 1983 Technical Toolboxes, Inc.

333

Unrestrained Liquid Pipeline Stress Analysis - Steel Pipe Longitudinal Stress Unrestrained Pipe

Reference: ASME B31.4 - 2009 Technical Toolboxes, Inc.

335

Values of E'n - Native Soil Modules of Soil Reaction


337

ASTM D 341 - Viscosity Temperature Relations for Hydrocarbons General:

Liquids log

Gases

Andrade's Equation

ASTM 2161: General form: log log Z = A + BlogT

Crude oil form: loglog( = A - BlogT

Explicit

A = log(log( ))+BlogT

B=(log(log( )/(log( ))))/log(T /T ) Where:

References: ASTM D 341

"Hydraulics for Pipeliners",Second Edition, C.B. Lester Technical Toolboxes, Inc.

339

Wheel Load Analysis SCOPE: The Wheel Load Analysis Program was designed to calculate the overburden and vehicle loads on buried pipe with a Single Layer System (soil only) or a Double Layer Systems (timbers, pavement and soil). The information used to design this program was taken from the Battelle Petroleum Technology Report on "Evaluation of Buried Pipe Encroachments" which considered the theoretical work done by M.G. Spangler on overburden and vehicle loads on buried pipe. REQUIRED INFORMATION:

1. Values for all of the following variables:

H - cover, vertical depth from the ground to the top of the pipe (ft.) B - trench width (ft.) Ds - weight per unit volume of backfill (lbs./ft.³) D - outside diameter of the pipe (in.) Lw - concentrated surface load (lbs.) (Wheel Load) (see Section 4, Page 11) H1 - thickness of the pavement layer (in.) (see Figure 2) SMYS - specified minimum yield stress of the pipe (psi.) P - pipe internal pressure (psi.) T - pipe wall thickness (in.)

2. The Design Class of the pipeline being analyzed (1-3) which is used to find the Maximum Allowable Combined Stress (% SMYS), see 7.

3. The Soil Type which is used to find the friction force coefficients (Km), see Table II. 4. The Pavement Type which is used to find the impact factor (I), see Table III, and the

elastic constants for layered media analysis (E1, E2, G1, & G2), see Table IV & Figure 2.

340

5. The Crossing Construction Type which is used to find the bedding constants for buried pipe (Kb & Kz), see Table V & Figure 3.

REQUIRED INFORMATION IF LONGITUDINAL BENDING STRESS OCCURS:

6. All the above information along with values for the following variables:

X - longitudinal distance over which deflection occurs (ft.) Y - vertical deflection (in.)

7. Maximum Allowable Internal Stress of 72% for Max. Levels (Per Code) and for Target Leveles (Temporary Crossings).

Wheel Load Analysis

341

Maximum Allowable Combined Stress of 90% for Max. Levels (Per Code) and 80% for Target Levels (Temporary Crossings) ASME B31.4 - 1998 allows effective stress due to internal pressure and external loads (including both live and dead loads) to be as high as 90% of specified minimum yield strength under highway and railroads. ( Sections 434.13.4 and 451.9) Figure 1 shows a cross sectional view of a pipe buried in a trench. As a first estimate of the soil load on the pipe it could be assumed that the backfill soil slides down the trench walls without friction. Additionally assume that all soil above the pipe is supported by the pipe itself and that the backfill soil on either side of the pipe does not assist in this support. These assumptions are very conservative but they help a great deal in initial understanding of the method of solution. The assumptions yield a soil load on the pipe equal to the weight of the backfill soil above the pipe. This analysis provides an estimate of soil loads on the buried pipe if nothing else is known about the system. The basic analysis developed by M.G. Spangler follows similar arguments to that given above. In this analysis, Spangler includes frictional forces between the trench wall and the backfill. This permits the weight of the overburden to be partially carried by the surrounding soil and reduces the total soil load on the pipe. The resulting equations for calculating the pipe load due to overburden are as follows:

Cd - trench coefficient. B - trench width (ft.). H - cover, vertical depth from the ground to the top of the pipe (ft.). Km - coefficient of friction force between the backfill soil and the trench wall. Cd determines how much load is carried by the pipe. If there is no soil friction Cd becomes equal to H/B and the entire backfill load must be supported by the pipeline. The term Km provides a coefficient of friction force between the backfill soil and the trench wall. A high value of Km implies that friction between the backfill and trench wall is high and the weight of the backfill is supported largely by the wall friction. A low value implies that there is little friction encountered and the backfill is allowed to settle more such that the weight must be supported by the pipe. Table II provides values of Km used in the program for five different soil types. Also in Table II are examples of values for Ds, the density which is the weight per unit of backfill, which may be used if an actual value is not known. Note: If a value for Ds is already given use that value instead of the one in Table II. Table II

Friction Force Coefficients For Various Soils

Soil Type Km Ds

(lbs/ft³) (1) Granular Materials without Cohesion 0.1924 90-100

(2) Sand and Gravel 0.165 110-120

(3) Saturated Top Soil 0.150 110-120

(4) Clay 0.130 110-120

(5) Saturated Clay 0.110 120-130

342

The soil types and coefficients given in this table represent the range that could normally be expected. Saturated clay has little internal friction so that it has the smallest value for Km. This implies that almost all of the soil load is carried by the pipe. Granular materials have a great deal more internal friction. Their value of Km is higher which leads us to the conclusion that the pipe carries less of the backfill load. Spangler, in his work, recommends using the value for clay in most instances. Higher values may be used when there is adequate evidence that the internal friction is higher and warrants a higher value of Km. Spangler's recommendation provides a conservative estimate for common buried pipe situations. Marsh and bog areas, however, have friction properties more similar to saturated clay such that a value for Km equal to 0.110 should be used in these areas.

Wc - load per unit length of the pipe due to overburden (lbs./in.). B - trench width (ft.). Ds - density which is the weight per unit of backfill (lbs./ft.³). H - cover, vertical depth from the ground to the top of the pipe (ft.). Km - coefficient of friction force between the backfill soil and the trench wall. A Pavement Type must be determined in order to select an Impact Factor (I) to be used in the Wv equation. Table III provides Impact Factor values for the three different pavement types used in this program. A Pavement Type is also used to select the elastic constants for layered media analysis. The variables E1 & G1 will be used to represent the elastic constants for the top layer and E2 & G2 will be used to represent the elastic constants for the soil. See Figure 2 for a visual explanation of the elastic constants for the top layer and the soil. These values will also be used in the Wv equation. Table IV provides the values for the three different pavement materials used in this program. Table III

Impact Factor

Pavement Type Factor

(I) No Pavement 1. 5

Asphalt 1. 3

Timber Mats (2" x 12" minimum) 1.2

Concrete 1.0

Wv - average load per unit length of pipe for vehicular load (lbs./in.). D - outside diameter of the pipe (in.). E1 - modulus of elasticity of the top (timber or pavement) layer (lbs./in.²). E2 - modulus of elasticity of the soil cover (lbs./in.²). G1 - Poisson's ratio of the top (timber or pavement) layer.

Wheel Load Analysis

343

G2 - Poison's ratio of the soil cove

H - thickness of the pavement layer plus the depth of the soil from the pavement interface to thetop of the pipe (ft.). (See Figure 2) H1 - thickness of the pavement layer ("0" is used when there is no pavement) (in.). H2 - depth of the soil from the pavement interface to the top of the pipe (ft.). I - impact factor. Lw - concentrated surface load (a value of 16,000 lbs. is recommended when the maximum is unknown), wheel load in lbs.. Examination of equation Wv shows that this equation also may be used with a Single Layer System because the Pavement Material on the Top Layer chosen is "Soil", which makes E1 equal to E2, G1 equal to G2, and H1 equal to zero which cancels out the second and third part of the equation. Thus when there is no pavement layer the revised equation will provide a solution for soil cover only. Table IV provides the values for E1, E2, G1 & G2 that will be used in the program. Table IV

Elastic Constants for Layered Media Analysis

Pavement E

Material (psi.) G

(1) No Pavement (Soil Only) 1. 5 x 104 0.35

(2) Asphalt 1. 0 x 105 0.40

(3) Timber Mats (2" x 12" 1. 2 x 106 0.25

(4) Concrete 2. 0 x 10 6 0.15

Sc - circumferential stress due to pipe wall deflection (PSI). D - outside diameter of the pipe (in.). E - pipe material modulus of elasticity (2.9 x 107). Kb - bending coefficient which is a function of the crossing construction types. Kz - deflection coefficient which is a function of the crossing construction types. P - pipe internal pressure (PSI). T - pipe wall thickness (in.). Wc - load per unit length of pipe due to overburden (lbs./in.). Wv - average load per unit length of pipe for vehicular load (lbs./in.). Note that the equation Sc includes pressure in the denominator so that bending stresses are reduced by increasing pressure. Equation Sc, as well as equation St, have two constants which depend upon the bedding material upon which the pipe is placed. This bedding material is based on the crossing construction type. When the pipe is placed on a rigid bedding such as an Open Cut-Rock,

344

little soil deformation occurs so that the load application area on the bottom is very small. However if the pipe is placed on soil, the support conforms to the pipe somewhat and the load is distributed over a larger area (See Figure 3). The latter case produces less pipe stress and is preferable. Spangler's formulation includes both of these possibilities in order to provide a conservative estimate for the rigid bedding case without penalizing the soil bedding case. It does so by varying the constants Kb and Kz. Spangler's recommended values for the constants are provided in Table V. Table V

Bedding Constants for Buried Pipe

Width of

Uniform Crossing

Soil Reaction Construction

(Degrees) _ Type Kz Kb

0 (1) Open Cut-Rock 0.110 0.294

30 (2) Open Cut 0.108 0.235

90 (3) Bored 0.096 0.157

Sh - hoop stress due to internal pressure (PSI). D - outside diameter of the pipe (in.). P - pipe internal pressure (PSI). T - pipe wall thickness (in.).

St is the total circumferential stress in the pipe wall due to pressure (hoop) stress and bending stresses resulting from circumferential flexure caused by external loads measured in PSI. The first term on the right hand side of the equation is the formula for hoop stress due to internal pressure (Sh) and the second term is the formula for circumferential stress due to pipe wall deflection (Sc). Longitudinal Bending Stress (Sb) is when the overburden and vehicle loads on buried pipelines will cause pipe settlement into the soil in the bottom of the trench. This settlement occurs because soil is not as stiff as the pipe and will deform easily as the pipe is "pushed" downward. Under uniform soil conditions and overburden loading, the pipe will settle evenly into the trench bottom along its entire length. Soil is not generally uniform, however, and regions of "softer" soil will occur adjacent to regions of stiff soil, so that the pipe will settle unevenly and hence bending will occur. A load that is applied on only one portion of a pipeline will cause the section of pipe under the load to settle more than the unloaded pipe, such that bending will also result. Longitudinal bending stress occurs in tension on the outside of the bend and in compression on the inside of the bend. Tensile stress is represented with a positive value for Sb; conversely, compressive stress takes a negative value for Sb. The longitudinal bending stress is calculated as follows:

Wheel Load Analysis

345

Sb - longitudinal bending stress (PSI). D - outside diameter of the pipe (in.). E - pipe material modulus of elasticity (2.9 x 107). X - longitudinal distance over which deflection occurs (ft.). Y - vertical deflection (in.). A negative value will be used when calculating the total combined stress (S). This will result in a larger (more conservative) combined stress. Note: If longitudinal bending stress does occur, click onto the designated box next to "Longitudinal Bending Stress" . If the box is not marked then the program will assume "0" for Sb.

S - total combined stress by Von Mises (PSI). Sb - longitudinal bending stress (PSI). St - total circumferential flexure caused by external loads (PSI). Note that if longitudinal bending stress is not present then the S will equal St. The final calculation is % SMYS. This is calculated to determine if the current conditions exceed the Maximum Allowable Combined Stress determined by Transcontinental Gas Pipe Line Corporation.

S - total combined stress by Von Mises (PSI). SMYS - specified minimum yield stress of the pipe (PSI). References: ASME B31.4 - 1998 Edition "Pipeline Transportation Systems for Liquid Hydrocarbons and other Liquids", Art. 404.3.1(c) "Evaluation of Buried Pipe Encroachments", BATTELLE, Petroleum Technology Center, 1983 Technical Toolboxes, Inc.

347

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348

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