TA-143-D00-G-TD007_0_Annex II, Fluid Systems.pdf

National Iranian Steel Co.

Baft Steel Complex

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Annex II to Employers Requirement

Engineering Standard

Fluid Systems

TARA TARH Engineering & Technological Co.

DR & Material Handling Plant Project NISCO

Page 1 of 1Fluid Systems Baft Steel Complex

Table of Contents Doc No.: TA-143-D00-G-TD007 16-Sep-07 Rev 0

Engineering Standard, Fluid Systems

Table of Contents Page

1 Introduction 1

1.1 Scope of Standard 1

1.2 Standards and Codes 1

2 Piping Design 3

2.1 General 3

2.2 Pressure-Temperature Rating 3

2.3 Selection of Pipes for Different Fluids 3

2.4 Piping Installation Design 8

3 Main Fluid System Equipment 15

3.1 Horizontal Centrifugal Pumps 15

3.2 Vertical Wet-Pit Centrifugal Pumps 17

3.3 Evaporative Cooling Tower 18

3.4 Plate Heat Exchangers 21

3.5 Pressure Vessels 23

3.6 Liquid Storage Tanks 26

3.7 Blowers 28

3.8 Hydraulic Systems 29

3.9 Lube Systems 38

3.10 Heating, Ventilating and Air Conditioning Systems 38




Section 1 Doc No.: TA-143-D00-G-TD007 16-Sep-07 Rev 0

1- Introduction

1.1- Scope of Standard

Scope of the present standard is to give the necessary criteria for design and selection of

materials and equipment for the fluid network to be installed in The Employer Plant taking into

account the operating and climatic conditions.

This standard covers:

x Raw water

x Treated water

x Softened water

x Demineralized water

x Domestic water

x Oxygen

x Nitrogen

x Argon

x Compressed Air

x Natural Gas

x Waste water and systems for equipment and machinery include of:

x Lube oil systems and grease systems

x Hydraulic Systems

x Heating, ventilating and air conditioning systems

The criteria shown shall be followed by the contractor for design and supply.

Any deviations shall be approved by the Employer.

1.2- Standards and codes

The standard and codes, on which the work shall be based, are to be properly selected within the

following:

ANSI American National Standard Institute

API American Petroleum Institute

ARI Air Conditioning and Refrigeration Institute

ASHRAE American Society of Heating, Refrigerating and Air Conditioning Engineers





ASME American Society of Mechanical Engineers

ASTM American Society of Testing and Materials

AWS American Welding Society

AWWA American Water Works Association

BSI British Standard Institute

DIN Deutsche Industerie Normen

EJMA Expansion Joints Manufacturers Association

FM Factory Mutual Engineering Corporation

ISO International Standard Organization

NACE National Association of Corrosion Engineering

NFPA National Fire Protection Association

NIGC National Iranian Gas Company Standards

NPC National Plumbing Code

UL Underwriters Laboratories, Inc.

UNI Unificazione Nazionale Italiana

All codes and standards referred to, shall be the latest edition of such documents unless

otherwise specified by the Employer.

Where special piping and equipment, not covered by these standards, is required, the Contractor

shall submit to the Employer, for approval, a description of the selected materials and design

criteria adopted.

The following regulations are to be used for performance testing of the related equipment:

EUROPUMP - Code dessais des pompes hydrauliques

HIS - Hydraulic Institute standard

PNEUROP -Turbo and reciprocating compressors for the process industry.





2- Piping Design

2.1- General

Piping specifications are classified for the general selection of materials for the class of services.

The maximum design pressure and design temperature, together with the fluid in line, govern the

selection of size and material specifications. Deviation of material from class specifications may

occur due to specific design conditions. These deviations shall be permissible only if they are

equal or better than the individual class requirements. For piping inside the package unit, vendor

standard piping specification are applied.

2.2- Pressure- Temperature Rating

The nominal pressure, the maximum working pressure, and the test pressure, according to the

type and temperature of the fluid to be considered, shall be as per UNI table 1284-71, Pressure

temperature rating for iron and steel pipes.

2.3- Selection of Pipes for Different Fluids

The pipes shall be designed according to item 2.2, and shall be capable of supplying the desired

flow rate. The velocities indicated for various fluid pipings shall be followed by the Supplier for

design.

Carbon steel pipe sizes 1 ",2 ",3 ",5",7",9",22" and 26" or their metric equivalents shall

not be used except for connection to the equipment. Pipe size 2 " may be used for fire hydrants

and/or control valves connections.

Pipe size smaller than " shall not be used except for instrumentation and analysis.

2.3.1- Raw and Treated Water Piping

The maximum velocity in the raw and treated water pipes shall be 2.5 m/s, but at pump suction

pipework velocity shall not exceed 1.5 m/s. Pipe material shall be ASTM A53 GrB or approved

equivalent.

Valves and fittings 2" and larger size shall be flanged ends type. Installation of raw and treated

water piping shall take into account provisions of item 2.4.

In case of underground pipe lines, if the carbon steel material is used for piping , the cathodic

protection shall be considered .





2.3.2- Softened and Demineralized Water Piping

Requirements of treated water piping shall be followed except that pipes, fittings and valves shall

be either lined with corrosion resistant lining or the materials of fabrication shall be of corrosion

resistant material and suitable for the service.

2.3.3- Domestic Water Piping

The minimum flow at which the branches are to be sized is 2-2.5m3/h.

The maximum suggested velocity is 3 m/s.

Galvanized pipe of ASTM GRB material or approved equivalent shall be used for domestic

water piping. Installation of domestic water piping shall be according to item 2.4.

2.3.4- Compressed Air Piping

Compressed air pipes are to be sized for the maximum velocity of 20 m/s, but in any case the

maximum pressure loss upto most remote user under maximum flow conditions shall not exceed

7% of the pressure at the compressed air room boundry. Compressed air temperature

downstream of the compressor after coolers shall not exceed 50c.

Piping shall be complete with sufficient condensate traps and the slope of compressed air

pipework should be generally 1: 200 in the direction of flow.

Where automatic drain traps are used they shall be fitted with stainless steel floats, heads, and

seats and be installed with a filter and manual bypass. Pipe material shall be galvanized ASTM

A53 GrB or approved equivalent. Valves and fittings 2 and larger size shall be flanged ends

type. Installation of compressed air piping shall be according to item 2.4.

2.3.5- Argon and Nitrogen Piping

Argon and Nitrogen pipes are to be sized for the maximum velocity of 25m/s, but in any case the

maximum pressure loss upto most remote user under maximum flow conditions shall not exceed

10% of the pressure at the air separation plant boundary.

They shall run overhead. Design temperature shall allow for solar radiation effects. Pipe material

shall be ASTM A53 GrB or approved equivalent. Valves and fittings 2 and larger size shall be

flanged ends type, Installation of Argon and nitrogen piping shall be according to item 2.4.





2.3.6- Natural Gas Piping

Design, fabrication, inspection and testing of natural gas piping including all its components

shall comply with the requirements of ANSI Z223.1 and/or NIG-SR-1007 (a NIGC standard)

and guidelines hereunder given.

Safety shall be the prime consideration in the design, installation, operation, and maintenance of

natural gas piping, the system shall include all overpressure protection devices, emergency shut-

off valves, manual shut-off valves, pressure regulators, alarm devices, etc.

The natural gas pipes shall run overhead and shall be designed so to offer reliable operation

(including all necessary duplication and bypassing of equipment to ensure security of supply to

critical areas).

Design temperature shall allow for solar radiation effects in addition to the given temperature.

Max. gas velocity through pipework (excluding control valves and similar equipment) shall not

exceed 30 m/s on gas filtered down to 250P m, 20s

m on unfiltered gas and 16 m/s on pipework

adjacent to meters but in any case pressure drop upto most remote user shall not exceed ten

percent of pressure at the outlet of natural gas pressure reducing station, Pipe material shall be

API 5L GrB or approved equivalent, Pipes smaller than 2 shall be seamless. Fittings shall be

welding ends type. Fittings material for pipes 2 and larger shall be ASTM A234 Gr WPB.

Fittings shall be of standard weight and according to ANSI B16.9. Flanges shall be according to

ANSI B16.5.

Valve body shall be of ASTM A216 Gr WCB material and meeting all requirements of API 6D,

Valves shall be have at least 150 lb rating.

It is compulsory that certain points of the natural gas piping be connected to steam or nitrogen

lines in order to purge the natural gas pipeline.

Valves shall be hydrostatically strength and leak tested according to the procedures outlined in

section 5 of API specifications 6D- steel, pipeline, valves.

Where valves are lubricated, seals shall be provided to minimize the amount of excess lubricant

that may enter the gas stream. When natural gas may be used in conjunction with air or oxygen

non-return valves or other approved devices shall be installed as close as possible to the point of

use.

Isolating valves shall be installed in the following positions:





x At the start of all main lines.

x At the start of all main branches.

x Up stream of all filters.

x Up stream of all flow-meters.

x Up stream of all regulating sets.

x Up stream of all gas consuming equipment.

x Up stream of road crossings and other potential hazards.

Where necessary, a bypass shall be provided for the isolating valve to facilitate the controlled

pressurization of down stream pipework containing sensitive equipment such as meters.

Upstream of all sensitive equipment such as control valves, regulating valves and meters, filters

of approved type shall be fitted. The filtration requirements will depend on the sensitivity of

equipment, upstream filtration, and pipe length.

Filter shall be rated to carry the maximum flow at the specified pressure drop, shall permit easy

access for cleaning or changing elements (without trapped particles entering the system), and

shall be fitted with all necessary purge, vent and drain connections.

All the gas piping shall form a continuous electrical conductor and shall be bonded to pipe

supports at intervals of not more than 20 meters. The pipe supports shall in turn be bonded to the

main grounding system where this is available near the supports, otherwise they shall be bonded

to an earth conductor directly buried along the run of the pipe or pipes.

Adequate provision shall be made to safely venting, purging, and draining the sections of pipe

work or equipment.

Vent points shall be located in positions which allow the elimination of air or gas from the

system.

2.3.7- Oxygen Piping

Oxygen piping shall be designed, fabricated and tested according to the requirements of ANSI

B31.3.

Oxygen pipes are to be sized for the maximum velocity 25m/s, 20m/s and 15m/s for pipes with

pressure up to 12, 21 and 51 bar respectively. Oxygen pipe material shall be stainless steel AISI

304L or approved equivalent, only long radius elbows shall be used for oxygen piping. All pipe

fittings shall be of AISI 304 L materials or approved equivalent. Valve body and internals shall





be of material suitable for oxygen service.

Oxygen piping shall run overhead.

All safety requirements of NFPA 51 shall be followed when oxygen is to be used together with

natural gas.

A clearance of 500 mm shall be kept between oxygen pipe and electrical cables and in case of

bare conductors; the clearance shall be 1000 mm.

2.3.8- Wastewater Piping

Industrial wastewater and sanitary sewer system piping shall be PE (underground) and CS

(aboveground).

Buried lines shall be protected against damage by surface loads.

Sewers shall be adequately sloped and properly sized. No sewer shall be less than 4 size.

All sewer branches shall be connected to mains at an angle of 60 or less.

All sewer connections to manholes shall be water sealed.

2.3.9- Hydraulic System Piping

The piping shall be so located and protected to prevent damage from external forces, heat, and

any hostile atmospheric condition.

The operating pressure shall be selected according to the necessities of the system.

For mineral oils, the maximum velocity shall be as follows:

x Discharge line of the pumps: 4.5 m/sec.

x Suction and drain lines: 1.5 m/Sec.

x eturn lines: 3 m/sec.

Design pressure for pipes and tubes shall be at least 1.33 times the working pressure. When

hoses are to be used, the hose shall be of two wire braid construction with permanently attached

fittings.

Hydraulic system piping shall be supported and securely fixed at regular intervals of not more

than:

x 1 m for pipes upto and including 3/4 .

x 2 m for pipes above 3/4 and upto and including 1 .





Pipe-work shall be supported and fixed immediately before and after bend or offset.

Pipe supports shall incorporate suitable vibration damping material and the supports assembly

shall in no way damage the pipe.

For installation see item 2.4, of this Standard.

2.3.10- Lubricating Oil Piping

Operating pressure shall be selected by the Contractor according to the necessity of the system.

Maximum velocity shall not exceed the following:

x 4.5m/sec at the discharge line of the pumps.

x 1.5 m/sec at the suction and drain lines.

x 3 m/sec at the return lines.

The pipelines shall be anchored to the machinery or installed in special ducts and properly

supported. Where there is movement or vibration that could cause breakage of pipeline, hoses

shall be provided.

For installation see item 2.4, of this Standard.

2.4- Piping Installation Design

2.4.1- General

As a general rule, raw and treated water piping, routed outside of the buildings, shall run on the

pipe bridge or be buried. On the other hand, compressed air, oxygen, natural gas, nitrogen and

argon piping must be overhead and grouped in banks (where possible) and arranged to facilitate

supports and provide for convenience in maintenance.

Sufficient clearance shall be provided in order to remove valves and other equipment without

removing other accessories installed in the vicinity.

Unions or flanges shall be installed in all piping connection to equipment, valves, control valves,

instruments, and miscellaneous specialities, and wherever necessary to facilitate the dismantling

of piping and removal of valved equipment or other items requiring maintenance or repairs.

The pipes shall be as far as possible horizontal and when necessary provided with eccentric type

reducers to avoid pockets in lines.

The following items show some rules that shall be followed as a general guide. It is the





responsibility of the Contractor to determine the size of the pipes, piping components, and

relevant supports, anchors, and guides, by means of proper and detailed calculations that shall be

submitted to the Employer, if requested, When making these calculations, the Contractor must

take into account the weight of the piping, fluid, internal pressure, and thermal stresses, the

overload due to wind (and other weather conditions, if any), earthquake, internal fouling, the

weight of personnel and devices for erection and maintenance, weight of cleaning and/or testing

fluid. On the other hand, for underground piping, the calculations must include the overloads due

to the weight of the earth covering the pipes as well as loads due to traffic passing over the pipe.

2.4.2- Underground Piping

2.4.2.1- General

Buried piping shall be installed in trenches excavated in firm soil and as far as possible, shall be

kept clear of any major foundations.

When it is impossible to avoid crossing the foundations, the pipes crossing the foundations or

walls shall be installed in concrete culverts or shall be protected by pipe Sleeves, ( see item

2.4.2.3 ).

Pipes passing under roads and railways shall be arranged to cross at 90 and be routed through

ducts, Buried pipes shall be coated or wrapped. Where soil conditions demand, pipes shall be

suitably protected to resist corrosion.

The trenches for buried pipes shall run at such a depth sufficient to avoid damages due to dead or

live surface loads.

The bottom of the trenches shall be graded to provide a continuous firm bearing support to the

pipes.

Design installation, inspection, and testing required to ensure safe crossing of steel pipe lines

under railroads and roadways shall be according to API 1102 or approved equivalent.

2.4.2.2- Lines under Railroads or Roadways

All piping installed under railroads or roadways shall be protected with a reinforced concrete

culvert, reinforced concrete culvert pipe, steel casing pipe or sleeve, where the depth of cover is

between 600mm and 1800 mm from the bottom of roadway bed to the top of the underground

pipeline being considered.





Where the depth of pipe is less than 600 mm, special consideration by the Supplier shall be taken

and the calculations shall be given to the Employer for approval.

Where the depth of pipe is more than 1800mm no special protection is required.

The culvert shall be laid true to line and grade with the bottom quadrant in contact with the

undisturbed trench bottom and without tamping.

Wherever possible the protecting culvert shall be extended beyond the end of the railroad ties or

roadway bed till a distance equal to the depth of the bottom of the pipe.

In cases where the extension of the protecting culvert will interfere with other structures, specific

drawings shall be performed showing the embodying and other protections.

If protection is made with concrete pipe, it shall be reinforced concrete culvert pipe.

The casing pipe should be at least two nominal pipe sizes larger than the service pipe.

Service pipe installed in a casing should be held clear of the casing pipe by property designed

supports, insulators or other devices, and installed so that no external load will be transmitted to

the service pipe.

2.4.2.3- Piping Through Foundations and Walls

Pipe sleeves shall be provided for all piping passing through foundations, walls, floors, roofs,

etc.

Where sleeves are located in floors, walls of pressurized rooms or other similar installations,

they shall be packed with mineral wool, grout, or other approved material and shall be protected

with cover plates or other approved means.

Sleeves in floors or roofs shall be set sufficiently above the floor or roof to prevent drainage

through them.

Approved heads and flashing shall be provided for sleeves and piping passing through roofs.

Where required, pipe sleeves shall be of sufficient size to permit the passage of flanges or fittings

assembled with the piping.

Generally these sleeves shall be indicated on the drawings.

2.4.2.4- Floating Prevention

In the installation design, a special caution shall be taken to prevent floating due to water flowing

into the trench, caving, flushing, or puddling.





2.4.2.5- Manholes and Vaults

Vaults, manholes, and footings shall be provided around and under valves including all

embedded steel, deck, stairs and handrails.

The design of totally enclosed or roofed vaults shall incorporate sufficient escape provision for

personnel which may be otherwise trapped inside in event of flooding or other emergency.

A minimum of two manholes shall be provided for all those vaults where, because of their size,

handling, maintenance to, or replacement of valving equipment would require the simultaneous

presence in vault of more than one person at any one time. Manholes shall be of suitable size and

shall be located on vault roof in opposite location.

A separate run ladder arrangement shall be provided at each manhole for easy access to vault and

exit from the same. Vault size shall be such as to guarantee free movement of personnel

executing maintenance and/or repair work to underground valves.

Valve vaults which because of their design or construction could become, in any way, hazardous

to human life will not be approved by the Employer.

All concrete construction for underground pressure piping shall conform to the General

Specification.

2.4.2.6- Underground Piping Valves

As a principle on main headers gate valves shall be installed while on branches for water supply

to the different utilities, butterfly valves shall be installed.

Valves having size smaller than 32 shall be hand operated ( less than 6 normal hand operated

and 6 to 32 sizes gear hand operated), while valves having size 32 and larger shall be

equipped with electrical actuator.

2.4.2.7- Concrete Anchoring

When pipe joints are used that have little or no ability to resist tension, suitable concrete anchors

shall be provided at angle points, side outlets, valves, on steep slopes and other location in the

pipe line where unbalanced pressures may exist or develop which will tend to cause movement

when the pipe is under normal or test pressure.





2.4.2.8- Breather Pipes and Drainage Pipes

Breather pipes shall be installed in the most elevated points of underground piping; the same

shall be installed inside special manholes.

On the other hand, drainage pipes equipped with valves shall be provided in the lowest point of

each pipe branch included between two interception valves.

The drainage pipes shall be connected to the nearest sewage or pump.

Where necessary; pump sumps shall be provided sufficiently sized to receive a portable sump

pump.

2.4.3- Overhead Piping

2.4.3.1- General

Overhead piping shall run in straight lines parallel to major building axes, where possible, and

sloped for proper drainage where necessary.

Piping shall be grouped together (where possible) in order to facilitate the design of the supports,

In open yard the piping shall run on specially designed structural steel supports. Unless

otherwise specified, overhead pipes shall run at a sufficient elevation to allow clearance for

cranes, trucks, special transportation means and maintenance equipment.

As a general rule, the minimum net heights must be as follows:

x 8m in correspondence of crossing of main roadways.

x 5m in free yards or on branches parallel to roadway, unless particular conditions of traffic

requires higher heights.

Where possible it shall be permitted to install electrical cable conduits on the pipe support steel

structures.

2.4.3.2- Supports

All the following supports and relevant accessories shall be provided by the Supplier; anchors,

hangers, rollers, clamps, guides, sway bracings, vibration dampeners, expansion joints, etc, for

aligning and controlling the piping movements.

Inside buildings, additional structural members shall be provided such as struts, purlins, etc.,

Between trusses or columns, if required, to support the piping.

The use of wood and wire for piping supports shall be limited to riggings and temporary supports





during erection, and if used, these materials shall be replaced with proper permanent supports

before the lines are tested.

Vertical supports shall be spaced to prevent the pipe from being overstressed from the

combination of all loading effects.

Horizontal steel piping shall be supported at sufficiently close intervals to keep them in

alignment and to prevent sagging.

In any case, the maximum hanger spacing for standard and heavier pipe shall not be more than

indicated in the following table based on ANSI B 31.1. :

Nominal Pipe Size

(inches)

Maximum Spacing Water

Service

(ft)

Maximum Spacing Gas,

or Air Service

(ft)

1 7 9

2 10 13

3 12 15

4 14 17

6 17 21

8 19 24

12 23 30

16 27 35

20 30 39

24 32 42

In case of pipes of sizes and schedules different from those listed in the above table, pipe

supports shall be spaced according to a proper calculation.

Piping systems shall be designed, fabricated and installed so as to have sufficient flexibility to

prevent thermal expansion or contraction from causing excessive bending moments at joints, or

undesirable forces or moments at points of connection to equipment at anchorage or at guide

points.

Flexibility shall be provided by changes of direction or by use of bends, loops or offsets.





2.4.3.3- Valve platforms

All required valve platforms, valve stands, access ladders, hand rails, etc. shall be designed for

proper operation and maintenance.

2.4.3.4- Drip Legs and Appurtenances

Drip legs shall be provided and supplied for all piping systems requiring their use.

The supply of drip legs shall include the complete assembly of all appurtenances required for

their operation, and the necessary provisions for disposal of undesirable fluids such as

condensate, sludge, etc.

Where required, this shall include all traps, valves, or other items.

Drip leg on mains 6 inches and over shall be at least 75% of the main diameter with a depth

twice the diameter of the main or 600 mm minimum from the center line of the main to the trap

offtake.

Drip legs on mains smaller than 6 inches shall be full diameter of the line.

2.4.3.5- Drains for Overhead Piping

Drains shall be provided at all low points in all liquid piping systems. They shall be of sufficient

size to adequately drain the lines with respect to the time required and type of liquid.

Only gate valves or plug cocks shall be used for these drains.

2.4.3.6- Vents

Plugged vents shall be provided at high points in all piping systems subject to hydrostatic tests.

2.4.3.7- Pipes Painting

Pipes and steel structural supports shall be painted according to specification which are described

in volume 8 (Engineering standards, general).





3- Main Fluid System Equipment

3.1- Horizontal Centrifugal Pumps

3.1.1- General

When centrifugal pumps are provided, they shall be complete with, but not necessarily limited to

the following; electric motor, coupling and guard, pressure gauges (suction and delivery sides),

motor independent speed reducer or increaser (where required), bedplate and bolts, first fill of oil

and grease, and all other equipment for the safe and efficient operation of the pump.

Pumps up to and including 100 m3/h shall generally have end suction and those above, split

casings.

The contractor shall submit to the Employer:

x Characteristic curve at rated speed

x Manufacturer s catalogues

x Overall dimensioned drawings

Pumps shall be designed so that accidental reverse rotation does not damage any components of

the pump and the design of the pump shall, as far as possible, provide hydraulic balance of

impeller, rotor and shaft.

3.1.2- Operating Features

Unless specified otherwise, the preferred operating speed of all pumps shall be 1450 r.p.m. Pump

rotation is to be clockwise looking from driving end unless otherwise agreed by the Employer.

All pumps required to operate in conjunction with pressure and/or flow control valves shall be

designed for closed valve conditions.

Pumps are to be suitable for continuous duty.

Pumps required to operate in parallel, shall have their characteristics specifically selected to

ensure stable operation over the range of output from minimum to full design rating and be

capable of starting against closed valve conditions.

The pump shall be selected such that at least 5% increase in impeller diameter may be obtained

later, if required by replacing the impeller assembly. All components shall be designed in

accordance with the maximum impeller diameter that can be used.





3.1.3- Design

3.1.3.1- Casing

Pump casing material shall be selected considering the fluid to be handled.

Pump casings shall be provided with valved vents and drains.

Pump casing shall be of such thickness to be suitable for the maximum discharge pressure with

maximum impeller size at pumping temperature and hydrostatic test pressure at ambient

temperature, with suitable corrosion allowance related to the fluid to be handeled.

3.1.3.2- Impeller

Impellers can be open or closed due to particular specification. They shall be in stainless steel,

gun metal or bronze. Other materials may be used depending on the service and with the

Employer approval.

3.1.3.3- Couplings

Couplings shall be generally of semi-flexible type, they shall be designed to connect shafts

which are misaligned either laterally or angularly.

The motor, side half-couplings shall be supplied by the pump manufacturer, but machined by the

electrical motor manufacturer, in agreement with the pump manufacturer.

3.1.3.4- Bearings

Ball bearings shall be used for inboard and outboard bearings. Ball bearings used in centrifugal

pumps shall normally be grease lubricated. For large shafts and heavy-duty pumps, roller

bearings shall be used.

The design of the bearings shall accommodate any residual axial imbalance that may occur.

3.1.3.5- Seals

Seals may be special asbestos rings or mechanical seals, according to the particular application

and to the Manufacturers practice.

All mechanical seal plates shall be carbon steel except:

x Seal plates for alloy steel casing shall have corrosion resistance equal to casing.

x Seal plates for carbon steel and nodular iron casing with specified corrosion allowance over





3 mm shall be 18% Cr, 8% Ni.

When mechanical seals are used and sealing water is required, the Supplier shall supply the

pumps necessary to insure the proper water pressure. The sealing water quality shall be specified

by the Manufacturer.

If cooling is required to maintain the mechanical seal within its temperature limitation, the pump

manufacturer shall provide means to cool flushing fluids from the pumps discharge.

All seal plates shall have both in and out water cooling connections, if required, due to

pumping temperature.

3.1.3.6- Electric motors

Motors shall be selected to meet the end of curve duty of the pump with the impeller 5% larger

than supplied impeller.

3.1.3.7- Bedplates

All bedplates shall be common to pump and motor, made from cast iron or fabricated from wide

flanged, heavy section, mild steel joints, channels, or plates, stiffened with gussets at the point

of loading and machined all over the top and bottom pad surfaces.

3.2- Vertical Wet-Pit Centrifugal Pumps

3.2.1- General

These pumps shall be complete with, but not necessarily limited to, the following: electrical

motor, coupling, pressure gauge at delivery side, base, bearing spider, suction strainer, oil or

water lubricating system, motor independent speed reducer or increaser (where required), and all

other equipment for the safe and efficient operation of the pump.

The Supplier shall submit to the Employer:

x Characteristic curve at rated speed

x Manufacturers catalogues

x Overall dimension drawings

Pump rotation is to be clockwise looking from the driving end unless otherwise agreed by the

Employer.





The pump shall be constructed of materials specifically chosen to resist deterioration by pitting,

erosion and corrosion.

3.2.2- Electric Motors

Motors are to be rated to meet the maximum power of the pump or 20% of margin power,

whichever is larger.

3.3- Evaporative Cooling Tower

3.3.1-General

Cooling towers shall preferably be induced counterflow type.

All equipment shall be suitable for outdoor operation and adequately weather-proofed.

The design shall ensure that water losses are kept to a minimum.

Towers shall consist of a series of self-contained units, or cells of rectangular construction, each

complete with its own fan and structure arranged so that the number of units can be increased.

Within towers, it shall be possible to isolate units for maintenance while the remaining units are

in operation.

Central dividing walls shall be provided to prevent air flows from one side to the other.

Basins shall be designed to collect any solids in a settlement chamber designed to allow easy

maintenance.

3.3.2- Water Quality

The concentration cycle shall be selected considering make-up water analysis and acceptable

analysis of the referred cooling circuit.

3.3.3 - Structure

Up to 65C, the structure shall be in reinforced concrete and consist of a network of beams and

columns. Also, the deck where mechanical equipment is anchored shall be in reinforced

concrete.

Above 65C, the cooling tower shells shall be constructed of treated timber.

The design of the structure shall be such that all loads are evenly distributed to the foundation.

Loads used in the design shall allow for extreme site conditions.





The structure shall be designed to ensure that its natural frequency is well clear of any frequency

or harmonic generated by the drive system or fans.

Tower basins shall be of concrete construction with concrete posts to support tower internals and

partition walls.

A fall in both directions shall be provided in the floor of the basin to allow complete drainage of

the basin for cleaning.

3.3.4- Packing

Packing shall preferably be of splash type, packed with asbestos cement, or red wood. Plastic

shall not be used where water temperature above 55C will be encountered.

The packings are placed inside the cooling tower designed in such way to create max contact

surface between air and water without any risk of clogging due to suspended solids in water, all

material will be designed to be resistant to chloride content of the water.

3.3.5- Cladding

Cladding can be waterproof covered bricks, reinforced concrete, or asbestos- cement, or other

approved material.

3.3.6- Distribution System

Depending on the water temperature the main channel and distribution channels shall be in

asbestos- cement or fiberglass with the approval of the Employer.

3.3.7- Fans

The type of fan shall be axial, statically and dynamically balanced at operation velocity.

Fans shall be of the multi-bladed, adjustable blades, in light, alloy covered with synthetic resin or

rubber that shall be specified by the Manufacturer.

The number of blades and speed of rotation shall be selected to avoid vibration and air pulsation.

Blades shall be locked to the hub in an approved manner.

The fan should have a low sound level and be able to operate continuously in hot, humid

atmosphere, without undue deterioration.

Automatic, variable pitch fans shall not be supplied.





Fans shall be designed such that air recirculation is eliminated.

Devices to prevent reverse rotation shall be fitted to the fans.

3.3.8- Gear Reducer

Gear reducer shall be designed specifically for cooling tower duty i.e. hot and humid

atmosphere.

The case must be sealed to prevent water leakage.

Water condensing inside the case should not break down the lubricating oil, and should be easily

drained off, A gauge should be installed outside the fan cylinder to show oil-level in the gear

reducer.

AGMA standards should be considered in gear reducer construction.

The driving shaft should be dynamically balanced and should require little or no maintenance.

The couplings of the drive shaft should be made so as to be easily replaced while the shaft is in

position on the tower.

3.3.9- Electric Motors

Electric motors shall be able to operate continuously in a hot, humid atmosphere and to be shut

down for several months at a time without damage, The motors should be totally enclosed and

self-ventilated, and must have a safety margin of power of 15% more than the maximum power.

Motor protection shall be IP65.

Number of start-stops in an hour for hot conditions and full load should be 5, of which 3 should

be done one after the other.

3.3.10- Vibration Limit Switch

Motor should be protected by means of a vibration limit switch.

3.3.11- Access Ladders, Platforms and Access Decks

Ladders and hinged access doors shall be supplied for internal maintenance of tower.

All necessary staircases, ladders and platforms shall be supplied and provide access to gallery,

fan deck, and cooling tower roof.

Handrails, kneerails, and kicking planks shall be provided around the periphery of the tower at





fan deck, roof levels, and stairways.

Ladders shall have protective hoops and cages within 2 m of local grade level or intermediate

platform level.

Non-slip surfaces shall be provided where necessary, Walk-ways, not forming of the tower

structure, shall have open grid flooring.

3.3.12- Pipework Connections

All pipework, nozzles, and valves shall be flanged, Counter flanges shall be supplied.

3.3.13- Galvanizing and Protective Coatings

All ferrous materials used shall be galvanized in accordance with B5 729, Part l,or equivalent

standard to resist corrosion. All timber used in construction shall be suitably treated with a

chemically prepared preservative in accordance with BS 4072 or equivalent standard.

3.3.14- Bolts

Bolts shall be of stainless steel where necessary.

3.3.15- Control and Instrumentation

Minimum instrumentation and process control shall be furnished as specified and listed below.

Any additional instrumentation and controls as deemed necessary for the smooth and safe

operation of the cooling tower under all specified operating conditions shall be provide.

x In all cold wells a level control, a temperature transmitter, pH meter, a conductivity meter

and Inhibitor analyzer (if necessary) shall be considered.

x All the open system shall be fitted with a chlorine analyser.

x All the circuits shall be completed with a corrosion rack device for corrosion coupons.

3.4- Plate Heat Exchangers

Plate heat exchangers shall be used for temperatures not more than 100C and pressures not more

than 10 atm. They shall be designed to facilitate inspection, cleaning, and maintenance.





3.4.1- Plates

The plates shall be of the high number of heat transformer units.

3.4.2- Frame

The frame shall have one fixed end to which upper and lower carrying bars shall be attached.

The carrying bars shall be supported and held apart at the other and of the frame by a supporting

column.

The frames shall have extended nozzles mounted directly on the frame.

3.4.3- Gaskets

Unless otherwise specified, rubber gaskets shall be used.

3.4.4- Mounting

Unless otherwise specified exchanger shall be complete with support cradles for mounting on

concrete foundation, complete with stud bolts and washers.

3.4.5- Vents and Drains

Vent and drain connections shall be provided in accordance with the installation requirements

and all such connections shall be fitted with valves.

3.4.6- Instrumentation

Inlet and outlet connections on the nozzles shall be provided with temperature and pressure

indicators.

3.4.7- Materials

Unless specified otherwise, plate heat exchangers shall be constructed from the following

materials:

x Frame- Carbon steel or mild steel

x End movable pressure plate-Carbon steel

x Gasket- Rubber

x Plates-Stainless steel or titanium depending on the analysis of fluids concerned.





3.5- Pressure Vessels

3.5.1- General

Pressure vessel design, fabrication, inspection and testing, shall be according to ASME Section

VIII, Division 1 or 2- Pressure Vessels.

Design conditions shall allow for the most severe combination of internal and external loads and

forces to which the vessel may be subjected.

3.5.2- Design

3.5.2.1- Basic Allowable Design

The basic allowable stresses for pressure parts shall be the value established by the applicable

code.

The basic allowable stresses for non-pressure parts, except as modified below, shall be parts,

except as modified below, shall be 33 1/3% of the ultimate tensile strength, 66 2/3% of the yield

strength, or that producing a creep rate of 7% in 10,000 hours, whichever is lower.

(a) Welds attaching non-pressure parts to the pressure shell, and supports for important

internal equipment such as cyclones, grids, etc., shall be designed to the allowable stresses

for pressure parts.

(b) Anchor bolting shall be designed to a basic allowable stress of 1000 kg/cm2 based on the

net area of the thread unless a lower stress is specified by the codes.

3.5.2.2- Design Pressure

Vessels protected by safety relief valves shall be designed for an internal pressure that exceeds

the maximum specified operating pressure or anticipated pressure conditions by 10% (1 kg/cm2

minimum), when conventional or balanced (bellows)

type safety valves are used, and by 5% safety valves are used.

Vessels without pressure relieving devices shall be provided with an outlet which cannot be

completely blocked off. The outlet opening shall be sized so that the maximum pressure which

can the developed in the vessels is not greater than the design pressure.

Only those vessels actually subjected to external pressure in operation shall be designed for

external pressure.





3.5.2.3- Design Temperature

The design metal temperature vessels shall be at least equal to the maximum operating

temperature of the fluid in the vessel.

3.5.2.4- Corrosion Protection

The corrosion allowance for each vessel shall be determined by its intended service and shall be

added to all pressure parts, Parts or surfaces which are fabricated of, or their surface is protected

with corrosion resistant material shall not require corrosion allowance.

When the service conditions are such that it is not practicable to provide corrosion allowance by

added base metal, a corrosion resistant lining with 3mm, minimum thickness, shall be attached to

the pressure part, or integrally clad plate with 3mm minimum cladding thickness, or solid alloy

material shall be used.

3.5.2.5- Pressure and Instrument Connections

Connections shall be 1 in, nominal pipe size minimum, except that pressure and temperature

instruments connections may be threaded 6000 lb standard couplings, 3/4 in, nominal pipe size.

Pressure connections 1 in, and larger shall be flanged except as follows:

(a) Stub welding ends may be used when blinding is not required.

(b) Threaded 6000 lb standard couplings in 1 in, and 12

1 in, nominal pipe sizes may be used

for connections to piping with ANSI rating of 150 and 300 lb.

3.5.3- Construction

3.5.3.1- Nozzles

Nozzle flanges shall be according to ANSI or equivalent approved standards.

3.5.3.2- Bolting

Bolt holes in flanges shall straddle the vessel center lines unless otherwise approved by the

Employer.





3.5.3.3- Manholes and Handholes

All vessels shall be provided with inspection and or access openings such that the inside of the

vessel may be visually inspected.

Vessels less than 1000mm inside diameter shall be provided with handholes, while vessels

greater than 1000mm inside diameter shall be provided with manholes.

Manholes shall be located in such a position as to facilitate access by personnel, Circular

manholes shall be a minimum of 600mm inside diameter and other manholes shall be a

minimum of 600 mm x 500 mm.

Circular handholes shall be a minimum of 125mm inside diameter and other handholes a

minimum of 125mm x 80mm.

Manholes located in the horizontal plane shall be fitted with hinges and balance weights,

Manholes located in the vertical plane shall be fitted with davits.

3.5.3.4- Internals

All internals spanning a chord or diameter of the vessel shall be provided with means for

allowing differential expansion between the part and the vessel shell.

Internal non-pressure piping for carbon steel vessels shall be fabricated from extra strong

seamless carbon steel pipe. All internals (fixed and removable) shall be supplied by the vessel

manufacturer unless approved otherwise by the Employer. Baffles or wear plates shall not be

welded directly to the shell (or head) but shall be bolted to support attachments which are welded

to the shell.

3.5.3.5- Welding

All welding shall be in accordance with the latest edition of the design code applicable to the

particular vessel. Only welders who are qualified in the accepted procedure shall be employed.

The size of welds for all internal attachments shall include the corrosion allowance.

3.5.3.6- Stress Relieving

Vessels shall be stress relieved in accordance with the selected code.





3.6- Liquid Storage Tanks

3.6.1- General

The selection and design of the type of tank to be used for a specified liquid will be based on the

design temperature and the absolute vapor pressure, toxicity, and corrosiveness, and the value of

stored liquid. Tanks suitable for the service conditions shall be provided in accordance with the

following table:

SELECTION OF TANKS

Type of Tank Design Conditions Construction

Liquid storage Atmospheric API 650

Large Low Pressure storage

tanks

Greater than 0.04 kg/cm2 gage, but

not exceeding 1kg/cm2 at 90 C.

API 620

Water Storage

Tanks

Atmospheric API 650

AWWA D100

Tank parts, accessories, and attachments which are furnished as a regular part of proprietary or

standardized equipment shall be in accordance the tank or equipment manufacturers or

recognized industry standards suitable for the design conditions.

When a code, rule, or regulation is specified, the design of tanks shall conform to such specified

requirements and to such portions of this specification as do not conflict.

3.6.2- Design

3.6.2.1- Design Conditions and Basic Allowable Stresses

Tanks and their supports shall be designed to resist the effects of combined loads within the

limits of stress specified herein. Wind and earthquake loads shall not be assumed to occur

simultaneously.

The basic allowable stresses for design or test conditions shall be of the values established by the

applicable code except as follows:

The allowable tensile stress for carbon steel threaded parts such as anchor bolts and rods, based

on the root area of the thread shall be 1000 kg/cm2 unless a lower stress is specified by code.





3.6.2.2- Corrosion Protection

In general, no allowance for corrosion beyond that inherent in the thickness of the material used

or that required by the applicable code shall be added to tank parts except that in a severely

corrosive service, a corrosion allowance as determined by the service shall be added to all

pressure parts and non-removable internal parts and all surfaces exposed to the contained

medium.

Parts or surfaces which are fabricated of, or surface protected with, corrosion resistant material

shall not require corrosion allowance.

When service conditions are such that it is not practicable to provide corrosion allowance by

added base metal, consideration shall be given to the use of special liners or coatings.

3.6.2.3- Structural Steel

Atmospheric and low pressure tanks under 6m in height shall be provided with a ladder without

cage, and 6m and over in height with spiral stairways. Primary access to elevated water towers

and open tanks shall be by ladder only.

Atmospheric dome roof tanks shall be provided with walkways complete with handrail

extending to the center of the roof for maintenance of roof mounted accessories.

Pressure tanks shall be provided with platforms and ladders as required, for access to manholes,

relief valves, instruments, etc., requiring maintenance.

Ladders shall have safety cages when the ladders extend 6m above grade, and top rail hoops only

when ladders extend less than 6m above grade.

Hand railing shall be provided for all open sides of platforms, walkways, stairways, and near

ladder and stairway landings.

3.6.2.4- Supports and Foundations

Horizontal tanks located above grade shall be supported on steel saddles or supporting towers

depending on the tank height. Vertical tanks may be supported by skirts, columns, or the bottom

of tanks.

Vertical tanks supported on skirts shall have the center lines of skirt and shell plates

approximately coincident.





(a) When necessary (to maintain the calculated stresses within the allowable), skirts shall be

attached to the flanged portion of the head. The skirt shall be positioned so that the tank

girth seam can be inspected.

(b) All skirts shall have at least an 18 in, nominal diameter access opening.

3.6.2.5- Appurtenances and Accessories

Appurtenances and accessories shall be provided as per service requirement and design code.

3.6.3- Materials, Fabrication, Inspection and Testing

All materials and fabrication shall be in accordance with the requirements of the applicable code.

Tanks shall be inspected and tested in with the applicable code.

3.7- Blowers

3.7.1- General

Rotary-lobe type blowers shall comply with the requirements of relevant sections of API 619,

and requirements hereunder mentioned as do not conflict. In case of any confliction the

Employer will decide which one should be complied with.

The straight two-lobe cyclonical rotor units shall be formed by a pair of mated contour rotors,

rotating in a casing with a suitable contoured internal surface.

The movement of the rotors shall be synchronized by two keyed gears on the shafts. The shaft

shall be pressure mounted on the rotors.

These blowers shall be used for high vacuum, low compression, with ratio of compression about

1.7, 3 and capacity upto 56,000 m3/hr.

3.7.2- Bearings and Lubrication

For blower capacity upto 400 m3/hr, bearings shall be ball type, for higher capacities, roller

bearings shall be considered. No lubrication shall be made on the parts in contact with the

conveyed fluid,

in order to guarantee the complete absence of oil at the delivery, side.





3.7.3- Drive

Unless otherwise specified, blowers shall be directly driven by means of electric motor coupled

with flexible coupling to driving shaft.

3.7.4- Instruments and Accessories

Connections shall be considered for pressure and temperature indicators on the suction and

delivery sides.

Units shall be complete with but not necessarily limited to the following:

x basement provided with shock absorber

x air fitter

x silencers on delivery and suction sides

x safety valve

x foundation bolts

3.7.5- Material

The following materials are recommended for construction of blowers:

x Casing: Gray iron (30000 psi yield)

x Rotors: Ductile iron

x Shafts : AISI 4150 Alloy

x Gears: AISI 4130 Alloy

x Basement: Cast iron

Other materials may be substituted if proved to be of advantage.

3.8- Hydraulic Systems

3.8.1- Scope

This section of standard covers the hydraulic systems required for various units. The term

"hydraulic systems" referred herein generally covers the following: Hydraulic fluid reservoirs,

pumps, various kinds of valves, accumulators, hydraulic cylinders and pistons, oil heaters (if

any) and coolers, hydraulic motors, various accessories such as filters, strainers, hydraulic

pipework, fittings, flexible hose assemblies with end connections, Supports for equipment and

pipework, sealing devices, instruments for indicating, recording and integration of various





parameters such as pressure, temperature, velocity etc. , control devices for manual and

automatic operation of the system, safety devices and alarms for abnormal operating conditions,

interlocks for sequencing and safe operation, and fluids.

3.8.2- General

The design and construction of the hydraulic systems shall be suitable in every way for the

service intended and shall be oriented towards maximising interchangeability of components and

minimising maintenance. Each system shall be complete in all respects including all accessories

essential for proper installation, operation and maintenance, irrespective of whether such systems

are specifically mentioned in contract document or not.

In hydraulic systems provided in the vicinity of open flames, high temperatures, molten metal,

etc, special care shall be taken to prevent breakout of fire in case of breakout of hydraulic

system.

3.8.3- Standards

The hydraulic systems shall be designed, manufactured, erected, tested and commissioned as per

the standards laid down in this section.

Any aspects not covered herein shall be as per the codes and practices adopted by German

standards (DIN), ISO, UNI or approved equivalent.

3.8.4- Design Basis

3.8.4.1- General

The design should ensure that the components of the hydraulic systems are compatible with the

hydraulic fluid selected at operating conditions in the plant and under ambient atmospheric

conditions.

In selecting the hydraulic fluids the operating temperature of the system shall be given careful

consideration.

Detailed specification of the hydraulic fluid for each system shall be furnished by Contractor,

wherever available equivalents produced locally shall be indicated.





3.8.4.2- Hydraulic Circuits

Each hydraulic circuit shall be designed to minimize surge pressure, Suitable accumulators of

adequate size shall be used to withstand maximum rate of surge pressure rise as well as the peak

surge pressure. All components shall be capable of withstanding the peak surge pressure.

Each hydraulic circuit shall be designed to minimize generation of heat in the system by

adequately sizing the pipework and valves and by reducing bends and restrictions but without

sacrificing the functional efficiency of the system.

Hydraulic fluid temperature shall be controlled so as not to exceed the Contractors

recommendations. Under continuous operation, the temperature of mineral oil at the pump inlet

shall not exceed 50C.

Each circuit shall be designed such that the load variations and changes in fluid temperature shall

not cause such variations in the operation of system.

Design of each circuit shall be such as to achieve quick response to functional needs, economic

operation of the system, and minimum maintenance. The circuit design shall also ensure safety

of the staff and of equipment actuated by the hydraulic system in case of emergencies such as

power failure, bursting of hose or pipe connections, opening of safety valves and other devices

etc.

The hydraulic system shall be designed taking into account the maximum pressure encountered.

Each circuit shall incorporate a reservoir of adequate capacity, pumping equipment, filters to

eliminate undesirable particulate contaminants, generously sized pipework, accessories and

hoses, adequate cooling system to cool the hydraulic fluid where required, accumulators, all

valves and all necessary audio-visual alarms, Unless otherwise specified hydraulic equipment

located in unattended areas, basements, etc, shall have remote control facilities to ensure safety

of the main equipment served.

The circuits shall incorporate necessary stand-by units, by-passes, isolation devices etc, to ensure

continuous operation of the systems even when some components are under maintenance,

cleaning or repair.

The circuit design shall incorporate necessary connections, valves and appurtenances to facilitate

testing, flushing, draining, and recommissioning the systems.

The system design shall incorporate necessary safety features to reduce the hazard of ignition of

hydraulic fluid at points of application and at locations around hot zones.





Fluid sampling outlets with isolating valves shall be provided at suitable locations in the system.

Drain lines shall be independent of other return lines. Pilot return lines shall be independent of

power return lines.

Bleed points shall be provided to safely release air which would cause malfunction of the

system.

Power units shall be of integral construction. Power units and valve stations shall be provided

with adequate lifting facilities and be capable of being lifted safely and without distortion.

A drip tray shall be provided which shall have suitable means of draining and be at such a height

to allow drainage into a suitably sized container.

Piping shall not be used to support equipment. Where line mounted equipment is unavoidable,

the pipe shall be adequately supported either side of the item of equipment or the equipment

itself shall be adequately supported.

3.8.5- Equipment

3.8.5.1- Reservoirs

Reservoir shall have a working volume adequate to contain all the fluid that will return from the

system, maintain the fluid level within adequate working limits during operation and feed the

system for a minimum of 5 minutes, at the rated pumping capacity. For small systems, the

reservoir shall have a working volume to meet a minimum of 7.5 minutes, at the rated pumping

capacity.

The minimum fluid level shall be at least 100 mm above the upper most point of the suction

strainer.

The reservoir shall be designed and constructed to prevent entry of foreign matter, including

water and shall be separate and removable from the equipment base. Reservoirs shall be

fabricated from structural steel of adequate strength and thickness. Cast reservoirs shall not be

used.

All reservoirs shall have separate provisions for oil filling and air breathing. The filler hole shall

have a course strainer and be equipped with a cap permanently attached to the reservoir by

suitable means. Breather hole shall be protected by an air cleaner containing indicative type

silica-gel for moisture trapping. The air cleaner shall be of sufficient capacity to maintain

approximate atmospheric pressure even at maximum demands of the hydraulic system.





An additional 50mm threaded connection Should be provided for an external filling line.

Reservoirs shall be designed for adequate heat dissipation by generous tank wall surfaces and so

installed as to allow unhindered air flow

over all surfaces.

Return fluid shall have peripherial flow along reservoir side wall from suitably bevelled cut pipe.

A suitable bent stem dial thermometer protected and mounted in a bulbwell shall be installed in

the reservoir with at least 100 mm immersion.

The bottom of the stand alone reservoir shall have a minimum clearance of 150 mm from the

floor.

The reservoir shall be equipped with a vertical glass type fluid level indicator.

Markings shall be provided to indicate high and low levels with pump running and where

necessary, high level with pump stopped.

Low level alarms shall be provided on each reservoir to sound an alarm for low level indication

and to shut down pumps at a lower level. High level alarms shall be provided where automatic

make-up is provided to shut down make-up pump.

Both the intake and return pipes shall be brought down below the minimum working fluid level

so as not to cause cavitation or aeration. Return pipe shall be located as far as possible away

from suction strainer for efficient and smooth suction.

Suitable tubing connection shall be made for seepage fluid return from glands and packings.

The outlet pipe end of this connection shall be kept above maximum fluid level in the reservoir

to facilitate free return of low pressure seepage fluid.

Suitable provision shall be made for efficient cleaning of reservoir. A suitable opening with

hinged cover shall be provided. Where possible the size of the opening shall be suitable for a

man to go into the tank.

An accessible means shall be provided to empty the reservoir without spillage. The reservoir

bottom shall be shaped to facilitate emptying and cleaning by providing about 4 per cent slope at

the bottom. The drain shall be piped out for further disposal.

3.8.5.2- Pumps

Pumps shall be designed to meet at least 125 per cent of system flow rates and 125 percent of

system operating pressures.





Pump motors shall be adequate to operate the pump continuously at 125 per cent of the system

operating pressure without being overloaded. It shall be a high starting torque motor, if the

system requires starting with the pumps under load.

Unless otherwise specified pumps shall be provided with at least one stand-by unit for each

group of 2 or 3 pumps. The stand-by pumps shall be connected to the circuit and kept ready for

operation. Where only one operating pump is required, an identical stand-by pump shall be

provided.

Where possible, flooded suction shall be provided for the pumps. Direct coupled pumps shall be

securely mounted in a manner to assure alignment under normal operating conditions.

3.8.5.3- Valves

All valves shall be sized to meet the intended flow rates, with low pressure drops.

Lockable adjusting type valves shall be used to prevent change of adjustment caused by

equipment vibration and/or tampering, Where practical, directional valve of large capacity shall

be hydraulic pilot operated.

Valves shall not be mounted in reservoirs.

Suitable valve stands shall be used for mounting valves for the ease of operation and

maintenance.

Valves shall be kept above high fluid level of reservoir except where the functions of the valves

require them to be below the fluid level.

The operation of a valve shall not produce detrimental surges in the hydraulic system.

Solenoid operated valves shall be designed, constructed and installed to eliminate destructive

hammering of the solenoid or spool. Internal leakage shall be separately drained to reservoir or

to vented manifold to prevent blocking of plunger type controls.

Solenoid operated valves shall incorporate all features required by the service.

All hydraulic valves, accessories, and devices shall be plainly identified as to the function shown

on the diagram. Such identification shall be shown on a metal tag mounted adjacent to, and not

on, the component.

All valve porting shall be identified adjacent to ports by ISO thread designation.

All solenoids operating hydraulic equipment shall be identified. Each solenoid shall have the

same identification on both the electrical and hydraulic diagrams.





Wherever cylinders, actuators, or motors may experience externally induced forces, the circuitry

shall include protective devices (such as suitable cushioning and relief valves) to prevent

detrimental pressures and component.

All valves shall have frame sizes, ports, connection etc, conforming to ISO or equivalent

standards.

3.8.5.4- Accumulators

The accumulator shall be sized to meet the functional needs and shall be designed according to

ASME section VIII pressure vessel code or approved equivalent.

Test certificate for accumulators shall be provided by Contractor.

Means shall be provided for safely relieving of the accumulator gas and liquid pressure before

the accumulator can be disassembled. Automatic bleed-off or shut-off when system is shut down

shall be provided. Suitable charging equipment for accumulator shall be provided along with the

accumulator.

Shock bottles shall be installed on all valve stands and anywhere else necessary for shock

elimination.

3.8.5.5- Cylinders and Pistons

Hydraulic cylinders shall be designed to meet the working pressure of the system and tested to a

minimum of 150 per cent of the system operating pressure.

Cylinder bores with fitted pistons shall have a finish consistent with the type of service intended

and shall be free of porosity or other defects.

All cylinders bore shall be coated with hard chromium of appropriate thickness.

Cylinders shall be installed so that no side or radial load shall occur on piston rod or ram.

Cylinders shall be easily replaceable.

Cylinder body, heads and body flanges shall be of steel. Heads shall be bolted to cylinder body

flanges with heat treated, high strength steel bolts.





3.8.5.6- Coolers and Heaters

Coolers shall be fitted external to the fluid reservoir and shall be incorporated in the hydraulic

circuit if normal operation of the system would raise the fluid temperature to over 50C. Cooling

medium shall preferably be water, and the water flow shall be thermostatically controlled.

Heaters shall be used if the viscosity of the hydraulic fluid in cold seasons would affect the pump

operation adversely. The heaters shall be of electrical type, having a heating intensity to prevent

cracking of the hydraulic fluid due to local overheating.

Electrical heaters shall be of cartridge type, suitable for mounting in reservoir and shall be

thermostatically controlled.

Heat exchangers shall be protected against excessive pressure or pressure surges by suitable

means.

Thermometers shall be provided for checking inlet and outlet temperatures of the hydraulic fluid.

3.8.5.7- Filters, Strainers and Magnets

Adequate filtration shall be provided in accordance with manufacturers recommendations.

All filters shall have differential pressure switch connected to inlet and outlet of filter to give

indication of clogging.

Pressure and return line filters shall be so constructed and installed that the filter element can be

changed for cleaning or replacement without disturbing the piping or equipment operation. For

this purpose twin filters with suitable valving shall be provided.

Component parts of filter in contact with hydraulic fluid shall be of materials compatible with

the fluid and resistant to the corrosive effects of moisture.

Materials for filter elements shall be stainless steel or phosphor bronze.

3.8.5.8- Sealing Devices

All sealing devices shall be of suitable materials which will not be adversely effected by the

hydraulic fluid. Systems using phosphate ester, water glycol, invert emulsions or mineral oil,

shall be provided with viton seals, or approved equal.

Whenever possible, sealing devices shall be of the pressure sealing type.

Sealing devices for reciprocating or rotating shafts shall prevent all leakage, except that required

for lubrication of such devices, under all working conditions, without damaging shafts.





3.8.5.9- Devices for Circuit Control, Protection and Safety

Balanced piston type relief valves shall be provided on the discharge side of all positive

displacement pumps and over pressure protection shall be provided elsewhere in circuits where

damage to the equipment or hazards to personnel may result if design pressures are exceeded.

Check valves shall be provided on the discharge side of all pumps to prevent any back flow.

Hydraulic motor speeds shall be controlled by suitable pressure compensated flow control valve.

Sequence control shall be primarily governed by mechanically actuated limit switches, electronic

timers, sequence valve or any other position sensing device.

All pressure and volume controls shall be constructed so that they are not adjustable outside the

system safe working ranges. All pressure controls shall be marked to indicate minimum and

maximum pressures. A pressure gauge with shut-off valve shall be provided with each pressure

control valve. All relief valves shall be piped directly to the reservoir and not into a return line

with any back pressure.

The machinery and all connected equipment shall be brought to a safe stop upon failure of

electric power, control power, hydraulic power, or control components. The system shall remain

inoperative after restoration of service until the controls are reset.

If an unscheduled stop would result in an unsafe condition then the failure shall be announced by

audi-visual alarms and stand-by or stored power shall be provided that will permit a delayed or

gradual stop under manual or automatic control.

In the event of a failure in the controls, manual controls shall be provided that would permit

bringing the system to a safe operation or stop.

Where pumps are operating in parallel, manual valving which will permit removal of one pump

while the others are still in operation shall be provided downstream of the relief valve.

Where loss of working pressure on the discharge side of a pump or pumps may result in damage

to the equipment, in loss of accuracy, or in danger

of injury to personnel, means shall be provided to prevent operation under these conditions.

Electrically and pneumatically controlled hydraulic devices shall be applied in such a manner

that in the event of electrical or pneumatic circuit failure, there will be no damage to the

equipment or danger to personnel.





3.9- Lube Systems

3.9.1- Lube Oil Systems

When lube oil systems are provided, they shall be complete with, but not necessarily limited to

the following: tanks, pumps, water coolers, heaters, (where necessary), valves, instruments, (i. e.

pressure switches, temperature switches, etc.), piping, strainers, gauges, etc.

Wherever possible and practical, lubrication system shall be of the centralized type.

For the lubrication of gear speed reducers, splash lubrication may be sufficient in some cases.

When forced lubrication is required, the lubrication system shall be complete as indicated above.

Where there is a movement or vibration that could cause breakage of pipeline, hoses shall be

provided.

3.9.2- Grease Systems

When grease systems are provided, they shall be complete with, but not necessarily limited to,

the following: pumps, fittings, tanks, etc.

The central pumping unit shall be a time-clock controlled automatic unit and hand operated unit.

Where there is a movement or vibration that could cause breakage of pipeline, hoses shall be

provided.

The system shall be installed and clamped in order to minimize exposure to mill damage and to

be adequately protected from shock and vibration.

All lubricating lines on each piece of equipment shall be brought to a common header station.

3.10- Heating, Ventilating and Air Conditioning Systems

Equipment, ducting, diffusers, piping, controls, etc required for heating, ventilating and air

conditioning of spaces such as control rooms, switchgear rooms, transformer rooms (when

located in closed rooms), crane operator cabins, compressors rooms, emergency generator room,

shall be provided by the Contractor. Design, fabrication, inspection and testing of heating,

ventilating and air conditioning systems and components shall be accordance to ASHRAE

Standards and Handbooks.

Inside design conditions of spaces shall be as per equipment manufacturer's recommendations

and personnel comfort (when the space is permanently manned), which shall be established as

per ASHRAE recommendations.

Documents

TA-143-D00-G-TD007_0_Annex II, Fluid Systems.pdf