bfv std.specdamper

7/30/2019 BFV Std.specdamper

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T2.00 INTENT OF SPECIFICATION

This sub-chapter is intended to cover design,

materials

procurement,manufacture/fabrication,shop testing

and

supply of various types of valves the C.W.system

of

2 nos 210 MW units.

Scope of Work:

The contractor's scope of work shall include

Design,

engineering, Manufacture, Shop testing,

painting,

Packing, loading at works, Transportation to

site,

Unloading, Handling at site, Storage,

comprehensive

insurance, Preservation, Erection,Testing

commissioning of the required number of valves

as

listed below along with a pair of counter flanges

with

necessary nuts, bolts, washers and gaskets for each

of

the valves.

Scope of Supply

i) The scope of supply of the contractor

covered

under this specifications shall include the

valves

as specified in the following paragraphs; and

ii) Mandatory spare parts and special

maintenance

tools and tackles.

T2.01 Equipment Specifications

T2.01.01 The valves shall be designed, manufactured and

tested

as per relevant Indian Standards or as per

otherInternational standards acceptable to the Purchaser

and

will be suitable for the duty conditions

specified

below.

T2.01.02 Motor operated Butterfly Valves

i) No.of valves - 6 Nos.


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ii) Nominal diameter - 1600 mm.

iii) Type of valve - Flanged Butterfly

valve

as per BS -

5155/AWWA

C - 504 with

electric

actuator.

iv) Location - Indoor in pump house.

T2.01.03 Motor operated butterfly valve


ii) Location - Makeup water pipe

to

forebay.

iii) Nominal diameter - 600 mm.

iv) Type of valve - Flanged Butterfly

valve

as Per BS -

5155/AWWA

C-504 with

electric

actuator for make-

up

water.

v) Location - Outdoor

T2.01.04 Gear operated butterfly valves

A. i) No.of valves - 8 Nos.

ii) Location - 4 nos. on tappings

forheat exchangers & 4

nos.

on makeup water

pipeline

as shown in the drawing.

iii) Nominal diameter - 600 mm


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iv) Type6 of valve - Gear operated

Flanged

Butterfly valve as

Per

BS- 5155/AWWA.

B. i) No.of valves - 4 Nos.

ii) Location - Cooling Tower Hot

water

inlet (2 Nos. per

tower)

iii) Nominal diameter - 1600 mm

iv) Type of valve - Gear operated

Flanged

Butterfly valve as Per

BS

- 5155/AWWA.

T2.01.05 Manually operated butterfly valves



iii) Type of valve - Manually

operated

Flanged Butterfly

valve

as Per BS- 5155/AWWA

for

blow-down water.

T2.01.06 Miscellaneous valves

Gate/sluice valves shall conform to IS:780-1984

and

IS:2906-1984(R.A.1990)Class PN 1.0 as applicable.

Globe valves shall conform to IS:778-1984, Class

I.

Non-return valves shall conform to IS:5312-1986,Part

I.

Butterfly valves shall conform to AWWA C-504/BS 5155.

Flange drilling of all valves shall be as per table

11


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of IS:6392-1971.

T2.01.07 All the Butterfly valves shall be of 6 Kg/cm2

rating

and conform to B.S -5155-1984 or ANSI/AWWA-C-504-

1987.

The valves shall be double flanged type and shall

be

supplied with matching flanges ,bolts,nuts

and

gaskets.

Drilling of flanges shall be as per table-11

of

IS-6392- 1971. The analysis of liquid to be handled

is

given in Annexures-D & E.

T2.01.08 All electric actuator driven valves shall be :

a) Complete with electric motor ,necessarygear

drive, position limit switches ,torque

switches

and terminal board.

b) Complete with Micro switch for disconnecting

power

supply when the valve is operated manually.

c) All limit and torque switches shall be dust

and

water proof.

d) The climate prevailing at site is tropical

and

humid with maximum temparature of 50 Deg.C

and

100% humidity but both not occuring

simulta-

neously. The equipment shall be designed to

suit

this condition.

T2.01.09 Direction of flow shall be clearly indicated on

the

valve by embossing an arrow on the valve body.

T2.01.10 All the valves shall have a permanent stainless

steel


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name plate and stainless steel tag fixed on the

valve

body indicating the tag number,diameter,pressure

rating

and manufacturing standard code of the valve.

T2.01.11 The valves shall be designed for 100% water tight

shut

off.

T2.01.12 All the valves shall be provided with hand

wheel/

lever. The face of the wheel/lever shall be

clearly

marked with the words OPEN and CLOSE and an arrow

to

indicate the direction for opening/closing.

T2.01.13 All the valves shall be supplied with companion

flanges

made of Carbon Steel plates conforming to IS:2062-1992

Gr.2A and drilled to I.S.6392-1971 Table-11.

Materials of construction:

1. Body : C.I. IS-210 Grade FG260

2. Disc : C.I. IS-210 Grade FG260

3. Seat : Nitrite rubber/S.S (304)

4. Shaft : S.S. (304)

5. Seat retaining : S.S. (304)

rings/and screws

6. Shaft bearing : Self lubricated

T2.01.14 TECHNICAL SPECIFICATION FOR MOTOR ACTUATORS FOR VALVES

AC Motors

- Motor shall be totally enclosed, fan

cooled,

squirrel cage type.

- Degree of protection for motors, bearings

and

terminal boxes shall be IP-55.

- Shaft extension as per requirement.

- Bearing suitable for running of motors in

either

direction.

Terminal box

- Terminal box of all motors shall be

liberally


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sized to accomodate termination of

Aluminium

Conductor PVC armoured cables as per

enclosed

table.

- Terminal box shall be provided normally on

the

right side when viewed from the driving end or

on

the top.

Cooling

- Motors shall be TEFC design

- Ventilation system shall be effective

irrespective

of direction of rotation.

Quality of operation

- Rotor shall be dynamically balanced.

- Vibration and noise level shall be as

per

IS-12O75- 1991 & IS-12O65-1987 respectively.

Electrical Design

- Motors shall be suitable for DOL starting

- Shall be suitable for 415V + 6% , 50HZ + 3%

- Motors shall have class B insulation

with

temperature rise limited to 65 deg.C over

an

ambient of 55 deg.C.

- All motors shall be provided with 2 nos.earthing

bolts.

- All motors shall be designed conforming to IS-

325-

1978.

Limit switches


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- All limit switches shall be of

robust

construction, capable of withstanding

repetitive

operations.

- Shall be lever or rotating cam type

depending

upon requirement.

- Shall be provided with 10 A, 2 NO + 2 NC

contacts.

- Shall be housed in robust metalic, dust

and

weather proof, enclosure conforming to IP-

65

enclosure, suitable for outdoor installation.

- Earthing studs (2 nos) shall be provided

- Shall be provided with suitable cable gland

plates

with knockout holes of required size

T2.02 INSPECTION, TESTING & SHOP PAINTING

T2.02.01 Inspection & Testing

The tests to be conducted at shop for various

sub-

assemblies/assemblies of equipment shall include,

but

not limited to the following:

- Material test

- Testing during manufacture/fabrication

- Dimensional checking

- Hydrostatic testing of body and seat.

- Demonstration of guaranteed opening &

closing

time.

Any other test, as required to prove the

functional

requirement of various parts of equipment/system.


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T2.02.02 The final tests shall be conducted in the presence

of

the Purchaser's representative. Test certificates

for

different tests shall be made available to

the

Purchaser. Material test certificates for bought

out

items shall be obtained from original

manufac-

turer/reputed test house. For all bought out

items,

test certificates as relevant to the items shall

be

furnished by the contractor.

T2.02.03 All the equipments shall be subject to stage

inspection

by the contractor's own inspecting

authority.

However, Purchaser's Inspector may visit theworks

from time to time who should have free access to

all

the places of the manufacturing premises where

any

part/parts are under manufacture.

T2.03 Shop Painting

a) Surface preparation shall be as per St-2 and/

or

St-3 of Swedish standard SIS 055900 or

GERMAN

STANDARD DIN 55928 Part 4

b After surface preparation, two coats of

single

pack air drying phenolic modified

alkydcomposition primer with Zn phosphate as

per

IS:2074-1992 shall be applied. Dry Film

Thickness

of each coat should be 40 microns(minimum).

c) Two coats of single pack air drying high

gloss


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phenolic alkyd modified synthetic enamel

paint,

suitably pigmented shall be given as

Final

paint.Dry film thickness of each coat shall

be

25 microns.

T2.04 Performance Guarantee and Warranty

- The valves supplied shall be guaranteed

for

satisfactory performance as per

General

Conditions Of Contract.

LIST OF MANDATORY SPARES FOR VALVES

The following mandatory spares shall be included in

the

contract for Butterfly valves of each size.I) For DN 1600 motor operated butterfly valves.

1. Valve disc. - 1 Set

2. Shaft - 1 set

3. Shaft key - 1 set

4. Bearings - 1 set

5. Allen screw - 1 set

6. 'O' rings - 1 set

7. Gland packing - 2 sets

8. Seal clamping units and bolts - 1 set

9. Position indicator - 1 set

10. Actuators (as applicable) - 1 set

11. Torque/limit switches - 1 set

12. Handle - 1 set

II) For DN 1600 gear operated butterfly valves.


2. Shaft - 1 set


4. Bearings - 1 set






10. Actuators (as applicable) - NA11. Torque/limit switches - NA

12. Handle - 1 set


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iii) For DN 600 motor / gear operated butterfly

valves.


2. Shaft - 2 set


4. Bearings - 2 set






10. Actuators (as applicable) - 2 set

11. Torque/limit switches - 2 set

12. Handle - 2 set

Iv) For DN 300 manually operated butterfly valves.


2. Shaft - 1 set

3. Shaft key - 1 set4. Bearings - 1 set






10. Actuators (as applicable) - NA

11. Torque/limit switches - NA

12. Handle - 1 set

Notes:

1. One set shall be applicable for one valve of

each

size.

DATA SHEET FOR VALVES

I) MOTOR OPERATED BUTTERFLY VALVE AT PUMP DISCHARGE

1) Name of manufacturer : Fouress

2) Nominal diameter of valve

in mm. : 1600

3) Test Pressure -

a) Body -Kg/Cm2 : 9

b) Seat -Kg/Cm2 : 6


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4) Quantity - Nos. : 6

5) Manufacturing Standard : BS 5155

6) Drilling Standard for flanges : As per BS 4504 PN-10

7) Length over flanges - mm : 440

8) Thickness of valve disc - mm : 190

9) Details of motor actuator.

a) Make : Auma

b) Model : SA30E90

c) Type of motor : 3 Phase AC motor, sq.

cage

d) K.W. : 2.5

e) motor speed : 2800

f) Output RPM : 90

g) Class of Insulation/

degree of protection : CL B / IP68

h) Voltage : 415 V

i) Frequency : 50 Hz

j) Duty : S2-15

10) Valve opening/ closing time

in seconds : 75 + 5

11) Materials of construction

a) Body : IS 210 Gr. FG 260

b) Disc : IS 210 Gr. FG 260

c) Drive Shaft : AISI 431

d) Stub Shaft : AISI 431

e) Seat Ring : Stainless Steel

f) Clamping Ring : S.G.Iron


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g) Bearing : Teflon

h) End Cover Plate : IS 210 Gr.FG 260

i) Shaft Pin : AISI 431

j) Seal : Nitrile rubber

k) Gears : S.G.Iron

l) Hand Wheel : Fabricated steel

m) Eye Bolt : Steel

n) Integral Flanges : IS 210 Gr. FG 260

o) Matching Flanges : Carbonsteel.IS2062,Gr-2A

p) Bolts : Iinternal SS304/External

HTS/CS

q) Nuts : HTS/CS

r) Gaskets : Nitrile Rubber

12) Weight of Valve Assembly Kg. : 5650 (approx)

II. MOTOR OPERATED BUTTERFLY VALVE ON MAKE-UP WATER PIPELINE



in mm. : 600

3) Test Pressure -

a) Body -Kg/Cm2 : 9

b) Seat -Kg/Cm2 : 6

4) Quantity - Nos. : 2

5) Manufacturing Standard : BS 5155

6) Drilling Standard for flanges : IS 6392-1971 Table-11 /


8) Thickness of valve disc - mm : 80

9) Details of motor actuator.


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a) Make : Auma

b) Model : SA12E63

c) Type of motor : 3 Phase AC motor, sq.

cage

d) K.W. : 1.1

e) Motor speed : 2800

f) Output RPM : 63

g) Class of Insulation/

degree of protection : CL B / IP68

h) Voltage : 415 V

i) Frequency : 50 Hz

j) Duty : S2-15

10) Valve opening/ closing time

in seconds : 42 + 5








g) Bearing : Teflon

h) End Cover Plate : IS 210 Gr.FG 260



k) Gears : S.G.Iron



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m) Eye Bolt : Steel


o) Matching Flanges : Carbonsteel.IS2062,Gr-

2A

p) Bolts : Iinternal

SS304/External

HTS/CS

q) Nuts : HTS/CS


12) Weight of Valve Assembly Kg. : 600 (approx)

III) GEAR OPERATED BUTTERFLY VALVE



in mm. : 600 1600

3) Test Pressure -

a) Body -Kg/Cm2 : 9

b) Seat -Kg/Cm2 : 6

4) Quantity -Nos. : 8 4

5) Manufacturing Standard : BS5155

6) Drilling Standard for flanges: IS 6392-1971 Table-11/

BS4504 PN10

7) Length over flanges -mm : 267 440

8) Details of gears :








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g) Bearing : Teflon

h) End Cover Plate : IS 210 Gr. FG260



k) Gears : SG iron


m) Eye Bolt : Steel


o) Matching Flanges : Carbonsteel.IS2062,Gr-

2A

p) Bolts : Iinternal

SS304/External

HTS/CS

q) Nuts : HTS/CS


10) Weight of Valve Assembly : 530 kg 5650 Kg

(appx)

IV) MANUALLY OPERATED BUTTERFLY VALVES



in mm. : 300

3) Test Pressure -

a) Body -Kg/Cm2 : 9b) Seat -Kg/Cm2 : 6

4) Quantity -Nos : 2

5) Manufacturing Standard : IS 5155

6) Drilling Standard for flanges: IS 6392-1971 Table-11



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8) Materials of construction :






f) Clamping Ring : SG Iron

g) Bearing : Teflon

h) End Cover Plate : IS210 Gr.FG 260



k) Hand Wheel : Fabricated steel

l) Eye Bolt : Steel

m) Integral Flanges : IS 210 Gr. FG 260

n) Matching Flanges : Carbonsteel.IS2062,Gr-

2A

o) Bolts : Iinternal

SS304/External

HTS/CS

p) Nuts : HTS/CS

q) Gaskets : Nitrile Rubber

9) Weight of Valve : 120 kg(approx)

10) Any other information

GUARNTEED DATA FOR B.F.VALVES


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The contractor guarantees that each Butterfly valve

for

cooling water system shall meet the following

performance

requirement :

1.00.00 Design working pressure of

Butterfly Valve (Kg/cm2(g)) : 6

2.00.00 When valve fully closed : 6

2.01.00 Rate of leakage : Nil

2.02.00 Maximum shut-off pressure,

(Kg/cm2(g)) : 6

3.00.00 Valve operating time in secs. : For 1600mm dia

from open to close and vice- : 75 +15 sec.

versa (only for electrically : For 600mm diaoperated valves) : 42 +5 sec.

4.00.00 Guarantee Characteristic curves: Not Applicable

for regulating valves submitted

Note : This Guaranteed Performance Data is applicable

for each size of the valve.

SIGNATURE OF THE

contractor ............

NAME ...................................

DESIGNATION ............................

NAME AND ADDRESS OF COMPANY

......................................

..

DATE ...................................

COMPANY SEAL:

T3.00 INTENT OF SPECIFICATION

- This sub-chapter is intended to cover

design,

materials procurement,

manufacture/fabrication,


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testing and supply of various types of

fabricated

and boughtout pipes,fittings,expansion

joints,

gates, screens and other miscellanious

items

connected with the circulating water system

of

2 x 210 MW units.

C.W.PIPING

Scope of Work

The contractor's scope of work shall include

design,

engineering, supply of steel plates,

accessories,

loading, unloading at site, comprehensive

insurance,

fabrication of required circulating water pipingat

site, outside surface coating and wrapping of

pipes,

inside painting for pipes above 1600mm dia.,

painting,

handling of fabricated pipes at site, erection,

testing

and commissioning of circulating water piping

system.

The scope of work also includes Civil works

like

excavation, and back filling, construction of anchor

/

thrust blocks chamber of man holes / air valves

and

other miscellaneous civil works that would be

required

for installation of piping.

Scope of Services

All piping systems as shown in enclosed

drawings

No.MEC/S/P123/A04/S4/01 and 02 complete with all

final

joint welding at Battery limits viz., piping from

inletand outlet of condensers, cooling water pipe for

heat

exchangers (inlet and outlet), connection of C.W

piping

at cooling tower inlet, make up water pipes

and

blowdown pipes.


19/39

All bends , reducers, tees distance pieces, dished

ends

etc. of all sizes and shape required for complete

the

system.

All piping and fittings for vents, drains,

instruments

tapping points with stubs and root valves and

stubs

for the thermowell connections etc.

All counter flanges, blank flanges, caps etc.

necessary

for the piping. All necessary bolts, nuts, and

gaskets

required for installation of the system.

All flanges, manhole and manhole covers, flanged

tees

with blank flanges, automatic air-vent

valves

required on above piping are included in

the

contractor's scope of supply.A minimum number of 6

nos.

automatic air release cum vacuum break valves

(Double

air vent) for each unit (total 12 nos.) shall

be

provided on CW piping.The air release valves shall

be

of 200 mm dia with separate 200mm dia isolation

gate

valves.

Manhole shall be provided on either side of

the

Butterfly valves for maintenance purpose (except

for

300mm dia.).

- The pipework covered under this section shall

also

include internal pipework for the pumphouse

and

piping between pump house and main plant and

other

units as indicated in the drawings enclosed

with


20/39

the specification and described in

various

paragraphs of the specification. G.I. pipe

work

for drinking water, service air and instrument

air

piping etc., pipe work for service water air

is

also included in the scope of the contractor.

- The term 'pipework' referred herein

generally

covers pipes, fittings (such as bends,

tees,

reducers, plugs, nipples, sockets,

unions,

flanges, crosses, etc) valves, throttling

pieces,

stubs for primary sensing instruments etc.

T3.01 The pipes shall be manufactured/supplied asspecified

below:

i) Upto 150 mm nominal size - M.S ERW Black

pipes

conforming to

IS-

1239-1984

Part-I

(Medium Duty)

With

Plain ends.

ii) 200 mm to 350 mm size - M.S. ERW

Pipes

conforming to

IS-

3589-1973 but

thick-

ness as

specified

below :

Nominal Dia O.D X Thickness in mm

DN 200 mm : 219.1 x 6.35

DN 250 mm : 273.0 x 7.14DN 300 mm : 323.9 x 7.14

DN 350 mm : 355.6 x 7.14


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iii) 400 mm to 600 mm size - Spirally Welded

M.S.

Pipes( Manufactured

at Rourkela

Steel

Plant) of

commercial

quality.

Nominal Dia O.D X Thickness in mm

DN 400 mm : 406.4 x 7.14

DN 450 mm : 457.0 x 7.14

DN 500 mm : 508.0 x 7.90

DN 600 mm : 610 x 9.50

iv) 1600 mm and above - Fabricated from

M.S.

plates as

specifiedin para T3.02

a) For Service Air : IS:1239 - 1984 (Part-I)

Heavy duty/IS:1978 -

1984

St.25 seamless

b) For Instrument Air : IS:1239 - 1984 (Part-I)

Heavy duty/IS:1978 -

1984

St.25 seamless (Hot dip

galvanised)

c) Drinking water : IS:1239 - 1984 (Part-I)

Heavy G.I.

d) Service water : IS:1239 - 1984 (Part-I)

Heavy / IS:3589.

T3.02 Fabricated Steel Pipe lines

T3.02.01 All fabricated pipelines specified below shall

be

fabricated from tested quality M.S. plates

conforming

to IS-2O62-1992 Grade -A by submerged arc

weldingprocess as per IS-10234 or equivalent having

thickness

indicated against the pipe dia:

-------------------------------------------------------

Nominal dia Outside dia Plate thickness

of pipe mm of pipe mm mm


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-------------------------------------------------------

16OO mm 1632 16

24OO mm 2432 16

-------------------------------------------------------

T3.02.02 All fabricated pipes shall be manufactured by

cold

bending using a plate bending machine. The

plates

shall be gradually bent to true cylindrical shape

sothat no undue stress develops in the

plate.The

tolerances on dimensions of pipe fabricated from

plate

shall be as follows:

i) On outer diameter

as calculated from

circumference : + 1/4 of plate

thickness.

ii) Out of roundness : + 3 mm & -1.5 mm

iii) Out of straightness : 1 mm per metre length

(Max.)

T3.02.03 The pipe circumferential weld shall be done in such

a

way that the longitudinal welds become staggered in

any

two consecutive sections.

T3.02.04 Pipe sections in straight lengths delivered at

erection

site shall be of suitable length to minimise

field

joints as far as possible. End preparation shallbe

done at the fabrication yard to facilitate

site

welding.Straps shall be provided at field joints.

T3.02.05 The contractor shall submit detailed working

drawings

of pipelines and fittings including

fabrication


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drawings for approval by Purchaser/ Consultants.

These

drawings shall indicate design parameters,

complete

bill of materials, welding and all other

fabrication

details. Details of hydrostatic and ND tests

proposed

to be done shall also be specified.

T3.03 Pipe fittings

Fittings shall be supplied as per IS:1239-1992 Part

II

for pipes upto 150 mm dia and shall be fabricated

from

pipes for dia 200 mm and above.

All root joint welding from headers for service

air,

instrument air, service water and drinking wateretc.,

shall be carried out by the contractor.

Gate valves, Drain valves, Root valves, Blind

flanges,

pipe flanges, Gaskets, Bolts, nuts and washers

etc

shall be supplied in quantities and sizes as

required

during detailed engineering with price included in

the

lumpsum quoted.

T3.04 Fabrication of pipelines and welding of pipe joints

T3.04.01 The contractor shall arrange at his cost all

tools,

plant, welding transformers, instruments

and

consumables including any acytelene and oxygen

gascylinders, welding electrodes for electric arc

welding

and filler rods, fluxes etc. for gas welding

for

carrying out the welding at site. Submerged orc

welding

as per IS 10234-1982 shall be carried out as

per

relevant International code.


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The contractor shall indicate the procedure he is

going

to follow for fabrication/erection/hydraulic testing

of

M.S.Pipes.

T3.04.02 The contractor shall arrange at his own cost for

all

tests outlined in this section.

T3.04.03 Requirement of welded joints

The contractor shall ensure the following

requirements

while welding the plates/ pipejoints etc.

i) Strength-equality with parent metal

ii) Absence of defects

iii) Corrosion resistance of the weld shall not be

less

than that of the parent metal in

agressive

environment.

T3.04.04 Method of Quality Control in Welded Joints

Following steps shall be taken by the

contractor,

besides controlling quality in general, to

make

effective control in carrying out welded joints.

a) Welding procedures shall be prepared in line

with

IS:7307(Part-I)-1974, reaffirmed in 1991 and

tests

shall be carried out to quality procedures.

Number

of procedures will depend on variables

like

positions of welding, thickness range etc. Once

a

welding procedure is qualified, strict

adherence

to it shall be made during actual welding.

b) Welders employed shall be qualified as per

IS:7310

(Part-I)-1974, reaffirmed in 1987 after

passing

necessary tests.


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c) Welding consumables shall be of approved

type.

Such consumables are, however, subject

to

qualifying initial check tests as per IS:814-

1991.

d) The contractor shall strictly follow

approved

welding procedures during actual welding.

Besides,

the following stages of inspection shall also

be

carried out :

i) Weld edge preparation before welding,proper

fit up, position of welding, cleaning of

slag

between the passes, proper weld profile

etc.,

shall be checked visually, amongst others.

ii) Non-destructive tests of weld of

welded

joints shall be carried out as per

approved

procedures/ drawings.

T3.04.05 Preparation of joints

The contractor shall prepare the edge correctly to

the

shape, size and dimensions of the vee-grooves as

per

ANSI B-16.25 unless otherwise specified

in

drawings/documents.

The welding surfaces shall be smooth, uniform and

free

from fins, teers, notches or any other defect which

mayadversely afect welding and shall be free from

loose

scale, slag, rust, grease, paint, moisture or any

other

foreign material. The clean surface shall extend

to

about 10 mm beyond the welding faces to

avoid


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contamination of the weld metal with foreign

material

and to avoid unsound weld deposit.

T3.04.06 Assembly, Alignment & Welding

The sequence of welding shall be so planned

and

followed that there shall be a balance of welding

about

the neutral axis of the fabrication. The

contractor

shall employ sufficient number of welders working

at

the same time in diagonal quadrants of the shell

using

back-step method of welding. The rate of progress

of

each welder shall be more or less equal and

quality

uniform.

The general direction of welding shall be towards

the

free end of the joint, but in a long joint as in

shell

fabrication, back-step technique shall be used

to

reduce distortion.

To minimise internal locked up stresses due to

welding,

the vertical joints for the shell shall be welded

and

completed to a circular course and then the

horizontal

circumferential seam welded. However, before

the

welding of horizontal seam started, the

complete

circular course shall be aligned and adjusted for

theircorrect axes.

Alternatively, the contractor shall complete

each

course in all respects on ground and then the

pre-

assembled course shall be lifted and placed

in


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position. In such a sequence and planning, the

same

principle of balancing of weld about the neutral

axis

shall be followed and the method of fabrication of

each

course shall be similar to fabrication of

penstock

pipes or transmission/industrial pipelines of

bigger

diameter.

Pipe and attachment shall be aligned properly

by

accurate and permanent methods prior to welding.

If

tack welds are used, the tack shall be either

fused

into the first layer of weld or else chipped out.

T3.04.07 Tests on welded joints

(a) Visual examination

The contractor shall conduct visual examination

and

measurement of external dimensions of the weld for

all

joints. Before examining the welded joints, areas

close

to it on both sides of the weld for a width not

less

than 20 mm shall be cleared of slag and

other

impurities. Examination shall be done by a

magnifying

glass which has a magnification power of ten (10)

and

measuring instrument which has an accuracy of + 0.1

mm

or by weld gauges. Welded joints shall be examined

from

both sides. The contractor shall examine the

following

during the visual examination :-

i) Check the correctness of shape and size of

thewelded joints

ii) Incomplete penetration of weld metal

iii) Influx

iv) Burns

v) Under cuts


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vi) Unwelded crates

vii) Cracks in welded spots and heat affected zones

viii)Porosity in welds and spot welds

ix) Compression in welded joints as a result

of

electrode impact while carrying out

contact

welding

x) Displacement of welded element.

The contractor shall carryout any or all tests

as

specified hereinafter to satisfy the Purchaser

about

the acceptability of the welded joints, as directed

by

the Purchaser. However minimum 10% DPT or MP

test

shall be carried out in the fabricated pipes.

(b) Liquid Dye-penetrant Test

Liquid dye-penetrant tests shall be carried out

in

accordance with IS:3658-1981, reaffirmed in 1991

for

surface/sub-surface defects.

(c) Test by Blowing

The surface of the weld shall be covered with

soap

solution consisting of one (1) litre of water

and

hundred (100) grammes of soap. Compressed air shall

be

blown from the opposite side at pressure of 4to

5 kg/cm. sq. The distance between the tip of base

and

the weld shall not be more than 50 mm. Any formation

of

soap buble will indicate welding defects.

Portable

compressor shall be arranged by the contractor,

if


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necessary, for this purpose.

Tolerance

Deviations for assembly of welded joints may

be

permitted to the following extent :

Tolerance

-------------------------

Manual arc

Automatic

a) Source butt-joints

i) Gap between the + 2.00 mm + 1.00 mm

ends of plates - 1.00 mm

Tolerance

-------------------------

Manual arc

Automatic

ii) Stepping of one

plate over the

other 1.00 mm 2.00 mm

b) Single Vee-groove Joints

i) Bevol angle + 5 deg. + 5 deg.

- -

ii) Gap between two + 2.00 mm + 1.00 mm

- 1.00 mm

iii) Stepping of one

plate over other 2.00 mm 2.00 mm

c) Lap Joint

i) Overlap 5.00 mm 5.00 mm

ii) Gap between the

surface 2.00 mm 1.00 mm

d) Tee-filler joints

i) Gap between the 2.00 mm 2.00 mm


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edge of the web

and the surface

of the flange

T3.05 Rubber Expansion Joints

T3.05.01 Design and Construction

Design of the expansion joint shall take care of

the

axial, angular or rotational movement of the bellow

and

/ or the equipment vibration, as stipulated in the

data

specification sheets enclosed. The expansion

joint

shall be designed such that no periodic adjustment

is

required.

T3.05.02 Body

Expansion bellow shall be of heavy duty

construction

manufactured from high grade abrasion resistant

natural

or synthetic rubber, as specified in data sheets,

with

integral flanges at both ends. Split retaining rings

of

adequate design shall be supplied for securely

holding

the expansion joint with connecting pipe flanges.

T3.05.03 Carcass

Fabrics of high strength synthetic fibres shall be

used

in suitable number of plies to hold the shape of

the

bellow at the working condition. All fabric plies

shall

be impregnated with rubber or synthetic componentsto

permit flexibility between them.

Copper coated steel wire or solid endless rings

embedded

in the carcass shall be used for reinforcement of

the

expansion bellow.


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T3.05.04 Cover

The exterior and interior surfaces of the bellow

shall

be coated with suitable material to protect the

carcass

from outside damage and fluid corrosion.

Protective hypalon coatings may be applied at

the

exterior.

T3.05.05 Control Rod Assembly

Each expansion joint shall be supplied with control

rod

assembly to prevent excessive elongation or

contraction

of the bellow. Control rod assembly will consist

of

long bolt, nuts & lock nuts, sphericalwashers,

connecting plates (gusset plate) for fixing the

assembly

with mating flanges.

Control rod assembly shall allow transverse

and

rotational movements under limiting axial conditions

of

the expansion joints.

Design of the control rod assembly shall take care

of

the maximum axial thrust across the bellow calculated

on

the basis of maximum fluid internal pressure and

the

internal diameter of the arch.

T3.05.06 End Flanges

The expansion joint shall have integral

fabric

reinforced full face rubber flanges. The bolt hole

on

the flange shall have no eccentricity in relation to

the


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corresponding bolt hole of the flange on the other

face.

The end rubber flange shall be drilled to suit

the

companion pipe flanges. The companion flanges shall

be

suitably match marked for easy identification

during

erection by others.

T3.05.07 Counter Flanges

Counter flanges shall be as per AWWA C-207.

Required numbers of carbon steel nuts, bolts,

washers

and rubber gaskets shall be furnished.

7.05.08 Hydrostatic Pressure Test and Vacuum Test

a) Pressure Test

All expansion bellows shall be subjected to

internal

hydrostatic pressure test at a value of one and a

half

(1.5) times the maximum working pressure under

the

following conditions for thirty (30) minutes:

i) Free position of the bellow

ii) With permitted (design) elongation and

lateral

deflections

iii) With design contraction and lateral deflection

Inspection for leakage from the bellow shall be

carried

out during pressure test.

Before the hydro test and after the hydro test is

over,

the bellow shall be dimensionally inspected to

check

deformation, if any.

During the test, the control assembly shall be

suitablyadjusted to obtain the test conditions of the bellow.

b) Vacuum Test

All expansion joint shall be subjected to a vacuum

test

at 700 mm of Hg vacuum. The test shall be conducted

in


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three different positions for a minimum period of

thirty

(30) minutes duration in each position. These

positions

are as described above for pressure test.

c) Additional Tests

Purchaser shall have the right to demand

additional

tests as may be found necessary for quality

assurance.

All the above tests shall be carried out without

extra

cost to Purchaser.

T3.05.09 The Rubber Expanson Joints shall conform to

the

following standards/codes:

i) Expansion joints manufacturers' Association,

USA

standards

ii) Fluid sealing Association, USA

Design of Expansion joint shall take care of the

axial,

angular or rotational movements of the bellow and/

or

the equipment vibration.

The body of expansion joint shall be made from

abrasion

resistant rubber.

The expansion joints shall have integral flanges

at

both ends complete with split retaining rings.

The external and internal surfaces of the

expansionjoint shall be of Neoprene of 3 mm thickness with

a

shore hardness of 65 + 5 deg.

Steel wire/synthetic fabric shall be used

for

reinforcement of the expansion bellows.

Tie rods shall be provided in the expansion joints.


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T3.05.10 Design Requirement

i) Qty. - 5 Nos.


iii) Type - Single arch type.

iv) Design pressure - 6 Kg/cm2

v) Liquid to be handled- Circulating water

(for analysis see

Annexure-D & E).

vi) Working temperature

(oC) (Max./Min.) - 44/30

vii) Maximum flow

(M3/hr) - 16500

viii)Location - Indoor

ix) Test pressure

(kg/cm2g) - 7.5

x) Vacuum design - 750mm of Hg vacuum

xi) Vacuum test - 700mm of Hg vacuum

xii) Freelength (mm) - Manufacturers std.

xiii)Counter flange - AWWA-C 207, 1-50 lb

class

slip on type

xiv) Axial elongation(mm)- 15

xv) Axial contraction

(mm) - 15

xvi) Lateral deflection

(mm) - 15

xvii)Angular deflection

(deg.) - 0.5

xviii) Torsional movement

(deg.) - 0.5

xix) Pump speed (rpm) - 497


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T3.05.11 Materials of Construction

Bellow - Synthetic Rubber

Carcass - Synthetic fibre

Stiffening ring - Manufacturers standard

External cover - Hypalon or approved

equivalent

Internal cover - Manufacturer's standard

Control assembly - Manufacturer's standard

Retaining ring - Galvanised Steel

Flanges/Counter flanges - Carbon Steel IS:2062

Gasket - 3 mm thick reinforced

rubber

Nuts, bolts and washers - Carbon Steel - ASTM A

307

Grade A

Pipe thickness - 16 mm

DATA SHEET FOR RUBBER EXPANSION JOINT

1.00.00 GENERAL

1.01.00 Service : C.W.System

1.02.00 Nominal size (NB)/Qty. : 1600mm - 5 Nos.

1.03.00 Duty : Continuous

1.04.00 Type : Spool type

1.05.00 Overall dimensions (mm) : 750

1.06.00 Gross weight of the complete

assembly (kg) : 1750 kgs (appx)


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1.07.00 Model No. : During Detail engg.

2.00.00 PERFORMANCE CAPABILITY

2.01.00 Axial elongation / contraction

(mm) : 15/15

2.02.00 Lateral deflection (mm) : 15

2.03.00 Angular movement : 0.5o

2.04.00 Torsional movement (degrees) : 0.5

2.05.00 Axial spring rate (N/mm) : 1925 (Appx)

2.06.00 Torsional spring rate

(kg/mm/deg) : 180

2.07.00t Frequency of vibration (Hz) : During detail Engg.

2.08.00 Maximum pressure drop throughthe expansion joint at design

flow rate, Kg/cm2g : < 0.01

3.00.00 DESIGN AND CONSTRUCTION

3.01.00 Design standard : As per spec.

3.02.00 Design pressure (kg/cm2g) : 6

3.03.00 Design vacuum in mm of mercury: 750

3.04.00 Design Temperature (oC) : 60

3.05.00 No. of arch / corrugation : Single

3.06.00 Flange pressure rating and

drilling standard : BS 4504 PN-10

3.07.00 No. of limit / control rods : 6Nos./Per Joint

3.08.00 Bursting pressure of bellow : Twice the design(kg/cm2g) pressure

4.00.00 MATERIAL OF CONSTRUCTION

4.01.00 Bellow : Synthetic Rubber

4.02.00 Carcass : Synthetic fibre

4.03.00 Bellow exterior : Neoprene Rubber


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4.04.00 Bellow interior : Neoprene Rubber

4.05.00 Metal reinforcement : IS 2062 Gr. A Sq. Annular

Ring

4.06.00 Control rod assembly: IS1367 Gr.63.8/6.0, stretcher

plate IS-2062 Gr.A.

4.07.00 Retaining ring segments: IS:2062 Gr.A Galvanised

4.08.00 Flanges/counter flanges: IS:2062 Gr.A

4.09.00 Fasteners : IS:2062 Gr.4.6/4.0

4.10.00 Gaskets : Not recommended as Internal

Rubber flange shall act as

self gasket

5.00.00 INSPECTION AND TESTING INCLUDED

5.01.00 Materials Test Certificates : Yes

5.02.00 Certificates for bought out items : Yes

5.03.00 Dimensional tolerance as per specification : Yes

5.04.00 Hydrotest as per specification : Yes

6.00.00 ACCESSORIES INCLUDED

6.01.00 Control rod assembly with gusset plate, nuts

spherical washers etc. : Yes

6.02.00 Counter flanges with nuts, bolts etc. : Yes

7.00.00 LIST OF TECHNICAL DOCUMENTS ENCLOSED WITH THE CONTRACT

7.01.00 Dimensional General Arrangement drawing

as specified : Yes

7.02.00 A cross-sectional drawing of the

expansion bellow : Yes

7.03.00 Manufacturers standard catalogues and

Literature : No

7.04.00 A write-up on the manufacturing inspection

and testing facilities available at the

manufacturer's works :

7.05.00 Any other information :


38/39

LIST OF MANDATORY SPARES FOR R.E. JOINTS

1. Rubber Expansion Joint : 1 set

Complete assembly of 1600 mm dia.

2. Slip-on type matching flange : 1 set

with bolts, nuts and gaskets

3. Reinforced Rubber Gasket for above : N.A.

R.E. Joints

4. Control rod assembly complete with : 2 sets

nuts etc.

Note: One set corresponds to the quantity of

particular

part used in one R.E. Joint.

GUARANTEED DATA FOR R.E.JOINTS.

The contractor guarantees that each rubber expansion

joint

for CW system shall meet the following minimum

performance

data.

1.00.00 Design working pressure of

bellow (kg/cm2 g) : 6 Kg/cm2

2.00.00 Minimum bursting pressure of

bellow (kg/cm2 g) : 12 kg/Cm2

3.00.00 Axial elongation/contraction

(mm) : 15/15

4.00.00 Lateral deflection (mm) : 15

5.00.00 Angular movement (degrees) : 0.5

6.00.00 Torsional movement (degrees) : 0.5

7.00.00 Flange standard : BS 4504 PN-10

SIGNATURE .........................


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NAME ..............................

DESIGNATION .......................

NAME AND ADDRESS OF COMPANY

.................................

..

DATE ..............................

bfv std.specdamper

Documents