4 General Technical Specification of Bhilai Steel Plant, SAIL ...

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General Technical Specification
vii) Tolerance for clearance between flanges and flange rings :
Not more than 2 mm.
05 Erection of valves and fittings
- Before erection, the valves, cocks and other fittings, to be mounted on pipelines,
shall be dismantled, cleaned, oiled and reassembled. Glands shall be packed
with suitable materials as per approved drawings.
- All moving parts of the pipe fittings should move freely without jamming.
- Valves shall be tested hydraulically for leakage by applying pressure on up
stream side with valve in closed position.
- Bolts & nuts shall be cleaned and lightly oiled.
- Proper grades of gaskets shall be used for erection as per approved drawings.
Testing of BF Gas, Cold Blast, Nitrogen, Instrument Air, Steam and LPG pipelines
- Preliminary acceptance test for erected pipelines shall be carried out as follows :
a) Checking of metal marked as per manufacturer’s certificate/ approved drawings.
b) Checking of test result of mechanical tests for welding/ radiographic tests.
c) Visual examination of welds.
d) Dimensional checks as per the approved erection drawings.
e) Checking of welded joints by chalk kerosene test.
- In case defects are found by visual examination, these shall be rectified prior to
leakage test.
- Checking of proper installation of supports, expansion joints, valves and fittings.
- The pipeline shall be cleaned from inside, all debris removed and pipeline blown
with air to remove all dirt, rust particles, etc.
Strength and leakage test for BF gas, Cold Blast, Nitrogen, Instrument air, Steam and
LPG pipelines :
Test fluid for BF gas, Cold blast and LPG shall be air and for Nitrogen, Instrument air &
Steam service pipelines, test fluid shall be water.
All mounted equipment / instruments, control valves, etc. on pipelines shall be
temporarily replaced by spool pieces. End connection near equipment connection shall
be temporarily disconnected and blanked.
For BF gas, test pressure equivalent to 1.25 times the maximum operating pressure but
not less than 0.2 Kgf/cm 2 (g) shall be applied using air as per the certified
drawings and instructions of OWNER/ MECON for ascertaining the strength.
For cold blast, compressed air, nitrogen & LPG test pressure shall be 1.25 times the
maximum working pressure.
For steam service pipelines test pressure shall be 1.5 times the maximum working
pressure.
a) For BF gas, cold blast, compressed air, nitrogen & LPG pressure test shall be carried out
by maintaining the test pressure indicated above for a minimum period of 1/2 hour. For
steam pipes, the minimum duration shall also be 1/2 hour.
Gases & Liquid Fluids
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GS-02