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Reg. 374
STEAM-PIPES AND FITTINGS
Test Pressure
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a)
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Each completed pipe and fitting
shall be tested by hydraulic pressure as per requirement
of Chapter II. |
| b) |
Pipes and fittings with flanges
for steam pressure exceeding 7 kg/cm² (100 lbs. per
sq. in.) shall be tested with blank flanges bolted or
clamped on. All other pipes, if straight, may be tested
between the heads of an ordinary hydraulic pipes testing
machine. |
| c) |
The piping system shall, after
erection, be subjected to a hydrostatic test pressure.
The hydrostatic test pressure at any point in the piping
system shall not be less than 1.5 times the design pressure
but shall not exceed the maximum allowable test pressure
of any non-isolated components such as vessels, pumps
or valves. At no time during the hydrostatic tests shall
any part of the piping system be subjected to a stress
greater than 90% of its yield strength (0.2% off set)
at test temperature.
Notwithstanding
anything contained in this clause, for boiler external
piping and non-boiler external piping which are open to
atmosphere such as vent and drain pipes, the hydraulic
test for the portions of such pipes located beyond the
last isolation valve may be dispensed with provided the
weld joints in the pipe under reference are tested 100%
by approved non-destructive examination and found
satisfactory.
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| d) |
Special arrangements shall
be made, according to circumstances, for testing bends
and other fittings which are not flanged. |
| e) |
Hydraulic testing of butt welded
and socket welded joints shall be conducted either at
maker’s work or at user’s premises on completion
of fabrication of pipes by the Inspecting Authority. |
| f) |
Hydraulic testing of fabricated
pipes having attachments of flanges, fittings, butt joints,
branch joints and weldolets shall be done at manufacturer’s
works or alternatively at site at 1.5 times the design
pressure. Where hydraulic testing of fabricated pipe joints
is not carried out at manufacturer’s works, dye-penetrant
test shall be carried out on the welded joints alongwith
five percent radiography of such joints. |
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