Volume-II of IV - GAIL

MECON LIMITED
REGD. OFF: RANCHI (BIHAR)
PROCESS & PIPING
DESIGN SECTION
NEW DELHI
TITLE PIPING FABRICATION AND
ERECTION
STANDARD SPECIFICATION
SPECIFICATION NO. PAGE 8 OF 62
MEC/S/05/62/06 REVISION 0
9.7 Pressure gauges shall be installed on line to measure test pressures. In case of
longer lines two or more pressure gauges shall be installed as directed by
COMPANY. One gauge shall be installed at the discharge of the pressurising
pump. Pressure gauge used for hydrostatic testing shall be calibrated with dead
weight tester in the presence of Engineer-in-charge. Range of pressure gauge
shall generally be 1.5 times the test pressure.
9.8 Orifice plates and restriction orifices shall not be installed until hydrostatic testing
is completed. Temporary gaskets shall be used during testing.
9.9 First block valve of pressure instruments shall be half open & plugged at the
time of hydrostatic testing. Temperature connections shall be blanked off during
testing.
9.10 All equipments, in line instruments, relief valves shall be disconnected from
piping system by means of blinds during testing. Control valves shall be
replaced by spool pieces during testing.
9.11 High point vents and low point drain required for testing in addition to those
marked in the drawings shall be provided by CONTRACTOR at his own cost.
9.12 All welded and screwed joints shall be kept clean for detecting leaks during
testing.
9.13 Test pressure shall be maintained long enough to facilitate complete inspection
of the system. Minimum duration of test shall be 6 hours unless other wise
specified. Pressurising equipment shall be isolated immediately after test
pressure is attained.
9.14 After successful completion of hydrostatic testing, the piping system shall be
dewatered. All lines shall be completely dried using compressed air.
CONTRACTOR shall make his own arrangement for supply of compressed air.
Drying of lines shall be considered complete on approval by COMPANY.