Volume-II of IV - GAIL

MECON LIMITED
REGD. OFF: RANCHI (BIHAR)
PROCESS & PIPING
DESIGN SECTION
NEW DELHI
STANDARD SPECIFICATION
TITLE Flushing and Testing SPECIFICATION NO. PAGE 7 OF 9
MEC/S/05/62/11 REVISION 0
For jacketed pipes testing of core pipes shall be done on individual pieces where
the pipe is continuously packed, before it is jacketed. The outer jacket shall be
tested separately as a system for piping with discontinuous jacketing, the eore
pipe and the jacket shall be tested as separate system.
4.3 Testing Modes, Test pressure and Test Pressure Gauges
4.3.1 Testing Modes
In general all pressure test shall be hydrostatic using iron free water, which is
clean and free of silt. Maximum clorine content in water for hydrostatic testing
for MS piping shall be 15-20 ppm. Air shall be used for testing only if water
would cause corrosion of the system or overloading of supports etc. in special
cases as directed by Engineer-in-charge.
Where air/water tests are undesirable substitute fluid such as gas, oil, methanol
etc. shall be used as the testing medium, with due consideration to the hazards
involved. These test fluids shall be specified in the line list given to the
contractor.
4.3.2 Test Pressure
The hydrostatic/pneumatic test pressure shall be as indicated in the line list or as
per the instruction of Engineer-in-charge.
The selection of the piping system for one individual test shall be based on the
following :-
Test pressure required as per line list.
Maximum allowable pressure for the material of construction of piping
depending upon the above requirements and based on construction progress,
maximum length of piping shall be included in each test.
4.3.3 Test Pressure Gauge
All gauge used for field testing shall have suitable range so that the test
pressure of the various system falls in 40% to 60% of gauge scale range.
Gauge shall be of a good quality and in first class working condition.