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 3 OF 9
MEC/S/05/62/11 REVISION 0
In line instruments like control valves, orifice plates, rotameters, safety valves
and other instruments like thermowells which may interfere with flushing shall
not be included i m the flushing circuit.
From all permanent strainers the screens/meshes shall be removed before
flushing. Screens/meshes shall be re- installed after flushing but before testing.
In case an equipment such as column, vessel, exchanger etc. forms part of a
piping circuit during flushing, this shall be done with the approval of Engineer- in
- Charge. However equipment thus included in the circuit, shall be completely
cleaned and dried with comprss4ed air, after flushing is completed.
During flushing discharged water/air shall be drained at the place directed the
Engineer- in - Charge. If necessary, proper temporary drainage shall be
provided by the contractor.
Care shall be taken during flushing so as not to damage/spoil work of other
agencies. Precautions shall also be taken to prevent entry of water/foreign
matter into equipment, electric motors, instruments, electrical installations etc. in
the vicinity of lines being flushed.
The contractor shall carry out all the activities required before, during and after
the flushing operation, arising because of flushing requirements, such as but not
limited to the following.
Dropping of valves, specials, distance pieces, online instruments and any other
piping part before flushing. The flanges to disengaged for this purpose shall be
envisaged by the contractor and approved by the Engineer-in-Charge. These
flanges shall be provided with temporary gaskets at the time of flushing.
After flushing is completed and approved, the valve, distance pieces, piping
specials etc. shall be re-installed by the contractor with permanent gaskets.
However, flanges of equipment nozzles and other places where isolation is
required during testing, only temporary gaskets shall be provided.