VII. Pre-Installation and Installation Instructions
Pre-Installation and Installation
CAUTION: After the valve is uncrated and protective devices removed, exercise
care to prevent dirt and other foreign matter from entering either the inlet or the
outlet port.
Mounting Instructions
CAUTION: Pressure relief valves should be mounted in a vertical, upright
position. Installing a valve in any other position will adversely affect its operation
in varying degrees as a result of induced misalignment of parts.
No stop valve should be placed between the pressure vessel and its relief valve
except as permitted by Code regulations. If a stop valve is located between the
pressure vessel and pressure relief valve, its port area should equal or exceed the
nominal internal area of the piping from the vessel to the relief valve must not
exceed 3% of the valve set pressure when it is flowing at full capacity.
Flanges and gasket surfaces must be free from dirt and debris when valves are
installed. The length, size and maximum change in height of the remote sensing
line should be verified through analysis, taking into account the requirement to
re-charge the dome through the pilot valve. On request, BHGE will assist in the
analysis to determine the appropriate length, size and maximum change in height
for the sensing line and to determine the correct capacity of the pressure relief
valve. Before start-up, be sure all threaded joints are tight and secure.
Hydrostatic Testing
Prior to hydrostatic test of the pressure vessel system, the pilot-operated safety
relief valve should be removed and the mounting flange for the valve blocked.
Service Considerations
For best performance, pressure relief valves should be serviced annually unless
maintenance history dictates otherwise. They should be located for easy access and
removal for service.
Remote Sensing
If the pressure drop between the source of pressure in the equipment to be
protected and the pressure at the relief valve inlet exceeds 3%, the sensing line to
the pilot valve should be connected directly to the equipment being protected. The
optional sensing ring should not be installed. For remote sensing, .375” (9.53 mm)
diameter tubing is adequate for distances up to 10 feet, (3.048 m).
For block valve and other special installation features consult API 520 or the factory.
Always install valve
in a vertical, upright
position.
Prevent dirt from
entering outlet or
inlet port.
Decontaminate or
clean if necessary
before pretesting or
disassembly. Safety
and environmental
precautions must
be taken for the
decontamination or
cleaning method used.
14 | BHGE
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