3
Introduction
These installation and maintenance instructions
are being provided to ensure the proper
installation, repair and safe operation of Farris
pressure relief valves. Pressure relief valves are precision instruments and
should only be installed and repaired by personnel who have been properly
trained and qualified to provide this service. Correct installation is essential
for plant, property, personnel and public safety. Failure of a pressure relief
valve can lead to catastrophic overpressure of equipment and/or the
release of effluent under pressure. Effluent may be hazardous and all
precautions should be taken to ensure safe disposal.
Receiving Inspection,
Storage & Handling
Cleanliness is essential to
the satisfactory operation
and tightness of a pressure
relief valve. Prior to installation the following practices
should be followed:
Upon receipt, look for any shipping damage.
Inspect packaging for evidence that the valve
has been tipped over or dropped.
Verify the nameplate data against ordering documents.
Confirm that factory wire seals are in place and not broken.
If it appears that the wire seal has been broken, the name plate
information does not match documentation, or if the packaging or
valve appear to have been damaged in transit, please contact your
local Farris representative.
Inlet & outlet covers should be left in place until the valve is installed.
Valves should be moved and installed with the stem upright,
in the vertical position.
Note: Pilot operated relief valves should never be lifted or handled using
the tubing, piping, pilot, or pilot brackets. Use the lifting eyes provided
on the main valve body to move the valve.
Care should be taken to keep the inlet and outlet clean and free of
foreign material.
Valves that are not immediately installed in service should be stored
indoors, in the original container and in an area free of dirt and other
contamination. The storage area should be at normal temperatures
(50 to 100°F/10 to 38°C).
Pre-Installation
Testing
Before installation, it is important to confirm the set
pressure and seat tightness. This testing should
only be performed by trained and qualified
personnel using proper test equipment.
When performing pre-installation testing please
note the following:
Testing must only be performed using the correct
test fluids. Air, gas and vapor service valves must be tested using air as
the test fluid. Liquid service valves should be tested on water and steam
service valves must be tested on steam.
Note: For pilot operated relief valves on liquid service, introducing
liquid into the dome area of the main valve and pilot assembly during
pre-installation testing may later cause problems when the valve is
placed into service. An air test may be substituted to confirm valve
functions, but set pressures may vary from actual setting due to the
difference in test media.
Set pressure testing must be performed first, followed by seat leakage
testing. Seat leakage testing is performed at 90% of set pressure.
For valves set at 50 psig (3.45 barg) or below, the test pressure is
5 psig (0.35 barg) below the set pressure.
If qualified personnel and proper test equipment are not available the
pre-installation testing should be skipped.
Installation
Pressure relief valve performance can be
adversely affected by improper installation. To
ensure good performance and safe operation of
the valve these guidelines should be followed. Failure to do so could result
in valve failure, serious injury or death.
Pressure relief valves may contain sharp surfaces. Proper personal
protective equipment (PPE) should be used.
Before installing a valve, depressurize the system.
Always install valves upright with the stem in the vertical position and
the inlet at the bottom. Remove the optional test gag, if supplied.
Install valves close to the pressure source so that inlet pressure loss is
no more than 3% of set pressure.
To avoid reducing the valve’s actual capacity, be sure piping connected
to the valve’s inlet/outlet connections is equal to or larger than the
valve connections.
Avoid installing valves close to equipment that can cause pressure
fluctuations, such as compressor discharge lines.
WARNING
WARNING
WARNING
Failure to inspect, store and
handle the PRV can cause
improper functioning of the
valve. Please read and
follow these instructions.
NOTICE
Failure to follow proper test
procedures or to use proper
test equipment will lead to
incorrect test results,
damage to the valve and
will void the warranty.
NOTICE
