Australian Pipeline Valve - Installation, Operation and Maintenance Manual
11
LUBRICATED PLUG VALVES - SAPM/SAPL
Also to be considered is condensation-induced pressure surges that occur when a fluid’s speed is changed
by rapid condensation, or when a rush of water is accelerated by contact with stream. (For example,
when condensation collects on one side of a closed valve that has steam on the other side, opening the
valve will cause steam cavities to collapse, sharp pressure surges, and acceleration of condensation).
Condensation-induced pressure waves can result in pressure pulses that are significantly higher than
those produced by a sudden valve closure. In such events, non shock-rated grey iron valves installed in
steel piping systems are particularly vulnerable to catastrophic failure. Traps are required to prevent the
accumulation of condensation, and blow-off valves located at the low point in the system are needed to
ensure condensation drainage. Personnel involved in operation and/or maintenance must be familiar with
the function of both these devices in relation to the shutoff valve operation and how to keep these valves
in proper working order.
3 . 0 I N S T A L L A T I O N
3.1 INSTALLATION INSTRUCTIONS
a) APV Standard Type plug valves are bidirectional, and can be installed vertical (stem operating end at
the top), horizontal or any angle in between. Operating torque will increase considerably if the valve is
installed in any other position, possibly resulting in seizure. The actuator may require support if it is not
vertically above the valve. Ensure access to the sealant fitting, gland nuts and any drain plugs.
b) Flanged joints require compressive loading onto the gasket material where the normal line pressure
forces are prone to separate the joint. There is to be no misalignment between the valve and mating
faces.
c) Installation of flanged valves should follow prevailing site standards. When such standards do not exist
the following should be used as a guideline.
d) Ensure the pipeline and flange faces are cleaned thoroughly and free of any debris which may be
detrimental to flange sealing.
e) Ensure pipework has the correct gap to allow for the valve face to face length plus assembled gasket
material width.
f) Locate the valve between the pipe ends and slide in the gaskets. If necessary, lever the mating flanges
gently apart to allow for easy fitting of the gasket. Care should be taken to prevent damage to the
sealing surfaces. Correct lifting equipment must be used when handling valves for operator safety.
g) Ensure bolts are of the correct size, length, and material for the service intended.
h) Screwed Ends - Pipe wrenches can be used to grip the valve body adjacent to the connection, while
tightening it. Use of a thread sealant is recommended to ensure a pressure tight joint.
i) Assemble all bolts and loosely tighten. Diametrically and evenly tighten the bolts to the correct torque
required for the specific gasket material, as per the gasket manufacturer’s recommendations.
j) It is recommended that the valves are left in the open position during fitting.
