Application: Man Hours 1
This applies to safety relief valves installed on boilers, steam lines, and other
equipment. The safety valves are designed to safely relieve excessive pressure,
thus preventing rupture or explosion of the pressure parts. Safety valves differ
from relief valves in that the safety relief valve opens fully when the applied
pressure exceeds it's lifting set-point and remains open until the applied
pressure drops below it's reset point. Relief valve start to open when pressure
overcomes the spring pressure and remains open to the degree that the applied
pressure pushes it open. When pressure drops, the spring closes the valve.
Special Instructions:
1. The safety relief valves are designed to be operated by steam and should only
be tested when sufficient pressure exists to clear the seating area of any
debris.
2. Check with Supervisor and operating personnel before performing this test.
Items to Check & Initial Completion:
1.___ Inspect condition of spring, flanges, and threaded connections.
2.___ Inspect and hand lift the manual lifting lever, checking for binding of the
stem or seat. Note that valve returns to proper position when the lever is
released.
3.___ Inspect support brackets and tighten as required.
4.___ Check that the discharge piping support is tight and not causing stress on
the valve.
5.___ Clean the valve body.
6.___ Lubricate the stem and lever pivot.
Tools and Materials:
1. Standard Tool Kit Plus Pipe wrenches to 24"
Tubing cutters
Flaring tool
Small acetylene outfit
Packing tool kit and packing
3/4" socket set
Crescent wrenches to 14"
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