PSVs and SRVs
PSVs and SRVs
(OP)
Is there any difference between a Pressure Safety Valve and a Safety Relief Valve?
or are these just 2 names for the same valve?
if there are differences, what are they please?
Thanks,
Matt.
or are these just 2 names for the same valve?
if there are differences, what are they please?
Thanks,
Matt.





RE: PSVs and SRVs
- A Safety Relief Valve (SRV) will (automatically) open in case of too high upstream pressure. And relief the excess pressure.
- An Emergency Shutdown Valve (ESD) will close in case of an emergency like a high pressure. And block the high upstream pressure.
- A Pressure Safety Valve (PSV) can be both. However be carefull! PSV is also often used for Pressure Shutdown Valve. Which will be the closing type again.
Good luck!
Terje
RE: PSVs and SRVs
RE: PSVs and SRVs
A. Safety Valves. A safety valve is an automatic pressure relieving device actuated by the pressure generated within the boiler and characterized by full-opening pop action. It is used for steam service. Valves are of the spring-loaded pop type and are factory set and sealed.
B. Safety Relief Valves. A safety relief valve is an automatic pressure relieving device actuated by the pressure generated within the boiler. It is used primarily on water boilers. Valves of this type are spring loaded without full-opening pop action and have a factory set nonadjustable pressure setting.
In UG-126 the first sentences state “(a) Safety, safety relief, and relief valves shall be of the
direct spring loaded type.
(b) Pilot operated pressure relief valves may be used, provided that the pilot is self-actuated and the main valve will open automatically at not over the set pressure and will discharge its full rated capacity if some essential part of the pilot should fail.
For process equipment use ASME PTC 25 for the pressure relief device definitions.
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RE: PSVs and SRVs
JAC
RE: PSVs and SRVs
A Safety-relief valve is a Section VIII valve: Unfired pressure vessel. 10% OP (16% for combination valves, 21% for fire). Can be Spring, Pilot, Rupture disc, Breaking pin. Steam, Gas, Liquid. Manual lifting gear mandated for steam, air, water at over 140F. Bonnet is usually closed/vented.
RE: PSVs and SRVs
JAC
RE: PSVs and SRVs
SV (or PSV): for compressible fluids
RV (or PRV): for incompressible fluids
SRV: general name for both previous types
Small people talk about others, average people talk about things, smart people talk about ideas and legends never talk.
RE: PSVs and SRVs
Safety relief valve – an automatic pressure relieving device that may be used as either a safety or relief valve, depending on application. A safety relief valve is used to protect personnel and equipment by preventing excessive accumulation.
Safety valve – an automatic pressure relieving device actuated by static pressure upstream of the valve and characterized by rapid full opening or pop action. It is used for gas or vapor service.
Relief valve – an automatic pressure relieving device actuated by static pressure upstream from the valve, which opens in proportion to the increase in pressure over the opening pressure. A relief valve is used primarily for liquid service.
Small people talk about others, average people talk about things, smart people talk about ideas and legends never talk.