Could Safety-relief valves be used in gas services?

[aidini]

Safety valves are used in gas services while Relief valves in liquid services.
Is it possible to use Safety-relief valves in gas services?
If yes, how is their reaction to pressure excess, do they pop-up like safety valves or gradually open?

[ibnu.zaenal]

In gas service, pressure relief valve is used only for pump discharge also known as 'by pass valve' to prevent overpressure in discharge pipe. The pressure setting is lower than safety valve

[gtaa]

For the most part, safety valves and relief valves are the same thing. I've seen them referred to as PRVs (pressure relief valves) and PSVs (pressure safety valves).

I think by relief valves in liquid service you may be thinking of thermal relief valves. These are very small (typically 1 x 1.5") and open momentarily to relieve pressure resulting from the heating of a trapped liquid stream. Note however that liquid systems may also have 'proper' relief valves - particularly on the discharge side of positive displacement pumps.

To answer your question though, yes. PRVs/PSVs are indeed used in gas service for overpressure protection. However, it is more common to find them on vessels and equipment rather than piping itself. They are sized for a variety of duties, including external fire, control valve failure, blocked discharge to name a few.

For more information, get yourself a copy of API 520 Part 1 and have a read.

[gtaa]

For the most part, safety valves and relief valves are the same thing. I've seen them referred to as PRVs (pressure relief valves) and PSVs (pressure safety valves).

I think by relief valves in liquid service you may be thinking of thermal relief valves. These are very small (typically 1 x 1.5") and open momentarily to relieve pressure resulting from the heating of a trapped liquid stream. Note however that liquid systems may also have 'proper' relief valves - particularly on the discharge side of positive displacement pumps.

To answer your question though, yes. PRVs/PSVs are indeed used in gas service for overpressure protection. However, it is more common to find them on vessels and equipment rather than piping itself. They are sized for a variety of duties, including external fire, control valve failure, blocked discharge to name a few.

For more information, get yourself a copy of API 520 Part 1 and have a read.