API-RP-576

Type
Characteristics
Mediums
Limitations
Safety Valve.
valve that is actuated
by the static pressure
upstream of the valve
and characterized by
rapid opening or pop
action.
normally used with
compressible fluids
(air, steam,
gaseous)
should not be used in/where;
(1) corrosive services.
(2) the escape of process fluid around.
blowing valves.
(3) in liquid service
(4) impose any backpressure
(5) as pressure control or bypass valves.
Relief Valve.
The valve opens
normally in proportion
to the pressure
increase over the
opening pressure.
normally used for
incompressible
fluids
should not be used in;
(1) steam, air, gas, or other vapor services
(2) impose any backpressure
(3) as pressure control or bypass valves.
Relief valves usually reach full lift at either 10% or 25% overpressure. Valves have closed
bonnets to prevent the release of corrosive, toxic, flammable, or expensive fluids. Better
degree of tightness than conventional valves.
Fion Zhnag/ Charlie Chong