<Li> Safety valve (SV): Used in gas service . Most SVs are full lift or snap acting, in that they pop completely open . </Li> <Li> Safety relief valve (SRV): A relief valve that can be used for gas or liquid service . However, the set pressure will usually only be accurate for one type of fluid at a time . </Li> <Li> Pilot - operated relief valve (POSRV, PORV, POPRV): A device that relieves by remote command from a pilot valve which is connected to the upstream system pressure . </Li> <Li> Low - pressure safety valve (LPSV): An automatic system that relieves by the static pressure of a gas . The relieving pressure is small and near the atmospheric pressure . </Li>

Where is the safety relief valve usually located