This recommended practice covers methods of installation for pressure-relief devices for equipment that has a maximum allowable working pressure (MAWP) of 15 psig (1.03 bar g or 103 kPA) or greater. Pressure-relief valves or rupture disks may be used independently or in combination with each other to provide the required protection against excessive pressure accumulation. As used in this recommended practice@ the term pressure-relief valve includes safety relief valves used in either compressible or incompressible ?uid service@ and relief valves used in incompressible ?uid service. This recommended practice covers gas@ vapor@ steam@ two-phase and incompressible ?uid service; it does not cover special applications that require unusual installation considerations.