설계
Pressure Relief Device
Chorl.Jeong
2011. 1. 11. 11:01
■ The Relevant Codes
1. API 526, Flanged Steel Pressure-Relief Valves
2. API RP 520, Sizing, Selection, and Installation of Pressure-Relieving Devices in Refineries
3. API RP 521, Guide for Pressure-Relieving and Depressuring Systems
4. ASME BPV, Section VIII, Divion 1, Nonmandatory Appendix M
5. ASME B 31.1, Power Piping, Nonmandatory Appendix II
■ Definition of Pressure Relief Device
A pressure relief device is actuated by inlet static pressure and designed to fully open
during an emergency or abnormal conditions to prevent a rise of internal fluid pressure
in excess of a specified value.
The device also may be designed to prevent excessive internal vacuum.
■ Type of Pressure Relief Device
1. Relief valve
A spring-loaded pressure relief valve actuated by the static pressure upstream of the vlave.
The valve opens normally in proportion to the pressure increase over the opening pressure.
A relief valve is used primarily with incompressible fluids.
2. Safety valve
A spring-loaded pressure relief valve actuated by the static pressure upstream of the valve
and characterized by rapid or pop action.
A safety valve is normally used with compressible fluids.
3. Safety relief valve
A spring-loaded pressure relief valve that may be used as either a safety or relief vlave
defending on the application
4. Balanced pressure relief valve
A spring-loaded pressure relief valve that incorporates a means for minimizing the effect of
back pressure on the performance characteristics
5. Rupture disk device
A nonreclosing differential pressure relief device actuated by inlet static pressure and desinged to
fuction by bursting the pressure-conntaining rupture disk.
■ Open Discharge Installation
An installation where the fluid is discharged directly to the atmosphere or to a vent pipe that is
uncoupled from the safety valve.
Where, L ≤ 4 * Do, M ≤ 6 * Do