Discussion on the determination of the set pressure for safety valves
Thread Content
According to clause B4.7 of GB150, the setting pressure Pz of the safety valve is determined based on the operating pressure Pw of the container; generally, Pz is taken as (1.05~1.1)Pw”； Then, the regulations in the fixed-volume code state that the setting pressure of the safety valve only needs to be lower than the design pressure of the container. These days, many regulations require that the setting pressure of safety valves in chemical plants should be between 1.05 and 1.1 times the operating pressure, which is quite confusing. Also, what is the relationship between the setting pressure of the safety valve and the magnitude of the process interlock high-pressure alarm?
What’s confusing? Aren’t they the same?
HG20570.2 contains a table showing the relationship between the design pressure of the protection system and the pressure of the safety valve. The setting pressure can be taken as 110% of the operating pressure, while the relief pressure can be set at 16% or 21% in the case of a fire. It is advisable to set the design pressure of the storage tank at 90% or 95%.