PSV relieving temperature

[the2ast]

PSV relieving temperature is sometimes above the design temperature of the equipment being protected.
I need you guys `s advice whether to change design temperature of the equipment, pipe line connected to PSV, gasket inside pipe to the relieving temperature or to keep the design temperature as it is. Thank you in advance.

 

[JLSeagull]

I would not be concerned if the PSV relieving temperature is above the design temperature of the equipment being protected - only for the fire sizing case.

 

[the2ast]

Do you have any reference on your opinion ?
Please tell me !!!

 

[JLSeagull]

API 52O Part I states that "Pressure relief devices protect a vessel against overpressure only; they do not protect against structural failure when the vessel is exposed to extremely high temperatures such as during a fire."

Fire case issues exist regarding flange ratings. If you select the PSV based upon the fire contengency case and include the pressure and temperature of the fire case then the flange must be rated for the higher class if applicable. The PSV vendors will not sell you a valve with a flange rated lower than required for the pressure and temperature.

I know of no requirement that the protected equipment must comply with the fire case temperature. API 521 addresses vessel ptotection from heat input.