5 replies to this topic

[Mrinmayee Marathe]

Dear All,

 

I have few Pressure Safey Valves, where for non-fire cases, the relieving temperature is lower than the design temperature of the equipment on which the PSV is mounted.

 

In such cases, while selecting the valve size as per API 526, which temperature shall be taken into consideration - the design temperature of the equipment or the relieving temperature?

[fallah]

Hi,

 

The relieving temperature should be considered; because it's the coincident temperature of relieving pressure as design pressure of the relevant equipment...

[Mrinmayee Marathe]

Dear Sir,

 

Thank you so much for your reply. It is of great help to me.

[rajudhir01]

I will go with the design temperature same as vessel.

[Ahsan67]

Hi,

 

The relieving temperature should be considered; because it's the coincident temperature of relieving pressure as design pressure of the relevant equipment...

Dear Fallah,

 

Can you please guide me if it was a fire case and obviously relieving temperature will be higher than the operating for example in one of our case the vessel design temperature is 50C and the Fire relieving temperature is 128C  , should we still consider relieving temperature against the set pressure in API 526, it will be much helpful if you can provide reference for same.

 

Regards

Ahsan

[mirandomka]

Is the question regarding flange rating or design condition of the PSV inlet piping?

For design condition, I would suggest to check with your piping engineers and confirm if the short term exemption is whether or not applicable for your fire case.

For flange rating, you can follow the API 526 annex B to confirm based on your relieving temperature.

Edited by mirandomka, 04 November 2016 - 11:43 AM.