B31.1 pressure protection

[don1980]

I have a B31.1 steam header (nonboiler external piping) that is protected by multiple PSVs. This is a 600# system and the gap between the operating pressure and the PSV set pressure is low. So, I want to minimize the risk of popping the PSVs by setting them as high as possible. But when I look in B31.1 I don't find any rules regarding set pressure and peak allowable relief pressure. I read paragraph 107.8.3 (Pressure Relief Requirements on Nonboiler External Piping), but it doesn't address set pressure or peak allowable pressure, nor are these questions answered in the referenced paragraphs of Sec VIII.

Can anyone shed light on the answers to my questions, or point me to where those answers can be found. Thanks.

 

[davefitz]

See asme b31.1 par 107.8.3, which references asme sect I or sect VIII div 1.

ASME div 1 par PG 67 requires max overpressure of drum boilers to be less than 106% of MSP, and less than 120% of design pressure of the outlet header for once thru steam generators

ASME sect VIII div 1 allows 116% overpressure for many pressure vessels and 121 % max for instances of fire, but the details are more complicated- read the code .


"Nobody expects the Spanish Inquisition!"

 

[don1980]

Dave - thanks for the response, but B31.1 107.8.3 doesn't reference either of the paragraphs that you mentioned. Thus, my problem.