A181-I Flange Rating

[engpes]

I am modifying a nozzle on an existing ASME VIII vessel. The vessel was built several years ago and the drawings and U1A report state that the nozzle flange material used was A181-I.

I am running the analysis in Compress and it is telling me that the MAWP for a 300# flange with A181-I material is only rated for 590 psig.

My existing vessel has a design pressure of 600 psig and this is listed on the original construction drawing and U1A report.

My question is:

1.) Is this correct that a 300# flange made of A181-I is only rated for 590 psig?

2.) Does anyone have a flange rating chart for A181-I flanges?

Thank you very much!

 

[engpes]

Sorry, I meant to mention that my design temperature is 150F.

 

[puigi]

The ASTM A-181 specification is a standard for carbon steel forgings general purpose piping. Are you sure that is the correct specification for the flange material in question?

 

[engpes]

Yes, the vessel was built in the early 1980's.

 

[Bobfromoh]

See attached page for class B flanges.