ASME B16.5 pressure ratings << ASME 8

[nick262b]

I was doing some work today which involved assessing several piping runs to see if a 150 class line was good for 300 class pressures so I could produce an in service justification.

When a standard B16.5 #150 flange is assessed using the criteria in ASME 8, depending on bolt force e.g. 50% yield L7, it can be shown to seal to a considerably higher pressure than indicated in B16.5 (at same temp). Just wondered what the reasons are for this and what the background to the B16.5 code is?

Kind Regards

Nick

 

[LittleInch]

Try looking first in appendix A of the B 16.5 code which had a few pages on how the pressure ratings are determined, but it considers a lot of other things than just bolt force. Flanges are subject to other forces and stresses than simply proessure, but the appendix will probably give you the info you need. It refers to other codes and has some tables which may not be fully explained, but that's the start point.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way