ANSI Flanges

[Bobfromoh]

Does anybody know how the pressure/temperature rating was determined for ANSI B16.5 flanges made of SA-181 forged material? I have some older vessels that need rerating but how do I rerate the flanges. There must have been some way to detemine the rating because I see so many in service in the older vessels.

SA-181 is listed in the ASME Code but is not supported by the ANSI Standard. I know there is an Appendix in ANSI B16.5 that explains the rating procedure but that is for materials only included in the standard.

Can anybody help?

 

[jte]

Bob-

A181 material is listed in my copy of B16.5-1977. I know there was a 1988 edition also so I don't know when the material was delisted. In 1977, the A181-II material was listed as a group 1.1 material alongside A105 while the A181-I material was listed as a group 1.4 material alongside A515-60. The temperature/pressure ratings have not changed from the 1977 to the 1996 edition (at least for class 150 and 300), so you can use the current t-p ratings if you have class 150 or 300 flanges.

jt

 

[ab1234]

Hi!

Please note that SA181 specification covers non standard Forgings and thats the reason (probably) that it has been removed from ASME B16.5.

As mentioned above by yourself, please refer Annexure-D of ASME B 16.5 which tells that basis of classification in various groups are based on almost similar allowable stresses and yield strength as per ASME Sec II Part-D. You should compare the values of SA181 with others material of Group 1.1 (or 1.4 or...)and if they are similar then select Pressure#Temperature rating from that group.

bye