ANSI Flanges
ANSI Flanges
(OP)
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?
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?





RE: ANSI Flanges
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
RE: ANSI Flanges
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