Gibbers_1981
Aerospace
- Oct 7, 2023
- 1
Hi Everyone:
Was hoping to find some guidance/information on changes to the UHA-51 exemption allowance changes that occurred in the Code around 2000. I have a cryogenic vessel (SA240-304L) built in 1998 that was impact testing exempted in accordance with UHA-51 (d)(1)(a), exempting when MDMT is not less than -425 deg. F. However, by the 2004 ASME Code, this same section of Code had been adjusted to say impact testing is exempted when MDMT is -320 and above.
I understand the issues with trying to impact test at liquid hydrogen and liquid helium temperatures and the Code making allowances for impact testing at -320 when utilizing those lower temperatures in newer versions of the Code, but what was the impetus for the exemption change from -425 to -320?
Thank you!
Was hoping to find some guidance/information on changes to the UHA-51 exemption allowance changes that occurred in the Code around 2000. I have a cryogenic vessel (SA240-304L) built in 1998 that was impact testing exempted in accordance with UHA-51 (d)(1)(a), exempting when MDMT is not less than -425 deg. F. However, by the 2004 ASME Code, this same section of Code had been adjusted to say impact testing is exempted when MDMT is -320 and above.
I understand the issues with trying to impact test at liquid hydrogen and liquid helium temperatures and the Code making allowances for impact testing at -320 when utilizing those lower temperatures in newer versions of the Code, but what was the impetus for the exemption change from -425 to -320?
Thank you!
