Dear Dave/Richard,

As per Latest ASME B31.3 code, Definition of SL is as follows:

SL = stress due to sustained loads; in systems where supports may be active in some conditions and inactive in others, the maximum value of sustained stress, considering all support conditions, shall be used

By default, alternate sustain cases also prepared based on the temperatures in C-II.

My query is that why alternate sustain cases are not mandatory in C-II ?

Regards,
Bhavin Shamalia