HI,
I have a querry about the Occasional Load factor for stainless steel( ie 316L), the code has an allowable of 1.33 times allowable sustained stress when it comes to occasional loads.

It is not clear what happens when using a material who’s basic allowable stress value (from Appendix A of B31.3) starts to become more than 2/3 of the material yield at temperature and even reaches 90% of yield. This is denoted in the tables (per the general notes) by Italic font where 2/3 is exceeded and bold font where it is 90%.

I would like to understand what occasional load factor to use for these materials at temperature.Thinking of the logic that in most cases the 33% (ie 1.33) factor is based on using the remaining 1/3 of yield left over from the basic allowable stress as the margin for the occasional loading. So when, at the higher temperature, you don’t actually have 1/3 remaining and you really don’t want to exceed yield then you HAVE TO REDUCE the occasional load factor manually in CAESAR to the maximum of yield.

This is more of a concern with a sustained wind case than a earthquake case due to the nature of the load. If we don't change the load factor how do we enure the pipe doesn't catstrophically deform in heavy winds?

Are my assumptions right or do we not need to reduce the occasional load factor?

Thanks,
Guy

In B31.1, Occasional load factor k only affected by duration of loads.
Cycles and duration of loads.
And allowable stress at temperature, 'Sh' already consider temperature. The Sy reduced relatively as temperature goes up.
You said 'at the higher temperature, you don’t actually have 1/3 remaining'. But if temperature incresed, would Sy be also decreased? I guess the 1/3 still remaining.