Hi All,

I find many stress analysis specifications giving the stress criticality criteria for pipe size and temperature as given in attachment. Could anyone explain me how these charts are generated.

Thanks in advance.

I am not able to open it.

Reattach it.

Regards,
GSP

The file size is large. I have reduced the file size and reattached. Sorry for inconvinence.

There are no specific code rules that generate size/temperature charts for stress review. Different engineering firms and owner/operators have developed different preferences and criteria based on the experience of their people and operating history.

It gets fun when the engineering company and the operating company have different charts and you have to negotiate to come up with a standard both sides can agree on.

Futher to what Ed says...
Years ago I ran across this quick criterium from an engineering company. Using nominal inches and degrees Fahrenheit, if OD*T is greater than 1500, then analyze. If not, don't.
Why would this work? OD indicates stiffness and T indicates strain. That's k & x. Multiply those to get F (as in F=kx). A simple rule, and, as Ed says, "All the world is a Spring".
Looking at your chart I see a similar trend (for "Class II"): 4 inch at 150C (300F) and 6 inch at 100C (200F) gives OD*T of 1200 (instead of my 1500).
There is no "standard". And there are many other criteria indicating the need for analysis.

Thanks Edward & Dave for sharing your views.