Dear all,

reg. ASME B31.1 Power Piping the use at temperatures above maximum in stress tables given is generally not permitted.
That means in fact you can use ASTM A106 Grade B until 800 °F (426°C) for Power Piping and not above...
Are there any exceptions? For example low pressure?

In our special case we have Design Conditions from
p= 0,5 barg (7.25 psig) T=435°C (815°F) Vacuum Application.
We really don´t really want to use high alloy- material (F11).

Thanks for every helpful answer.

Tim

hello,

sorry but B31.1 does not have exeptions allowing to exceed the temperatures for which stress values are listed.

Alternatives could be:

1. Your company applies for a Code Case with Subcommittee Power Piping, with a technical justification to exceed the temperature limit.

2. Provided that the power piping is part of a the piping beyond the "jurisdictional boundary" and the customer and the jurisdiction at the location of installation is accepting the deviation from B31.1, your company may certify the piping as "similar to 31.1".

3. Invest in consultancy of a competent Authorized Inspection Agency which might be able to explore more economic solutions tayler made to your problem.

I hope this information is of assistance to you!

best regards

Horst Michael
ASME Delegate Germany

Thank you for the quick answer. Solution 2 is not possible with our very "strict" customer. But we will try 1 and 3.

A last and,hopefully not unqualified,question:
Please correct me if I´m wrong but isn´t it a solution if the customer change from B31.1 (Power Piping) to B31.3 Process Piping? In B31.3 I found stress values until 450°C for ASTM A106 Grade B.
On the other hand, if I´m right, it seems not really logical
because of conversion of carbon to graphite (graphitization) at temperatures above 425°C..
To concretize my questions:
Is it allowed to use ASTM A106 Grade B until 450°C in B 31.3?
Thanks in advance for every helpful post.

Best regards