API 5L Gr B Carbon Steel pipe - Low temperature limits

[BesantVarghees]

I came across a Piping Material Specification (PMS) from a reputed Oil and Gas company, where they have used API 5L Gr B pipes for 31mm thickness at 0degC. As per ASME B31.3 (Table A-1), API 5L Gr B falls under Curve B for finding out the minimum temperature limit with respect to temperature. Therefore as per Table 323.2.2A, the minimum temperature acceptable at 0degC is approx 25mm for API 5L Gr B.
Can someone give an explanation. I'm sure there is a provision in B31.3 for exceeding the limits set in Table 323.2.2A. Thanks in advance.

 

[LittleInch]

You need to read section 323.2.2

Table 323.2.2 type of material 3, Column B refers. Basically impact test base metal, weld metal and HAZ

Remember - More details = better answers
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[BesantVarghees]

Thanks for the quick response. But the client's piping material spec does not enforce Impact testing for such a case. Can you please explain me section 323.2.2? I find it little hard to understand.

 

[LittleInch]

They may simply not have realised that 31mm falls outside of the range in B31.3 or that the difference in temperature is "only" 6 degrees.

323.2.2 isn't the easiest section to follow with multiple references and notes, but the key section to follow, IMO, is box B-3 of table 323.2.2.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.