B31.3 min design temperature question

[KernOily]

Guys I have a question on how you all interpret the codebook on min temperature.

Sec. 323.2.2ff of 31.3 details the requirements of design/operating below the min design temp provided in Table A-1. My questions are in regard to the way the code is written.

1) If my design/operating temp is below the min temp in A-1 and its supporting tables, does that mean I do NOT have to otherwise do a PQR and impact testing if I have done stress analysis and I can show that my stress level due to combined loadings is < 0.4Sc? While one might otherwise do a WPS/PQR as a normal part of the project, it seems to me I can skip the impact testing if the stress analysis calcs out.

2) If I do impact testing as part of the weld PQR (we are still talking P-1 materials here), does that testing cover the Code impact requirements for the base metal also? I think the code says 'yes' to this one - I'm just looking for some reinforcement . So to me that says if my PQR has impact testing and has passed then I am also covered for my base metal.

Thanks in advance for your time and help!

Thanks!
Pete

 

[jay165]

Pete:

My response to your question is based on my copy of B31.3 which is the 1996 edition. There is no section ff in 323.2.2. If there is a change in the later editions, I apologize.

1. Yes, but I don't know where you got the .4Sc criteria from. Per note 3 of Table 323.2.2: Impact testing is not required if the design temperature is at or above -50F and the maximum operating pressure of the components will not exceed 25% of the max allowable design pressure at ambient conditions and the combined longitudinal stress due to pressure, dead weight and displacement strain does not exceed 6 ksi.

2. Yes per note 3 of Table 323.3.1.

 

[KernOily]

jay165 - Thanks for your reply. ff is not a code subsection but is a shorthand for "and following sections". So one would read that as 323.2.2 and following sections. Sorry.

OOPS -- 0.4Sc comes from B31.5, paragraph 523.2.2 (f) (4). Sorry about that! B31.3 gives you a max of 6 ksi in Note 3 of Table 323.2.2. I got my codes mixed up.

Thanks - you verified my question. That was how I read it, also.

Thanks!
Pete

 

[bvi]

Hold on............74Elsinore go back and look again and jay165 get a new book as soon as the 2004 edition is published.

The 6 ksi thresshold is gone from ASME B31.3. There is a figure, and at a low enough stress level, no impact testing is required down to -155F. So 1) is correct. You do not need to do impact testing as part of your weld procedure qualification testing if the stress levels are sufficiently low. You need to look at component ratings, etc as well.

Regarding question number 2, the answer is no. Testing for weld procedure qualification does not qualify the base material for construction. If impact tested material is required, you need to purchase impact tested material. The impact testing done as part of the weld procedure qualification only qualifies the welds.