Wellhead welding procedure 4130 to A106B

[engr2GW]

In a production facility, the line pipes in the well pad are designed per ASME B31.3 and the welding procedures were developed without charpy impact testing because the minimum design temperature is not more than -20F, here are my questions

1. what determines the temperature of the system, ambience (weather), flow stream, or both?

2. If a system (e.g. a production facility) that is designed per B31.3, and the ambient temperature of that region sometimes get below -20F during the winter, does that mean that the welding procedure to weld that facility has to be sharpy impact tested

3. Does number two above apply for wellhead transition welding from API 6A flange (4130 material) to flow line pipe (A106 B)?

4. For the wellhead head case in 3 above, is charpy required if the ambient temperature never gets below -20F since there's a combination of API and ASME B31 code in the piping?

Thank you.

 

[stanweld]

As a general rule, ambient temperature does not apply to MDMT for B31.3 designs. The temperature of the material while under pressure is the determining factor. If that temperature is the minimum ambient, it must be considered.