Minimum Ambient Temperature

[Goahead]

Hello,

On the subject of minimum ambient temperature allowed for welding, I found two different requirements.

1 - Minimum allowed 0F (-18C), for Bridges etc., see

http://www.thruway.state.ny.us/business/design-manual/appendixf.pdf

2 - Minimum allowed 32F (0C), for Piping, Pressure Vessels etc., see

http://www.wbdg.org/ccb/NASA/NASAASC/NS15055.pdf

Questions:
Is the above specified also in major Code requirements?

Are the requirements based on experience or on scientific inquiry?


Thanks,
Goahead

http://www.welding-advisers.com/

 

[metengr]

Yes. For ASME Codes and Standards, the minimum temperature for welding is generally specified at 50 deg F. Below this temperature requires the application of preheat. The minimum preheat can be determined by calculation from formula's using chemical composition and thickness, see below;

http://homepage3.nifty.com/yurioka/exp.html

Minimum temperature and preheat requirements for welding on pressure retaining items are also referenced in the National Board Inspection Code (2004 Edition), Appendix B.