Our Sites

Clearing up ASME B31.3 code confusion

Q: I am unclear about a section relative to the ASME B31.3 code for chemical plant piping.

The area of this code referring to the type of welding process that is acceptable—328.2.2—states welding procedures qualified by others may be used, provided that the following conditions are met: The welding process is SMAW or GTAW or a combination.

Does this mean that the only acceptable process for welding has to be either SMAW or GTAW? Is GMAW allowed as long as it follows a written and acceptable WPS? If so, must it be performed by a certified welder who has been qualified in that WPS?

ASME Section 328.2.2 Explained

A: ASME Section 328.2.2 is specific to the use of weld procedures qualified by others (not qualified by you). When fabricators want to use these procedures, they face many limitations. One of those, as you’ve discovered, is the process used. Many other processes are allowed, but all would require you to produce a qualified weld procedure specification (WPS).

According to ASME B31.3 Section 328.2.1, qualification of the welding procedures to be used shall conform to the requirements of Section IX. GMAW is included in Section IX as an allowable process, but you will need to qualify a WPS to do so.

Is Qualification in the WPS Needed?

As for your welder being qualified to the new WPS, that is a bit of a “chicken or the egg” scenario. A welder typically wouldn’t be qualified to a WPS before the WPS has been tested and developed, and a WPD won’t be qualified until a competent welder completes it. Code writers recognize this. ASME notes that a procedure qualification has a distinctly different purpose than a welder qualification. For more information, check out ASME Section IX QW-100.1 and Welder Qualification QW-100.2.

It sounds like you need to qualify the GMAW process, and this can be done by any of your competent welders. Once your welder has successfully completed the process qualification testing, he or she will be considered qualified. The limiting factor will be that the process will be qualified within a given range of essential variables and the performance (welder qualification) will be qualified within a different given range of essential variables.

Once the WPS is completed, the welder who qualified it may need additional testing to use it in your specific application.

About the Author
Braun Intertec

Paul Cameron

Braun Intertec

4210 Highway 14 East

Rochester, MN 55904