CJP Specification

[jcox]

Does the fabricator have to call out a weld specification for a field CJP weld. The previous fabricator I worked for always just showed CJP felds on the erection drawings, but was never specific about the procedure. The place I work nows head engineer insists that ALWAYS calling out a specific weld procdure for erection and shop drawings is not only necessary, but you are negligent if you don't. I'm mainly talking about putting notations on the weld such as TCU-4A. I believe that if the engineer want or needs a very specific weld then they should specifically call it out. Beyond that engineers are not usually welding experts. I think that shop weld and field welds should be called out fairly generically so that the welders can choose the procedure that suits there need. I think that if all your looking for is a CJP weld, any of the prequalified welds provided by the AWS will accomplish this.

Just looking for other peoples thoughts or recommendations.

 

[HgTX]

You're completely right.

AWS D1.1-2002 page 6, 2.2.5.3 says "Contract documents do not need to show groove type or groove dimensions." There's really no difference from one CJP weld to another as long as all other code requirements are satisfied (proper qualification, some restrictions on use of backing bars).

Hg

 

[jcox]

I saw that, and was wondering if that only applied to the engineers drawings (the structural set). Does the same go for fabricator's erection prints as well?

Thanks for your help.

 

[HgTX]

Oh, sorry. I saw the word "engineer" and answered the completely wrong question. The fabricator needs to show the weld symbol, which will indicate type of groove, backgouging, backing bar, all that good stuff, even for CJP welds. See D1.5 section 2.2.5. Designations like "TCU-4A", the process used (e.g., FCAW or SMAW), and the specific welding procedure specification (WPS) number (not the same as the designation above) are all useful but not strictly speaking required unless so stated in the contract documents. It's not a bad idea to have all that though.

Until quite recently we required our fabricators to put the WPS # in the tail of the weld symbol. Now all we ask is that they let us know what WPS they plan to use. It turned out to be cumbersome to have to approve shop drawing changes whenever the fabricator wanted to change a weld procedure that was their option to begin with.

The reason I got confused is because the arguments you make about what the engineer vs. the welder should know and be responsible for are the way I think about responsibilities of designer vs. fabricator. Within the fabricator's organization, ideally there should be someone in charge of welding procedures, qualification, etc., who does know about welding, and who is capable of selecting the right weld for the job and putting it on the drawing. Even if a weld is prequalified, you still need a WPS, and whoever administers those is qualified to pick which one is to be used and get it put on the drawing.

Hg