Are we talking about ASME Section IX and B31.1 or real world?

Keep in mind that the codes, ASME, AWS, etc., define the minimum requirements that have to be met. None of the codes prohibit doing things above and beyond the minimum requirements defined by the standard.

The details of the groove design are considered nonessential variables when working to ASME Section IX and the ASME construction codes with some exceptions. Most of the exceptions I am familiar with are for B31.X “pressure piping codes” where the use of a permanent backing ring is prohibited (high pressure per B31.3), the use of a socket fitting when the ratio of run pipe to branch diameter exceeds "X" and so on. The groove details are not going to influence the mechanical properties, i.e., yield strength, tensile strength, etc. assuming the filler metal/base metal combination is correct. Joint details will influence the ease of welding or another way to view it; the welder's skill will determine whether the joint is welded successfully or not.

I like to use the phrase "sound engineering judgment" on occasion and this is one of those occasions. ASME puts the responsibility for the selection of joint details squarely in the lap of the contractor responsible for the welding. Considering the liability for the work lies with the contractor doing the work, this makes some sense. You have to understand that ASME doesn't tell you how to build anything. There is no direction provided by ASME regarding the selection of the proper filler metal to be used to join different base metals, what is or isn’t a good joint detail (other than a few joints that are out-right prohibited), and so on. ASME's stance is that the contractor is responsible for all aspects of the design and construction and the individual tasked with the responsibility is qualified and versed in the subject matter. So, the individual tasked with drafting the WPS should be a "welding expert" in those matters and should know what joint details will result in acceptable welds. The reality is often times far different from what ASME expects.

This is where sound engineering judgment comes into play. An individual that has welding expertise should use sound engineering judgment when proposing a new WPS which is then qualified to demonstrate the resulting welds meet minimum code requirements. Sound engineering judgment comes into play when specifying the joint details as to what groove angle, root opening, root face, etc. will be successfully welded by a welder possessing sufficient skills. The minimum welder skills are verified by a demonstration (by the welder) that he/she can deposit a sound weld. If the employer/contractor/installer/erector feels it is prudent (cheap/inexpensive) to require the welder to pass a specific test as required by the code, all is well. If the employer/contractor/installer/erector recognizes there is a high degree of difficulty requiring above normal skills, additional welder qualification testing (above and beyond code required testing) can be required, again based on sound engineering judgment.

So, in a nut shell, the contractor can use nearly any joint design they feel is appropriate. They don’t have to demonstrate the particular detail is workable. Few WPSs written to meet ASME Section IX or an ASME construction code includes sketches of acceptable joint designs. Instead you see things like “all grooves and fillets” listed under “Joints”. In my humble opinion this is done because some people tasked with writing the WPSs don't actually know what a welder can and can’t weld easily, so they off load the responsibility onto the welder.  When things go badly it is all too easy to place the blame on poor welding skills when in fact the problem was insufficient direction was provided to the welder. 

How many times has the question of “How do I weld an integrally reinforced branch fitting” come up? That question should never be asked by the welder. That information should be included in the WPS or other work instruction.

“Do I have to weld the pipe to the inside diameter of the slip-on flange?” Again, that issue should be covered by the WPS.  A simple sketch can indicate the welding requirements and the weld sizes required.

Don’t sit back and say, “A good welder already knows that information.” Bull pucks! The welder usually isn’t aware of what construction code he’s working to. Each of the ASME’s construction codes has different requirements. It is the contractor’s responsibility to provide that information to the welder and the easiest means of doing so is with the WPS.

ASME isn’t my whipping boy, the same argument holds true for any of the welding standards and their accompanying WPSs. Some people writing WPSs for AWS are just as guilty of leaving out information regarding joint design and tolerances. I see entries like, “C-U2” along with a host of other joint designations. That information is only useful to the welder if he/she has a copy of D1.1 in their tool box. Most welders can’t even tell you the color of the cover, nor do I expect them to. The welder’s job is to weld; management’s job is to provide complete and proper direction/instructions.

Management has failed their responsibility when the welder has to ask, “How big is that weld supposed to be? What is the proper groove angle? What is the root opening for this? How much “pull-back” is required? ……….?”

OK, I done with my evening rant. I feel better now, thank you. It’s time to bait a hook or two. ;)

Best regards – Al 

Gerald,
Thanks for the clarification. That would be the way to cover it.
I reviewed that as well, but decided the para I mentioned would cover it more simply. But given that my thinking was bassackwards (the indication being lighter not darker for excessive pen) my assessment was mistaken.