Welding Procedure for API 650 tank

[AK8824]

I have a question about API 650 requirements for welding procedures that should be used for tank welding.

Section 9 requires that the welding procedures should be qualified as per ASME Section IX except for those items such as ladders and platforms, handrails, stairways and miscellaneous assemblies.

The tanks I have they require rafters and support columns. My contractor argues that these are also exempted from ASME Weld procedures. That means he will use structural welding procedures as per Canadian Welding Bureau. He will use welders that are not qualified as per ASME Section IX.

My question is - Can we consider support columns and rafters miscellaneous assemblies? If yes then the contractor can use structural welds.

Thanks.

 

[Duwe6]

It is a poorly defined area; what does your API-653 Inspector recommend? If it was my project, either to run or to be the Inspector, I would require the 'structural' welders to submit their qualification papers. An AWS plate test is very similar to an ASME plate test, and I personally treat them as interchangeable. If the welders had valid AWS plate qualifications, I would deem that to be adequate for rafters, handrails, etc. I would not allow non-certified welders to work on anything, especially the stairs and handrails. Those are Life-Safety items.

My best guess is that when you say 'Section IX' the contractor hears 'open-root pipe test in the 6G-position'. Your contractor may not be aware that Sect IX has provisions for plate tests and even 'fillet only' tests. And when you say 'Sect IX procedure' he hears 'pay for a new PQR'. A good review of the WPS for shell welds will probably reveal that they are sufficient for the rafter work you need. If the contractor is not qualified to do shell work, don't use them!

Personaly, if the contractor does not have any Sect IX WPS, and intends to avoid qualifying one, I would have to decline using that company. If they make an accidental torch nick into your roof, or have a weld lead short out and put massive arc strikes on your floor, how would Mr. "I'm a structural contractor ONLY" propose to fix these small pressure-boundary defects?

 

[AK8824]

API 653 inspector is not in the picture. I argued with the contractor that the column and the rafters cannot be construed as 'miscellaneous assemblies'. The contractor has agreed to use ASME Section IX WPS.

 

[qcrobert]

Normally welding procedures and applicable code and/or standards are specified on the PE stamped drawings. Disputes between the Verification (Owner) Inspector and the Contractor Inspector are addressed to the EOR for disposition since the EOR is the person who performed the design & caluculations of the vessel/tank.

 

[IFRs]

9.3.2 The welders and welding operators who weld pressure parts and join nonpressure parts, such as all permanent and temporary clips and lugs, to pressure parts shall be qualified in accordance with Section IX of the ASME Code.

What's not clear about this?

When welding to the pressure parts, ASMW IX is required. The code is silent on other part, ergo it is up to the owner and contractor to agree. All API cares about is the critical welds.