Our design drawings for some components for a large outdoor radio antenna structure require conformance to AWS D1.1 and submittal of WPS, PQR, welder and inspector qualifications, etc.
The contractor has submitted a WPS and corresponding PQR that are based on ASME IX. I am a structural engineer and am not familiar with pressure vessel and piping codes.
Since the WPS indicates that the qualified thickness range is 1/16" to 0.672", and the steel plate to be welded is 1" thick, I don't have any problem rejecting the submittal.
However, if the next submittal is also based on ASME IX, I wonder how to evaluate it. Reject it outright? Buy ASME IX and meticulously compare it to AWS D1.1 (no time or budget for that!)? Ask the contractor to compare the steel grades, other variables, and test performance requirements of the two codes for me? What would you do? Any suggestions?
Thanks!
AWS D1.1 allows for prequalified welding procedure specifications if the applicable requirements of D1.1 are met.
ASME, in general, does not have prequalified WPSs if you discount the use of Standard WPSs permitted by some ASME construction codes. The essential variables listed in ASME and the required testing may not be the same as those needed to qualify a WPS in accordance with AWS D1.1 (assuming the conditions of prequalification are not met). The visual acceptance criteria used to evaluated a test sample per AWS D1.1 is different than ASME. AWS D1.1 requires each test sample be subjected to RT or UT before mechanical testing. ASME does not require any RT or UT of the test samples.
The base metals may also be different. I assume the base metal being welded is carbon steel. In most cases, any carbon steel approved for use as a pressure boundary (P number) by ASME Section VIII is most likely approved for use by AWS D1.1. However, a comparison must be made to verify the base metal used to qualify the WPS is listed in AWS D1.1 table 3.1 and a matching filler metal was used when the procedure was qualified. ASME doesn't provide any direction on what filler metal is used to joint which base metals.
The situation can get sticky very quickly.
Best regards - Al
Does the 1" plate on the outdoor structure have full penetration welds? The thickness limitations of ASME IX apply only to the thickness of deposited weld as related to the joint(s) of a full or partial penetration weld and not to fillet welds.
It is very common for the engineer to accept ASME IX WPS in lieu of AWS WPS, in fact in my shop such is written in our manual. I prefer ASME WPS simply because the WPS does require testing whereas AWS does not necessarily.
ASME lists base metals by "P-Number" whereas AWS lists in Tables by Group. What are the materials, typically?
D1.1 allows WPS and welder qualifications to other standards, based on the type of structure, or service conditions, or both, but the engineer is responsible for their acceptance. I agree with Al that a comparison needs to be made to verify that the base metal used to qualify the ASME IX WPS is listed in AWS D1.1 table 3.1 and that a matching filler metal was used when the procedure was qualified. Also, as jon20013 mentioned, the material thickness isn't an issue as long as fillet welds are used. Basically, It seems to me that as long as the ASME documents meet the prequalified criteria of D1.1, and the essential variables are not affected, there shouldn't be a problem, unless I've missed something. I know that some companies allow welders holding certifications in accordance with ASME Section IX to weld to AWS welding procedures. I think it's a good idea to ask the contractor to compare the steel grades, other variables, and test performance requirements of the two codes and submit them to you for your review.
Lucky for me I have not been in this situation before but have heard about it being done as long as the AWS criteria is met. But would you still need to prepare an AWS WPS?
Curious.
Brian
No. not if you accept the ASME one. There's really no big deal to it, I mean mechanically, both codes are very similar in their testing requirements. Naturally there are certain applications for each where a particular WPS may not work but not too many that come to mind right off hand....
If this were my project, I might be willing to accept a WPS qualified to ASME IX if the PQR material is the same as the structure to be welded, the WPS is qualified for the range of groove weld thicknesses to be welded, the preheat and welding electrodes meet Tables 3.1 and 3.2 in D1.1 for the material of construction, minimum/maximum fillet weld sizes are per D1.1 for the electrode diamters used, Charpy V-notch tests meet the design specification (if required), and workmanship requirements of Section 5 of D1.1 are met.
Again, I haven't heard mention of the base metals being joined. If all the requirements for prequalification are met, i.e., base metal, filler metal, process, joint, weld type, etc. No big problem. However, if the conditions of prequalification are not met and the procedure qualification is required, AWS acceptance criteria is more stringent than ASME. AWS limits for the bend tests are no open discontinuities larger than 1/8 inch and no greater than 3/8 inch when summed. ASME has no sum limitation. Corner crack limitations must be compared to see if they are the same as well.
Best regards - Al
prequalification vs qualification does not matter. The engineer has the perrogative to accept either way. True, AWS qualification is more restrictive than ASME thats why many engineers, myself included will not qualify a AWS procedure unless we get it shoved down our throat...
You may also want to check local and state building codes. Some engineers are not willing to push the envelope when building codes specify AWS for structural applications. Likewise, they do not accept AWS qualifications when they are working in a state that requires conformance with ASME for pressure vessels and piping systems, etc.
No one checks too deeply until something snaps in the middle of the night and the lawyers get into the picture.
Best regards - Al
This issue could probably result in a record length thread but "typically" AWS WPS' may not be used for ASME work with the exception of certain B2.1 SWPS. One reason I prefer ASME WPS' is they require mechanical testing, not permitting any "prequalified" status.
In my humble opinion, where qualification is required within D1.1, it is overly restrictive... for example, rod diameter has no affect on the mechanical properties of the weldment.
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