In the context of welding on code equipment, SWPSs occupy an interesting place. One can use a readymade SWPS directly on the job, without having to do a procedure qualification. This seems attractive. However, can one really use a SWPS directly?
This article explores a few aspects related to SWPSs.
Please note that most of the discussion herein is pertinent to ASME BPVC Section IX only.
What is a SWPS?
Ordinarily, Section IX requires that each organization shall qualify their own WPS before taking up production work. That is, an organization cannot borrow (or steal) WPS qualified by another organization and use it directly. Section IX has always been very clear on this (reaffirmed by several interpretations) that work of WPS qualification must be done by the organization itself, and cannot be subcontracted to another.
Assume that you are trying to qualify P-No. 1 + P-No. 1 combination welded with ER70S-2 at root and E7018-1 for fill passes, over a thickness range of 3/16 inch (5 mm) to 8 inches (200 mm). This qualification, regardless of where it is done, will throw up a PQR/WPS that will be qualitatively same anywhere. Probably recognizing that such common qualifications need not be repeated; an organization should be able to start production welding right away if it had access to an already made WPS, and the organization could demonstrate ability to competently use that WPS. Thus was born the concept of SWPSs.
Who Prepares SWPSs?
SWPSs, short for Standard Welding Procedure Specifications, are developed by American Welding Society (AWS), and they are available on pubs.aws.org for anyone wanting to buy. Basically, one can buy a SWPS and start using it on job straightaway without having to do a procedure qualification. There are some rules that need to followed however. These rules, which we will discuss in brief later in this article, are contained in Article V of Section IX.
The data on SWPSs is derived from PQRs maintained by AWS. The PQRs are not shared with the buyer of SWPS. The work of qualifying these PQRs and preparation of SWPSs is done following a rigorous set of rules. It can therefore be safely taken for granted that the welds made with these SWPSs will have a high probability of successful application.
When Can A SWPS be Used?
Since the year 2000 onwards, Section IX permits the use of SWPS instead of the regular WPSs. So, SWPS may be used in fabrication work for any construction code (or referring standard/ specification) that invokes use of Section IX, unless specifically prohibited by that code (or referring standard/ specification).
SWPSs, however, cannot be used for applications requiring impact toughness – as this is prohibited by Section IX itself.
Conditions For Using SWPS
SWPSs may seem like a godsend at first; however, the matter is not as straightforward. Section IX allows use of SWPS but under some conditions that are defined at Article V of Section IX. The Article V comprises of some administrative requirements, besides welding and testing of a Demonstration coupon, followed by documentation and certification of the resulting Documentation Record.
Once an organization procures the SWPS from pubs.aws.org, the Article V requires the user organization to fulfil following requirements before putting the SWPS to use in production welds:
- Name of organization shall be entered on the SPWS at relevant place.
- The relevant person of the organization shall sign and date the SWPS.
- The governing code or specification (such as ASME Section III NB or ASME B31.3, or a contract document etc.) according to which welding needs to be done shall be mentioned in the SWPS (As discussed elsewhere in this article, this entry can be revised without having to redo the demonstration).
- Carry out a demonstration coupon welding and testing. The variables used in making this coupon, the tests done and results shall be recorded. This document shall be certified by the user organization. This work must be done before the SWPS can be used for production purposes.
Demonstration Coupon
The user organization is required to make a groove weld coupon using the SWPS.
The actual value of variables used in preparation of this coupon must be recorded (a recommended format is given at QW-485). It should be kept in mind by the code user that these values should fall within the range specified on the SWPSs. These variables, enumerated under QW-510, are mostly same as the usual essential and non-essential variables for manual welding processes. Following the welding, testing of coupon needs to be done, which is defined under QW-510.
The testing comprises of: i) visual examination, and, ii) mechanical testing or volumetric examination. The method of testing and acceptance criteria of these tests are the same as those for performance qualifications (given at Article III of Section IX). In essence, the demonstration coupon is quite similar to a performance qualification. The tests done and their results must be recorded along with variables used.
The Demonstration coupon is required primarily to establish that the user organization is capable of using the SWPS. This demonstration is a mandatory requirement, and must be carried out carefully to ensure that the SWPS is fully followed. The identity of Supporting Demonstration must be noted on the SWPS before the SWPS can be used. Like a PQR, the Supporting Demonstration must be available for review by inspector, whenever asked.
Are SWPSs useful?
Essentially, a SWPS saves the trouble of doing the mandatory bend tests and tension tests that are required for the usual procedure qualification. If your company has X-ray facility, you can get done with the demonstration coupon by simply doing visual examination and radiography – completely avoiding the mechanical testing. However, SWPSs come at a price. Last I checked, an ordinary SWPS costs nearly 250 USDs. So, it is not exactly cheap. It is very difficult to find pirated versions on the internet either. Smaller private-run organizations probably find doing the mechanical testing (for doing the regular WPS qualification) cheaper.
But for big organizations, where this cost does not mean much and who want to avoid the time delay in preparation of test specimens and mechanical testing, SWPS are surely useful.
Technically though, in the grand scheme of life – SWPSs have little to offer to the code user. When using a SWPS, you are rigidly bound to follow it. Code users are not allowed to make changes to a SWPS. On the other hand, if you qualify your own PQR, you own that document. Changes are allowed to be made to the resulting WPS according to your needs.
The demonstration coupon of a SWPS can also be utilized to qualify the welder simultaneously, since testing required for performance qualification gets covered within that of demonstration coupon. All that one needs to do is write the WPQR, in addition to the Demonstration record. This saves some time and resources.
Frequently Asked Questions
Q1: A SWPS permits both with and without PWHT. The demonstration coupon should be heat treated or left as-welded?
A1: If the demonstration coupon has been left as-welded, the SWPS can be used for welds in as-weld condition only (i.e. must not be heat treated). If the demonstration coupon has been heat treated according to the PWHT listed on SWPS, the SWPS can be used for production welds in PWHT condition only (i.e. cannot be left as-welded). In short, when a SWPS permits both with and without PWHT, it essentially means two demonstration coupons should be made – one with PWHT, and one without.
Q2: Can a SWPS be revised?
A2: No, unlike ordinary WPSs – SWPS cannot be revised by users (AWS can revise them of course), except that the governing code or specification, which is required to be listed on a SWPS before using it, can be revised without further demonstration.
However, the code does allow the user to supplement a SWPS by attaching additional instructions with a SWPS that might help the welder in achieving the desired quality of weld. However, these instructions must not violate the SWPS in any way, and must be within the boundaries set by SWPS.
For example, the SWPS specifies J-groove and U-groove, and single side welding. The supplemental instruction sheet may restrict the welder to use only J-groove (since J-groove is obviously permitted by SWPS), but may not ask the welder to use a groove design other than the two mentioned on SWPS (double V-groove with back-grinding, for example).
Q3: Can a SWPS be supplemented by a PQR to enhance its scope?
A3: No. This is prohibited by Article V of Section IX. As mentioned in Q2 above, it is not allowed to revise a SWPS at all, except for changing the governing code or specification.
Q4: Can a user make some minor changes in non-essential variables on a SWPS?
A4: No. SWPS is a ready-made document, prepared by AWS. Users are not allowed to change it. Once issued to a welder, he is expected to comply with it in full. Also, there is no such thing as non-essential variables on a SWPS. All variables are equally essential.
The demonstration coupon is thus a chance for the organization to satisfy itself that it is able to follow the SWPS in full. If it is not able to follow the SWPS (may be for justifiable reasons), then perhaps SWPS is not the right path for that organization; a regular WPS should be qualified instead.
Q5: A SWPS lists multiple processes (e.g. GTAW at root, followed by SMAW for fill). Can a user use only the GTAW part and ignore the rest?
A5: No. When a multiple-process SWPS is used, all processes mentioned on SWPS must be used in the order and manner specified on SWPS.
Q6: Can a joint be made partly with a SWPS and partly with a regular WPS?
A6: No. This is not permitted by Section IX (QW-540(d)).
For example, a SWPS specifies welding with GTAW only. A company wants to use GTAW for root, and SMAW for remaining thickness. The company wants to use SWPS for root welding, and its own regular WPS for SMAW portion. Is it permitted to do this?
No, this is prohibited by Section IX.
A SWPS therefore, before its adoption, should be carefully assessed by the user. As in above case, if the company wants to use both GTAW and SMAW in a joint, they should consider using a different SWPS or follow the regular route of qualifying a WPS and use it.
In any case, the demonstration coupon offers an apt opportunity to not just the user organization but also the inspector, to judge whether the organization is capable of using the SWPS in full, in relation to all variables, or not.
Q7: Is it mandatory to certify the Supporting Demonstration record?
A7: The Supporting Demonstration holds a similar status as the regular Procedure Qualification Record (PQR). As such, Section IX requires that the user organization welds, tests the demonstration coupon, and certifies the resulting Demonstration Record. As such, the recommended format of Section IX (at QW-485) for recording Demonstration lists a certifying statement at the bottom.
Q8: Can the demonstration coupon be welded and tested in parallel to the use of SWPS on job?
A8: No. Welding, Testing, and Certification of demonstration coupon must be done before SWPS can be used for production welding. This is given at QW-540 (f).
Q9: Can SWPS procured by an organization be used by sister units of that organization falling within the same corporate ownership?
A9: Although Section IX says nothing explicitly on this, and no interpretation seems to be available either, it can be reasonably assumed that the rules applicable for regular WPS are intended for SWPS as well. In the writer’s opinion, provided the quality programs of the sister units address the operational control of the procedure qualifications, SWPSs can be shared within them.
Q10: Is a separate demonstration coupon required for every SWPS?
A10: No. Once an organization demonstrates a SWPS, similar SWPSs can be used without further demonstration. Similar SWPS means that it must have same process, P-numbers, PWHT condition, F-number, mode of transfer (i.e. globular/pulsed/spray etc.), F-number, preheat. These variables (within which the new SWPS must lie) are defined at QW-520.
That is all. Thanks for reading. Feel free to share your thoughts in comments section below.