I'm 95% positive about this but I want to be 100%, I was reviewing a WQTR and noticed it was rev'ed to rev 4. The rev. was to remove the backer from the vee beveled groove test. The supporting PQR and WPS are both at the original revision and the backer is NOT removed. As I understand it, this is an essential variable and would require a new PQR and WPS.
It is easy to confuse the WPS, PQR, and WPQ requirements.
If ASME is the governing standard, the essential variables listed for the welding process in Article II must be addressed and recorded on the PQR. The WPS must address all the essential and nonessential variables listed in Article II. If notch toughness is invoked by the applicable construction code, the supplementary variables must be addressed and recorded (as essential variables) on both the PQR and WPS.
The essential variables for welder performance testing are addressed in ASME Section IX, Article III. The essential variables are not the same as those listed in Article II.
The welder can be qualified in accordance with a WPS that isn't necessarily the same as that used in production welds as long as the ranges qualified (performance qualification) are adequate to cover the needs of production.
Example: The welder can be qualified using a WPS written specifically for performance testing. The WPS can be very specific with regards to the filler metal classification and diameter, permitted current range, and just one groove detail. The groove detail could be 3/8 inch thick plate meeting SA36 requirements with a backing, 45 degree groove angle, no root face, etc. that specific WPS could be supported by the same PQR that supports the WPS used for production.
The WPS used for production could be qualified for base metal thicknesses greater than 3/8 inch, it could be for all P1 base metals, and the production WPS could include single grooves with backing or without backing, it could include double groove welds that includes a back gouge operation, it could include fillet welds, and it could be used to weld structural shapes as well as piping.
The welder that passed the performance test described would not necessarily be qualified to weld everything the production WPS covers.
Fun stuff, but one must be well versed with the ins and outs of ASME codes.
Best regards - Al