AWS D1.1 Table 4.5 Para 34: The omission, but not included, of backing or back gouging
You can applied the Backing for making better penetration concept, but it does not mean the applied PQR (PJP) is qualified as WPS (CJP) joint, in case of wrong approved WPS (CJP) with supporting PQR (PJP) !!!! Be careful.
Short guideline for inspection of these variables on Non-tubular structure:
1: In the stage of WPS approval and review:
If the applied PQR with CJP sample, your WPS will cover all type of joints including CJP & PJP, also do cross-check with the WPS register (it will detail with what kind of joint will apply on each WPS No.), also check the dimension tolerance in accordance with Para 33.
If the applied PQR with PJP sample, your WPS will have limits to cover only the PJP joint only (no change to Square or vice versa), also do cross-check with the WPS register (it will detail with what kind of joint will apply on each WPS No.), also check the dimension tolerance in accordance with Para 33.
2: In the stage of application WPS at site:
There’s no more concern about that the WPS is CJP or PJP. In this stage, all WPS have approved at earlier stage above. What you will do is to check the application of WPS No. is correct or not! Refer to the Fabrication drawing and approved WPS register to check that any PJP WPS applied for CJP joints in fabrication drawing. For tubular structure, the CJP WPS without backing/gouging may make you confuse with the definition of PJP, see this: What is CJP in welding and para 3.12