If the TPI is making a case, he should be able to point out the clause that is violated in the applicable welding standard. What applies in one standard does not apply in another.

AWS, ASME, and other welding standards are pretty clear that the thickness of the test assembly is the determining factor in establishing the thickness range. In this case, the appropriate table in clause 4 lists the thickness of the test assembly and the thickness for which the WPS is qualified.

Al