In section 8 of API 650 it states that the NDE personnel should meet the requirements of ASNT SNT-TC-l
A. This for RT and UT.
It's acceptable to have all the NDE technicians certified by ISO 9712 instead of ASNT SNT-TC-l
A?
The latest version makes the ASNT qualification mandatory. Thus, it would appear that some form of official interpretation will be required. Personally, I prefer ISO 9712 because of its requirements for an independent examination. This can be matched by ASNT if the ACCP option is applied. You may be able to rationally argue that since ISO 9712 is, effectively, ASNT + ACCP, then equivalence is readily demonstrated.