I think from this article (ART 212 ASME PCC-2) that the pressure "P" to be used in the calc, is the residual pressure, that is the pressure the patch should only withstand due to lack of thickness of the equipment or pipe, and not the total design pressure.

I will appreciate your comments.

Regards,
Carlos M.

As per Part 1 of PCC-2, Engineering judgments shall be consistent with good engineering practices and such judgments shall never be used to overrule mandatory requirements.

It is my understanding that under 212-3.2 Internal Pressure Loads, the standard makes a mandatory requirement by considering P=internal design pressure for cases where the resultant stress is membrane stress.

In addition, by 212-3, PCC-2 asks for an additional engineering analysis for cases where the component to be repaired is subject to bending, torsion, wind loads or to fatigue.

Thanks for your answer Mariog. I understand that if the patch is installed due to a leak, the pressure used for calculating the patch should be equal to the design pressure, on the other hand, if the patch is installed to cover a local thin area, the pressure for calculating this should be a pressure lower than the design pressure, it would correspond to the residual pressure between the design pressure and the pressure that can withstand the local thin area plus the expected corrosion.

Regards,
CMP.

Is your interpretation based on your engineering judgement or is supported by PCC-2? For the first one, see Part 1 of PCC-2.

Side question: Is PCC-2 available in PVElite?

See 212-3.1 (g)

Regards,