PMI Testing on pipes fittings valves and welds

Hi all,

Can anyone please give some guidance on PMI Testing standards and requirements.
Is PMI testing required for SS material Trim on a CS body valve.
Who determines it. If the quality requirement says all ss pressure controlling and pressure containing parts and parts that are exposed to process fluids need to be PMI tested whether all materials are covered(flanges,valves,pipes,fittings,bolts nuts washers etc.Mainly PMI is tested for SS material

I heared that PMI testing cannot be accurate and if some discripancy occures the chemical test of materials is recommended.Can any one please tell is there any recomendation by standards.Does client decide the extend of testing simply by some assumptions or to make life difficult for vendors.


Regards,
Deepu Varghese

Just checking, "PMI testing" is positive material identification?

Yes PMI is Positive material identification.Thanks

SO I have to ask, as a "Piping Designer" WHY WOULD YOU CARE? This is an issue for your materials procurement agent, especially if they are purchasing items from a cheap 3rd world supplier. Should this agent have to verify, to their superiors, that what they are ordering IS what is showing up at the receiving dock, then this test could be required.
As a Piping Designer you don't designate (other then by drafting notation) or verify what materials are used, you use the piping spec designated for the system that clearly states what materials, schedules, ratings, & connection types to use for the appropriate sizes. Worrying about something you have NO control over is a waste of time, effort, & efficiency.