Because a materials mix-up can happen at any stage of the process from the alloy fabricator to installation of a part at the refinery, each petroleum refinery, chemical plant, petrochemical plant etc. should develop a material verification program to minimize this risk. It is important to check every alloy and component multiple times during every stage; this is known as a 100% PMI protocol.
The material verification program/PMI process should begin at the incoming materials warehouse, where product may be tested via a PMI spot check method as part of the receiving process. As well as PMI testing, a material verification program should provide complete and accurate documentation indicating which materials have been tested and what the results were.