What is Positive Material Identification?
Positive Material Identification (PMI) is the analysis of a metallic alloy to establish composition by reading the quantities by percentage of its constituent elements. Typical methods for PMI include X-ray fluorescence (XRF) and optical emission spectrometry (OES).
The need to use PMI has dramatically grown over the last 10 years to the point where in many refinery’s and Petrochemical plants 100% alloy material verification is now carried out.
If Inspectors are correctly trained to carry out PMI it ensures that the correct material has been used and we therefore have a greater assurance that failure should not occur due the wrong material being used.
What are the responsibilities of a individual who carries out PMI?
An individual certified to PMI Level 2 has demonstrated competence to perform NDT according to PMI procedures. Within the scope of the competence defined on the certificate, Level 2 personnel may be authorised by the employer to:
- Select the PMI technique for the test method to be used;
- Define the limitations of application of the testing method;
- Translate NDT codes, standards, specifications and procedures into NDT instructions adapted to the actual working conditions;
- Set up and verify equipment settings;
- Perform and supervise tests;
- Interpret and evaluate results according to applicable standards, codes, specifications or procedures;
- Prepare PMI written instructions
- Carry out and supervise all tasks at or below Level 2;
- Provide guidance for personnel at or below Level 2, and
- Report the results of PMI test