Positive Material Identification

Positive material identification (PMI) uses portable X-ray fluorescence (XRF) or optical emission spectrometry (OES) instruments to verify the elemental composition of metals and alloys directly on the job site. Results are available within seconds, enabling material traceability without cutting samples or sending materials to a laboratory.

PMI is critical in industries where the accidental substitution of a lower-grade alloy — for example, carbon steel installed in a high-alloy stainless steel service — can lead to catastrophic failure. OSHA Process Safety Management (PSM) guidelines and API RP 578 recommend PMI programs for all new construction and repair activities on process piping and pressure vessels.

Arc Inspection Services performs PMI on incoming materials at the fabrication stage, on installed piping and equipment during turnarounds, and as part of post-weld heat treatment (PWHT) verification programs. Our instruments are calibrated to NIST-traceable standards and all reports include element-by-element composition data and alloy grade confirmation.