Definition:
Inspection, Testing, and Preventive Maintenance (ITPM) is the set of recurring, scheduled field activities that confirm process equipment and safety systems remain fit for service. ITPM is the implementation arm of a mechanical integrity (MI) program: the MI program defines what equipment is in scope and how it must be managed, while ITPM is the work actually carried out in the field to keep that equipment reliable.
ITPM is an industry term popularized by CCPS and related guidance, not by a specific regulation. The acronym does not appear in IEC 61511, IEC 61508, or OSHA PSM; those documents require inspection, testing, and maintenance, but they do not label that activity “ITPM.”
Key Points:
- ITPM is the field-level execution of an MI program — the recurring inspection, testing, and preventive maintenance that keeps equipment fit for service.
- Proof testing of a safety instrumented function (SIF) would be considered an ITPM activity.
- As-found failures and overdue or deferred tasks identified during ITPM feed back into the engineering team.
Example:
A high-pressure shutdown SIF is designed for SIL 2 with an assumed proof test interval of 12 months, supporting a PFDavg of roughly 1E-2. The facility’s ITPM program schedules the full-loop proof test every 12 months, along with quarterly partial valve stroke tests and routine transmitter calibration. The facility could have a correction. The facilities proof test program could be called the ITPM program or the proof test program. Either is perfectly fine.
See Also: MI, proof test, AIM
Cited Source:
- IEC 61511-1:2016, Clause 16 — SIS operation and maintenance
- CCPS — Center for Chemical Process Safety, Guidelines for Mechanical Integrity Systems