Service
Mechanical Integrity
Mechanical integrity programs that keep containment and safeguards fit for service, aligned with recognized engineering practices.
What mechanical integrity covers
Mechanical integrity (MI) is the set of activities that keeps process equipment and safeguards fit for service: designed and installed correctly, inspected and tested at the right intervals, and repaired before deficiencies lead to a loss of containment or a failed safeguard.
Under OSHA PSM (29 CFR 1910.119(j)), MI applies to pressure vessels and storage tanks, piping systems and their components, relief and vent systems and devices, emergency shutdown systems, controls (including monitoring devices, sensors, alarms and interlocks) and pumps. In practice, an effective program also covers every safeguard credited in PHA and LOPA studies.
Building blocks of an MI program
- Equipment identification
A complete, maintained list of covered equipment and safety-critical devices, linked to PSI and PHA safeguards.
- Inspection, testing and preventive maintenance (ITPM)
Tasks, methods and intervals for each equipment type, justified by RAGAGEP, manufacturer guidance and operating experience.
- Written procedures
Procedures for ITPM tasks and for repair and alteration, so work is done consistently.
- Training
Maintenance personnel trained in the process hazards and the procedures applicable to their tasks.
- Deficiency management
Defined acceptance criteria and a process to correct deficiencies before further use, or in a safe and timely manner with documented interim measures.
- Quality assurance
Checks that new equipment, spare parts and materials are suitable for the application and installed correctly.
- Records and performance
Inspection and test documentation, trending and metrics such as overdue tasks and repeat failures.
Recognized and generally accepted good engineering practice
PSM requires inspection and testing to follow RAGAGEP. Commonly applied documents include:
| Equipment | Examples of applicable practices |
|---|---|
| Pressure vessels | API 510; National Board Inspection Code |
| Process piping | API 570; ASME B31.3 for design |
| Atmospheric storage tanks | API 653; STI SP001 for shop-fabricated tanks |
| Risk-based inspection | API RP 580 and API RP 581 |
| Relief devices | API RP 576; NBIC |
| Safety instrumented systems | ANSI/ISA-61511 |
| Ammonia refrigeration | ANSI/IIAR standards, including IIAR 6 for inspection, testing and maintenance |
How we help
- MI program gap assessments against PSM and RAGAGEP
- Covered-equipment lists and safeguard (IPL) registers
- ITPM plans and interval justification
- MI procedures, deficiency management and QA processes
- Integration of PHA, LOPA and SIS outputs into the MI program
- MI performance metrics and management review
Scope note
Our mechanical integrity services focus on program design, technical assessment and engineering review. Where field inspection, nondestructive examination or certified inspector services are required, we can help you define the scope and work with qualified inspection providers.
Frequently asked questions
How are inspection intervals determined?
From applicable codes and standards, manufacturer recommendations, damage mechanisms, the consequence of failure and the facility's own experience. Risk-based inspection (API RP 580/581) is one structured way to set and justify intervals.
Can equipment with a known deficiency stay in service?
PSM requires deficiencies outside acceptable limits to be corrected before further use, or in a safe and timely manner when necessary means are taken to assure safe operation. That decision should be documented with an engineering assessment and interim measures.
Make your MI program defensible
We can assess your current program, fill specific gaps or help build one for a newly covered process.