The Mechanical Integrity (MI) element of OSHA's Process Safety Management (PSM) Standard [29 CFR 1910.119(j)] has been a difficult element for many facilities to implement. The results of PSM audits by OSHA have consistently demonstrated that MI is a PSM element receiving a large number of citations at most facilities. In some cases, it has been the last PSM element to be fully addressed. This is not to say that inspection, testing, and preventive maintenance programs do not exist at PSM-covered facilities, nor that the maintenance programs at these facilities are "breakdown-only" programs. Preventive and predictive maintenance programs have existed in the chemical/process industry for many years. What have been lacking in some cases are complete integrated MI management system programs that address all of the sub-elements of MI, as it is defined in the PSM Standard. There are several reasons for this situation:

  • The MI element of the PSM regulations is written in very broad, performance-based language - even more so than the remainder of the PSM Standard. Interpretation of these broadly stated MI requirements and the matching of these requirements to actual facility policies, practices, and procedures can be a difficult process.

  • There is still a distinct impression by some that MI means only preventive maintenance and therefore MI is assigned solely to the Maintenance Department/Group. Actually, because MI includes a wide variety of tasks and activities, the responsibilities for MI activities are spread widely across the facility and many of these personnel may not realize that their job includes an activity that is a regulated part of the MI program.

  • MI activities cover the entire life cycle of the covered equipment, not just theongoing maintenance activities, and therefore many requirements of the MI element may not be completely implemented.

  • Currently, there is no overall industry-published, consensus guidance on establishing and implementing a MI program (Note: AIChE/CCPS plans to help rectify this situation by publishing a comprehensive guidelines book on MI in 2005).

This article will explore these issues, including the interpretation issues that confound many sites, the responsibilities of various site personnel for executing MI activities, and typical weaknesses in MI programs. It is hoped that the information contained herein will clarify these points and thereby help sites to improve their MI programs.

Interpretation of the MI Element of the PSM Standard

The PSM Standard states in 29 CFR 1910 .119(j)(1) that the MI element applies to the following process equipment:

  • Pressure vessels and storage tanks;

  • Piping systems (including piping components such as valves);

  • Relief and vent systems and devices;

  • Emergency shutdown systems;

  • Controls (including monitoring devices and sensors, alarms, and interlocks) and,

  • Pumps.

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