“A man who lacks reliability is utterly useless” – Confucius

Mechanical Integrity is an essential element of an efficient process and a safe, cost-effective facility. Furthermore, OSHA’s PSM Standard (29 CFR 1910.119[j]) requires it.  And yet, for decades Mechanical Integrity has been a leading cause of OSHA citations.  For all of the studies and journal articles written on the subject, why is Mechanical Integrity still such a tough nut to crack?

One confusing element is the OSHA standard itself.  It’s brief (little more than half a page) and its language is vague. Words like “timely” and “applicable” are used without further clarification, instead relying on the equally vague “Recognized and Generally Accepted Good Engineering Practices”, or RAGAGEP.  While such ambiguities are likely intended to give facilities room to personalize their Mechanical Integrity programs, in practice they may actually discourage compliance by making the standard more difficult to interpret.

Another complicating factor is the scope in which Mechanical Integrity is intended to operate.  It doesn’t only apply to the act of preventative maintenance, but also to the network of people and record-keeping that support that maintenance.  Such a large, integrated project requires time and resources that many operations departments either do not have or are not encouraged to use.  What results is a tautology in which efficiencies are not implemented because they take time to create, but extra time cannot be created without increased efficiencies.


What is Mechanical Integrity?

Mechanical Integrity (MI) includes the full lifecycle of a piece of equipment – and helps to maintain, repair and replace it.  The types of equipment specifically named in the PSM standard are:

  • Pressure vessels and storage tanks
  • Piping systems
  • Relief and vent systems and devices
  • Emergency shutdown systems
  • Controls
  • Pumps

In practice, however, the list of covered equipment is much more extensive.

For example, despite the OSHA cut-offs for pressure vessels, non-registered vessels and those that operate below 15 psig are still included in a Mechanical Integrity program if they contain PSM-covered materials.

Similarly, the following unspecified equipment should also be included in a Mechanical Integrity program (provided it comes into contact with PSM-covered materials):

  • Heat exchangers
  • Eductors
  • Other non-pump rotating machinery
    • Compressors
    • Fans
    • Blowers
    • Agitators
  • All forms of relief and vent systems and devices
    • Relief valves
    • Rupture disks
    • Conservation vents
    • Vent systems
    • Vacuum breakers
    • Flares
  • All piping system components
    • Filters
    • Strainers
    • Flanges
    • Gaskets
    • Valves
    • Mechanical elements of instrumentation


Quality Assurance

Ensuring the quality of equipment is the very first line of defense against equipment failure. Systems that are designed to a certain standard must contain equipment that is purchased and/or built to that same standard.  Likewise, it is equally important to control the quality of components and replacement parts used to perform maintenance and repairs.  Towards this end, it can be helpful to write a procedure for “controlling nonconforming components” in order to train maintenance staff.


Preventative Maintenance

Regardless of how often a preventative maintenance (PM) task is required, scheduling and record-keeping are vital to their success.  Not only is time spent more efficiently, but good documentation creates a maintenance history that can then be used to improve the program in the future.

A side note: The status of PM work in a facility is a clear representation of the health of their Mechanical Integrity program. If you have a backlog of PM work orders, your MI program isn’t working!


Written Procedures

Written procedures are one of several ways to discourage personnel from operating equipment outside the conditions for which it was originally designed.  They help ensure that tasks are performed adequately, safely, and consistently. Procedures are an important part of personnel training and they reduce human error.  They are also important during and after organizational and personnel changes to ensure continuity of the program.



Written maintenance procedures are useless if personnel are not properly trained in how to carry out the instructions. MI tasks should be performed by personnel qualified to do those tasks.  Training is how personnel become qualified.


Correcting Deficiencies

Acceptable limits are defined by the process safety information (PSI).  Deficiencies in equipment outside these limits should be corrected.  A successful MI program includes plans for recognizing and reacting to deficiencies so that corrections can be made before further use, or in a safe and timely manner.


Why is it important?

Mechanical Integrity helps to reduce the likelihood that equipment will unexpectedly fail due to a lack of maintenance, thereby also reducing the likelihood of a sudden release of PSM-covered materials, as well as the damage and injury that the release may cause.

Because the PSM standard is specifically geared towards hazardous materials, it is particularly important to minimize the likelihood that such materials will be released because equipment is worn out due to a lack of regular maintenance.

Mechanical Integrity also helps extend the life of equipment by installing an informed PM and inspection program.

Mechanical Integrity helps customize PM schedules to an individual facility, rather than relying on standard equipment specification sheets.  Helps keep resources where they are most needed. Prevents unexpected breakdowns and the injuries/losses that may result.

Mechanical Integrity also helps budget for equipment replacement (because you know when a piece of equipment is most likely to fail).


What is RAGAGEP?

RAGAGEP: Recognized and Generally Accepted as Good Engineering Practices

Although RAGAGEP is a substantial element of OSHA’s Mechanical Integrity standard, it is also one of the most perplexing, as OSHA’s PSM standard does not provide a concrete definition.  The clearest definition comes courtesy of the Center for Chemical Process Safety:

“RAGAGEPs are the basis for engineering, operation, or maintenance activities and are themselves based on established codes, standards, published technical reports, or recommended practices (RP) or similar documents. RAGAGEPs detail generally approved ways to perform specific engineering, inspection or mechanical integrity activities, such as fabricating a vessel, inspecting a storage tank, or servicing a relief valve.”

In 2013, OSHA solicited public comment on a proposed adoption of this definition to the PSM standard.  In 2015, The OSHA memorandum RAGAGEP in Process Safety Management Enforcement referenced this definition.  But the reference to this definition was removed with the 2016 memorandum that rescinded and replaced the previous memorandum titled RAGAGEP in Process Safety Management.


RAGAGEP in Practice

Without a formal definition to lean on, how is RAGAGEP defined and used?  OSHA has provided some clarification, with four examples of RAGAGEP; widely adopted codes, consensus documents, non-consensus documents, and internal standards, naming NFPA, ASME and ANSI as examples of organizations with acceptable codes and standards.

Codes and standards used for design and engineering and preventive maintenance must be identified and documented as RAGAGEP.  Several organizations (API, ASME, ISA, NFPA, etc.) publish standards and guidelines that can be the basis for establishing your mechanical integrity RAGAGEPs.  The memorandum states, “If an employer selects and follows widely adopted codes or consensus documents or widely adopted non-consensus documents for RAGAGEP, OSHA will accept such materials as RAGAGEP where applicable and appropriate.”

Internal standards must still represent recognized and generally accepted good engineering practices. OSHA states multiple reasons an employer might choose to follow internal standards and makes note that an employer using internal procedures as RAGAGEP has an obligation to document that it equipment complies with RAGAGEP.



Your Mechanical Integrity program ensures your process continues to perform in the way you initially intended it to.  Mechanical Integrity goes above and beyond the average maintenance program to provide benefits such as:

  • Improved safety performance
  • Reduction of equipment failures
  • Reduced operating cost
  • Improved maintenance consistency and efficiency
  • Reduction of unplanned maintenance time and costs
  • Extended life of equipment
  • Better capital planning
  • Improved equipment reliability
  • Improved spare parts management
  • Improved contractor performance
  • Compliance with government regulations


Is your Mechanical Integrity Program lacking?  There are several references out there to help.

Check out AIChE CCPS reference book: Guidelines for Asset Integrity Management