Reynolds Wrap Up: Does Your Site’s Fixed Equipment Program Differentiate Between FEMI and FER?

By John Reynolds, Principal Consultant at Intertek. February 24, 2022


There is a major difference between fixed equipment mechanical integrity (FEMI) and fixed equipment reliability (FER). It’s important to differentiate between the purpose and reasons for the two programs even when they are often mixed together for organizational and staffing reasons. From my perspective, FEMI is primarily about preventing equipment and piping failures that result in loss of primary containment (LOPC), hence the “mechanical integrity” in FEMI. On the other hand, FER is primarily about preventing functional failures of fixed equipment that could inhibit the site’s ability to meet the business plan. Most of FER does not involve LOPC, but rather the failure of fixed equipment to function per design and expectations to produce the intended product. Clearly, the two fixed equipment programs are related and overlap and that’s the reason they are usually conducted together and often assigned to the same department in the organization. But it’s important for us to focus on the differences between the two programs for the reasons below.

The Venn diagram in Figure 1 can be used to visualize the overlap of the two focus areas (circles in this case). In this figure, the size of the circles are the same for purposes of explanation and simplification. However, in reality, the FEMI circle is much larger than the FER circle simply because of the amount of time and effort that FEMI takes to achieve excellence relative to the time and effort that it takes in FER to achieve reasonable reliability of fixed equipment. The other simplification in the diagram is the amount of overlap shown between the two circles. It can be argued (rightfully so) that the amount of overlap is more than the 75% shown in the diagram; but for purposes of simplification and discussion, I show the amount of overlap at about 75% in the diagram. The double-ended arrow on the bottom of the equipment is for fixed equipment availability (FEA), which is impacted by all the issues in the circle in the center orange overlap and the yellow (right side) of the diagram.

Figure 1. The Relationship and Overlap between FEMI and FER Events.
Figure 1. The Relationship and Overlap between FEMI and FER Events.

FEMI Programs

As mentioned in the introduction, FEMI is primarily about preventing equipment and piping failures that result in LOPC and the consequences of LOPC which can be anywhere from a minor leak to a catastrophic loss with injuries, fatalities, equipment destruction, and even become a threat for the site/company to continue in business (i.e., a wide range of FEMI risks). Anyone who has read some of my previous Inspectioneering Journal articles, as well as my book, knows that I believe FEMI is a much larger topic than FER, requiring more time, more management systems/procedures, more high priority focus to achieve excellence, etc., than does FER [1]. FEMI failures encompass most of what can happen if the requirements and recommendations in the 40+ API FEMI Codes and Standards are not rigorously implemented at the site [2].

The central orange overlap in the two circles of FEMI and FER shows where the higher priority FEMI issues can (and do) cause bigger LOPC events that can result in injuries, fatalities, fires, explosions, and destruction that lead to shutdowns, slowdowns, or other impacts on production from LOPC events. Clearly when that sort of FEMI event happens, it affects reliability, which is the reason the two circles overlap.

In the reddish area on the far left of the diagram is where the smaller FEMI events (e.g. leaks, unexpected severe thinning) do not cause much impact on reliability and, hence, are not included in the orange overlap area. These involve LOPC events (or near events) that have little or no impact on process safety including leaks that are promptly stopped by some sort of unplanned maintenance (e.g., temporary clamps, flange bolt tightening, repacking valves, switching to stand-by equipment, etc.) plus fitness-for-service analysis of unexpected discoveries of damage, which then allows continued safe operation for some period of time.

FER Programs

On the other hand, fixed equipment reliability (FER) is all about loss of functionality of fixed equipment that does or does not involve LOPC. When LOPC issues cause process unit slowdowns or shutdowns, they obviously cause significant FER impacts, hence the large overlap between the FEMI and FER circles in Figure 1 (central orange area). However, the reason there are two circles (one for FEMI and one for FER) is that there is a portion of each circle that does not overlap with the adjacent circle. Cases where FER issues that impact production that do not involve LOPC are represented by the far right side of the FER circle where there is no overlap with FEMI. Those kinds of FER impacts are the result of equipment damage not involving LOPC such as:

  • Column trays that corrode, foul, become dislodged, or otherwise malfunction
  • Missing or significantly corroded or loose tray hardware
  • Downcomer fouling or trash collection (e.g., due to lack of cleaning from the previous turnaround)
  • Corrosion thinning and changes in clearances of downcomers and weirs that alter their correct functioning per design
  • Fouled, corroded, deteriorated, or dislodged demister mats
  • Vortex breaker corrosion or dislodging
  • Tray levelness or bulging due to misoperations, such as flashing or fluid surges
  • Loose nuts and bolts holding internals in place
  • Feed and reflux distributers are no longer in place with properly sized slots/holes
  • Spray nozzles on headers missing or significantly deteriorated
  • Vessel nozzles and instrument taps being fouled or nearly plugged
  • Piping valves failing to open or close
  • Process piping fouling/plugging

These are just a few of the FER issues that do not involve LOPC but can have an impact on fixed equipment reliability; hence they are not typically considered FEMI issues. They are still important, even if they don’t rise to the level of importance of preventing LOPC events, and somebody should be paying attention to them during inspections and maintenance. That person can be the certified inspector conducting internal inspections, especially if the inspector has been trained by someone knowledgeable with FER issues so that they can make the appropriate inspections and repair recommendations. Sometimes the certified PV inspector is not trained to look closely nor fully understands the importance of all the issues that can affect production reliability. If that is the case, then it pays to have a knowledgeable process engineer to accompany the inspector into equipment during inspection where internal hardware is important to equipment reliability.

Of course, I am discussing only the fixed equipment impacts on reliability (FER) in this article while recognizing that the other equipment disciplines like instrument and control systems, electrical, and rotating equipment have much larger impacts on reliability and are typically a major focus of those disciplines (even more so than LOPC). The vast majority of site managers understand this, but they may not understand that FER is a lower priority in our discipline, which is more focused on the LOPC overlap of the two circles in Figure 1, and not on the part of the FER circle that does not involve LOPC.

Another aspect of FER at some sites is what I call the “Hey, inspector can you help me?” syndrome. This can come about due to the fact that we (in inspection) are typically support staff and not considered to be “on the front lines” like those in operations and maintenance. Hence inspectors are often very eager to please those that wield more power and authority at operating sites, so we are often subject to requests like:

  • “Can you order a new spare HX bundle for me?”
  • “Can you order some spare parts for me for this repair job you recommended?”
  • “Can you supervise this contract welding job since you will be involved anyway?”
  • “Can you look up this information for me so I can do my job?”

Few inspectors exist that haven’t been subjected to these types of requests that are more related to unit reliability and maintenance issues than they are with preventing LOPC. All such work lands on the far right side of Figure 1 and can interfere with our responsibility for higher priority FEMI work. When that happens in excess, the inspectors need to be encouraged to bring it to the attention of their supervisors or other FEMI management. Some of these efforts are acceptable if the site is staffed sufficiently to get all the higher priority FEMI tasks accomplished, as well as contributing to the FER effort. Otherwise, participating in this type of FER efforts can detract from important FEMI efforts that may eventually result in leaks or big releases.

The key to drawing attention to the difference between these two fixed equipment programs is to emphasize that in spite of the importance of both preventative fixed equipment programs, FEMI programs are more important because of their impact on process safety. At some sites, there are managers that would like to have more emphasis on FER programs because increasing FER can lead to more production and, therefore, result in improving their performance rating and remuneration. All too often, lack of management attention and resources for necessary FEMI programs that eventually lead to major LOPC events are considered akin to be an “act of God” or someone else’s fault, so they don’t provide enough incentive for some managers to give sufficient focus and priority to FEMI.

Fixed Equipment Availability (FEA)

As mentioned above, the double-ended arrow on the bottom of Figure 1 shows fixed equipment availability (FEA). This is the situation where equipment damage and/or deterioration prevents the equipment from being available to meet the business plan. As shown in the Figure 1, anything in the FER circle and most of the FEMI circle that results in loss of production impacts FEA. The only part of Figure 1 that does not result in loss of production is shown by the reddish part of the diagram on the far left side. That type of minor LOPC or other equipment damage can be fixed on the run and does not impact FEA or have much impact on process safety. Clearly FEA is an important part of the FEMI/FER interaction because if FEA is too low, then the site can suffer a threat to “continuing in business.” Even though FEMI is our major priority, FER and FEA are also important. It’s simply a matter of what’s higher priority for our time and efforts. Typically at most sites with continuous processing, 96+% of FEA is good to excellent; whereas 90-95% FEA may be reasonable in some cases, but could stand some improvement depending upon margins and market demand, and less than 90% FEA typically needs improvement.


The purpose of this Reynolds Wrap Up is to highlight the overlap and differences between FEMI and FER events so that we can keep the priority of each program in perspective. Both FEMI and FER have many preventative aspects that are important to site success, but FER events (as the name implies) involves reliability failures while FEMI events involve potential LOPC which is typically a process safety problem which is usually higher priority than FER events. As shown in Figure 1, there is a large overlap between FEMI and FER events in that any FEMI LOPC event that is large enough to involve a shutdown, slowdown, taking equipment off-line and/or damage/destruction of fixed equipment assets is surely going to impact equipment reliability. That area of the diagram is shown as the large orange overlap area in the middle of Figure 1.

The key to drawing attention to these two programs is to emphasize, in spite of the importance of both preventative programs, that most of our FEMI programs are important because of their impact on process safety. At some sites, there are managers that would like to have more emphasis on FER programs because increasing FER can lead to more production and, therefore, enhance their own objectives when they don’t fully understand all the efforts it takes for us to keep the site free of LOPC [1].

As always, I welcome your feedback and comments.

Questions to Consider

Do your site’s FEMI results have an impact on FEA? If so, what aspect of FEMI needs to be strengthened to improve upon FEA? Is there a clear understanding at your site of the differences in FEMI and FER priorities? Do lower priority FER activities in your group detract from your site’s FEMI results?


  1. Reynolds, J., 2015, 101 Essential Elements in a Pressure Equipment Integrity Management Program, Second Edition Inspectioneering, LLC, The Woodlands, TX.
  2. API, January 2018, Mechanical Integrity – Fixed Equipment Standards & Recommended Practices, American Petroleum Industry, Washington D.C..

Comments and Discussion

Posted by Nain Aguado on April 4, 2022
Excellent article!!! Thanks Log in or register to read the rest of this comment.

Posted by Grady Hatton on April 4, 2022
Thanks John. I always enjoy reading your articles... Log in or register to read the rest of this comment.

Posted by John Reynolds on April 4, 2022
Thanks for the feedback, Grady. Glad the article... Log in or register to read the rest of this comment.

Posted by [Removed] on April 4, 2022
In my experience it is about a balancing act as... Log in or register to read the rest of this comment.

Posted by John Reynolds on April 4, 2022
Concur. Thanks for your comment. Log in or register to read the rest of this comment.

Posted by Christos Christoglou on April 5, 2022
Thank you, John, for this article. I believe... Log in or register to read the rest of this comment.

Posted by John Reynolds on April 5, 2022
Thanks for the feedback. Indeed, I'm much more... Log in or register to read the rest of this comment.

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