How to Reduce Your Exposure to High Consequence FEMI Events

Introduction 

This article is oriented toward identifying and assessing the risk of potentially high consequence, but usually lower likelihood, fixed equipment mechanical integrity (FEMI) issues that could cause a big event at operating sites if sufficient safeguards or barriers are not in place. A big FEMI event is basically any large loss of primary containment (LOPC) that could cause a large loss of assets with the potential for a major process safety impact (e.g., chemical releases, fires, explosions, fatalities), especially when the fluid being processed involves:

• light hydrocarbons that could result in a vapor cloud explosion
• higher temperature, higher pressure flammable hydrocarbons that may auto-ignite or produce a jet fire
• hot hydrocarbons that could produce a large pool fire from a major large release 

For those of you that use a risk matrix like the one shown in Figure 1 from API 581, the type of events I’m addressing here are ones that could have the type of consequences depicted in Columns D&E of the risk matrix (i.e., the boxes colored red and orange). Typically, the top of Columns D&E (colored red) are more likely to be recognized in PHA/HAZOP analyses and have effective safeguards/barriers in place to avoid such events. But the lower down we go in Columns D&E into the red/orange/yellow boxes in Rows 1, 2, and 3, the less likely effective safeguards/barriers and systems are in place to avoid such events. This is because they are assumed to be less likely to occur than those in the upper portion of those columns. 

This article is about understanding those risks in the lower portion of Columns D&E and what can be done to avoid those risks. Having worked on FEMI issues in our industry for more than 50 years, I can tell you that those ‘lower likelihood – high consequence’ FEMI events do happen, and though they may be rare at any one operating site, I have seen numerous reports of them happening all over the world.

Examples of Lower Likelihood – High Consequence FEMI Events