Anyone who knows me knows that Risk Based Inspection (RBI) and Risk Management are true passions of mine. I have dedicated much of my career to studying them, understanding their intricacies, and witnessing the benefits of their successful implementation. This article briefly discusses the history of RBI and provides a short, yet persuasive justification for investing in establishing an effective RBI program.
Evolution of RBI
Let me start with a bit of historical perspective on where RBI came from. In the “old days” inspection programs were designed as a “hit or miss” activity. In general, during continuous run operations, we inspected pressure vessels and piping every 3 years. In batch run operations, we often inspected more frequently (especially for fragile equipment, i.e., glass lined, rubber lined equipment, etc. and equipment requiring corrosion control due to extremely high corrosion rates where substrate exposure to the process media would lead to quick leaks/failure), and hopefully found a potential problem before it resulted in a leak, failure, or worse, a process safety incident.
The next stage of inspection program evolution was condition-based monitoring. At this stage, we were calculating corrosion rates and thinking about damage progression, damage morphology, etc. The next inspection was based on the condition at the last inspection along with consideration of the anticipated future damage state. This was better than before, but consequences of failure were not yet factored into the decision making process. Condition-based monitoring was followed by RBI.
One of the primary advantages of a well-implemented RBI program is that the following key question is answered:
“How much confidence do I need to have in what I believe to be the condition of the equipment?”
Relative risk values, targets, and other triggers will tell you when more information is needed (i.e. when the current or future level of uncertainty about the true damage state of the equipment is acceptable or unacceptable). The analysis results should be credible and the risk drivers clearly identifiable. How accurate do you need to be about what you believe to be the condition of the equipment? How much uncertainty is acceptable? Relative risk can dictate this.
One may use additional elements of the relative risk equation as action triggers (e.g. damage factors, a sub-factor of the Probability of Failure in the API Recommended Practice 581 RBI methodology, probability of failure, etc.) too. The owner-operators’ strategy for managing equipment reliability, safety, and integrity would dictate how the triggers (e.g. Integrity Operating Window ranges and Management of Change) are used. Other defined criteria, such as health and safety consequences, financial consequences, environmental impact, and inherent risks should be considered as appropriate, as in keeping with your company strategies, regulatory, and insurer requirements.
Why Use RBI?
That is why it is important, prior to beginning a program, for any organization considering RBI implementation to first understand its reason for utilizing RBI for Risk Management. As Stephen Covey stated: “Begin with the end in mind.” It is important that we ask ourselves, “Why do we inspect equipment in oil and gas producing, refining, petrochemical, chemical, pipelines, mid-stream gas and terminals facilities?” There are many reasons. Consider these examples:
- Metal loss can signal a potential effect in contamination of product purity, e.g. unwanted Fe ions and/or rust may contaminate the product.
- Regulators/regulations require it.
- Insurers require it.
- And most commonly, to “fine tune” the reliability prediction. In other words, to confirm the degradation rate so actions can be taken to insure, as best we can, that negative events are avoided and that reliability and availability targets are achieved.
These reasons will influence your motives for investing in an RBI program. These motives are key to direction, consistency, trust, sustainability, team cohesion, and overall success of RBI.
I have to emphasize a point here: RBI should never be utilized as a means to cut corners or solely to reduce cost. Points such as those exemplified by reasons 4 and 5 should not be the primary objectives of implementing RBI, but rather are possible results of a responsibly planned and implemented risk management program.
Simply put, we use RBI (which costs money and takes time) to obtain information for our risk analysis to tell us if we need to “fine tune” the reliability prediction. Why? We get this additional information for health and safety, business, environmental reasons, so we don’t incur a leak that will shut the unit down or that could lead to a catastrophic event, potentially injuring people, damaging the environment, and also to optimize total cost of ownership for our equipment. When we need to, we are collecting more data to know, to an “appropriate” level of accuracy, the true damage state of the equipment. This empowers us to manage equipment integrity better than we have in the past. Risk tells us if the accuracy of our current and projected future knowledge about the condition of our equipment is acceptable for making run/inspect/modify/repair/replace decisions. Based on risk targets, RBI systematically points our resources in the right direction to effectively manage risks and optimize OPEX and CAPEX costs related to equipment reliability.