Risk Based Inspection Planning and Scheduling

One of the most significant advancements to come along in the fixed equipment mechanical integrity (FEMI) business in the past two decades is the application of risk-based inspection (RBI) for inspection prioritization, planning, and scheduling. The most important standard for RBI in the petroleum and petrochemical industry is API RP 580. The second edition includes many important updates and improvements that everyone involved with RBI should be aware of, including an entirely new chapter covering the potential pitfalls that many users have experienced when implementing a RBI program. The third edition is now in the balloting stages where the committee is planning on changing some of the RBI work process recommendations to requirements (i.e. a number of “shoulds” will be changed to “shalls”). Publication of the third edition is expected in early 2015.

API RP 580 is intended to provide guidance on implementing a RBI program for fixed equipment and piping. It includes: all of the key elements of RBI, how to implement a RBI program, how to sustain a RBI program, initial planning for RBI, RBI data gathering, identification of damage mechanisms, how to assess probability of failure (POF) and consequence of failure (COF), risk calculations, managing inspection activities with RBI, RBI reassessments, and documenting the results. After implementation, risk-based inspection strategies are usually more economic and often result in a more reliable facility by ensuring that higher risk equipment is inspected at higher frequencies and with more effective inspection methods.

Note that I said “after implementation”, as there is clearly an up-front investment in RBI implementation in order to achieve the long term benefits. As of the date of this publication, it appears to me that the industry is close to the 50% mark of refineries that have converted (or are in the process of converting) their inspection planning programs from the more traditional rule-based and/or time-based planning to risk-based (RBI).

API RP 580 is intended to supplement API 510, API 570 and API 653. Each of those API inspection codes and standards allows owner/users latitude to plan their inspection strategies and increase or decrease the specified code allowable inspection frequencies and activities based on the results of a thorough RBI assessment. The assessment must systematically evaluate both the probability of failure and the associated consequence of failure. The probability of failure assessment must be evaluated by considering all credible damage mechanisms in any process unit.

Keep in mind that the API RP 580 RBI standard is a general RBI guidance document that provides all the guidance and information needed to make sure that your RBI program is all inclusive and covers all of the important aspects of the RBI work process. As such, it is differentiated from its sister document API RP 581 which provides users with a step-by-step process that describes exactly how software can be compiled to conduct RBI in compliance with API RP 580 and 581. Other RBI software is available from several commercial sources or has been developed independently by owner-users. One of the most important steps in choosing the specific RBI method you wish to employ is to make sure it complies with the entire RBI work process outlined in API RP 580. Do not just assume any particular commercial method complies with API RP 580 because their marketing pitch says it does; make sure you inquire into the important issues outlined in each section of API RP 580 to better ensure that any particular RBI program and accompanying software that you may be considering will deliver all of the vital aspects covered in API RP 580.

API RP 580 and 581 are both based on the knowledge and experience of numerous RBI practitioners with extensive experience in RBI implementation. It was not written in a vacuum by just a few “experts”. Both API RP 580 and 581 were written, reviewed, balloted, and approved following the rigorous ANSI standardization process by many engineers, inspectors, risk analysts and other personnel that have been involved in implementing an RBI program. 

I have seen several sites make “false starts” when implementing a RBI program that failed to deliver what was expected; and with those false starts, RBI gained a bad reputation at the operating site. In my experience, all such false starts resulted from a failure to closely follow the guidance provided in API RP 580. If you short-cut the process or do not follow the guidance in API RP 580, you are likely to end up with poor results and frustrated, disappointed stakeholders that then falsely blame the “RBI” work process for their own failure to implement the RBI process effectively. The sites that have been most successful at RBI implementation have done so under the guidance of a full-time, knowledgeable RBI “champion,” with full backing and proactive support from site management for both human and capital resources. As API RP 580 indicates, the RBI work process is dependent upon an effective team of SMEs with knowledge of inspection, corrosion/materials, fixed equipment mechanical integrity, process engineering, and operations. Site management must recognize the need for those resources and provide them for the RBI team efforts on a timely basis, or the process will be unnecessarily prolonged and frustrated. 

Another cause for RBI false starts that I have witnessed at operating sites occurs when site management decides not to implement a RBI program with focused resources (e.g. a separate project), and instead just piles the entire RBI implementation project on top of the existing inspection resources that are already fully loaded with day-to-day operating, maintenance and engineering support.

Has your site gained the efficiency, cost-effectiveness and improved process safety associated with implementing a competent, risk-based inspection planning and scheduling program? If not, you may be falling behind the industry leaders.

This article originally appeared in the 101 Essential Elements in a Pressure Equipment Integrity Management Program. The entire guide is available for download now. Simply click the button below to get it.