This ISA author Q&A was edited by Joel Don, ISA’s community manager. Performance-based Fire and Gas Systems Engineering Handbook is co-authored by Austin M. Bryan, Elizabeth Smith, and Kevin J. Mitchell, senior staff members at Kenexis Consulting Corporation.
Performance-based Fire and Gas Systems Engineering Handbook is co-authored by Austin M. Bryan, Elizabeth Smith, and Kevin J. Mitchell, senior staff members at Kenexis Consulting Corporation. In this blog Q&A, Austin provides important insights on the book’s value and significance. The book provides a thorough overview of fire and gas (FGS) design lifecycle presented in the ISA-TR84.00.07 technical report on performance-based design of fire and gas detection systems for process industries. With the release of the report, risk-based techniques for detector placement have become prevalent in FGS design.
The ISA book exams each phase of the lifecycle and the practical activities required to develop an FGS design. In addition to discussing the design process, the book also provides valuable appendices that contain data for FGS-system risk analysis, FGS risk-grading procedures, and a discussion of the FGS mapping techniques used to verify the achievement of the newly defined coverage targets.
Q. OK, let’s start with the ISA-TR84.00.07 technical report. Could you explain its importance and purpose?
A. The ISA-TR84.00.07 technical report provides the basis of performance-based FGS design. Before the report’s development, FGS have largely been designed through prescriptive standards, such as National Fire Protection Association (NFPA) 72. Prescriptive standards lay out precise requirements in terms of equipment requirements, location of equipment, alarms, etc. While these work well and have been in use for decades for fire protection of occupied buildings, they are less useful in an industrial processing setting.
Industrial processes may have many additional concerns, such as combustible or toxic gas, with often several exterior locations. There has been scant guidance on how to design a detection system for these areas beyond a few basic heuristics and rules of thumb. The industry desired a means of designing an FGS with greater engineering justification than these heuristics could provide. ISA-TR84.00.07 takes the basic concepts used in performance-based SIS design and shows how they could be applied to design of an FGS.
Q. What exactly is performance-based design in relationship to a fire and gas system?
A. Performance-based design is the design of a system around achieving a specified level of performance. With the more traditional prescriptive-based design, systems tend to be designed to a “one-size-fits-all” basis.
This is less flexible and can lead to over- or under-designed systems if the risk associated with the protected equipment is lower or higher than was originally assumed in the prescriptive design. Performance-based design requires the designer to perform a risk assessment to determine the level of performance required, then design the system to meet that performance. This allows for a greater level of flexibility in design options.
Q. So, your book, Performance-based Fire and Gas Systems Engineering Handbook, focuses on the practical steps required to implement this type of performance-design?
A. Yes, our book provides guidance on how the concepts presented in ISA-TR84.00.07 can be practically implemented. While the technical report describes how the concepts of performance-based design can be applied to FGS design and special considerations that must be made to do so, it does not provide any explanation on how to actually develop such a design. How does one analyze the risk of a process?
What level of performance should be required? A sound understanding of these concepts is required to complete a performance-based FGS design, but there is scant guidance in the technical report on how to implement them. The handbook presents the FGS lifecycle and associated workflow with guidance to allow designers of FGS for industrial systems to understand the performance-based design concepts underlying the technical report and practical guidance on how these concepts may be implemented in FGS design.
About the Author
Austin M. Bryan is a senior engineer for Kenexis Consulting Corporation. He has been involved in numerous projects covering such diverse operations as oil and gas production, petroleum refining, and specialty chemicals. He has extensive experience using risk analysis in designing engineered safeguards, particularly in fire and gas systems and safety instrumented systems. Bryan has a master of science degree in chemical engineering from Michigan Technological University.
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About the Author
Elizabeth Smith, a senior engineer at Kenexis Consulting Corporation, possesses extensive experience in designing both safety instrumented systems and fire and gas systems. She has been involved in projects comprising offshore and onshore upstream oil and gas, petroleum refining, and petrochemical production and shipping. She also has been responsible for determining and verifying safety integrity level requirements for SIS, as well as determining fire and gas performance targets and verifying fire and gas systems coverage.
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About the Author
Kevin J. Mitchell, vice president at Kenexis Consulting Corporation, has worked in the risk management and process safety fields for more than 20 years. Specializing in risk assessment of toxic, flammable and explosive hazards, he has contributed to than 500 projects across oil & gas production, refining, petrochemical, specialty chemical and general manufacturing. Leveraging risk assessment and cost-benefit analysis to support engineering and business decisions, Mitchell possesses extensive experience in the design of safety instrumented systems and fire & gas systems. He is also highly experienced in accident investigation, root cause analysis, and litigation support.
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