Keith Brumbaugh

Keith Brumbaugh is a Senior Specialist with aeSolutions. He has a B.S. in electrical engineering with a minor in computer science from Texas Tech University. Keith is both a Professional Engineer (P.E.) and a Certified Functional Safety Expert (CFSE). He has over ten years of experience in instrumentation and safety systems engineering.

White Papers by Keith Brumbaugh:

Can we achieve Safety Integrity Level 3 (SIL 3) without analyzing Human Factors?

Many operating units have a common reliability factor which is being overlooked or ignored during the design, engineering, and operation of high integrity Safety Instrumented Functions
(SIFs). That is the Human Reliability Factor. In industry, there is an over focus on hardware reliability to the n’th decimal point when evaluating high integrity SIFs (such as SIL 3), all to the detriment of the human factors that could also affect the Independent Protection Layer (IPL). Most major accident hazards arise from human failure, not failure of hardware. If all that were needed to prevent process safety incidents is to improve hardware reliability of IPLs to some threshold, the frequency of near miss and actual incidents should have tailed off long ago – but it hasn’t. Evaluating the human impact on a Safety Instrumented Function requires performing a Human Factors Analysis. Human performance does not conform to standard methods of statistical uncertainty, but Human Reliability as a science has established quantitative limits of human performance. How do these limits affect what we can reasonably achieve with our high integrity SIFs? What is the uncertainty impacts introduced to our IPLs if we ignore these realities?
This paper will examine how we can incorporate quantitative Human Factors into a SIL analysis. Representative operating units at various stages of maturity in human factors analysis and the IEC/ ISA 61511 Safety Lifecycle will be examined. The authors will also share a checklist of the human factor considerations that should be taken into account when designing a SIF or writing a Functional Test Plan.

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How taking credit for planned and unplanned shutdowns can help you achieve your Safety Integrity Level (SIL) targets

Achieving Safety Integrity Level (SIL) targets can be difficult when proof test intervals approach turnaround intervals of five years or more. However, some process units have planned and predictable unplanned shutdowns multiple times a year. During these shutdowns, it may be possible to document that the safety devices functioned properly. This can be incorporated into SIL verification calculations to show that performance targets can now be met without incorporating expensive fault tolerance, online testing schemes, etc. This can result in considerable cost savings for an operating unit.

This paper will discuss various solutions to meet a SIL target, taking credit for planned and unplanned shutdowns to help meet a SIL target, justification for applying diagnostic coverage in SIL verification calculations, summary of determining diagnostic credit, applying diagnostic credit from a shutdown event, and a case study.


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Improving the Safety Instrumented System (SIS) Design Process with Graphic Diagrams

During a Safety Instrumented System (SIS) implementation project at a plant site new to the ANSI/ ISA 84 process safety lifecycle world, we discovered the importance of utilizing graphic diagrams in the development of SIS‐related documentation to support the on‐site team meetings and document decisions. The author will present examples of the different types of graphic diagrams, methods in which the diagrams were utilized, and the benefits that each provided in the implementation of certain phases of an ANSI/ ISA 84 SIS lifecycle project. These diagrams were considered to be valuable process safety information and part of the final SIS Front End Loading design.

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