Paul Gruhn


Paul Gruhn is a Global Functional Safety Consultant with aeSolutions in Houston, Texas. Paul is an ISA Fellow, a member of the ISA 84 standard committee (on safety instrumented systems), the developer and instructor of ISA courses on safety systems, the author of two ISA textbooks, two chapters in other books, and over two dozen published articles, and the developer of the first commercial safety system software modeling program. Paul has a B.S. degree in Mechanical Engineering from Illinois Institute of Technology, is a licensed Professional Engineer (PE) in Texas, and both a Certified Functional Safety Expert (CFSE) and an ISA 84 Safety Instrumented Systems Expert. Paul’s hobbies include home brewing, golf, painting, guitar, and reading.

Posts by Paul Gruhn:

December 20, 2018

Process Safety Management, Jenga, Drift, and Preventing Process Industry Accidents

Blog by Paul Gruhn, P.E., CFSE, Global Functional Safety Consultant, aeSolutions       Have we really learned anything from previous accidents? There have been many well publicized process industry accidents over the last several decades. Articles and books have been written about many of these events. However, most books essentially reviewed what happened the […]

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December 17, 2018

Happy Holidays from aeSolutions

Christmas is a time of year that we reflect back on how much each of us personally value the relationships we have with our clients. We hope that together we have achieved project objectives in 2018 that make a difference in the lives of your employees and ours well into the future.   Very best wishes […]

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November 16, 2017

The significant financial benefits of proper front end loading on a Burner Management System project

aeSolutions agrees with the findings of the Construction Industry Institute (CII). The CII has done extensive research on improving project success. Through quantitative analysis of 62 projects, as noted in Analysis of Pre-Project Planning Effort and Success Variables for Capital Facility Projects, they found that the front end loading (FEL) “effort level directly affects the […]

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September 8, 2016

Control Engineering – How to Keep Process Facilities Safe

Proper safety management can be taken to minimize risk. Modern industrial life has its rewards, but it also comes with risks. There is no such thing as absolute safety or zero risk. When major industry accidents happen, regulations often follow. In 1992, 29 Code of Federal Regulations (CFR) 1910.119 “Process Safety Management of Highly Hazardous […]

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White Papers by Paul Gruhn:

Process Safety Management, Jenga, Drift, and Preventing Process Industry Accidents

Process Safety Management, Jenga, Drift,
and Preventing Process Industry Accidents

Paul Gruhn, P.E., CFSE

Global Functional Safety Consultant

aeSolutions, Houston, TX



There have been many well publicized process industry accidents over the last several decades. Much has been written about them, and many lessons learned have been proposed. Yet evidence would indicate there has not been a lessening of industry accidents. More recent realization of the complexity of modern processes, and the organizations responsible for designing, building, running, and maintaining them, has resulted in a broader understanding of accident causation, and what can be done to try and prevent further incidents. This paper will review the previous thinking process and recommendations, and offer an alternative approach and recommendations.



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Burner Management System Challenges and Opportunities in Brownfield Installations

A two‐prong templatized approach to multiple brownfield burner management system upgrades can result in significant cost savings. The first step requires coming up with an equivalent design for the safety instrumented burner management system following the ISA 84 safety lifecycle, as allowed in current NFPA standards. The second step utilizes a templatization approach for multiple units with common functionality that will allow an organization to further maximize savings. Actual experience doing this on repeat BMS projects indicate the level of overall savings can be as high as 75% on the safety lifecycle, 70% on the control system design and integration, and 35% on the operation and maintenance activities. The combined overall savings are roughly 60%.

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Integrating ICS Cybersecurity and Process Safety Management (PSM)

The majority of process plants today are controlled and operated by automation systems built on Ethernet TCP/IP networks and legacy Microsoft operating systems. These systems are vulnerable to cybersecurity breaches resulting in potentially significant risks. Standards have been developed on how to assess and mitigate cyber risks to these systems. This paper provides an introductory summary of these topics.

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Understanding Safety Instrumented Systems (SIS) Field Device Fault Tolerance Requirements

The IEC 61511 standard includes a table listing the fault tolerance requirements for field devices for different safety integrity levels. There are clauses stating how the fault tolerance requirements may need to be increased in some cases, may be decreased in some cases, and alternative fault tolerance tables from IEC 61508 may be used in some cases. This paper will summarize all these requirements, as well as changes in the table that will appear in the second edition of IEC 61511 that is expected to be released in the summer of 2016.

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Upcoming Changes in IEC 61511 2nd Edition

It has been over 10 years since the first release of IEC 61511. That committee has worked diligently to create a 2nd edition. A CD (Committee Draft) went out for review and comment by the national committees in 2012. The FDIS (Final Draft International Standard) went out to the committee in November 2015. The standard should be released in 2016. Note that there may still be editorial changes to the standard, but no further technical changes will be accepted for this edition. This paper summarizes the differences between the first and second editions of IEC 61511.

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