In today’s episode of the Dust Safety Science podcast, Dr. Paul Amyotte explains how inherently safer design (ISD) can be implemented using bowtie analysis.
His interview is the third in a series about the collective work being done by the Wood Pellet Association of Canada, WorkSafeBC, the BC Forest Safety Council, Dalhousie University, and Dust Science. The previous episodes were:
- History of the Wood Pellet Association of Canada with Gordon Murray
- Identifying & Implementing Critical Controls in Wood Pellet Facilities with Cherie Whelan
Dr. Amyotte, who is a Professor of Chemical Engineering at Dalhousie University, previously appeared in Episode #53, titled An Overview of “Methods in Chemical Process Safety, Volume Three.” He is also the editor of the Journal of Loss Prevention in the Process Industries and served as Dr. Chris Cloney’s Ph.D adviser.
Inherently safer design is a way of thinking and a design philosophy.
Dr. Amyotte explained that the principles of inherently safer design have been around “forever.” The basic idea is to determine whether something can be dealt with at its source before you add devices and procedures.
“Trevor [Kletz] first brought attention to formalizing and naming some of these principles,” he says. “That was in response to an incident in the mid-70s in the UK at Flixborough, which was a Caprolactam plant, a Nylon intermediate.”
Trevor was the first person to question whether new regulations and safety add-ons were truly necessary and summarized ISD in his 1978 paper ‘What You Don’t Have, Can’t Leak.’ Dr. Amyotte and his research partner Faisal Khan expanded the concept in their article ‘The Role of Inherently Safer Design in Process Safety.’
He emphasized that ISD doesn’t cure all problems, but it can still play a critical role in process safety.
“Before you automatically dismiss ISD and jump to betting on safety devices, ask the questions. Can I minimize inventories? Can I substitute a different material? And many times you can’t, particularly in the world of chemical process engineering. It’s hydrocarbons, that’s your product. You can’t substitute the hydrocarbon per se, but there may be other opportunities to substitute.”
Bowtie analysis is a process hazard analysis that also addresses risk.
Dr. Amyotte explained that bowtie analysis was a type of “what we in the chemical industry call a PHA- process hazard analysis. [But] it’s not just hazard. It gets into risk as well. You might bring in a risk matrix to decide on whether you need additional safety measures.”
Bowtie analysis is a graphic technique that provides a picture to help identify where new or enhanced controls may be worthwhile. The bowtie is the hazard that will lead to an undesired event, usually the loss of containment and release of materials. There are also threats that can lead to this undesired event, and the goal is to place a barrier between the threat and the potential outcome.
“Preventive barriers on the left-hand side, as I’m looking at a bowtie between threat and top event, and mitigated barriers between threat and consequence on the right-hand side of the bow tie,” Dr. Amyotte says.
He added that safety measures can fail.
“[Therefore], we have what are called degradation factors. If PPE- personal protective equipment – is one of my preventive barriers, they are also mitigation barriers. I have to remember that people might not wear PPE, so there’s a degradation factor. So how can I control that degradation factor? Training, education, etc. So that every barrier has a degradation factor, and every degradation factor has a control measure.”
The goal is to do more than produce a bowtie simply lays out threats, barriers, top event, barriers, and then consequence. Possible barrier failures have to be reviewed, in order to prevent them from happening.
“So to tie ISD with bowtie analysis, we want those barriers to be inherently safer,” Dr. Amyotte says. “We at least want to see in the bowtie some of those barriers being thought of as minimizing, moderating, substituting, simplifying and so on. It may be the barrier itself or maybe the degradation factor control. So we have a procedure as a barrier. People might not follow the procedure because it’s too complex. If we can simplify the procedure, make it easier to understand, then we’re bringing an element of inherent safety into the procedural safety level. So that’s what we’re trying to do in our recent research- explicitly incorporate inherent safety concepts into bowtie analysis.”
Applying ISD to bowtie barriers was a natural result of 20 years of research.
Dr. Amyotte recalled that around 20 years ago, he began thinking that inherent safety needed to be brought more explicitly to process safety management. Then, a couple of years ago, he spoke to Kayleigh Rayner-Brown, who was working on her Masters, and suggested another PHA technique bowtie analysis that put inherent safety front and centre. She did a great job, and is still with Dr. Amyotte’s team as a research associate.
The team is presently working with the Wood Pellet Association of Canada and Dr. Chris Cloney on WorkSafeBC’s Innovation at Work Project. It has also received an alliance grant from the provincial health authority to further the implementation of inherent safety into bowtie analysis.
Conclusion
Dr. Amyotte says that his critical research will continue.
“PHA is, in many respects, never done. There’s always room for improvement, and continuous improvement is just one of the cornerstones of process safety management.”
If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Dr. Paul Amyotte directly:
Email: [email protected]
LinkedIn: https://www.linkedin.com/in/paul-amyotte-364a2216/
University Webpage: https://www.dal.ca/faculty/engineering/peas/faculty-staff/our-faculty/paul-amyotte.html
If you have questions about the contents of this or any other podcast episode, you can go to our ‘Questions from the Community’ page and submit a text message or video recording. We will then bring someone on to answer these questions in a future episode.
Resources mentioned
Dust Safety Science
Combustible Dust Incident Database
Dust Safety Science Podcast
Questions from the Community
Dust Safety Academy
Dust Safety Professionals
Organizations
Wood Pellet Association of Canada
WorkSafeBC
BC Forest Safety Council
Publications
Inherently Safer Chemical Processes: A Life Cycle Approach
The Role of Inherently Safer Design in Process Safety
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