In today’s episode of the Dust Safety Science podcast, Kevin Cardwell, combustible dust consultant with Airdusco Engineering and Design Services based out of Memphis, Tennessee, talks about common challenges in combustible dust incident investigation. Kevin appeared in Episode #79, when he addressed baghouse maintenance issues, and today he uses his extensive experience to analyze difficulties encountered while investigating combustible dust fires and explosions.
Why Should a Company Do an Internal Investigation of Combustible Dust Incidents?
Kevin explained that any time a combustible dust incident occurs, whether it is a fire, flash fire, explosion or even just an unexpected combustible dust release, the company involved should do an internal investigation.
“[In] incidents where you have a loss, you need to investigate or have it investigated so you can determine what caused it, and you can then prevent that from happening again,” he says. “The main thing that needs to come out of any combustible dust incident is proper determination of the cause and origin, and the systemic failures or systemic issues that led to that incident. You have to determine that correctly so then you can design your mitigation to prevent it in the future.”
What Should You Look For During an Incident Investigation?
Kevin said that to develop the proper mitigations, you need to understand why your existing controls failed. This requires a deep knowledge of what your controls are and how they work, why they work, and more importantly, why they didn’t work in this case.
Depending on the severity of the loss, there are several different investigations that could be carried out. In the U.S., if an explosion results in injuries and equipment destruction, OSHA will come and investigate. In other countries, there will be safety officials looking into the incident. Their focus is going to be on compliance and enforcement, however: they’re not necessarily looking for solutions beyond compliance with the appropriate standards and regulations and laws.
“They want to know what you did wrong, basically,” Kevin says. “In all honesty, most of the time they actually require the customer to present them the plan to mitigate the hazards to bring them into compliance. And so while they may determine an origin and a cause and everything, they’re not necessarily looking at what needs to take place to keep that from happening again.”
Without the right knowledge and expertise, facility owners have a hard time developing the proper mitigation to prevent incidents from happening again. These incidents can be very complex, and it takes specific skills to actually figure out what happened in a lot of cases.
Many Challenges Arise From Lack of Understanding
Kevin acknowledged that he has seen situations where facilities make potentially unsafe adjustments to their safety equipment.
“They will have explosion venting on their dust collector. In areas that tend to get a lot of winter weather, they may have weather covers on them. It’s quite possible that the people that were there when those were installed actually understood how they worked. But I can’t tell you how many times I’ve gone in after these vents and weather covers have been installed for 15 or 20 years, and I see that people have caulked them and used the wrong type of caulk to actually hold them in place or they’ve screwed them in place – which kind of defeats their purpose…That is why you need to bring in a fresh set of eyes that is looking for that type of thing.”
Another Challenge: Getting Back to Business too Fast
Kevin noted that after a fire or explosion, the first thing facilities want to do is get back into operation as soon as possible.
“The first thing that they want to do is clean up the area, fix or replace the equipment, and get back into production. I understand that. Production is how they make their money. Unfortunately, the very act of cleaning up, replacing or repairing damaged equipment may make any investigation infinitely more difficult. You are destroying evidence that can lead an experienced investigator to the correct cause, origin, systemic failure or inadequacy. Without this information, you cannot accurately determine what occurred, how it occurred, what caused it, and how to prevent it.”
He recommended that after an incident, company management take certain steps to make a proper determination and mitigation strategy:
- Secure the scene using hazard tape or somehow restricting the access to the area – not only where the incident occurred but the associated equipment.
- Document the scene after the area has been secured. The more pictures that are taken in the immediate aftermath of an incident, the more information that the investigator has to work with.
- Hire a qualified investigator who has training and experience with combustible dust equipment and mitigation strategies. They can identify the cause and origin, making it easier to develop a proper mitigation strategy.
He recalled one customer who had several small explosions in a heated mixer but they never did anything about them. This happened on a fairly regular basis for years, until one day they had a catastrophic explosion in a mixer that propagated through the duct system and ended up killing an employee on another level of the facility. The plant manager was absolutely devastated and blamed himself for not having investigated previous incidents.
“It has haunted him ever since that he lost an employee over something that might have been prevented had they investigated the smaller explosions earlier,” Kevin says.
Conclusion
At the end of the episode, Kevin stated, “The one thing that I would like to leave the audience with is to make sure, especially if you have a large incident, that you do the things I talked about before. You secure the scene, you document it exhaustively. Even if you just have a minor incident, investigate it. If you can’t determine what caused it, bring in somebody who can – because just being lucky once or twice is no indication that you will be lucky the next time. And if nothing else, we have to learn from these incidents so that they don’t recur.”
If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Kevin Cardwell directly:
Email: [email protected]
Cell: 901-378-8038
LinkedIn: https://www.linkedin.com/in/kevin-cardwell-cfei-cfii-cfps-5935a182
Website: http://www.airdusco.com/
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
Dust Safety Share
Companies
Airdusco Engineering and Design Services
Previous Episodes
DSS079: Three More Challenges in Baghouse Maintenance with Kevin Cardwell
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