DSS035: Design and Certification of Explosion-Proof Vacuum Systems with Scott Boersma

In this episode of the DustSafetyScience Podcast, we interview Scott Boersma, Chief Operating Officer and Chief Sales Officer at Delfin Industrial corporation, about the design and certification of explosion-proof vacuum systems.

Scott has over 20 years of experience in the baking and food industries and has spent at least 10 of them serving the industrial vacuum market. He spends a lot of time educating Delfin customers and the public on what an industrial vacuum system is, why it’s needed, and how to use it, as well as the importance of certification.

One topic that we often discuss on the podcast is housekeeping, which is a two-part process. One is preventing the dust from being generated in the first place. The other is cleaning it up safely. Scott talks about the design and certification of explosion-proof vacuums, which are often used in facilities handling combustible dust.

What is an Explosion-Proof Vacuum?

Scott said that there are a lot of misconceptions surrounding what an explosion-proof vacuum system is. One of the issues contributing to the confusion is the following question:

Are you handling combustible dust in a non-hazardous environment OR
Are you in a classified hazardous environment handling combustible dust?

In the U.S., any environment that is considered a hazardous location will be categorized under a class and division system that identifies the hazardous product:

Class I: flammable vapours and gases
Class II: combustible dust
Class III: fibres and flyings
Division I: the substance is normally present in the environment
Division II: the substance is abnormally present in the environment

Scott explained that explosion-proof vacuums are designed to address the fact that dust is being sucked into an enclosure and mixed with air in the presence of ignition sources like a motor or static build-up. Even in a non-hazardous environment, the same level of protection is applied because combustible dust is being handled.

He added that the NFPA has put together new standards that address the following:

What is being handled
How it is being handled?
Is it in a hazardous environment or does it just need to be protected in a non-hazardous environment?

NFPA 652 and 654 indicate that there must be basic protection bonding in the vacuum system, meaning that each system component is able to conduct any type of electricity through it without causing a spark or electric arcing that could ignite the product. There must also be safe paths to ground the vacuum out. These bonding and grounding controls protect the unit from the three types of arcing:

Electrical arcing: when electricity flows or discharges along an unintended path.
Static arcing: for static electricity generated by particles as they move quickly through the vacuum system.
Percussive arcing: when something hits the side of the vacuum.

Scott said those vacuum systems that are compliant for combustible dust are almost identical to what Delfin would sell for a Class II Division II environment, which is the baseline for anything with a KST greater than zero. In environments where the dust is always present, Delfin shifts to Class II Division I certification, which ensures that the vacuum exterior is protected to the highest level.

What is the Certification Process?

With vacuums designed for Class II Division II environments, Delfin fits the systems with an anti-static hose and accessories. All electrical circuitry, from the plug to the cord to the switch to the fuse to the motor to the connectivity to it, is also tested.

“The vacuum system needs to be certified as it’s built,” Scott insisted. “A company can’t build a vacuum with an explosion-proof motor and say that it’s explosion-proof. Certification of the motor is one step. All components need to be certified, and then there has to be an additional certification for the way they are connected together as the system is built.”

He added, “Some things we got passed in our certification and other things caught fire when tested, although the components were okay. But when we drew the fuses up to their maximum amperage, they caught fire or the switch melted. These are hazards that wouldn’t have passed the certification process for the component.”

The whole system must be certified, not only the components. In Episode #29, Jeremiah Wann talked about how one of his company’s dust collection systems, which consisted of military grade hardware, failed when tested to destruction because the latch wouldn’t hold. In Episode #24, Niklas Kitzhöfer stated that in China, a lot of explosion protection system manufacturers copy designs of larger companies and sell them without testing, which is dangerous.

What Do End Users Need to Know?

When a customer buys an uncertified vacuum cleaner, they assume a lot of risk. While unexpected events can still occur with certified products, risk is minimized due to the amount of testing that has been done.

It also makes a difference who does the testing. Ideally, it should be done by a nationally-recognized testing laboratory. Unlike ATEX in Europe, which allows self-certification for Zone 22, U.S. law requires manufacturers to prove that a vacuum model is acceptable before it can be released under a full production run.

Although companies like Delfin do self-certification based on years of testing and product knowledge, nationally-recognized testing laboratories confirm that a product has undergone all the testing and meets all the codes and regulations throughout all of the standards.

Facilities can still choose to use a non-certified product, but an OSHA rep or any other authority having jurisdiction, such as a fire marshal, can warn them about it. Insurance companies may also threaten to cancel policies for noncompliance. While these standards are not laws, facilities are heavily encouraged to follow them, which is why Delfin sells vacuum systems are in compliance with those standards and guidelines.

What Are Some Solutions for the Future?

When asked about general solutions for the future, Scott sighed, “That’s a big question. In every industry, the applications are so different and so are the needs of the customer and their personal goals. That being said, the Class II Div II stuff has come a long way, so think it’s the middle ground. The price range is reasonable. It’s easy to use and it’s readily available on the market.

“We try to talk customers into just starting with something to get the dust picked up in most of the areas. Get rid of the brooms, get rid of the blowguns – stop blowing stuff around and making the problem worse. Let’s get it collected and contained and start going toward a resolution.”

Scott mentioned the Mill City Museum in St. Paul, Minnesota, which is the former site of an old General Mills plant that experienced a fatal explosion. Delfin does on-site training on combustible dust hazards, but it has a partnership with the museum, which holds live demonstrations of small and contained dust explosions for educational purposes.

Conclusion

Scott identified education as one solution to combustible dust safety. The other measure is to get a certified explosion-proof vacuum system and start making the facility safer. These are small steps that can yield great results, like the 20-80 principle where 20% of modifications get 80% of the results. If the number of fatalities and injuries are reduced by 80%, other improvements should follow.

If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Scott Boersma directly:
Email: [email protected]
LinkedIn: https://www.linkedin.com/in/scottboersma1/
Website: https://delfinindustrial.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.