In today’s episode of the Dust Safety Science podcast, Roger Guerra, Business Development Manager for Nilfisk, talks about portable vacuum systems and, in particular, facts and myths around certification of these systems. A lot of excellent information already appears in the Nilfisk resource Combustible Dust Mythbusting Guide: The Facts You Need to Stay Safe, and Roger elaborates on key points during this interview.
Areas of discussion include:
- NFPA requirements for cleaning combustible dust
- Difference between unclassified and classified areas or hazardous areas
- Pneumatic and electrical systems
NFPA Requirements for Cleaning Combustible Dust
Roger explained that a recent revision of NFPA 654 specifies that electrical-powered vacuum cleaners must meet certain requirements to collect combustible dust in non-rated or non-classified environments. A failure to meet those requirements could result in OSHA fines or worse, a fire or explosion.
“You never want to be one of those companies, unfortunately, in that mix,” Roger said. “So you’ve got to make sure that you’re using vacuum cleaners that are rated for combustible dust even in non-rated or non-classified environments. And if you’re not, they must, at least, follow some general specifications like design requirements.”
These requirements include non-combustible construction except for the filter, as well as static-dissipative or conductive air delivery hoses. All conductive accessories, including wires and attachments, should be bonded and grounded. Some of the other vacuum cleaner design requirements include:
- Dusty air is not to pass through the fan or blower.
- Electric motors must not be in the dust-laden airstream, unless listed for Class 2 Div 1 locations.
- No paper filter elements for liquid or wet collection.
Roger pointed out that it’s set up this way so the requirements can provide specifications for vacuum cleaners used to remove incidental amounts of combustible dust from unclassified areas in order to maintain the unclassified area designation.
“So it’s really to make sure that you’re still able to work in that type of environment that’s considered unclassified because obviously once you get a certain buildup of dust, that could impact the classification of that environment,” he said.
Are There Additional Requirements for Portable Vacuum Systems in Classified Areas?
Roger stated that when combustible dust is present in a hazardous location, it needs to be identified first, so you can work within the existing parameters. It’s also important to have the authority having jurisdiction (AHJ) come in to confirm the classification of the area so that you have the right equipment for those designations.
“The important thing is obviously having the right classification and the right grouping, and you figuring that out with whoever you use to figure that out – whether it’s your local EHS manager, whoever that AHJ is. You want to make sure that’s clearly defined because that’s obviously going to directly correlate with what vacuum you’re going to select for that environment. So the important part is obviously assessing it properly, knowing kind of what environment you’re walking into. And then, once we have that figured out, then making sure that you’re working together with the AHJ’s recommendation on what vacuum you should go with.”
What Are the Differences Between Electrical and Pneumatic Portable Vacuum Systems?
Roger said that the biggest difference between these two systems is that one is electrical and the other is operated by compressed air. The electrical machine has the ability to be certified for a Class 1 Div 2 or Class 2 Div 2 environment.
“When you’re working with the pneumatic machines, they are made to a certain standard. At least the way we construct our pneumatic machines that are going into combustible dust environments, we have a machine that’s going to be fully bonded and grounded.”
“These vacuums will have a grounding strap to ensure that any charge generated within the vacuum has a clear path to the ground. We’re still going to equip it with anti-static wheels and anti-static main filter that has stainless steel weave within it to conduct any set of charges to the ground that could generate upon it as required for ancillary equipment and components in a number of references within the NFPA standards… It’s supposed to be constructed with low-sparking metals such as aluminum or stainless steel. So you’ll find that with ours, the big things are the collect container, the inlet and the deflector are all stainless steel – since those are low sparking metals. And that’s where you’re really going to get kind of that high speed or that more significant friction. You want to make sure that you’re working with something that’s low sparking. And then, obviously, you want to have a conductive air line.”
What is the Difference Between Explosion-Proof and Dust Ignition-Proof?
Roger said that only electrical equipment can be rated for explosion-proof or dust ignition-proof. Explosion-proof means the equipment prevents ignition of a gas or vapours surrounding the enclosure. Explosion-proof equipment must be tested and confirmed by an NRTL, an internationally recognized testing laboratory, for use in Class 1 locations. Dust ignition-proof means the equipment is enclosed to exclude dust and prevents arcs from causing ignition. This equipment must also be tested and confirmed by an NRTL, but it is only permitted for use in Class 2 locations.
“So it’s just another step of certification that you need to get for your machine to be full-blown EXP or explosion proof compared to being certified dust ignition-proof.”
Conclusion
Roger emphasized the importance of due diligence when acquiring vacuums.
“This is obviously something that is really serious, and can risk people’s lives at the end of the day because an explosion can turn into something a lot worse. It’s not just about a business or a company. It’s about like there’s people’s lives at stake if you don’t go about things the right way. So just make sure that you’re doing your due diligence, doing your proper research on the vacuums, and not just following some of the buzzwords like ‘intrinsically safe’ or or ‘explosion- proof.’ Make sure you’re doing your due diligence on what you’re purchasing and have the right kind of support when going through that process.”
If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Roger Guerra directly:
Email: rguerra@nilfisk.com
LinkedIn: https://www.linkedin.com/in/roger-guerra-16b15322/
Website: https://www.nilfisk.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
Organizations
NFPA
Standards
NFPA 654
Companies
Nilfisk
Resources
Combustible Dust Mythbusting Guide: The Facts You Need to Stay Safe
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