Combustible dust has been the culprit in thousands of costly and fatal infernos in industrial or manufacturing facilities over the years in the U.S. As such, vacuuming in hazardous areas classified by the National Fire Protection Association (NFPA) is much more than a workplace hygiene issue. It entails using explosion proof vacuum systems to clean surfaces in environments that have combustible dust. Typically, the right type of equipment for cleaning such areas must meet appropriate standards set forth by the NFPA and the Occupational Safety and Health Administration (OSHA).
Where’s the Danger in Not Using Appropriate Hazardous Area Vacuum Cleaning Systems?
Not every vacuum cleaner is built for use in explosion-prone atmospheres. There are even traditional industrial cleaners that lack the right explosion proof features. Manufacturers or plant supervisors have to be careful not to select vacuuming tools that offer basic functions only without explosion-proof features.
There’s a risk of causing fire or an explosion in not using hazardous area certified vacuum cleaning hardware in industrial facilities that generate combustible dust. These locations include food processing facilities, drug-making factories, and textile, rubber, and paint industries. Wood dust, gunpowder, coal dust, flour, graphite, or other combustible fine particles that readily ignite when exposed to electrical sparking are usually present in such areas, hence their “hazardous” designation.
Traditional vacuuming systems are inappropriate for use in environments with flammable substances because they usually do not have the required explosion-proof internal or external construction. While in operation, these tools can generate sparks, heat, or arcs, which may, in turn, start a fire in their surroundings. Still, non-hazard-area-certified systems may overheat and explode from inside, causing damage to surrounding property or even seriously hurting personnel. The need to bring safe, NFPA-certified cleaning apparatus to such areas cannot, therefore, be overemphasized.
What it Means to be Explosion Proof
If any apparatus is Explosion Proof, it cannot explode even if operating in an explosion-prone atmosphere. It also can’t easily cause a fire in its environment. When building such a device, manufacturers ensure that all its components, from the housing to internal mechanics, are incapable of igniting a fire or detonating explosive substances in the air.
As such, explosion proof vacuum cleaners are not just larger versions of their traditional alternatives. These are industrial-grade tools with built-in capabilities to remove combustible dust safely. They’re meant to get rid of flammable and potentially explosive solids and liquids from surfaces without triggering an explosion or causing a fire.
Critical Features of Explosion Proof Vacuum Cleaners
In addition to having a chemically neutral housing, a typical Explosion Proof vacuum cleaner should be able to dissipate static charges. It also boasts sufficient electrical insulation. Here are its main features:
- Heavy-duty housing: A sturdy stainless steel outer shell that does not break or dent makes it possible to contain any explosion inside the apparatus. The anti-sparking material minimizes the risk of an explosion due to electrical discharge. Reinforced fiberglass is also a suitable material for constructing Explosion Proof vacuum cleaner housing.
- An Explosion Proof motor: This internal component should have the ability to contain any pressure that builds up from within itself without disintegrating in the event of an internal explosion. Any gases or vapor coming out of the component through flame paths should not be hotter than the minimum ignition temperature (MIT) of the combustible substances in the atmosphere around the apparatus.
- Grounded components and accessories: These include motors, switches, and air supply lines. Grounding them ensures the continuous elimination of static electricity, preventing a dangerous buildup that could cause electrostatic discharge.
- Immersion separator: This unit is present in certain types of Explosion Proof vacuums. Its role is to minimize the risk of combustible dust igniting inside the equipment in question. It works by collecting and neutralizing combustible metal dust, such as magnesium and aluminum, in a non-reactive, safe fluid bath.
Other design/construction factors that make for Explosion Proof vacuums include:
- Non-electrical components or systems: Vacuuming tools that use compressed air rather than electricity don’t have electrical elements that may spark and ignite combustible dust
Non-moving parts: A design with no moving parts, including motors, minimizes the risk of explosion or ignition due to mechanical friction
The Difference Between an Explosion Proof and Intrinsically Safe Vacuum Cleaner
An intrinsically safe vacuum has built-in features designed to have the smallest possible risk of causing an explosion or a fire when used in a hazardous area. As such, explosion proofing a vacuum cleaner doesn’t necessarily make it certifiable for use in facilities that generate combustible dust and other dangerous debris.
Before looking up explosion proof vacuum cleaners prices online, you want to be sure that the equipment you’re buying is intrinsically safe and appropriate for the intended operating environment. There are proper directives to guide your search, especially National Electric Code (NEC) ratings as stipulated in the publication NFPA 70.
For example, NEC Class 2 Division 1 stipulates intrinsically safe standards for electrical equipment meant for use in an environment with combustible dust in the air. It defines wiring methods and rules for circuitry design to minimize the risk of explosion due to overheating or electrical discharges. Consider directives in this designation if you’re going to use your vacuum in an atmosphere with enough concentrations of combustible dust to create explosive mixtures.
A Class 2 division 2 designation applies if you’re using your vacuum cleaner under any of the following conditions in your facility:
- Operational faults have resulted in the release of combustive dust into air in proportions big enough to create explosive mixtures
- There’s been a build-up of combustive debris in the atmosphere, but it’s not sufficient to cause faults in electrical systems or devices
- Enough combustible dust has accumulated on, inside, or around electrical apparatus to hinder the elimination of heat from the device
Conclusion
The build-up of combustible dust in any confined area or within electrical equipment poses a risk to life and property in case of accidental sparking or discharge of static electricity. If your facility has this type of dangerous debris, you need to use NFPA-certified, explosion proof vacuum cleaners to tidy up your work environment.
Are you looking to buy an intrinsically safe, explosion proof vacuum device? Head on over to Intrinsically Safe Store for an extensive range of ATEX and NEC certified products!