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From the Industrial Fire Journal’s ComDust Blog

Posted on October 30, 2009

Nilfisk CFM looks at the importance of utilizing explosion proof vacuums when cleaning up combustible dust in the workplace

When the Dust Settles: A Tutorial on Explosion-proof Vacuums

A comprehensive maintenance plan is a solid first step in preventing a combustible dust-related fire or explosion and can greatly minimize the tragic effects of a secondary blast. By letting dust accumulate on surfaces, facilities are literally adding fuel to the fire and efforts should be taken to insure that dust deposits greater than 1/32”, the thickness of a paperclip, are promptly removed, according to OSHA’s Combustible Dust National Emphasis Program. While mops and brooms have their place in industrial facilities, the process is time consuming and often creates dust clouds, adding to the risk. They also are very limited in what they can clean. A properly-equipped, HEPA-filtered industrial vacuum cleaner suitable for collecting combustible dust, can get the job done in half the time and be used to remove dust from machinery, floors, walls, and overhead pipes and vents.

Even though purchasing an industrial vacuum cleaner to combat combustible dust sounds easy enough, there surprisingly is some complexity to the investment, especially if the vacuum will be used to collect classified hazardous materials like metal dust, coal, or even sugar. Naturally, most plant supervisors assume the machinery in their plants is explosion-proof, including the industrial vacuums, but if you plan on collecting hazardous materials, a certified “explosion-proof” vacuum (EXP) is imperative. In fact, using just a basic vacuum, made of metal parts and exposed motors, can actually add to the risk of explosion.

Certifiable Explosion-Proof: Beware of “Dress Up”

An “explosion-proof” vacuum (EXP) is explosion-proof to the core. This means that everything from the outer shell to the internal mechanics including the motor, switches, filters and inner chambers are grounded and constructed of non-sparking materials like stainless steel. Some industrial vacuum companies offer basic models dressed up with a few anti-static accessories and describe them as suitable for explosive material. These imposters can still create arcs, sparks or heat that can cause ignition of the exterior atmosphere and overheating that can ignite dust blanketing the vacuum.

Purchasing an explosion-proof vacuum approved by a nationally recognized testing agency such as the Canadian Safety Association (CSA) or Underwriters Laboratories (UL) is a must, as it protects buyers from purchasing a poser by providing legal certification that the vacuum can be used in a particular NFPA-classified environment. It ensures every component in the vacuum from the ground up meets strict standards for preventing shock and fire hazards.

Explosion-Proof vs. Intrinsically Safe

In environments where electricity is unavailable or undesirable, air-operated vacuums for hazardous locations are excellent alternatives. Properly outfitted pneumatic vacuums referred to as “intrinsically-safe,” can pack the same punch as their electric counterparts; just make sure they still meet the requirements for use in NFPA-classified environments.


Purchasing a high-quality, certified explosion-proof or intrinsically-safe vacuum is a solid first step in preventing a combustible-dust related explosion, and picking the right vacuum often raises a lot of questions, especially when it comes to disaster prevention. Like all investments, pre-sale research is key. Plant managers shouldn’t hesitate to ask the vacuum-manufacturer for an onsite analysis of their vacuum needs in order to recommend what type of explosion-proof vacuum, hose and accessories are needed for the application. With the right equipment, the vacuum can be used to meet OSHA requirements, collecting dust from the floor, booth walls, and even overhead pipes and vents. And naturally, every manufacturer will be responsive to your needs before you buy, so look for a company that will still be there after the “dust settles.” Excellent post-sale support and training will make things easier when it’s time to purchase replacement parts and filters or service the vacuum.

If used consistently and in conjunction with a comprehensive maintenance plan, the facility’s investment in an explosion-proof vacuum will result in much more than just a clean plant. It will increase productivity, protect your employees, and keep you out of the headlines. For more information visit www.explosionproof-vacuum.com.


OSHA ComDust Safety Bulletin

Electrical Equipment and Safety Standards

Dealing with the ATEX Directive
Canadian Electrical Code® (C.E.C.)


Note: This informative article examines explosion proof vacuums in the USA. Combustible dust in the workplace is a global issue. Check with your local governing body concerning use of equipment in a potentially explosive atmosphere so as to obtain the current regulations. I’ve provided links to ATEX and CEC in Canada. Additionally, IECEx is the IEC system for electrical equipment use in explosive atmospheres in many countries.