Grain Mills: Combustible Dust Housekeeping (Part 3) | Nilfisk Official Website
February 06, 2013

Grain Mills: Combustible Dust Housekeeping (Part 3)

[caption id="attachment_1362" align="alignleft" width="240"] Feed & Grain[/caption]

The potential for explosions to occur from dust collections made of flour, sugar, cinnamon or grain particles, for example, poses a significant risk to employee safety, facility maintenance and food purity. Traditional plant maintenance methods like sweeping and blowing down with compressed air only make the situation worse by spreading the explosive dust around and making it airborne. This actually increases your chances of a combustible dust explosion.

There is a lot of confusion in the food manufacturing sector regarding hazardous materials, particularly combustible dust. In short, just because your facility handles combustible dust does not mean you need an explosion proof vacuum but you might. According to OSHA’s National Emphasis Program (NEP) on combustible dust, dust accumulations greater than 1/32” or the thickness of a paper clip are considered hazardous. The standard calls for electrical vacuums used in dusty areas to be approved for the hazard-classified location. A solid maintenance plan with a HEPA-filtered industrial vacuum can significantly reduce the risk of a combustible dust accident. Vacuums equipped with features such as an external filter shaker and polyliner allow operators to easily/safely maintain the filters and dispose collected material. When dealing with classed materials within a grain mill, a certified explosion proof industrial vacuum is the best choice. Things to remember:
  • A certified explosion proof vacuum is grounded and constructed entirely of non-sparking materials such as stainless steel, from the outer shell to the internal mechanics including the motor, switches, filters and inner chambers.
  • Some industrial vacuum manufacturers dress up their equipment with a few anti-static accessories and describe them as suitable for explosive material. These basic models can still create arcs, sparks or heat that can cause ignition of the exterior atmosphere and overheating that can ignite dust blanketing the vacuum.
  • For peak safety and operating efficiency, the explosion proof vacuum should have a graduated filtration system which uses a series of progressively finer anti-static filters to trap and retain particles as they move through the vacuum. To eliminate combustible dust from being exhausted back into the ambient air, a HEPA or ULPA filter can be positioned after the motor to filter the exhaust stream.
  • Purchasing an explosion proof vacuum approved by a NRTL will protect buyers 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.
For more information on explosion proof vacuums for combustible dust, visit For housekeeping solutions on keeping your grain mill a clean and safe environment, catch up on the entire series: part 1 on general maintenance and part 2 on spill response.
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