OSHA News

CV Technology Confronts Fugitive Dust Explosion Risk and Remediation within the New OSHA Mandates

(Feb 15, 2008)-- Within the context of industrial dust explosions there has always been an appreciation for the hazard posed by fugitive dust. That can be defined as dust that escapes from process equipment and accumulates in layers on the floor or other horizontal surfaces and worst of all up in the rafters. The insurance industry reports the largest losses in dust explosion accidents often come from secondary explosions fueled by layers of fugitive dust.

To CV Technology, an International leader in dust explosion prevention and mitigation, this on-going problem is well understood and nothing new. However a new OSHA mandate has given the topic of combating fugitive dust a new challenge. What is new is that the amount of dust that can pose a hazard is much less than was appreciated until very recently.

According to the OSHA Directive on Combustible Dust promulgated in October, 2007, the maximum allowable dust layer is only 1/32nd of an inch. That is so little dust that it is debatable that it can be accurately measured. Upon learning of so strict a requirement it is not uncommon for industrialists to simply throw their hands up in despair.

At a recent meeting of task force members from the NFPA 654 Technical Committee as well as interested parties from related ASTM Committees, the dilemma was framed by a visiting executive from a major American manufacturing company. He reported that in one 100' x 300' high bay facility, his company has been using dedicated cleaning crews equipped with special platforms and rigging to safely clean the roof truss system where dust collects at the rate of approximately 1/16th of an inch per six months. This amount of dust is the suggested limit in NFPA 654. The cost for this twice yearly effort is $500,000.00 per cleaning, or $1,000,000.00 per annum. This company is now faced with doubling that expenditure unless other measures can be found to reduce the dust loading on the facility.

Why is such a small amount of dust considered dangerous? At that same meeting it was reported that testing a layer of dust 1/32nd of an inch deep, covering only a small fraction of the total horizontal area, roughly equivalent to the surface area of support trusses and beams in a typical general occupancy commercial building, upon being lifted into a dust cloud, proved more than sufficient to destroy said building after ignition. Thus, the small amount of dust necessary to pose a significant hazard, placed in counter-point to the high cost for clean up, clearly defines the dilemma faced by industry.

Bill Stevenson Vice President of engineering for CV Technology states, "The options for dealing with this dilemma are still not clear and there is much thought and discussion being expended to find remediation." Stevenson continues, "In the meantime even though it is doubtful if housekeeping is enough, it is a start. A common question we get is 'Is it safe to use compressed air blow down? '" To address this CV Technology offers the following set of guidelines.

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