EDITOR’S NOTE: This information was presented in the webcast “Combustible Sawdust - How to Protect Your Workers & Your Business,” which broadcast in March. Presented by Air Handling’s Jamison Scott, and sponsored by GreCon, the full webcast can be heard on-demand at WoodworkingNetwork.com/webcasts.
Combustible dust continues to make headlines. One of the top health and safety issues in the woodworking industry, it impacts companies of all sizes.
OSHA defines combustible dust as “fine particles that present an explosion hazard when suspended in the air, in certain conditions.” For a combustible dust explosion to occur, five factors must be present: fuel (combustible dust), ignition (heat or spark), oxygen (air), dispersion (dust suspension) and confinement. Removal of any one element will eliminate the possibility of occurrence. But far too often, this is not the case, sometimes with fatal consequences.
While OSHA has been following this issue for approximately 10 years, it recently has begun inspecting and fining companies for improper combustible dust exposure and possible hazards. In doing so, it has been citing the standards put forth by the National Fire Protection Agency (NFPA).
The NFPA, an International Codes and Standards Organization, creates voluntary consensus standards and provides guidelines for preventing combustible dust explosions. Those most applicable to the woodworking industry include: NFPA 664: Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities, and the soon-to-be-released NFPA 652: Standard on Combustible Dust.
While commonsense, housekeeping is one of the most important things a facility can do to control wood dust buildup. One of the most important things any facility can do is fully engage in housekeeping and fugitive dust control, said Jamison Scott, executive vice president of Air Handling. If the underlying surface colors of a machine, for example, are not readily discernible, there could be a dust deflagration hazard.
However, he cautioned, refrain from blowing the dust off with an air gun. That simply releases and stratifies the dust. Instead, use a vacuum. Then determine the source of escaping dust and repair it. For example, ensure all ductwork is airtight.
In addition to housekeeping, other steps for prevention include: Hazard Recognition/Assessment; Building Design & Engineering Controls; Administrative Controls; and Worker Training.
Hazard Recognition/Assessment includes determining if dust is combustible. This can be done via Dust Explosion Testing, which may include a Particle Size and Moisture Analysis, Explosion Severity Test, which tests the Kst value and Minimum Explosible Concentration (MEC). Hazard Recognition/Assessment also covers issues related to NFPA as well as state and local codes.
Building Design & Engineering Controls cover “fixed structures that are built into a facility or processing equipment designed to remove or minimize a hazard.” Building design focuses on preventing fugitive dust accumulation on beams and other flat surfaces, including rectangular shaped ductwork and flat surfaced lighting fixtures. Engineering controls focus on the equipment, such as dust collection systems or prevention devises such as spark detection in dust collectors and ductwork, and explosion venting and suppression systems.
Documentation, is one of the most important components of Administrative Controls. Agencies, such as OSHA, require written rules and procedures to ensure policies are fully understood and practiced by employees. In addition, various NFPA Standards have detailed proper methods for operating procedures, inspections, testing and maintenance procedures as well as training.
Who’s in Charge
The following is a list of some of the agencies and organizations involved in monitoring dust hazards in the woodshop.
OSHA: Since currently there is no specific standard related to Combustible Dust, the General Duty Clause is being cited for these violations, referencing NFPA as a resource.
Congress: Tired of waiting for OSHA to create a standard, Congress has begun introducing legislation to regulate combustible dust. The most recent has been H.R. 691, the Worker Protection Against Combustible Dust Explosions and Fires Act of 2013.
NFPA: Creates voluntary consensus standards used by OSHA, AHJ, Business Owner and other related parties.
AHJ (Authority Having Jurisdiction): This includes the fire marshal, building inspector, or any other local, state, or federal inspector having jurisdiction over your facility.
Insurance Company: The FM Global data sheet 7-76 Prevention and Mitigation of Combustible Dust lists “Woodworking” as the greatest number of “Losses by Industry” and “Dust Collectors” as highest number of “Losses by Equipment Type.”
Business Owner: Ultimately the owner has the responsibility to protect workers and the business, by using these and any other appropriate and relevant resources.
Employee: Worker training is of utmost importance for safety and the prevention of workplace incidents.
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