Combustible dust has become a top health and safety issue in the woodworking industry. Companies with as few as nine employees are being targeted for ComDust-related issues by OSHA. Occurrences of combustible wood dust related fires, some catastrophic, have been increasing, as have incidences of OSHA inspections related to combustible dust in woodworking facilities.
Dust from wood production is established as a risk. In its data sheet 7-76 on prevention and mitigation of combustible dust, insurer FM Global lists “Woodworking” as the greatest number of “Losses by Industry” and “Dust Collectors” as highest number of “Losses by Equipment Type.”
Still, a combustible dust explosion can occur only under certain conditions. But under just about any condition OSHA can inspect a facility. Since combustible dust is on OSHA’s radar, inspections have increased substantially — as have actual penalties. Congress, meanwhile, reintroduced H.R. 691, “Worker Protection Against Combustible Dust Explosions and Fires Act of 2013,” which would require the Secretary of Labor to address combustible dust issues.
What Is Combustible Dust?
OSHA describes combustible dust as fine particles — wood dust or wood flour included — that present an explosion hazard when suspended in air under certain conditions. The National Fire Prevention Assn. calls ComDust “a finely divided combustible particulate solid that presents a flash hazard or explosion hazard when suspended in air or the process-specific oxidizing medium over a range of concentrations.” NFPA is also the International Codes and Standards Organization that creates “voluntary consensus standards” used by building inspectors or fire marshals, known collectively as “Authority Having Jurisdiction” or AHJ. These are your local enforcers of dust rules.
In compliance inspections, OSHA now cites the “general duty clause” from the U.S. “Code of Federal Regulations,” [e.g., “SEC. 5. Duties. (a) Each employer (1) shall furnish to each of his employees employment and a place of employment which are free from recognized hazards] in classifying combustible dust violations. It levied a $5,000 penalty on one wood firm for not providing a place of employment which was “free from recognized hazards that were causing or likely to cause death or serious physical harm to employees in that employees were exposed to fire and explosion hazards caused by the presence of combustible dust.”
Another OSHA citation stated, “Layers of combustible wood dust were allowed to accumulate to depths over surface areas in quantities that exposed workers to fire and or explosion hazards.” OSHA referenced Title 29 CFR 1910.22(a)(1) from the U.S. Code. Part 1910 is the Occupational Safety and Health Standards; Section 22, General Requirements (a) Housekeeping: “All places of employment, passageways, storerooms, and service room shall be kept clean and orderly and in a sanitary condition.” In this case, combustible dust had accumulated on floors, I-beams and ceiling joists in direct violation.
Steps Toward Prevention
How you remedy the situation is important. This same citation also reported, “When combustible wood dust was cleared from surfaces, the employer used cleaning methods that increased the potential for a combustible dust deflagration and or explosion.” The employer used 30 psi compressed air to blow down and clear combustible wood dust; the current NFPA Standard calls for a low gauge pressure of 15 psi.
OSHA requires written rules and procedures and wants to ensure policies are fully understood and practiced by employees. In addition, NFPA Standards have detailed proper methods of operating procedures, inspections, testing and maintenance procedures as well as training, stating, “Safe work habits are developed, and do not occur naturally” enforcing the importance of a detailed training program.
One of the most important things any facility can do is fully engage in housekeeping and fugitive dust control. If underlying surface colors are not readily discernible, there could be a dust deflagration hazard.
If you can see the dust, clean it up — but do not blow off with an air gun. That simply releases and stratifies the dust. Instead, use a vacuum.
Then investigate to determine the source of the dust. If the ductwork is not airtight, then seal the joints to prevent the release of dust. When inspecting the workplace for dust accumulations, again review all flat surfaces including rectangular shaped ductwork, overhead beams, flat surfaced lighting fixtures, and all invisible areas such as hung or suspended ceilings.
Keep current on ComDust at airhand.com/combustibledust.aspx
Jamison Scott is executive vice president at Air Handling Systems and has over 20+ years of experience in the industry. He also serves on the Technical Advisory Board for Air Pollution Control and chairs the Industrial Dust Task Force for the Wood Machinery Manufacturers of America. He holds an MBA and is a licensed sheet metal contractor in Connecticut. For information contact (203) 389-9595, firstname.lastname@example.org; www.airhand.com.