Combustible Dust Safety Standards and Hazards

about combustible dust hazards

Combustible dust explosions form under a variety of conditions: explosive dust is present, airborne, in a concentration of explosive range, the atmosphere supports combustion, and an ignition source is present. It is not only the initial explosion that presents a danger; secondary dust explosions caused by fugitive dusts (dust suspended in the air, and/or in hidden places- such as on beams) often create the most damage and fatalities. Due to their volatility a comprehensive mitigation strategy is required to prevent losses, encapsulating housekeeping, ignition control, dust hazard analysis and compliance and more.

Some examples of combustible dusts include flours, grains, hops, sugars, charcoal, lactose, aluminum, wood dusts, rubbers, etc. Most natural and synthetic organic materials can form combustible dust, including metals. Combustible dusts are present many industries, but some are more vulnerable than others, including:

Food, grain and beverage
Pharmaceuticals
Mining and metal products
Manufacturing
Pulp and paper
Wood processing
Textiles

The Chemical Safety Board (CSB) concluded that between 1980 and 2005, there were 281 combustible dust incidents, excluding grain facilities. These killed 119 workers, injured 718 workers, and severely damaged the industrial facilities affected. OSHA's Grain Study reported (for the same years) 500 grain explosions, 180 deaths, and 675 injuries.

combustible dust losses

One of the earlier-recorded combustible dust explosions in history occurred in 1878 at the Washburn A Mill, which produced flour for General Mills. The blast, caused by a buildup of flour dust, killed 18 people and destroyed neighboring mills, and city blocks. This incident brought the dangers of combustible dust to light and prompted better safety and ventilation systems in factories.

A more recent case involving combustible dust occurred in 2008 at the Imperial Sugar Refinery in Georgia. Due to oversight of safety and housekeeping standards, a large amount of combustible sugar dust caught fire, rapidly spreading through the entire facility. The explosion resulted in 14 deaths, 38 injuries, and destroyed the plant. Imperial Sugar was cited with 124 safety violations (no charges were brought up) and posted a $15.5 million loss, primarily due to the explosion.

safety standards to prevent combustible dust explosions

There are four primary National Fire Protection Association (NFPA) codes that deal with and provide regulations for organic dusts:

NFPA 61: Standard for the Prevention of Fires and Dust Explosions in the Agricultural and Food Processing Industries
NFPA 652: Standard on the Fundamentals of Combustible Dust which now requires a DHA for existing processes and facilities by September 2020
NFPA 654: Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Solids
NFPA 664: Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities

OSHA's Grain Handling Facilities Standard (29 CR 1910.272) and its Combustible Dust National Emphasis Program (NES) also work towards reducing risk.

the importance of housekeeping and ignition control

At the heart of combustible dust safety lies housekeeping. Most combustible dust-related incidents are caused by accumulations of dust over an acceptably safe level. Combustible dust ignites when concentrations of the particles are brought into contact with a heat source. The ignition spreads to fugitive dust, causing secondary explosions. As such, dust layers as thin as 1/32 of an inch can be hazardous.

Cleaning of facilities is key to preventing accumulation of dust; it should be done at regular intervals, and in ways that do not produce dust clouds. Proper ventilation systems, as well as dust collection systems and filters also minimize the chances of dust escaping into the facility and sparking ignition.

Ignition control is also important when considering housekeeping. Engineered solutions such as appropriate wiring methods and electrical equipment, control of static electricity using bonding, and separator devices assist in preventing hazards. human-element solutions are also critical, and often cost-effective:

Control of smoking, open flames, and sparks
Control of mechanical sparks and friction
Proper use of industrial trucks
Proper use of cartridge actuated tools
Adequate maintenance of all tools can help prevent ignition of dust

expertise in dust hazard analysis and dust explosion prevention

TÜV SÜD Global Risk Consultants (GRC) experts are on-hand to assist you in identifying your fire and explosion risk exposures. We assist you in implementing a proactive risk management plan in case of such events.

Our dust hazard analysis and assessment services are designed to be up-to-date and thorough assessments of your facility. We offer comprehensive dust hazard services, from planning to completion, as well as explosion protection compliance services for international regulations. Our independent risk management services are unbundled from insurance providers, so you can be assured that the loss control inspections and services are customized to your needs, while meeting all regulatory standards.