When food products are manufactured indoors, small particles often become airborne and have the potential to do serious harm to people, products, equipment, and facilities. Dusts that are combustible can cause fires and explosions. Other dusts can contain ingredients that are harmful when swallowed, inhaled, or come into contact with skin. Dust also can cross-contaminate other products that are manufactured in the same facility. When combustible dusts are collected from the air into a dust collection system, the system itself can be a source of combustible dust explosions if not properly protected.
Here are frequently asked questions about controlling food dusts in order to maintain a safe work environment.
Q. What are common dust hazards in the food processing industry?
The biggest threats are occupational exposure and combustible dust explosions. Dust can cause dermatitis and allergic reactions. More seriously, dust particles can become embedded in the lungs and can cause respiratory problems like asthma—and even cancer. In addition, many solid food ingredients are combustible, including sugar, starch, spices, proteins, and flour.
Airborne dust particles also can damage other food products. For example, particles that contain gluten or peanuts could cross-contaminate products that are supposed to be free from these foods, causing severe allergic reactions for customers who trust those product labels.
Q. Which agencies regulate dangerous dusts?
The Occupational Safety and Health Administration (OSHA) is ultimately responsible for protecting employees from dangerous dusts. OSHA requires companies to control dust emissions in indoor workplaces and to comply with legal limits set for each ingredient and material. If no legal limits are applicable, the company must define in writing and implement and measure its own environmental safety plan. FDA’s Food Safety Modernization Act requires food processing facilities to implement measures to prevent or minimize contamination hazards.
In addition, the National Fire Protection Association (NFPA) plays a major role in recommending standards and guidelines for managing combustible dusts. If manufacturers do not follow these guidelines, they can be fined by OSHA, face legal scrutiny, and risk a damaged reputation—not to mention harm their employees.
Q. What equipment is used to capture hazardous food dusts?
Industrial dust collectors are used to capture and contain dust and other harmful particles from the air in plants, factories, and other processing facilities. Much of this airborne dust is too small to be seen with the naked eye. Collectors capture dust by continually cycling the dust-laden airstream through a series of filter cartridges. The dust remains on the cartridges, and the clean air is returned to the work environment.
Systems for high-volume dust collection capture food dust at the source using stainless steel pickup hoods at each production station. Whether attached directly to batch mixers or high-velocity slot hoods behind weigh stations, ducting pulls airborne particulates into the dust collector. Ideally, dust collectors are placed in a location where dust can be effectively and safely discarded. Several other design features are used to control cross-contamination from food dust, including filter orientation, filter media, and filter design.
Industrial dust collectors can be placed inside or outside the manufacturing facility. If processing combustible dust, placing the dust collector outdoors is the safest option to vent away from buildings and populated areas in case of an explosion. However, it is not always feasible to place them outside. Dust collectors placed indoors must have the appropriate explosion protection system if they will be handling any combustible dusts.
Q. How does an explosion occur in a dust collector?
A dust collector is a closed vessel, and any closed vessel that is full of dry particles is ripe for an explosion. An explosion usually begins when a suspended cloud of combustible dust is present in high concentration inside the collector. As the fan draws in large volumes of air, an outside spark or ember can be sucked into the collector and collide with the dust cloud under pressure, triggering an explosion. The source of the spark may be a production process, an ignition source drawn into a dust capture hood, or a static electricity discharge from improperly grounded equipment nearby.
Q. How do you protect a dust collector from a combustible dust explosion?
First, it is important to have all collectors sized properly for the facility they will be handling. Second, it is important to understand that combustible dust explosions cannot always be prevented from occurring in the dust collector; however, systems can be put in place to lessen potential harm from an explosion. There are a variety of explosion protection options.