Combustible dust is tiny particles, less than 0,5 mm, many practically invisible, with potentially hazardous effects. Combustible dust is a by-product of the manufacturing process of combustible raw material s.a. wood, grain, many chemicals and light metals. The dust can become explosive under certain conditions. Many industries are affected and need to take actions to prevent accidents causing injuries to employees and damages to facilities. In this blog article, I will introduce you to what combustible dust is and describe a few ways for you to prevent it.
What is combustible dust?
Processing of combustible raw material creates combustible dust. The dust has 1000 times or more larger surface, which results in a very quick combustion if ignited. This results in pressure increase and explosions in enclosed spaces.
Fine particles suspended in / mixed with air can be ignited when the concentration is above a threshold value. The value for many dust types is so high that normal view is obstructed, so this is normally not the main risk at workplaces. The main risk at workplaces is typically dust layers that become suspended in air by a sudden movement or cleaning with pressurized air.
Dusty processes are traditionally polishing, blasting, grinding, crushing, milling, transportation of granulates etc. Dust is also created in many processes using high-speed tools to achieve very smooth surfaces such as sawing, grinding and cutting. Also 3D-printing with powders generate dust that can be combustible.
Organic dust materials are explosive, such as wood, flour, sugar, grain and soybeans. Also, particles from pharmaceuticals and pesticides as well as rubber, textiles and plastics can be explosive. This even accounts for materials such as aluminum and iron that are not combustible in larger pieces but can be when in dust form. The US Occupational Safety and Health Administration (OSHA) has created a comprehensive list of materials that are combustible.
ATEX directive to create a safe working environment
Because such a wide variety of materials can cause explosive dust, many industries and workplaces are affected. Therefore, employers have a responsibility to take actions that protect their employees from any risks. To facilitate this process, the European Union has established two ATEX directives: The Employer directive and the Supplier directive
The directives describe what kind of work environment and production equipment that are allowed in areas with an explosive atmosphere. As of July 2006, all workplaces in the European Union must be compliant and the routines have been adopted by many other countries as well. The US is taking similar safety measures, according to the NFPA 652 Combustible Dusts Fundamentals standard.
Identify explosive atmospheres and choose the appropriate equipment
Dust can pile up almost anywhere in a workplace. Inside, on and around of machines and produced items. Rafters, roofs, suspended ceilings and ducts are also common areas, partly because they are located remotely and hard to reach. According to the ATEX directive, employers must investigate where in a workplace dust is created and whether it is combustible or not.
Dust production shall be minimized by selection of appropriate production methods, machines and tools. Areas with an explosive atmosphere needs to be specifically zoned and require ATEX educated employees. And correct ATEX marked equipment must be used within the area. As a spark or a hot surface can start an explosion, it is important to use machines and production equipment that have no sources of ignition and are equipped with adequate earthing. Above all, good housekeeping of the workplace is absolutely required.
Capture, contain and clean - Housekeeping routine to prevent combustible dust
With the right routines, it is easy to prevent combustible dust hazards. At Nederman, we use the model “capture, contain and clean” as a guidance to ourselves and our customers. The first step is to capture the dust right at the source, before it spreads into the work area. This is done by using approved and maintained dust collection systems. When the dust is captured, it shall be contained in equipment with appropriate ATEX safety systems. This will, correctly built and operated, ensure safe handling of combustible dust.
Last but not least, keep the work areas tidy and clean. By regularly removing dust that has not been captured or contained you prevent it from building up and becoming a risk. This includes hard-to-reach places such as overhead surfaces as well as narrow and concealed areas.
A professional combination of these methods and working procedures result in high safety and efficient, clean production. And reduced investments due to limited size of zoned areas.
Expertise and ATEX-compliant equipment and solutions
At Nederman, we have vast experience when it comes to developing and providing solutions for handling harmful particles, fibers, dust, gases, smoke and oil mist. Including combustible dust. We can help you create a safe and sustainable working environment by recommending and offering suitable equipment and routines. The solutions we offer are based both on your risk evaluation and compliance with the ATEX directives.
I hope you enjoyed reading this article and learned something new to prevent the hazards of combustible dust in your workplace. Do you need further information or have any questions?
In the below video, you will get to know how to determine whether your wood waste is explosive or not. Also, feel free to contact us to learn more!