Dust collectors are a necessity when it comes to day to day operations in many industrial applications to keep facilities clean and workers safe. While necessary, dust collectors also pose a risk of fire. It is important to understand why these fires start and how to mitigate the risk in order to maintain the safety and business continuity of your shop.
Fire hazards in dust collectors
If you know and understand the Fire Triangle, it is easy to see why dust collectors pose such a large fire risk. The first side of the fire triangle present in dust collectors is the fuel. From metalworking and woodworking to food processing, dust collectors constantly pull combustible dust off the shop floor. This dust, along with the filter material themselves, is a continuous source of fuel for the fire triangle.
The second area of the fire triangle present is oxygen. As the collector pulls the dust through, it is also pulling the air around it through at a high velocity. This means there is a constant source of replenished oxygen circulating through the dust collector. All that is missing is heat.
There are many things that can create heat to ignite a fire. In metalworking processes, such as welding, grinding, or cutting, sparks can get swept up into the dust collector and ask as the fuel to ignite a fire. Friction from processes can build up heat, which could build up enough to reach the flashpoint of the fuel within the collector.
Dust collector fire protection
To protect your shop and employees from the fire risks present, you need to ensure the proper fire protection measures are in place. Two options for dust collector fire protection is a handheld fire extinguisher or an automatic fire suppression system.
When manually fighting a dust collector fire with an extinguisher, the operator must first shut down the dust collector and wait 30 seconds. After waiting, the operator will need to open and access the interior of the dust collector. This can introduce more oxygen into the system, which could create a fireball upon opening. Additionally, having to wait to open the unit gives the fire significantly more time to build energy.
With an automatic fire suppression system, an operator does not need to intervene to suppress the fire. Upon detection of the fire, the system will release suppression agent at the source of the fire, before you realize a fire has started. Clean agents are the suppression agents used because they are nonconductive and noncorrosive, leave no residue, and will not harm the equipment or people. Watch a short video showing how automatic fire suppression works
It is important to note that fire protection is not the same as explosion protection – which will either isolate or vent the explosion. An automatic fire suppression system suppresses a fire that starts within the collector, usually around the filters. While having a handheld extinguisher present is a good back up measure, it is not ideal as the first line of defense against a dust collector fire. Dust collectors are enclosed systems, and it may be difficult to see when a fire ignites. An automatic fire suppression system will put out a fire before an explosion occurs or will put out a residual fire as the result of an explosion. This prevents further damage to the shop, equipment, and employees.