Fire Safety 101: Combustible Dust
Every contractor knows the various dangers that dust can cause to their workers, especially in enclosed spaces. Respiratory issues, skin damage and even cancer can result. Another hazard involved with some dust, however, is that of an explosion. If you work with combustible dust materials, it is vital to understand these fire safety hazards and how to prevent combustion to reduce the potential for injury and mitigate your own liability concerns.
There are three main factors that go into a fire: heat, oxygen and fuel. The combustible dust in this case forms the fuel. If dust is present and dispersed in a large enough concentration and quantity, a process known as deflagration can result. In deflagration, rapid combustion occurs when dust particles are compressed in an enclosed space where pressure creates heat.
This process, which involves the three fire factors plus dispersion and confinement, form what is known as the “Dust Explosion Pentagon.” Even worse, after the initial explosion, more dust can be released into the air or a containment system can rupture, causing an even more massive secondary explosion.
Housekeeping and Inspection
It is vital to identify the fire safety risk factors of explosions to ensure that they don’t result in catastrophic accidents. Site managers and employees should be trained to assess the risk factors involved in materials handled, operations, spaces and ignition sources.
To control dust, regular and thorough inspections, housekeeping, cleaning and testing should be engaged to ensure that dust is properly filtered and collected. Ventilation systems and equipment should be maintained to minimize dust escaping into the environment. Cleaning methods should be carefully considered so as to not result in clouds of dust, and proper vacuum cleaners that meet Occupational Safety and Health Administration (OSHA) standards should be used to collect particles.
During inspections, ignition hazards should be assessed as well as the presence of dust, to make sure that fire safety requirements are in place. All electrical equipment and wiring should be carefully and properly insulated. Steps such as ground bonding should be taken to avoid static electricity. All heat, heated surfaces and open flames should be kept far and separate from the areas where dust might collect. This includes smoking by workers.
Even vehicles can create an explosion hazard. It’s important to understand that anything that creates heat or sparks can result in an explosion if combustible dust is present. All tools and equipment should be used properly and all workers should be thoroughly trained in the right policies and safety procedures to avoid ignition. This includes the use of fire suppression and explosion protection systems in case ignition does occur.
OSHA maintains safety and data sheets for a broad variety of workplace risks, which outline not only the rules and regulations employers must meet, but suggestions for emergency preparedness and mitigating disastrous situations. Contractors should be well-versed in these issues and carry the proper liability insurance.