There is an inherent fire risk for dust collectors. Class A and Class B particles provide fuel, oxygen rapidly replenishes, and friction or sparks create heat which completes the fire triangle and ignites a fire. Automatic fire suppression systems provide fire protection and minimize damage caused by quickly suppressing the fire without human intervention. When installing a dust collector fire suppression system, a few factors will contribute to the selection process. You will need to consider either a low- or high-pressure system, and what is the best suppression agent to use?
There is no absolute correct answer as to which fire suppression system to install. Conventional wisdom says to protect a dust collector with a high-pressure carbon dioxide system. CO2 systems have high coverage areas, so you don’t need to wait for the dust collector’s ventilation to run down before pumping in the agent. A single system can protect larger dust collector. Furthermore, CO2 is also extremely cold when it discharges, cooling the heat of the fire.
However, depending on the specific dust collector and manufacturing or precision machining environments, other systems and agents may be more appropriate. Indirect-release, low-pressure systems using a clean agent are often used to protect dust collectors. Clean agents are nonconductive, noncorrosive, and leave no residue. After the system discharges, the dust collector is not damaged, and there is minimal downtime before it is up and running again. Unlike CO2, clean agents do not pose a health and safety risk to employees.
Indirect-release, low-pressure systems with dry chemical are also an option to protect dust collectors from fire. These systems are most common when Class B fires are the primary risk. Dry chemicals will coat the dust collector’s filter, preventing the fire from spreading. If the ventilation in the dust collector cannot quickly and easily be shut down in case of fire, dry chemical is likely the best option.
Before you make the final decision, always refer to the safety data sheet (SDS) for the material going into the dust collector which poses the fire risk. Regardless of whether the potential fuel is metal, wood, oil, or something else, the SDS will contain more information to inform your decision. Some SDSs will explicitly state which agent to use for fire suppression.