Grain bin fires commonly occur during harvest and are usually connected to drying operations. However, they can occur at other times. One cause can be that previously dry grain has gotten wet, for example from a roof leak, which can cause it to organically “heat up”. Another cause can be sparks generated from loading or unloading equipment.
Many fire agencies believe that the fire can be extinguished by applying large amounts of water into the bin via a top opening. This will generally not work and can exacerbate the problem.
First, there is no guarantee the water will reach the burning material as water will follow the path of least resistance. Second, adding water to already dry organic material will cause it to heat-up and spontaneously combust – in the same way a leak in the roof can cause a fire. It
can cause the grain to swell and push out the sides of the bin, creating a structural issue. Another problem created is that wet grain will crust creating additional danger for the farm owners/operators.
In any case of fire in a grain bin, completely unloading the grain bin, while a long and arduous process, is the only way to guarantee complete extinguishment. This is a combined effort of the fire department and the bin owner or manager. This is not only a combined effort but requires a very coordinated operation.
As the bin is unloaded watch for charred or hot grain or embers and water down those materials where it is exiting the bin. For this reason, firefighters will need to work with bin operators to make sure that fire is not inadvertently spread to bins or equipment during the unloading process by making sure the grain is being directed away from other parts of the operation. If possible, try to unload directly to a truck or grain wagon, or to the ground.
Firefighters should not enter a burning bin unless absolutely necessary. This may be necessary towards the end of the unloading operation, and if done remember that a grain bin is a confined space. If this is required, incident commanders must consider using personnel that have previous experience working around grain.
Burning or burnt grain should be separated from good grain coming out of the bin. Good grain can be salvaged for use. This grain may require “re-drying” before being placed back in the bin.
The bottom line is that grain bin fires are inherently stubborn and dangerous. Training in the proper management of grain bin fires is needed to ensure a safe operation for firefighters and to lessen the losses of the bin owner/operator.