Only You Can Prevent Combine Fires

By Dale Risula, P.Ag. Provincial Specialist for Special Crops, Pulses, and Forages, Crops and Irrigation Branch, Regina

When crops are harvested under low moisture levels, they become more combustible. Crops will have increased “fines” (finely crushed or pulverized material) due to the dry state they are in.

To reduce the potential for fires, the following are some practical measures that producers can use: blow dust, chaff and fines out of machinery during times of unloading or stops in the field; check for embers or the smell of smoke before parking machinery; and ensure that you carry fire extinguishers as standard equipment on your equipment.

Accumulated chaff from a previously harvested operation or dust not thoroughly cleaned from areas around the combine’s manifold or exhaust is potential fuel to start a fire. Search and clean all compartments or ledges within the combine that can harbour dust, chaff or fines that accumulate during harvest season to prevent a fire hazard.

Other factors that can contribute to a fire in harvest equipment include malfunctioning bearings or equipment problems where machinery component temperatures increase to extremely elevated levels.

Dust residues from various plant diseases are a contributing factor adding to potential fires during harvest operations. Sunflower seed growers have noticed that when there is significant sclerotinia in their sunflower crops the hazard increases. Pulse crops heavily infected by disease may emit fibrous dust particles, which increases the risks for combustion during harvest operations.

Environmental factors that contribute to fires include low relative humidity, high ambient air temperature, wind and very dry crop conditions. It is recommended to stop harvest when these conditions exist.

Desiccating plants can cause plant material to dry faster than drying naturally. Be aware when using diquat that this herbicide is activated by sunlight and will dissolve plant tissue and cause rapid moisture depletion.

Other causes of equipment fire include minor oil or diesel leaks, which ignite when they contact turbocharger or exhaust manifold, and sparks from collisions with rocks or other equipment. Early seeded crops are often harvested in August when temperatures can reach or exceed 30 C so fire risks can be high.

Reduce fire hazards, be aware of your surroundings and look for signs of fire before it gets too large. The smaller the fire, the easier it is to put out with an on-board fire extinguisher. If not, extensive damage is likely to result to the machinery and surrounding area.

Many farmers have water trucks or tillage equipment on site as a precautionary measure. However, when a combine fire starts, it can spread very quickly to the field and using water trucks or tillage equipment can be difficult. The quick action of an onboard fire extinguisher is more appropriate.

Dr. John Schutske at the University of Wisconsin who has studied combine fires extensively has an excellent website with a checklist that farmers can review to prevent combine fires.

Be safe and prepared in the event of a fire this harvest season.