It’s always difficult to forecast weather, but if dry field conditions persist, the potential for combine and field fires this fall could be a problem. All it takes is a single high-temperature source in the engine area or an overheated bearing to ignite dry plant material.

During harvest periods with increased fire potential, fires cause millions of dollars in property damage in Iowa, including loss of machinery, crops and time. Injuries to farm workers and firefighters also are an unfortunate outcome in some instances.

Modern, high-productivity combines are powerful machines; and power means heat. Fire cannot start without heat and fuel. Heat cannot be removed from the engine, hydraulics and other hard-working systems, but it can be removed from the fuel source by keeping a combine clean.

Field Agronomist Clarke McGrath and Agricultural Engineering Specialist Mark Hanna with Iowa State University Extension and Outreach offer these prevention and management tips.

Prevention tips

• Keep the machine clean, particularly around the engine and engine compartment. Use a high pressure washer or compressed air to remove caked-on oil, grease and crop residue.
• Check coolant and oil levels daily.
• Check the pressurized oil supply line to the turbocharger for wear areas that rub and may start an oil leak.
• Frequently blow leaves, chaff and plant material from the engine area with compressed air or a portable leaf blower. Doing this at night is better than in the morning when dew may make it harder to blow residues off.
• Remove plant materials wrapped on or near bearings, belts or other moving parts.
• Examine exhaust or hot bearing surfaces. Repair leaking fuel or oil hoses, fittings or metal lines immediately.
• Inspect and clean ledges or recessed areas near fuel tanks and lines.
• Prior to fueling, wait 15 minutes to reduce the risk of a spill volatilizing and igniting.
• Delay harvest when wind speeds exceed 30 mph and conditions are dry.

Management tips

In case of fire, call 911 first and then attack with fire extinguishers if it is safe to do so. Try to fight from the “black,” the area already burned; attacking fire from areas with combustibles (stalks for example) is much riskier.

Create lists of the 911 addresses for each of your field locations prior to harvest and have them easily accessible to family and farm employees. Many fire departments have GPS equipment onboard their apparatus to assist directing them to incidents. When an incident is called in with a 911 address, dispatch can more readily identify the incident location and relay this information to apparatus drivers. Precious time can be saved when apparatus are able to dispatch immediately with GPS guidance rather than having to double check maps and directions.

A fire can double in size in less than a minute. Burning embers blown downwind can spread a fire well beyond the control of a fire extinguisher in just seconds. Two ABC-type fire extinguishers are recommended: a smaller 10-pound unit in the cab and a larger 20-pound extinguisher at ground level on the combine.

Invert and shake the extinguishers once or twice a season to ensure machine vibrations don’t compact the powder inside. A shovel to throw dirt can also help.

Create an emergency plan
Fires may start from plant materials that have smoldered unnoticed for 15-30 minutes or more. The ignition source for field fires may have been the earlier passing of a truck, tractor or combine. Flames aren’t apparent until additional oxygen is supplied, perhaps by a gust of wind. Harvest crews and neighbors may want to discuss a plan for emergency tillage of a fire break should that option become advisable. Keep in mind that personal safety is more important than property loss.

Source: Clarke McGrath and Mark Hanna, Iowa State University