Dry Field Conditions Increase Harvest Fire Risks



AMES, Iowa—The National Weather Service issued a red flag warning for fire danger for western Iowa counties on Tuesday and Wednesday of this week and warned farmers to be careful as risk of field fires rises greatly in dry, windy conditions. An elevated fire danger exists in much of the rest of Iowa and will continue through the work week.

Harvest is a prime time for fire dangers, even if the weather has not been warm and dry. Fuel sources such as leaves, stalks, husks, dust, oil and fuel are always present when harvesting fields, and so are numerous sources of ignition on farm equipment or transport vehicles including exhaust, bearings and electrical wiring.

“A combine or tractor fire can halt harvest activities in an instant,” said Mark Hanna, Iowa State University Extension and Outreach agricultural and biosystems engineer. “Unfortunately, equipment fires happen all too often in Iowa, causing millions of dollars in property damage, lost time and crops during one of the busiest seasons of the year.”

Fire safety in the field has two key components -- prevention and preparation in case a fire does break out, according to Hanna. "Both are important, and can mean the difference between disaster and controlling the situation for a minimum of damage or work stoppage."

Hanna offers these tips to prevent combine fires:

  • Keep a clean machine, paying attention to the engine and engine compartment where 75 percent of all machinery fires start. Use a pressure washer or high pressure air to remove caked-on grease, oil and crop residue.
  • Check engine fluid levels (such as coolant and oil) at the beginning of each day.
  • Check the pressurized oil supply line to the turbocharger shaft for areas that may rub from wear and start an oil leak.
  • Frequently blow leaves and chaff off the engine with compressed air or a portable leaf blower, and remove wrapped plant materials 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.

Hanna advises all operators to carry two ABC-type fire extinguishers: a smaller 10-pound unit in the cab and a larger 20-pound extinguisher at the ground level on the combine. Invert the extinguishers once or twice a season and shake them to ensure that powder inside the extinguisher hasn't compacted by machine vibrations. He also suggests that operators carry a shovel to scoop dirt onto a fire and a cell phone to call fire department personnel.

In addition to the combine, Hanna said grain transport or pickup trucks with exhaust systems below the chassis also can ignite field fires. Catalytic converters operate at several hundred degrees.

"Field fires are sometimes started with the passing of a truck, and flames may not be noticed for 15 to 30 minutes," he said. "It's a good idea to not allow extra truck traffic through the field when conditions for fire are favorable."

The slight chance of thunderstorms in the forecast for western Iowa Saturday, spreading east on Sunday and Monday, is no reason to relax. Farmers should remain vigilant throughout this extremely warm, dry harvest season.

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