Hot, dry cropfields tinderboxes for combine fires
Since the first powered machines were introduced to agricultural production, fire has been a common threat. In fact, one of the first combines built and used successfully in North America was destroyed in an 1856 fire caused by an overheated bearing as it was harvesting a field of California wheat.
Because of their many hours of operation and the dry fodder that can collect on the machine, combines are especially vulnerable to fires, said Gail Deboy, Purdue University farm safety specialist.
During hot, dry weather very dry fodder provides an excellent source to fuel a flame whenever a fire is ignited, Deboy said. This year's early planting led to early maturing crops and, subsequently, unusually dry foliage at the beginning of harvest.
Researchers estimate 695 combine fires occur each year, at a total machinery loss of $10.5 million, Deboy said. The loss figure does not include lost production time, crops or leasing of replacement machinery.
"Machinery fires can be caused by a wide variety of agents, including overheated bearings and belts, exhaust components, clutches and brakes; electrical malfunctions; and sparks caused by damaged or improperly adjusted components and foreign material entering the processing path," Deboy said. "Even crop material that is plugging or wrapped around drive components can be heated to the point of combustion.
"As combines have become larger, they carry much larger quantities of fuel, lubricants and hydraulic oil. Even small leaks in any of the systems that use these flammable liquids can result in a small fire becoming a large one in seconds. For example, a leak causing diesel fuel to be sprayed into the engine compartment of a tractor or combine can cause the compartment temperature to go from ambient to over 1.000 degrees Fahrenheit in seconds. Fires of that intensity are almost impossible to extinguish before the machine is substantially damaged."
Combine fires can spread to nearby farm equipment, crops, trees and buildings. Personal injury and death also are possible, Deboy said.
Farmers can reduce the risk of farm machinery fires, Deboy said. Preventative measures include:
* Regular maintenance. "Keeping the machine clean, free of crop residue and free of fuel and oil leaks will prevent most fires from starting and spreading," Deboy said. "Regular inspection and maintenance of bearings, seals, potential crop wrap points and exhaust systems will minimize potential ignition points. Servicing equipment at the end of the day rather than the beginning of the day will help detect overheating components and even slowly smoldering fires that might erupt in the night.
"Maintaining the electrical system -- especially components that draw heavy electrical loads such as starter motors, remote actuators and heating and cooling systems -- can help eliminate ignition sources. Fuses that blow regularly should be considered an important warning sign that a circuit is probably overheating somewhere."
* Installing portable fire extinguishers on every large piece of agricultural machinery. "They should be suitable for extinguishing types A, B, and C, fires and be suitably sized for the potential fires that may occur," Deboy said. "For example, large harvesting units should have at least two 10-pound, type ABC extinguishers on board. As with extinguishers in any rough usage setting, they should be inspected and serviced on a regular basis."
* Keeping a cell phone or two-way radio handy. "A small fire on the machine or in the field can be prevented from becoming a big fire if emergency personnel can get to the scene early enough," Deboy said.
"Every fire has a cause and involves three elements: an ignition source, fuel and oxygen. By removing any one of these elements. a fire is prevented. As you examine the combine or any other agricultural machine or building, consider the potential for each element and where they are likely to come together to form a fire."
Additional information on preventing combine fires is available from the Centers for Disease Control and Prevention's National Ag Safety Database. The database can be found online at http://www.cdc.gov/nasd/ .