Reducing the potential for combine harvester fires should be front of mind for all grain growers and contractors as they embark on reaping this year’s crops.
The Grains Research and Development Corporation (GRDC) and farm machinery safety authorities are reminding harvester operators to implement fire prevention and safety measures and exercise caution over the coming months. They say Australian broad acre harvest conditions in some seasons are arguably the most hazardous in the world for fires.
Internationally-recognised agricultural engineer and harvester expert, Dr Graeme Quick, says the most common cause of harvester fires is in the engine bay, where material can collect on hot components such as the exhaust manifold and turbocharger.
“Crop materials collecting or clumping on hot components can ignite, then embers can drop down or are blown around the machine and into the crop to cause smouldering and spot fires,” said Dr Quick, who has investigated combine harvester fires over the past two seasons.
Supported in his research by the GRDC, Dr Quick said the key to avoiding harvester fires was diligence in clean down and inspection, and postponing paddock work during periods of extreme fire risk: low humidity, high winds and vulnerable crop conditions.
“Suitable equipment and operator diligence in a fire-prone environment is critical, and this calls for systematic preparation and prevention procedures.
“Preventative and precautionary measures are essential in limiting the fire risk.”Dr Quick said all operators should equip their machines with at least two fire extinguishers. A high capacity air compressor with air lances should be on board or at hand.
“Regular blowdowns are essential and in the worst conditions a blowdown may be needed as frequently as every half hour, or on each bin round.”
Dr Quick canvassed professional advice and industry opinions in Australia and the United States about combine fires, before investigating harvester fire incidents in southern Queensland, northern New South Wales and on the Yorke Peninsula in South Australia.
From his research, Dr Quick said apart from the engine bay, other causes of harvester fires included failed bearings or brake problems, electrical faults, fluid leaks and rock strikes.
“Incidentally, the evidence does not support static electricity as a prime cause of harvester fires, so that's another reason for extreme care in harvester hygiene.”
Combine harvester fire hazard reduction checklist
- Recognise the big four factors that contribute to fires, namely relative humidity, ambient temperature, wind and crop type and conditions. Stop harvest when the danger is extreme.
- Redouble service, maintenance and machine hygiene efforts at harvest on the days more hazardous for fire. Follow systematic preparation and prevention procedures.
- Use every means possible to avoid the accumulation of flammable material on the manifold, turbocharger or the exhaust system. Be extra wary of side and tailwinds that can disrupt the radiator fan airblast that normally keeps the exhaust area clean.
- Be on the lookout for places where chafing of fuel lines, battery cables, hot wires, tyres, drive belts etc, can occur.
- Avoid overloading electrical circuits.
- Periodically check bearings around the front and the machine body. Use a hand-held digital heat-measuring gun for temperature diagnostics on bearings, brakes etc.
- Drag chains, or better still drag cables or grounding conductors, may help dissipate electrical charge but are not universally successful in all conditions. In certain conditions a drag chain could even start a fire from rock strikes. On the other hand there are some invaluable fire-suppressing options on the market.
- Use the battery isolation switch when the harvester is parked. Use vermin deterrents in the cab and elsewhere, as vermin chew some types of electrical insulation.
- Observe the Grassland Fire Danger Index (GFDI) protocol on high fire risk days. Don’t jump to a conclusion that static electricity is a cause of fires; the evidence doesn’t support this as a prime cause on harvesters.
- Maintain two-way contact with base and others. And keep an eye out for hazards on machinery during the season.
The above checklist has been developed by Dr Graeme Quick and endorsed by the Grains Research and Development Corporation
Caption: Dr Graeme Quick was engaged by the GRDC to look at the causes of combine harvester fires.
Dr Graeme Quick
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0409 675 100