A few steps to preventing header fires
With research showing an average of 12 harvesters are burnt to the ground every year in Australia, agricultural engineers encourage care in keeping headers clean to reduce the potential for crop and machinery losses
- Most harvester fires start in the engine or engine bay
- Others are caused by failed bearings, brakes and electricals and rock strikes
- Regular removal of flammable material from the engine bay is urged
The last thing anyone needs at harvest, when the whole season is on the line, is for a header to burst into flames, destroying itself and potentially a large area of crop as well.
On average, fire destroys about 12 harvesters a year in Australia, but studies show the risk can be greatly reduced if growers or contractors adopt a few basic precautions.
Agricultural engineering and harvesting expert Dr Graeme Quick says there needs to be systematic preparation and prevention procedures in place, using equipment such as a high-capacity air compressor with air lances or an automated engine blowdown system. He says harvesters should also be fitted with at least two fire extinguishers.
On machines without an automated engine blowdown system, Dr Quick says it can be necessary to remove flammable material from the engine bay as frequently as every 30 minutes or every time the chaser bin is filled.
Dr Quick, who completed a GRDC-funded research project investigating harvester fires, encourages growers to avoid harvesting on high-fire-risk days because extremely hot engines combined with flammable crop dust and large crop throughputs are ideal conditions to spark a blaze.
The potent combination to cause fire hazards is high air temperature and wind speed, low humidity and dry crop matter.
Dr Quick’s research showed the most common cause of harvester fires is material collecting on hot engine components such as the manifold, turbocharger and exhaust. Once ignited, embers can blow into other parts of the machine or drop to the ground causing spot fires.
He says an extensive US study over 15 years showed that 77 per cent of harvester fires start in the engine bay. As such, Dr Quick says operators need to be diligent with clean down, using every means possible to avoid the accumulation of flammable material.
He says other fires are initiated because of problems with failed bearings, brakes and electricals and rock strikes.
Diesel engine exhaust temperatures can reach 650ºC and exhaust surface temperatures can approach 500ºC.
While crop residues can ignite at temperatures above 200ºC, Dr Quick says insulating muffs may bring the exhaust’s surface temperature down to 250ºC or lower.
Kondinin Group engineer Josh Giumelli, who has also independently investigated the causes of harvester fires, says periodic temperature checks of bearings and other moving parts can help locate hot spots.
Handheld infrared thermometers (priced from $50) allow readings to be taken from a distance or while standing on the ground, keeping operators away from moving parts.
“If a bearing is approaching 200ºC there’s something wrong,” Mr Giumelli says.
Dr Quick encourages growers to double their service, maintenance and cleaning efforts on hot, dry, windy days.
Some crops, such as chickpeas, sunflowers, lupins and lentils, are more flammable than others. Dr Quick suggests removing dust and debris even more regularly when harvesting these crops.
He also encourages growers to place a fire unit in the same paddock in which the harvester is working and to make sure workers know where fire-fighting equipment is located and how to use it.
Mr Giumelli agrees, adding that the ute and chaser bin need to carry large water extinguishers. “It also helps to have a dry-powder chemical extinguisher in case of a fuel or hydraulic oil fire.”
“In the event of a fire, open communication between harvester operators, chaser bin drivers and truck drivers is vital for a rapid response,” Dr Quick says.
Mr Giumelli says growers may wish to consider fitting fire-suppression systems to their harvesters. “Having a button on the dash that the operator could hit to drench the machine or the engine bay in fire retardant would help reduce the chance of burning a header to the ground,” he says.
An example of an alternative treatment is Fire Knock Out. The product is placed in, for example, the header’s engine bay. If a fire starts, a self-actuating device is triggered and the contents are dispersed rapidly to extinguish the fire.
Dr Graeme Quick
07 5494 9920
For a report on harvester fires, see www.grdc.com.au/Harvester-Fires-Report
GRDC Project Code DGQ00003
Region National, Overseas