Farm Management

Harvester fires a particular risk in lentil crops

Lentils are a notoriously dusty crop to harvest. Photo by Ben White.

The 2016-17 harvest saw a significant incidence of harvester fires in Western Australia, but growers can minimise the risks in 2017-18 with good hygiene, inspection and maintenance.

Growers are also advised to be especially cautious when harvesting pulse crops, particularly lentils which, along with chickpeas, have the highest susceptibility to starting harvester fires.

This is the message from agricultural engineer Ben White, of the Kondinin Group, who has reported to the Grains Research and Development Corporation (GRDC) on harvester fires.

Mr White said while the area planted to lentils in WA was still small, it was an emerging crop with increased plantings in the Esperance port zone and new lentil growers might not be aware of the risk associated with this crop.

“Research by the late Graham Quick indicates lentil crops are up to five times more fire prone than wheat during harvest,” he said.

“The ignition temperature, which is the temperature at which a fire will start in crop residue, varies between crops and from year to year.

“While further research is needed to confirm it, factors that may increase the risk include mould, varietal and agronomic influences.”

Mr White said harvester fires could damage equipment, destroy crop and infrastructure and endanger lives.

To minimise the risk, growers needed to address the two ‘fire factors’ – fuel and ignition – and be prepared in the event a fire occurred.

Mr White emphasised the importance of harvester hygiene, saying more than a quarter of all harvester fires were caused by dust, chaff and straw build up.

“Lentils are a notoriously dusty crop to harvest, meaning operators need to exercise extra vigilance when it comes to hygiene,” he said.

“Clean down equipment regularly and do this even more often in dusty conditions.

“When dust is extreme, a clean down of every boxful of grain may be required.”

Mr White also advised lentil growers to follow the lead of South Australian growers who harvest into the wind so residue and dust is blown away from the crop yet to be harvested.

“This also reduces the risk of any incendiaries being carried into the standing crop, and instead blows it into stubble which, for lentil crops, has a very low biomass,” he said.

Mr White said static could arguably attract dust but did not have sufficient potential energy to start a fire in dusty conditions.

He said preventative maintenance was essential and growers should periodically check bearing temperatures around the harvester front and the machine generally.

“Monitoring bearings, which can be done with an infrared temperature gun, and logging them for temperature variations is important,” Mr White said.

To be prepared in the event of a harvester fire, Mr White said WA growers should have at least the locally prescribed amount of water (typically 750 litres) on site.

“It is preferable to have water on a trayback, which is easier to navigate and reverse when visibility is poor, but a trailer is acceptable as long as it is attached to a vehicle at all times,” he said.

“Make sure extinguishers on the harvester are in good working order and rotate powder types regularly to prevent clumping.

“I suggest having a set of water and powder extinguishers near the cab steps and in the engine bay.”

To reduce the risk of harvester fires this year Mr White also recommends:

  • Monitoring ambient conditions and the fire danger index
  • Following shire harvest bans and stopping harvest if local conditions approach a Grassland Fire Danger Index (GFDI) of 35
  • Considering heat shield or exhaust modifications, such as:
    • Exhaust paints or coatings including ceramics and alumina silica which can minimise dust adhesion and reduce hot component surface temperatures
    • Exhaust bandages and blankets which are designed to insulate exhaust components
    • Double skins on the exhaust system (which are insulative, like a thermos)
  • Ensuring an electrical isolator system is used
  • Ensuring the fuel system is well maintained
  • Considering installing an integrated fire suppression system
  • Maintaining and keeping airflow systems clear
  • Checking concave doors are well sealed (minimise dust leakage which may in turn contact hot surfaces and create incendiaries)
  • Ensuring your harvest team has a plan and knows individual responsibilities in the event of a fire
  • If your harvester does catch fire, pull out of the crop, face the machine into the wind and call 000.

Source: GRDC

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