A fire starting in the header's engine bay can spread to the crop before it's noticed.
In the 10 to 12 minutes it usually takes to get water onto it, a crop fire can grow to 80 metres by 100 metres. On a day with 35km per hour winds a crop fire can grow to 10 to 15 hectares within 30 minutes.
Causes of harvester fires
Harvester fires can start from a mechanical fault like faulty bearings, hydraulics or brakes. But the vast majority of header fires start in the engine bay where dust and debris are blown by cooling fans, igniting on the hot exhaust manifold or turbo.
Preventing harvester fires
Prevention starts before the harvester even rolls
You should make fire safety a part of your harvest management plan.
- Talk to everyone working on your property during harvest so they know the plan:
- their responsibilities,
- where fire equipment will be located,
- how to react if there is a fire,
- who to call, and
- how to use UHF radio.
- You're in charge on your property and you're responsible for safe operations. All contractors on your property need to know what you expect from them.
- Plan where water carts will be positioned within the paddock. Many crop farmers have more than one. A water cart should be a dedicated resource.
- Maintain two-way communication between the harvest operator and people on the ground.
- Check all fire extinguishers are in place and are fully charged. Include dry powder extinguishers on all your vehicles and large water extinguishers on the header.
- You should create four-metre fuel breaks around the harvest area. This will help contain a fire should one start.
- During harvest you should not let the harvester get too far away from the water cart as you'll need to get water onto a fire quickly.
Maintaining your harvester to prevent fires
Having a pro-active maintenance and inspection routine will not only help reduce fire risk, but will also cut down your machinery downtime and prevent expensive repair bills.
Get to know your headers. Different makes and models can have different problem areas for fire. Talk to dealers and other growers to find out where your machine's fire risks are. Factors such as engine bay location and layout can make a difference.
When inspecting your harvester, pay close attention to risk areas like dust traps, rubbing or slipping belts and failure prone bearings.
During harvest operations the operator should take time to clean down the machine. The timing of this regular cleaning will depend on the crop type and how hot the day is. For example, lentils and lupins require more frequent clean downs as these crops are more prone to fire than cereal crops because the residue more easily sticks to hot surfaces. A harvester clean down can take minutes using a high-capacity air compressor with a long hose:
- Ensure you're wearing appropriate safety equipment like a dust mask and eye protection.
- Open the appropriate panels leaving the engine cover closed at first.
- Starting from the top of the harvester blow the chaff and dust off the machine.
- Once completed, repeat the process in the engine bay which is the most important area to keep clean.
- Once the top is cleaned down, move to the ground, open the panels, and blow out the dust and debris to ensure the harvester is thoroughly cleaned.
Fire safe harvesting practices
A fire typically happens when you get a build-up of dust and debris on the exhaust manifold or turbo. To meet emissions regulations, exhaust temperatures of modern equipment are much hotter than older machines. Exhaust manifold temperatures can exceed 600oC. Twice the temperature required to ignite crop dust.
Backing off your ground speed one or two kilometres per hour can reduce these temperatures to below ignition point for most crops. A good strategy is to slow down when wind is blowing dust and debris into and around the header. This will usually be when you're harvesting downwind. If necessary you can speed back up again when harvesting into the wind.
When to cease harvesting
The prevention of fire, and early suppression of accidental fires are likely to reduce damage to crops and machinery as well as, protecting life and property.
By monitoring conditions before and during harvesting, you can cut down the risk of fire.
Suspend harvesting operations when the local conditions are hot, dry and windy. CFA has worked with the Victorian Farmers Federation to develop the Voluntary Grain Harvesting Guide. This tool provides a simple way of checking when weather conditions become too dangerous for harvesting operations to continue. By simply comparing the current temperature and relative humidity (RH), you can find the wind speed that corresponds to extreme fire risk. You should stop harvesting when the average wind speed exceeds that level. Download the Voluntary Grain Harvesting Guide (PDF 162.8KB). Stickers for use in the cabin of your equipment can be obtained from your CFA District Office.
The guide applies to all grain harvesting and grain handling operations that occur "in the paddock", including operation of grain harvesters, vehicles involved in transporting grain, grain dryers and grain augurs.
The following video provides some useful tips on avoiding harvester fires.
Preventing Harvest Fires (PDF 749.5KB)
Page last updated: Friday, 11 August 2023 12:42:21 PM