Prevent combine fires during sunflower harvest

Photo Credit:

NDSU photo

Use an air compressor to clean off debris, chaff and dirt from the combine to prevent combine fires. (NDSU photo)

Dry, low-humidity conditions increase the risk of combine fires, especially during sunflower harvest.

Mix warm, dry harvest conditions with high wind speeds, and you have a recipe for fires, especially when combining sunflowers.

Autumn is one of the windiest seasons that North Dakota experiences. Producers can monitor current wind speeds, temperatures and humidity values, which are updated live every five minutes at https://ndawn.info/.

The high wind speeds and the large amount of extremely dry plant material in our fields and grasslands create perfect conditions for fire when provided with an ignition source, such as the hot exhaust from the combine’s turbocharger or exhaust manifold. These components can reach temperatures of over 1,000 degrees Fahrenheit. Additionally, electrical malfunctions in the plastic wiring harnesses on the combine can also create electrical shorts or arcs, which can also start a fire.

Combine fires can occur at any time with any crop in the right conditions. Sunflowers, however, pose a greater risk because of the large volume of dust and particulate they produce while being harvested.

Research from South Dakota State University shows that the white portion inside the stalk, known as the pith, breaks down into tiny, high-surface-area particles that easily get sucked into the fan as it pulls air through the radiator to cool the engine. That pith dust and particulate easily stick to the engine and exhaust components and can ignite when in contact with the turbocharger and exhaust system.

Use the following tips for reducing the risk of combine fires while harvesting sunflowers:

• Preoperational checks. Take time to walk around the combine before the start of each day during harvest season. Use an air compressor or leaf blower every day when the machine is off and cooled down to remove dirt, dust, chaff and other plant residue; always wear hearing, eye and respiratory protection, such as an N95 mask, when doing so. Look for residue in high-risk areas, such as the engine and engine compartments, exhaust systems and fluid systems, such as hydraulic pumps, pump drives and fuel lines. In addition, monitor electrical systems, such as fuse boxes, gearboxes, batteries and cables. When cleaning, take time to look for any issues that require repair, such as leaking hydraulic hoses that can be a perfect place for chaff to stick and build up, creating an easy fuel source for a fire.
• Maintenance. Take time to service the machine daily, based on the combine’s operator manual. Grease and lubricate bearings and chains, and continue to look for areas that have excessive wear or damage.
• Watch for wiring issues. Today’s combines are controlled by many sensors and highly complex electrical components. Take time to glance through the wiring systems to see where wires appear unrestrained or damaged from rubbing or contact with moving parts.
• Monitor gauges and warning signs. If you notice increased fuel consumption, loss of hydraulic pressure, fuses that regularly fail or “blow out,” or higher-than-normal temperature gauge readings, stop and determine the cause, as these are serious warning signs that something is malfunctioning.
• Use an infrared thermometer. Warm up the combine before taking it to the field, and use an infrared thermometer to determine the operating temperature of your combine’s bearings. Open the combine’s shields, and from a safe distance, point the infrared thermometer at a bearing to read the measured temperature. If the thermometer measures a bearing’s temperature that is much higher than others, it is time to replace that bearing, as it may be worn or damaged. Infrared thermometers are inexpensive (less than $50) and can be found at many hardware and farm stores. Hot bearings are a combustion source.
• Install an air intake kit. An air intake kit allows clean air above the combine’s “dust cloud” to enter the combine’s air intake screen, rather than dusty, dirt-filled air produced by harvesting. Avoid combining during fire danger conditions. Believe it or not, harvest conditions can be too good, meaning it can be too dry to combine. Relative humidity is low in the fall, increasing the risk of fire, especially in the late afternoon. Keep an eye on relative humidity values and wind speeds. As hard as it is to shut down for the day when conditions are favorable for harvesting, shutting down when relative humidity is low and/or when conditions are windy could prevent a fire. Find out if the area is in a fire danger zone by visiting https://ndresponse.gov/burn-ban-restrictions-fire-danger-maps.
• Cooling down for the night. Always allow equipment to cool down before parking it inside a shed for the night. Also, make it a safety practice to shut off equipment and allow it to cool before refueling.
• Carry fire extinguishers. Ideally, you should have two 20-pound, charged fire extinguishers on your combine. Have them ready and operational and review with workers how to use them when needed.
• Have a water truck in the field. If possible, bring a filled, ready-to-use water truck in the event of a fire.
• Create a soil perimeter. If harvesting during high-wind and high-temperature conditions, make a tillage pass around the perimeter of the field to prevent a fire from spreading.
• Strategically park harvest equipment. While harvesting a field, park semis, trucks, pickups, tractors, grain carts and other equipment in a location with minimal vegetation. Hot exhaust from these vehicles can ignite dry grass in the ditch. Before parking equipment and machinery in a shed or quonset for the night, let them cool down first to reduce the risk of a building fire.

Does static electricity built up from combines cause a concern? Research at SDSU indicates that it is unclear whether enough static electricity accumulates on a combine to ignite crop residue. Some producers have attached a log chain to their combine and allow the chain to drag across the field. In theory, this is to reduce static electricity charges created from the moving parts of the combine. However, limited research shows whether this is an effective practice in reducing combine fires. In some cases, it is of more concern that dragging a log chain with the combine could cause a spark if the chain hits rocks on the field’s surface.