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Combine Fires: Reducing the Threat

Thursday, August 22, 2013
filed under: Equipment

Gary Knell’s 2012 sunflower crop was looking good as harvest arrived. The Hazen, N.D., area farmer says it turned out to be one of the best crops he’s had in his 20 years of growing sunflower. But it was the harvest that almost didn’t happen.

On the first full day of Knell’s harvest, fire destroyed his combine.

“I shut the combine off at 7:00 p.m. The next morning, 13 hours later, my hired hand went back to the field to get the truck and didn’t see anything unusual. A short time later, the wind came up and the next thing we knew, the combine was engulfed in flames,” remembers Knell. “We saw smoke coming out back by the fuel tank. It was immediately engulfed. I think it had been smoldering all night, and once the wind came up the fire just took off. But the fact that the combine had been parked for 13 hours just baffles me.”

On the bright side, Knell was able to purchase a new combine and was up and running again in less than three days. Now, his new Tier 4 Case IH 8230 is part of a South Dakota State University study looking at combine fires—what causes them and how they can be prevented. A team of researchers in the SDSU Agricultural and Biosystems Engineering Department is working on this project, which is funded by the South Dakota Oilseed Council and the National Sunflower Association.

For Knell, the research has become personal. “I don’t want to lose another combine,” he says. “I’ve had fires before, but I’d never had one get away from me before, or one destroy my machinery. I know combine fires are more common during sunflower harvest, but I’d like to help understand why — and learn how to prevent them.”

Knell is one of four producers working with SDSU researchers this year. It’s the second year of the SDSU study, headed by ag engineer Dr. Dan Humberg. The study has three objectives: (1) to understand the basic characteristics of sunflower dust in the lab, (2) to see it in action in the field and how it interacts with different areas of the combine, and (3) to bring the data together to suggest potential engineering solutions that could serve to change or interrupt one or more of the factors present when a harvest fire starts. So far, the researchers say they’ve made progress, and even designed a device to keep sunflower dust from the hottest parts of the combine.

“We had a fairly successful experiment last year with a single combine,” Humberg says. “Now we are testing the device we created onto four different combines. We’re anxious to see how our device works on Knell’s Tier 4 combine because EPA rules that go into effect in 2014 will require new equipment to meet specifications of those machines.”

The device SDSU has designed (and has applied for a patent on) fits an enclosure around the exhaust manifold and the turbo charger of the engine—the two hottest components of the entire machine. Exhaust can get as hot as 1,000 degrees Fahrenheit, and researchers believe the fine sunflower dust goes through the radiator and into the air being blown over the engine. That means the dust is closer to the engine and often lands on the hot engine, where it starts to smolder. The device they’ve designed encloses those hot components, isolates them in a box and pumps fresh, clean air to the areas around the hot components. It also keeps sunflower dust out of the areas.

Humberg is confident this device works. “Last year we worked with a producer who, when he used the device, operated at full capacity with no fires,” says the SDSU ag engineer. “But when he combined without the device, he had several fires in several days. We think that’s proof it works.”

Humberg and his team are working hard now to get new systems together to put on several machines, including Knell’s new combine, this fall.

“Researchers will be coming up and retrofitting [the] combine with an air cleaner system. We’ll gather data for them during the harvest and keep as much information on how it’s working as possible because we do want to get to the bottom of the cause of these combine fires,” says Knell.

For Humberg, there is also work to do in the laboratory. His team has completed some lab work that helps back up their theory that most fires start at the exhaust manifold. They’ve done some work with electric sparks to see whether static electricity is a cause. Their lab tests haven’t been able to make a single spark start a fire. “Producers have long believed that static electricity is the cause for these fires, but everything we’ve done from a test standpoint so far suggests that is not a source of ignition,” says Humberg. “That’s not to say it never happens, but we are pretty confident most of the fires start at the exhaust manifold.”

There is still more research to do, much of which will happen when the sunflower harvest gets under way. SDSU researchers will closely monitor Knell’s progress and the progress of the other cooperators (all of whom are in South Dakota) and hopefully provide some answers and solutions for all sunflower producers to help prevent harvest fires. Producers are encouraged to review the results of the study so far and share their experiences and tips for dealing with combine fires. To do so, go online at combine-fire-responses/ and to

Meantime, there are things growers can do to reduce the risk of fires this harvest season, including:

• Prepare for fire hazards. Always keep in mind that sunflower is an oil-based crop, and fine fibers from sunflower seeds pose a constant fire hazard, especially when conditions are dry.

• Keep a clean work area when harvesting sunflower. The fire potential is always greater when conditions and the crop are dry. Blow the combine and grain dryer setup with an air hose daily. If dust collects on the machine, remove it regularly to eliminate the chance of fire — the potential for which is even greater when harvest conditions and the crop are drier. If possible, consider having a portable leaf blower on hand for this in the field.

• Try nighttime harvesting. If the threat of extreme dry conditions and combine fires persists, try harvesting at night when humidity levels are higher.

• Keep a small pressure sprayer filled with water on hand in the combine in case of fire. Without a doubt, a $25 fire extinguisher is a good investment if it can prevent the destruction of a $250,000 combine.

You can be certain Gary Knell will take these precautions to heart and cross his fingers for an uneventful sunflower harvest this year, for him and for other producers. “I hope we can find some way to deter the frequency of fires, because that would make harvest of sunflower a lot more enjoyable,” says Knell.

— Jody Kerzman

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