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Maintenance Can Prevent Silo Sorrow

8/31/2013 7:00 AM
By Philip Gruber Staff Writer

Elton Hurst, a farmer from Rothsville, Lancaster County, woke up at 3 a.m. Aug. 22 to electrical problems in his house and the sound of distressed cows in the barn.

He saw smoke coming from his barn and dialed 911. Around 50 firefighters turned out to douse the fire, which was probably started by an electrical problem in the feed room. The barn and the cows were safe, but the battle was still on in Hurst’s two silos.

Onto the scene came Eric J. Rickenbach, a fire instructor with Penn State Extension and Pennsylvania State Fire Academy who specializes in silo fires.

Rickenbach credited firefighters’ “very aggressive, very quick attack” with saving the barn, but he said silos require different tactics.

Silo fires are fairly rare but can be very dangerous, Rickenbach said. Fortunately, many of these fires can be avoided with proper maintenance.

Rickenbach, of Berks County, has been fighting fires for more than 30 years and typically consults as a volunteer on six to eight silo fires across the state each year. Last year, he helped with seven silos, including four at one farm.

The U.S. Fire Administration reports that there are 11,500 agricultural storage fires every year, including silos, barns, stables and other structures. While these fires tend to have fewer human fatalities than residential fires, farm fires cause higher-dollar losses. Farm structure fires account for as much as $250 million in losses each year.

Rickenbach hears of 10 to 12 silo farms in the state each year.

When he arrives on the scene, Rickenbach must first decide whether the fire is worth fighting. A farmer may think a fire has only been burning for a few hours, but it may well have been smoldering for days. By the time flames appear, it may be too late to save the feed or structure, and hosing it down will just waste water.

If the fire is worth fighting, Rickenbach formulates a plan of attack. Many conventional silos can be sprayed from the top or through the door at the bottom. As a last resort, the firefighters can lower someone onto the silage pack to probe where the fire is.

“That can be really dangerous,” Rickenbach said.

Silos are tricky because they are legally considered confined spaces, which makes fighting fires in them subject to extra regulations and safeguards.

Silos, however, are “not your typical confined space,” Rickenbach said. “They’re their own breed.”

He likes to get a picture sent by smartphone before he arrives on the scene. Verbal descriptions sometimes prove inaccurate, he said.

Silo fires have many causes, said Lloyd Henry, a former chief of Lampeter Fire Company in Lancaster County whom Rickenbach called “the grandfather of this business” of silo firefighting.

Electrical problems from faulty equipment are a common problem. Lightning strikes are a possibility.

Farmers should even take the time to clean the access chute, which is a prime place for a dust explosion to occur once a fire has started, said Henry, who has been fighting fires for 50 years or so and has written a book about silo fires.

A dust explosion occurred at a silo fire in Ephrata last year, though the Lancaster Newspapers report did not list where the explosion occurred.

Spontaneous combustion can start because the feed is too wet or too dry.

“Freshly cut forage is not dead,” according to a report from the Vermont Barn Fire Prevention Task Force. It is still breaking down sugars, which lets off heat. If the moisture content is over 20 percent, warmth-loving bacteria will grow.

The bacterial respiration raises the temperature even more, as high as 130 to 140 degrees. That temperature causes the bacteria to die, which makes the heat subside. After the temperature drops, the bacteria start to grow again. These heat cycles can last for several weeks after baling.

The task force recommends checking temperatures twice a day for six weeks after putting up feed. If the temperature climbs past 150 degrees, farmers should check more frequently.

“Each type of grain has a different moisture content” at which it should be ensiled, and farmers should know both what that percentage is and when their crop hits that mark, Henry said.

If a fire does break out, farmers should not expect firefighters to unleash a full-force deluge.

“We don’t like to use a lot of water because it can spoil the feed,” Henry, the former Lampeter chief, said. Water also adds additional weight that can damage the structure.

Pouring large amounts of water on tightly packed hay may actually prolong the fire response.

Mike Wieder, a Pennsburg, Pa., native who now heads the International Fire Service Training Association at Oklahoma State University, writes that because the fire is often deep in the hay, water does not get to the fire very well.

“By pouring large volumes of water on the fire, you are guaranteeing that the mess will smolder for days afterward,” he writes.

Rickenbach also mentions the most spectacular danger of silo fires: “Well, if you don’t handle them right, you can blow them up.”

Adding water to an oxygen-limiting silo can cause a hydrogen explosion. On occasion a silo will “take off like a rocket,” Henry said.

The U.S. Fire Administration details a 1993 incident in which two firefighters were thrown 100 yards, one through the roof of another building, when they sprayed a burning oxygen-limiting silo with water and firefighting foam.

Fires in those silos should be smothered with carbon dioxide or nitrogen, he said.

Silo firefighting technologies have improved over the years. Firefighters now use cameras with a nozzle on a 3/8-inch pipe to probe the silage and find where the fire is. Leaving the probe in too long can spread heat up the metal pipe and ignite more silage or cause an explosion.

Firefighters also have heat guns that can pinpoint the fire’s location, he said.

To get to the actual fire, firefighters sometimes have to unload the silo. Fire damage often makes the unloaders inoperable, so firefighters have to scoop the feed out of conventional silos through the top by crane. That process can take several days, and the cost does not make farmers’ insurance companies happy, Henry said.

Even if the unloader does work, the farmer must make sure not to run the amperage too high or the motor will burn out. That happened once at a silo fire Henry was helping with. Fortunately, one of the firefighters on the scene was an electrician, and he was able to install a spare motor.

“I’m not a magician. I can’t promise we’re going to get em, but we’re going to try,” Henry said.

Proper upkeep is the most effective way to prevent silo fires.

Farmers should check for cracks in concrete silos that can let oxygen in. Wiring should be inspected regularly. If applicable, farmers should also make sure the silo is sealed properly.

Prevention is especially important for oxygen-limiting silos because firefighters cannot enter them or spray them with water.

Rickenbach, the Berks County expert, estimates that he has consulted on fires at three of those silos in the past decade. Two were probably caused by spontaneous combustion aided by air leaks, while the other was ignited by a bad bearing on the unloader.

Those fires were the result of poor maintenance and were preventable, he said.

Rickenbach urges farmers to call the fire department if they suspect a fire. The firefighters would rather get to the site before the fire gets out of hand, he said.

Landowners should also consider inviting firefighters to the farm to learn where things are and to plan a response in case of fire.

Some fire departments do not have a ladder truck, which is necessary to get to the top of the silo, and outside the big farming counties like Lancaster, there are fewer farmers on fire departments, he said.

If firefighters do not know how to handle a silo fire, the best outcome is that the feed will be damaged. The worst outcome is that people will die trying to fight the fire, Rickenbach said.

“Not every fire company’s equipped to deal with this,” he said.

If the fire company does not know what to do, it should contact the state emergency operations center through a 911 dispatcher to get in touch with Rickenbach and the handful of other silo experts around the state.

“We want to see firefighters safe” and protect property and lives on the farm, Rickenbach said.


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