Your dryer just caught fire. First responders are a half-hour away. Five semi-trucks are lined up anxious to dump grain. You’d pay anything for water nozzles inside that dryer right now.
But it’s too late to invest in the internal fire suppression system you’ve been considering. That Custom Dryer Suppression (CDS) system likely could save the dryer, the grain and prevent fire from spreading. Saving the dryer also prevents your harvest from turning into a financial disaster, as tough grain backs up in the field.
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CDS runs two independent water lines to nozzles strategically located within the dryer. With CDS installed, your volunteer fire fighters show up and couple up to the standard Fire Department Connection and shoot water at the hot spot nozzles. A few farmers have developed their own water source to stave off waiting for first responders.
In some cases, not only is the dryer saved, but it’s up and running again the same day, says CDS inventor Wes Peterson.
In a phone interview, Peterson said that if the fire can be extinguished quickly without cutting up the sheet metal, dryer damage can be minimal.
In more typical cases, where there is no internal sprinkler system and cutting is required, the dryer is toast and the operation might be shut down for weeks while a replacement is located and installed. It throws an expensive monkey wrench into the works.
Peterson says his CDS is a one-time insurance investment that will last the lifetime of a dryer. Ballpark price tag is US$26,000 to install on an existing 18-foot diameter, 100-foot-high dryer. Prices are considerably lower on units installed on the assembly line at the dryer factory. From a risk management point of view, a fire disaster makes that investment seem miniscule.
After working in the dryer industry for 45 years and inspecting hundreds of fire sites, Peterson joined Custom Ag in Ohio in 2011 so he could focus on developing his plan for an internal fire suppression system, which he saw as a necessity for grain farmers.
Another motivator was his opinion that farmers have been exposed to a lot of wrong information when it comes to dryer fires. Peterson emphasizes that it takes more than just water to fight a fire. It also requires a big component of knowledge.
“Every manufacturer has a safety manual that gives you a list of things you should do when your dryer catches fire. But these manuals are obsolete. They do not touch on current protocol,” states Peterson. He has been lobbying manufacturers to produce a modern protocol defining the best fire suppression plans.
“For example, one of the old recommendations said you should dump the columns. For one thing, you’ve got a grain column 110 feet tall and you expect it to flow out of a hole that’s about six inches square.
“When you had grain right up to the top of the column, it didn’t have air so it just smoldered and smoked. It didn’t burn. Once you pull grain out the bottom, you create an air space at the top. Now it’s not smoke. It’s no longer smouldering. Now you have real fire. You did the exact wrong thing.
“The majority of the total losses I’ve witnessed have been based on that scenario. As soon as smoke becomes fire, it’s major. Then they make the 911 call, but they’ve already turned all that grain into fuel, a tall core of fuel. A lot of dry matter to burn.”
Peterson explains that if the fire can be extinguished on time, the operator can empty and clean it, then have it inspected for structural damage. He says operators who are aware of how the CDS works are faced with a decision. Should they buy insurance against equipment loss and business interruption, or make a more proactive decision to suppress the fire as soon as it’s detected? He says most opt for CDS because they want more control over their destiny.
“Although most new dryers are coming from the manufacturer with CDS installed, we’re also starting to see a lot of retrofits lately. If that dryer is your lifeline, then it doesn’t matter if it’s brand new from the factory or 20 years old. You need to protect that machine.
“You also must always do your absolute best to protect your first responders. Awareness of human safety is 100 times greater today than it was 20 years ago. Lethal grain entrapment is a good example. Look at all the excellent equipment that operators now have to prevent fatalities.
“It’s the same with CDS. The first responder runs the hose up to the FDC, makes the connection, then goes back to the pumper to open the valve. From there, everyone stands back and watches the water do its work.”
He explains that today’s firefighters are mainly trained to fight domestic, industry and large structure fires. They are trained to bring the fire out to them rather than go in chasing after it. That method works well for those common scenarios, but not for dryer fires. In attempting to bring the fire out to them, they start cutting big holes in the dryer.
“If you have no other instrument to fight the fire, that may be your only recourse. But the action of opening up the dryer nearly always results in a total loss. Beyond repair.”
Each CDS is made up of two independent systems, one to douse fire in the plenum and one to douse fire in the column. Each system has its own FDC. If it’s a trash fire in the plenum, then connection is made to flood the plenum. Peterson says fire generally starts here because of trash buildup. If it’s caught at that stage, before spreading to the column, the dryer is usually saved. If the fire has spread to the column, water is channeled to flood the columns.
“You can extinguish a fire in the grain column in about six minutes, without jeopardizing your first responders. Heat automatically gravitates toward a cool spot. So once your flood passes the hot spot, it immediately starts to cool it off. Water percolates down a grain column at a rate of about 17 feet per minute. For example, if you have an 80-foot grain column with nozzles at the top, you’ll be pushing water out the bottom in about six minutes.”
Three high volume nozzles penetrate each column to control water delivery. The riser pipes are anchored to their own weight-bearing structure, so their weight is not supported by the dryer.
CDS delivers 315 gallons per minute to the nozzles, 110 feet at the top of a dryer at the minimum pressure of 120 pounds per sq. inch. The risers are rated for a 350 p.s.i. maximum in which case it delivers 500 gallons per minute. For plenum dousing, nozzles are installed at different levels.
Dryer fires often start after the dryer is shut down for the night, so they go undetected for hours, until they become a major conflagration. Peterson urges operators to always inspect the interior of a dryer for hot spots and smoldering grain or trash after it has been shut down.
Contact ron.lyseng@producer.com
