Stubborn Cob Fire Presents Unusual Control Problems
Memphis Fire Department wages 29-day battle to extinguish corncob fire at Quaker Oats Plant
ONE OF THE MOST UNUSUAL and prolonged fires in the history of Memphis, Tenn., occurred last December when a 70,000-ton pile of corncobs burned at the Quaker Oats plant. The fire broke out on December 2 and was not fully extinguished until December 25. As far as we have been able to determine, there has been no record of this type fire anywhere in the country.
The Quaker Oats plant in Memphis manufactures furfural alcohol from corncobs. This product is used extensively in the manufacture of plastics and synthetics. The plant consists of 20 major buildings, several smaller structures, storage tanks for the alcohol, and the corncob storage area.
Manufacturing processes involve many hazardous operations, but the plant is well protected with sprinklers, standpipes, private hydrants and a well-trained fire brigade.
None of the buildings in the plant was involved in the fire although two large storage sheds adjacent to the cob storage area were exposed. These sheds are each 100 feet by 214 feet in area and are five stories high. Both are fully sprinklered.
Private protection for the plant consists of a looped hydrant system of 19 plugs on 6-and-8-inch mains, 1 1/2and 2 1/2-inch hose, two fixed monitors at the cob pile and a large number of minor appliances and equipment.
The cob storage area is located at the north end of the plant property. It was an “L” shaped area running roughly 500 feet along the outside edges, 200 feet wide on the east leg and 300 feet wide at the south leg. At the time of the fire, the pile was from 60 to 70 feet high and contained an estimated 70,000 tons of corncobs.
The pile was broken and loosely piled along the top and sides. The surface contained craters, gullies and depressions where the pile had settled. Footing on the pile was precarious and movement on it was difficult.
Fire goes “underground”
The fire was first detected by a plant watchman on the morning of December 2. At 4:43 a.m., an alarm was received from the plant by the fire department and apparatus was dispatched. The engine company first arriving on the scene laid a 2 1/2-inch line and the fire was quickly , knocked down. By 7:30 a.m., all companies had returned to quarters.
However, the fire had apparently tunneled into the pile through veins and soft spots without being visible from the surface. During later stages of the fire, as the pile was pulled down, we found charred areas running for considerable distances inside of the pile leading to burned out or smoldering pockets. In other places, we found craters up to 20 and 25 feet deep where fire had worked its way down into the pile from the surface.
Later in the fire, we also observed that combustible gases were generated in large quantities, and it is probable that pockets of this gas were ignited by flying brands and sparks at considerable distances from the main body of the fire itself. This undoubtedly also helped spread the fire.
Shordy after noon on December 3, the house watch at Fire Station 23, reported to the fire alarm office that a fire was visible at the Quaker Oats plant and a minute later, an alarm was received from the plant.
Companies were again dispatched and when they arrived, a considerable amount of fire was found on the east side of the pile. The fire department laid out three 2 1/2-inch lines, and two more lines were stretched by the plant fire brigade.
The visible surface fire was considerably reduced, and about four and a half hours later, a spare pumper was sent to the plant to help overhaul the pile. At the same time, most of the companies which had responded to the plant were returned to quarters.
A detail of firemen and plant employees continued overhauling the pile. At about 9:45 that evening, the fire broke out with renewed intensity, and shortly afterwards an additional pumper was sent to the plant. We then made a careful survey of the pile and at that time, it was determined that there was a very deep-seated fire in the east leg of the pile. We also suspected that the fire was working its way into the south leg of the pile, but we were not able to determine this definitely until about 24 hours later.
Heavy smoke condition
The fire started generating a very heavy volume of smoke and gases which made operations very difficult at the scene. Several men were overcome by carbon monoxide gas, and at 1:41 a.m. on December 4, an aerial ladder with self-contained masks and a resuscitator was dispatched to the plant.
Later in the morning, a meeting was called with plant officials, and we requested them to obtain bulldozers and draglines to begin moving the involved area of the pile.
Efforts were made by Quaker Oats officials to obtain a number of these implements, but because of the intensive construction program in the Memphis area, it was impossible to get as many bulldozers and operators as we needed. It was not until several days later that Quaker Oats officials were able to secure the desired amount of equipment. The equipment which was immediately obtained was put to work on a round-theclock basis moving the pile.
Considerable difficulty was experienced with carbon monoxide gas, and men working in the area were supplied with all-service and self-contained gas masks.
Despite the efforts of firemen and plant officials, the fire continued to spread and by the next day, the entire top of the east leg of the pile was involved. Aided by a westerly wind, the fire began to work its way down the west side of the pile and began channeling into the south leg. At the same time, gas conditions on the pile became so bad that all personnel were ordered to the ground.
Chemists at the plant analyzed the gas and smoke for us and found it to contain a large percentage of carbon monoxide. In addition, it contained acetone, acetic acid and methyl alcohol. These chemicals all have toxic properties, are harmful to the lungs and eyes, and in combination are liable to form explosive gases.
For these reasons, we supplied all personnel in tire area with gas masks, set up a first aid station and had samples of the gas and smoke analyzed every hour. As far as was possible, we also had personnel work on the windward side of the fire.
During the next few days, we brought additional pumpers and equipment into the plant, supplemented the private water supply with city water, and were able to get draglines and additional bulldozers to work.
Despite these efforts, the fire continued to gain ground. Hose streams concentrated at one point for several hours would be shut down, and the fire would immediately burst out again. At other times, gas pockets would flare up at considerable distances from the main body of the fire, and smoke and gases issued from all sides of the pile.
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On December 7, the first official meeting between Quaker Oats Company officials and the fire department staff officers was held at the plant. We mapped out plans for obtaining additional equipment and manpower. We ordered the water supply to be surveyed as to capacity, flow and pressures. At the same time, the health department made their own survey of the situation to determine if any public health menace existed.
Smoke conditions over much of northeast Memphis were heavy at times, but the smoke and gases were not dangerous, although they were a continual annoyance to residents of the city and county who could smell the burning cobs miles from the plant.
Plant reinforces fire fighters
On the morning of December 9, the Quaker Oats Company put 60 additional men at the disposal of the fire department. At the same time, we increased the number of bulldozers and had three draglines working 24 hours a day moving the entire pile.
We supplied the Quaker Oats employees with hose, nozzles and other equipment, brought in heavy stream equipment and other apparatus. We had one pumper supplying three lines of hose which were connected to the plant Siamese to supplement the plant’s own 1,000-gpm fire pump and reservoir.
By doing this we were able to obtain just over 1,200 gpm at 28 pounds residual pressure in the cob pile area, and still were able to maintain sufficient volume and pressure throughout the rest of the plant for fire protection.
Operations consisted of using the draglines to pull down the pile, and then having the bulldozers spread the burning and smoldering cobs out on the ground so that they could be thoroughly soaked. Hose streams were alternately used to knock down the surface fire on the pile and to cool down the burning pockets and craters as they were uncovered.
All during this of time, we worked in close harmony with officials of the Quaker Oats Company and conferred with them regularly on the actions we were taking to control the fire. They gave us every assistance and cooperation we asked for.
On December 13, we recommended that two 1,000-gallon diesel-driven fire pumps be brought in to replace our pumpers, some of which had been operating for almost two weeks. The next day plans were completed and the pumps rented by the Quaker Oats Company.
One of these was connected to a city hydrant and replaced a fire department pumper which had been pumping continuously for over 130 hours. The diesel pump supplies 1,269 gpm at 140 pounds pump pressure. This water was pumped into the plant system through six lines of hose and special connections which had been made at the plant.
The second pump was connected to a deep well close to the cob pile and discharged 1,000 gpm at 150 pounds pump pressure through a special header which we placed on the pump. Six lines were connected to the header to supply additional hose streams.
By using the two diesel pumps, we were able to obtain 2,000 gpm at the pile. Once these pumps were in operation, the fire department pumpers were shut down and put on a standby basis.
Moving the pile and wetting down continued until December 18. By this date, the fire had been reduced to a point where the hose fines could move in very close. The pile was also spread out enough for the bulldozers to operate directly on the pile. This speeded up operations considerably.
Special nozzles help
We used specially-built spear-point nozzles with dual heads to apply water to the subsurface fire. The nozzles were placed directly on the pile and forced down into the cobs to a depth of from 5 to 6 feet. We found this method to be very effective in putting out the subsurface fire in craters and hot spots.
Gradually the pile was pulled down and spread out over several acres and by Christmas morning, we considered the fire fully under control and withdrew most of our men and equipment.
At no time during the period of the fire, 23 days, was the city left without adequate protection. We used mostly spare equipment at the plant, once the scope of operations became apparent. These spares were 1,000 gpm pumpers, supplemented by an extra salvage corps truck, rescue squad truck and one firstline pumper.
When we did need first-line equipment, it was sent to the fire and its station immediately filled with a spare piece of apparatus, or another company covered up for it.
Some of the statistics on this fire may be of special interest. For example, the rescue squad used a total of 511 cubic feet of oxygen for first aid treatment. We also used 4,695 gallons of gasoline and 88 gallons of oil. Seven pumpers operated at the fire a total of 955 hours and 15 minutes.
This interesting factual account is taken from a paper delivered by Chief Klinck before the Twenty-Ninth Annual Fire Department Instructors’ Conference held in Memphis, February 19-22. Photos used to illustrate the story are by the Memphis Fire Department Photo Unit.