An overturned tanker lies in a ditch next to the highway, the unknown contents spilling freely onto the ground. Smoke rises from the engine compartment. Without action, fire may be eminent. The fire chief makes a instinctive decision based on his many years of experience.
"Pull the foam line," he orders. Beautiful white AFFF cascades from the nozzle across the spill. Yet, for some unknown reason, the foam is dissolving as fast as the firefighters can apply it. For some reason, the chosen foam solution is not the correct solution to the problem. Every face is turned toward the chief searching for an explanation. He has none to offer.
Based on the results of a two-week blind testing program conducted in February, foams without an alcohol resistant polymer were unsuccessful in extinguishing fires involving E-95, a blend of 95 percent ethanol and five percent gasoline. E-95 is the typical blend of ethanol shipped to distribution terminals by rail car, truck or barge.
Environmental issues have a huge impact on modern life, the fire service included. Until recently, if a fire department had a spill or a fire involving bulk quantities of motor fuel, the remedy was to apply either Alcohol-resistant aqueous film forming foams (AR-AFFF), alcohol resistant fluoroprotein foam (AR-FP), or alcohol-resistant film fluoroprotein (AR-FFFP). Then came ethanol, a biofuel alternative to gasoline.
In 2006, the ethanol industry produced 6 billion gallons, which was blended into 46 percent of our gasoline supply nationwide. Derived from grains such as corn, wheat or switchgrass, ethanol is used to oxygenate gasoline and raise the octane rating. It can be used as fuel in any combination up to and including pure ethanol.
Praised as a renewable source of energy, ethanol is being handled in ever increasing volumes in the U.S. However, ethanol is a water soluble polar solvent. Traditional non-alcohol resistant foams that are otherwise effective on gasoline and other class B liquid fire are not effective on ethanol. This has left firefighters to debate whether these same foams will work on fires involving ethanol blended with gasoline.
These differing opinions were the driving force being a recent project to determine through scientific analysis the most effective methodology for responding to a spill or fire involving a bulk container of ethanol or ethanol blended fuel. In order to document the challenges that face first responders in handling ethanol fires and spills, the United States Ethanol Emergency Response Coalition was formed. The organizations involved are the International Association of Fire Chiefs, Ansul Fire Protection, Independent Liquid Terminals Association, Virginia Department of Emergency Response, Williams Fire & Hazard Control and the U.S. Department of Transportation.
Fire departments and industry need to make informed decisions as to which foam concentrates should be used and the associated equipment and tactics to be employed based on the most significant risk. The EERC testing program, conducted in February, used UL 162 test methodology within a structural test environment, the 10,000-square-foot fire test house at the Ansul Fire Technology Center in Marinette, WI.
Forty-three individual tests were conducted on denatured alcohol, E95 and E10 or gasohol. Three foam application scenarios were used for the UL 162 tests -- type 2, which involves directing a stream of foam solution against a vertical surface, creating a more gentle application across the fuel; type 3, which involves a foam stream directed onto the burning surface of the fuel and sprinkler application like a truck loading rack.
Every test consumed 55 gallons of fuel with both E95 and E10 tested. The fuel had to be a minimum of 50 degrees F before ignition. Once ignited, a 60 second pre-burn period was observed for the type 2 and 3 testing, allowing the volume of the fuel to heat up. Sprinkler application only required a 15 second preburn.
If the foam was able to extinguish the fire, it was put through a burn back test to evaluate the foam's resistance to fire. The last corner of the 50 square foot pan to stop burning is used. A technician scoops out a portion of the foam blanket and re-ignites the fuel. After five minutes the foam blanket is inspected. If it has deteriorated by 20 percent since re-ignition, the foam fails the burn back portion of the test. However, if the foam does not lose 20 percent of its coverage, it passes.
Using the type 2 application, only one of the six foams was able to extinguish and pass the UL 162 burnback test for denatured ethanol fire -- alcohol resistant AR-AFFF. Alcohol resistant AR-AFFP foam extinguished the E95 at an increased application rate but did not pass the burnback test.
None of the foams extinguished an E95 fire with a type 3 topside foam application similar to a fire department using a monitor nozzle. Only the AR-AFFF was capable of passing a sprinkler application.
Similarly, only the AR-AFFF was considered successful in combating the gasohol fires. Both the AR-AFFF and the conventional AFFF extinguished the gasohol fire with a type 3 application at the UL specified application rate. But only the AR-AFFF could pass the burnback portion of the test and this required an increased application rate. Technically, this failed the UL test but still achieved the required results.
Two foams were able to pass the UL 162 sprinkler testing on gasohol -- AR-AFFF and conventional fluoroprotein foam. The alcohol resistant film forming fluoroprotein foam failed the sprinkler test on a gasohol fire, as did the conventional AFFF, Class A foam and the emulsifier.
Regardless of the manufacturer or brand, chemically these tests verified that if the foam is water soluble and does not contain an alcohol resistant polymer to create a protective coating between the foam the fuel it will not effectively put out a large ethanol fire.
Many firefighter put forward the theory that it is possible to dilute an ethanol spill with water. The lab work says otherwise. Lab tests show ethanol diluted to 500 percent will still burn steadily. Results do not support fighting a polar solvent tank fire by flooding it with water.
What does all this tell the fire service? Many fire departments use crash trucks to respond to gasoline tankers on fire. It used to work real good. A crash truck carrying 3,000 gallons of AFFF and applying it at 500 to 1,000 gpm can knock the heck out of a fire. But with ethanol involved, you might as well leave the crash truck at home. The way we fight flammable liquid fire has to change.
Testing this at home is simple. First, go to a gas station that sells E95. Buy a gallon and take it back to the fire house. After you pour it into a container, mix a quart of the foam solution you have on hand at the percentage you would use it at. Then pour it on the ethanol. You will find almost the same results with any foam that is not alcohol resistant.