WARNING – The integrity of a Class B Bubble Blanket can break down in under 20 minutes depending on conditions. A weak or damaged bubble blanket will fail to suppress potentially explosive Class B flammable vapors. Always be prepared to add more Class B concentrate.
WARNING – The integrity of a Class A/B Bubble Blanket can break down in under 20 minutes depending on conditions. A weak or damaged bubble blanket will fail to suppress potentially explosive Class B flammable vapors. Always be prepared to add more Class A/B concentrate.
WARNING – Class A bubble blanket is not designed to suppress potentially explosive Class B flammable vapors. It is not recommended using Class A foam as a vapor suppressing bubble blanket.
Special Training Required
It is not recommended to use Class A Foam on a Class B Fuel or Fire!
Likewise, it is not recommended to use Class B Foam on a Class A Fuel or Fire!
However, with proper, intensive, specific training in both Class B and Class A Foam concentrates, there may be scenerios that make exception. For example, Class A foam can knock down vehicle fires involving relatively small amounts of flammable liquids. Small vehicles could include automobiles, truck tractors, small boats, small airplanes, helcopters, etc. – However, the Class A Foam blanket is not designed to provide Class B vapor suppression and an explosive re-ignition is a real DANGER!!! .
Another exception: Class A foam can be used for a quick, temporary flame knockdown to affect a rescue. However, again, it must be remembered that Class A Foam is not designed to suppress the Class B vapors and an explosive re-ignition is a real DANGER!!!
What about a large aircraft? It depends on what is burning. The fuselage is basically a tube shaped Class A building. The hydrocarbon (Class B) fuels are generally in the wings. Class A CAF can be used to extinguish or protect the fuselage to affect rescue. Class A CAF MIGHT also knock down the hydrocarbon fire, but REMEMBER – Class A Foam is not designed to suppress the potential flammabe/explosive vapors of a Class B hydrocarbon fuel.
A-Foam can reduce the surface tension of a hydrocarbon fuel causing it to seep deeper into the ground making recovery difficult and expensive. A-Foam does not form a vapor barrier leaving firefighters exposed to dangerous flash ignitions of Class B hydrocarbon vapors. REPEAT – It is not recommended to use A-Foam to blanket a B Fuel.
Any use of Class A concentrate (or any other type of concentrate) on a Class B hydrocarbon fuel must be by the decision of the AHJ or Department management and should be based on thorough knowledge and training on both the Class A concentrates and Class B hydrocarbon fuel including training on Class B type incidents.
Utilize pre-plan training in your department to determine the acceptable use of foam concentrates on various scenerios. REMEMBER, it is up the the AHJ (and/or Fire Command) to determine the products utilized and the tactics implemented in the use of Class A concentrate as well as any other concentrate chosen by the department. REMEMBER – you are responsible for what you put down.
Also remember that different products may provide different results. Utilize DIY – Performance Evaluation and How to Purchase Concentrates. Provide thorough training before making any tactical decisions.
If you have any specific questions regarding the capabilities of a particular brand or type of concentrate, refer to the SDS or contact the concentrate manufacturer.
