Class B foam concentrates are typically mixed in proportions of _______________ ?

Class B foam concentrates are typically mixed in proportions of _______________ ?

• A. 0.1% to 0.5%
• B. 10% to 20%
• C. 0.5% to 2%
• D. 1% to 6%

Answer: (D)

Class B foam concentrates are used to create a foam solution that blankets hydrocarbon fuels, cooling the fire and separating the fuel from the air. The amount of concentrate you add is expressed as a percent by volume of the total solution, and the exact percent is determined by the product’s label and the fire scenario. For most Class B concentrates used in aircraft rescue firefighting, the typical mixing range is 1% to 6%. This means for every 100 units of solution, you have between 1 and 6 units of concentrate, with the remainder being water. A 1% mix is leaner and conserves concentrate for simpler fires, while a 6% mix provides a heavier foam blanket and faster knockdown for more demanding fires or when maximum burnback resistance is needed, all within what the product is approved to use. Rats outside this range aren’t standard for ARFF operations with Class B concentrates; 0.5% or 0.1% would generally be too lean for effective film formation, and 10% or higher would be far too concentrated and not typically approved for most products.

Class B foam concentrates are used to create a foam solution that blankets hydrocarbon fuels, cooling the fire and separating the fuel from the air. The amount of concentrate you add is expressed as a percent by volume of the total solution, and the exact percent is determined by the product’s label and the fire scenario.

For most Class B concentrates used in aircraft rescue firefighting, the typical mixing range is 1% to 6%. This means for every 100 units of solution, you have between 1 and 6 units of concentrate, with the remainder being water. A 1% mix is leaner and conserves concentrate for simpler fires, while a 6% mix provides a heavier foam blanket and faster knockdown for more demanding fires or when maximum burnback resistance is needed, all within what the product is approved to use.

Rats outside this range aren’t standard for ARFF operations with Class B concentrates; 0.5% or 0.1% would generally be too lean for effective film formation, and 10% or higher would be far too concentrated and not typically approved for most products.