foam and the fire triangle

Three things must be present in order to have a fire: Fuel, heat and oxygen. This is also known as the fire triangle. All must be present to ignite a fire. Remove one element and the fire goes out. As I am finding out, in fighting wildfires, it is not quite that simple. And putting the wildfire out may take time.

The AgCats used by the NJFFS are loaded with 300 gallons of water mixed with 1/2 gallon of firetrol foam additive. As I understand foam is a suppressant. Suppress or smother the fire, and it has no oxygen. Retardant on the other hand is designed to slow down a fire.

A more technical explanation of foam is that:

"foam products form bubbles when mixing with water. They adhere to the fuels and reduce combustion by cooling, moistening and excluding oxygen." SEAT Training, SEAT 2: SEAT Operations. Aviation Fire Fighting Course. Slide 20 of 48 obtained from https://www.iat.gov/Training/modules/seat/seat2.html on January 27, 2009.