Firefighting Foam

Inter-Canyon Fire/Rescue uses various forms of foam to fight both structural and wildland fires.  The use of Compressed Air Foam Systems (CAFS) in the rural setting undoubtedly offer great benefits, as do regular Class 'A' foams, for their penetrating and protective qualities. It has been shown that fire attack systems providing foam/air additives can assist firefighters greatly. A vast reduction in fire 'knockdown' and suppression times are being seen and the transition to lightweight attack hose-lines, where the air content creates a line that is half the weight of a normal water line, means firefighters are finding it much easier to advance and operate.

Compressed Air Foam

As in life, these are two very different fire classes:

Class A Fuels - Wood, cloth, some plastics

Class B Fuels - Flammable liquids and gases

The two foams used to fight fires are also very different. They may come in the same looking bucket, and make the same white bubbles on the ground, but they are very different chemistries and designed for very different missions.

Making foam is a very simple task – water + soap + air.
There are numerous variations in the makeup (consistency) of the foam. Knowing which variation to use when requires good equipment, training and practice. Using the wrong consistency at the wrong time makes for very unhappy firefighters and possibly a very unhappy situation.

There are 4 levels of effectiveness in firefighting liquids/foams:
The bottom level is water. Water has a high surface to mass ratio (STMR) – inefficient heat absorption; high surface tension – no penetration; repels carbon – won’t stick to vertical surfaces.

Structural Firefighting



Next up is Foam solution = water + concentrate.  Foam solution has a reduced surface tension – improves penetration. Carbon loving – it sticks horizontal, but not vertical. Still has high SMTR. Only slight improvement in heat absorption.

Next level up is Aspirated Foam – better than solution since it is in a bubble format – the bubbles result in an increased STMR for better heat absorption. These bubbles are fragile and cannot be applied at long distance – low energy.

Top level is CAF – penetrates, sticks, ultimate heat absorption (this is what firefighting is all about), high energy, small, strong bubbles – long reach.

Firefighting with Foam