In a Compressed Air Foam System (CAFS), air or another gas is compressed and introduced into the foam solution. Larger systems use a dedicated air compressor and compresses regular air from the atmosphere.

Smaller systems can use any inert compressed gas such as Carbon Dioxide (CO2), Compressed Nitrogen (N2) or smaller tanks of compressed regular air.

The simplest, most efficient and least expensive way of producing foam is with a portable foam eductor. These foam systems use regular hand lines and an eductuor 100 feet from the end of the nozzle. The eductor siphons foam solution from a tank or drum using the "Venturi" principal. When the foam solution reaches a standard fog nozzle, water pressure and the broken stream produced by the nozzle introduce air into the foam solution.

There are other forms of nozzles that introduce water using the "Venturi" effect that are not user adjustable like a fog nozzle.

The quick easy answer is regular air is used most commonly in fire fighting foam however CO2 and N2 can be used depending on the design of the system used.

In a Compressed Air Foam System (CAFS), air or another gas is compressed and introduced into the foam solution. Larger systems use a dedicated air compressor and compresses regular air from the atmosphere.

Smaller systems can use any inert compressed gas such as Carbon Dioxide (CO2), Compressed Nitrogen (N2) or smaller tanks of compressed regular air.

The simplest, most efficient and least expensive way of producing foam is with a portable foam eductor. These foam systems use regular hand lines and an eductuor 100 feet from the end of the nozzle. The eductor siphons foam solution from a tank or drum using the "Venturi" principal. When the foam solution reaches a standard fog nozzle, water pressure and the broken stream produced by the nozzle introduce air into the foam solution.

There are other forms of nozzles that introduce water using the "Venturi" effect that are not user adjustable like a fog nozzle.

The quick easy answer is regular air is used most commonly in fire fighting foam however CO2 and N2 can be used depending on the design of the system used.

Depending on the type of fire there are different option. Water, CAFS(Compressed Air Foam System) or a variety of fire extinguishers

Foam rubber has air gaps, which allow it to be squashed together, and is not completely contained so it can spread outwards instead of being compressed only downward.