Fire Safety, Inc. - Total Fire Protection

AFFF Foam Agents and Hardware

Simply stated, firefighting foam is a stable mass of small, air-filled bubbles with a lower density than oil, gasoline, or water. Foam is made up of three ingredients...water, a foam concentrate, and air. Water is mixed with a foam concentrate (proportioned) to form a foam solution. This solution is then mixed with air (aspirated) to produce a foam which readily flows over fuel surfaces.

How do foam agents work? Firefighting foam agents suppress fire by separating the fuel from the air (oxygen). Depending upon the type of foam agent, this is done in several ways:

• Foam blankets the fuel surface, smothering the fire and separating the flames from the fuel surface.

• The water content of the foam cools the fuel.

• The foam blanket suppresses the release of flammable vapors that can mix with air.

Types of foam agents: Aqueous Film-Forming Foam (AFFF), Alcohol-Resistant Concentrates (ARC), Protein Foam Concentrates, Fluoroprotein Foam Concentrates, and High Expansion Foam Concentrates

Types of proportioning systems are: bladder tanks, pump skids and In-line balanced pressure systems.

Types of discharge devices include:

Foam Monitors: Foam monitors are designed to control the horizontal and vertical directions of large capacity discharge streams. Water-oscillating monitors will automatically move side-to-side using water pressure as the energy source. Remote controlled monitors use an electric joystick tied into a hydraulic system. Other monitors are operated manually using a tiller bar to control direction and elevation. Various aspirating and non-aspirating nozzles are also available for use with monitors and/or handlines.

Sprinkler Heads: Sprinkler heads are available from various manufacturers in both non-aspirated and aspirated versions. Non-aspirated heads with AFFF agents are more economical and can be used in either open deluge or closed-head sprinkler systems. Aspirated sprinkler heads are required for protein and fluoroprotein foams in deluge systems.

Foam Chamber and Foam Makers: Foam chambers and foam makers are air-aspirating devices designed to protect flammable liquid storage tanks. Foam chambers apply expanded foam gently down the inside of the tank wall onto the liquid surface. high back pressure foam makers inject expanded foam through the tank wall near the bottom of the tank allowing foam to gently rise to the surface. Other types of foam makers are installed in the foam distribution piping where expanded foam is directed to specific hazards such as dike areas or floating-roof tank seal areas.

Foam Generators: Foam generators deliver large quantities of foam by expanding foam solution in the range of 200:1 to 1000:1. The high-expansion generator operates by coating its screen with high-expansion foam solution while air is blown through the screen to produce expanded foam. Because of its high expansion ratio, little water is required to generate large quantities of foam thereby reducing the potential for hazardous run-off or water damage. Jet-X foam® generators are water-powered and require no other sources of power.