By Robert Avsec
A Compressed Air Foam System uses a Class A foam concentrate, combined with water, and compressed air to form a fire extinguishing agent that is greater than the sum of its parts. The synergistic affect is a product with greatly reduced surface tension, compared to that of plain water, which enables the solution to penetrate burning fuels much faster and more efficiently.
When used as a firefighting agent, a CAFS fire stream has a very high heat absorption quality that will suppress a fire in a fraction of the time when compared to conventional firefighting tactics using plain water.
This improved effectiveness results in a decreased risk to firefighters during combat operations, enlarges the window of opportunity for rescue of occupants, reduces property damage and lowers overall operational costs.
The National Fallen Firefighters Foundation first published the 16 Life Safety Initiatives, part of its Everyone Goes Home program in March 2004. Initiative 8 states: “Utilize available technology wherever it can produce higher levels of health and safety.”
Initiative 16 states: “Safety must be a primary consideration in the design of apparatus and equipment.” The executive summary for the 16th Initiative concludes with this statement: “The 16th Initiative ratifies the belief that no firefighter should die in the line-of-duty due to apparatus or equipment-related issues.”
Elephant in the room
Sounds great, right? So, why has the U.S. fire service, as a whole, failed to embrace the quantum leap in firefighting capability that CAFS provides? Who doesn’t want to reduce risk to firefighters, improve the survivability of entrapped occupants, and reduce property loss and operating costs?
The most significant obstacle to the widespread use of CAFS as the principal firefighting agent for structural fires in the United States is tradition. That’s the “elephant in the room.”
It is the same as it was for the slow adoption of motorized fire apparatus, breathing apparatus, enclosed cabs on apparatus, and every other new technology that’s come down the road since firefighters began to roam the earth.
CAFS is by no means a new and unproven technology as CAF was invented more than 70 years ago for the U.S. Navy. It has been used in wildland firefighting operations since the 1980s; it has gained its greatest acceptance as a better firefighting agent for structural firefighting by those departments that regularly engage in wildland fire fights.
Los Angeles study
In 2001, the Los Angeles County Fire Department — a department that had been using Class A foam for fire suppression operations since 1988 — conducted a series of tests over two days to evaluate the fire extinguishment effectiveness and efficiency of water, Class A foam and CAFS.
LACFD test results
Water flow (gpm)
Water needed for knockdown (gallons)
Average time for interior temperature drop to 200 degrees F (min:sec)
LACFD used three identically constructed one-story, wood-framed single-family dwellings. The test structures, built in the 1940s, had previously housed workers at a nearby airbase.
Each of the test structures had an identical 1,105-square-foot floor plan consisting of six rooms; the building interiors were identically furnished as a typical single-family dwelling. The test structures were equipped with thermocouples to detect temperatures at various interior locations.
The results of tests conducted by LACFD to compare the relative effectiveness and efficiency of water, Class A foam, and CAFS as a fire extinguishment agent. The average interior temperature is the time required to reduce the interior temperature from 600 degrees F to 200 degrees F, a temperature more compatible for survival of entrapped occupants.
The numbers do not lie. The fire attacks using CAFS required less water, resulted in quicker initial knockdown of the fire, and a faster reduction of interior temperatures than either water or Class A foam solution — and it wasn’t close.
Additional studies conducted by the USFA, National Interagency Fire Center and the USFA in cooperation with the Boston Fire Department have also validated the greater effectiveness and efficiency of CAFS as a fire extinguishment agent.
1. CAFS reduces water used.
The less water you need for extinguishment, the less you have to use and the less water you have to bring to the scene. Consider how big of an issue water conservation is in those localities affected by drought and overpopulation.
2. CAFS reduces air pollution.
Quicker fire knockdown and ultimate extinguishment means less active burning and less release of products of combustion into the atmosphere.
3. CAFS reduces water pollution.
More water for fire extinguishment also means more contaminated water to run off into storm sewers, creeks, streams, etc. This is a greater problem than ever before when you consider what’s burning today and therefore what contaminants are getting into that runoff water.
4. CAFS reduces property damage.
The NIFC study concluded that 90 percent of the water used on test fires failed to extinguish the fire because the water did not penetrate the surface of the burning material. In another study, NIFC found that in Oregon, 75 cents of every dollar paid in fire claims was the result of water damage. So, if 90 percent of the water that we use for fire extinguishment is not getting the job done, and 75 percent of insurance claims in one state are for water damage, shouldn’t we be looking to CAFS?
5. CAFS reduces firefighter safety risk.
Quicker knockdown times means fewer fires will reach flashover stage. Faster reduction of interior temperatures means fewer fires where firefighters are exposed to high interior temperatures.
There is also a reduction of firefighter fatigue and resultant sprain and strain injuries incurred while advancing hose lines for fire attack — CAFS hose lines are much lighter and more maneuverable than conventional hose lines because 75 percent of the hose’s contents are air bubbles.
Sure, a CAF system is a significant cost item on a new piece of pumping apparatus — adding a 200 cfm compressor with a foam pro proportioner for a couple of CAFS discharges can add $35,000 to price of a pumper without CAFS. Actual pricing will vary depending on proportioner chosen and the number of CAFS discharges specified.
But at one time, so too were the costs for diesel engines, fully-enclosed crew cabs, breathing apparatus for all personnel on scene, portable radio systems, thermal imaging cameras, and the like considered prohibitive.
So the real question becomes: With all of the hard evidence showing CAFS improves firefighting ability and firefighter safety, can a department afford to not use it?