Water has been the traditional tool for suppressing fires since the beginning of firefighting, though foam appeared as early as 1877 as a new way to extinguish flames. Compressed-air foam, also known as CAF, contains three basic parts: water, foam concentrate and compressed air. In order to produce CAF, a compressed-air foam system (CAFS) is needed. CAF was invented more than 70 years ago for the U.S. Navy. After more than seven decades of trial and error, the product has improved tremendously and it is being used to great effect. For instance, while the state of Ohio is short on history concerning the use of CAF, the departments that are using it are having much success. Departments in the Western states and wildland firefighters also have documented improved efficiencies and overall success. In Texas, the Insurance Services Office will give bonus credit to any department that has a CAFS engine on the first-alarm assignment, and is considering similar programs for other states.

While the fire service is starting to look at CAF differently, it is far from commonplace in every fire department. The fire service, not only in the United States but worldwide, is rich in tradition. And although tradition is good, there are new and improved technologies that can make a difference by decreasing property loss costs, while protecting firefighters. CAF is one of those technologies. But some departments are so rigid in their thinking that they will not accept CAF, even though using it reduces property damage and injury, and possibly prevents death.

Foam changes the chemical makeup of water, reducing its surface tension. Even though water is a versatile resource and is the traditional method for extinguishing fires, even it has its limitations. For example, when extinguishing a campfire, water forms beads and rolls away — which may or may not extinguish the fire. Another problem in such scenarios is the smoke and hot steam that is generated when the water evaporates. When a foam solution is added to that water, the resulting solution does not run off but instead covers the fire; therefore, the fire is extinguished quicker and with less water. When firefighters add compressed air to this foam solution, depending on the mixing ratios, anything from soapy water to stiff shaving cream will result.

Breaking the Chain Reaction

The three essential elements of the fire tetrahedron are heat, fuel and oxygen. By separating or isolating these elements, the chemical chain reaction does not take place. CAF accomplishes this separation. It removes the heat by quickly cooling. The foam bubbles have more surface area and have less surface tension than water, resulting in less runoff. This increased moisture in the fuel reduces the occurrence of rekindles and smoldering. The bubbles ultimately form a foam blanket that separates the fuel from oxygen, ceasing the combustion process.

Numerous sources report that nearly 65% of firefighter deaths occur during fire attack due to structural collapse. Is department policy allowing firefighters to enter that many unsafe buildings or are firefighters making the buildings unsafe? If a structure is on fire, it already has begun to weaken. By the time the first engine arrives on scene, a structure has had several minutes to burn. Let us estimate that a firefighter in complete structural firefighting gear, including an SCBA, weighs 220 pounds and water weighs eight pounds per gallon. Let’s further surmise that the first attack crew has three persons and that crew is using a nozzle that is flowing at 125 gpm. Within the first minute of fire attack, 660 pounds of firefighters and 1,000 pounds of water — nearly a ton in total — to a structure that rapidly is losing its structural integrity. Add an additional attack line and the weight increases even more.

The U.S. Fire Administration conducted a series of studies and test fires and found that a CAF hose line is significantly lighter and easier to handle than a conventional water line. This is because the foam in the hose is mostly air. The study discovered that this line is about half the weight of a conventional water line of the same size. This reduces weight and increases maneuverability, directly reducing firefighter injury and fatigue. This study also found that CAF is much more effective at extinguishing a structure fire than just water.

The USFA study also showed that foam greatly conserves an engine’s water supply. The report indicated that CAF is five to 15 times more effective than water for extinguishment. So, a CAF-equipped engine carrying 1,000 gallons of water could extinguish the same fire load as an engine carrying 5,000 to 15,000 gallons of water — a great benefit for rural fire departments that struggle with limited water supply.

Another study, by the National Interagency Fire Center (NIFC) in Boise, Idaho, showed that 90% of water used on test fires failed to extinguish because the water did not penetrate the fire. Again, by adding foam to water, a solution with a reduced surface tension will result. This allows firefighters to cover fires with a foam blanket that inhibits the continuation of combustion, while using less water and creating a cooling effect.

A third study, conducted in Salem, Conn., tested the theory that CAF cools faster than water alone. The test measured the amount of time it took to lower the temperature from 1,000° to 212° four feet from the floor, at an application rate of 20 gpm. Water alone took nearly four minutes while CAF took only 38.5 seconds. This test showed that CAF is 480% faster at cooling than plain water when applied at the same rate. This rate also will have a direct effect on the firefighters’ fatigue and stress levels.

The USFA conducted another field study (in conjunction with the Boston Fire Department) that examined four key aspects of firefighting that are impacted by CAF: extinguishment, exposure protection, water usage and field installation. CAF provided effective extinguishing capabilities with less manual effort than would be required using water alone. It also reduced the labor required for overhaul, particularly in vehicle and trash fires. However, it should be noted that the experiments were not conclusive, as the evaluation was limited by the extent and duration of the program and by the limited number of times that CAF was tested in challenging fire situations.

Regarding exposure protection, the study concluded that CAF was a very valuable asset in a few very critical situations, with its adhesion to vertical surfaces proving very effective for exposure protection. The study further indicated that the use of CAF significantly reduces water usage, i.e., the 750 gallons of water carried would support more than 10 minutes of suppression activity. While this was not a major concern for the Boston Fire Department, which has a fire hydrant on nearly every corner, the USFA noted that CAF would be very beneficial in a rural setting with a limited water supply. Finally, the study indicated that field installation by city maintenance crews may not be the best approach, as the installations suffered some shortcomings. Also, retrofitting apparatus may compromise compartment space.

NIFC also did a study and found that in the state of Oregon, 75 cents of every dollar paid in fire claims was the result of water damage. If 75% of insurance claims are for water damage and 90% of the water that the fire service uses is not effective, could CAF be the answer? By using less water there is less chance of structural collapses due to the decreased weight, quicker fire knockdown and quicker cooling — all of which greatly increases firefighter safety and reduces fatigue.

The Los Angeles County Fire Department began using Class A foam in 1988. Using the same type house design, they set identical fires in four rooms, using an exterior fire attack from the front lawn and extinguished the fires. (See table at right.)

Water took the longest at 50 seconds and used 75 gallons of water. Class A foam was second with a knock-down time of 25 seconds using 44 gallons of water. CAF was the most effective with knock down at 11 seconds using only 16 gallons of water. That is very impressive in itself, but the interesting thing was that they were able to begin their fire attack from more than 35 feet away due to the velocity of CAF. They also experienced less water damage and pollution with CAF because of the reduction in water used and faster knockdown. And, with the CAF stream having a 33% greater reach than water or Class A foam, firefighter safety is greatly increased.

With water tenders being the most dangerous apparatus that fire departments have in their fleets due to the inherent danger of rollover, any precautions to ensure the safety of firefighters are very important. The use of CAF improves firefighter safety because by using less water there is less chance of structure collapse, and faster knock down results in less time being spent in the building.

Worth the Costs
As part of a research project for the Ohio Fire Executive program, I surveyed 50 fire departments about their use of CAF. The departments were split evenly between career and volunteer. Of those 50 departments, only six confirmed that they aggressively use CAF in fire attack.

Four of the six departments that currently use CAF stated that they had an average reduction in water usage ranging from 26% to 35%. Property loss reductions ranged from 16% to 25%, with one department reporting 36%.

All six departments responded that they would purchase a CAF system again and wished that the purchase had been made sooner. They also stated that improved firefighter safety and faster knockdown are benefits to both the department and the firefighters.

The fire service possesses many unique sources for funding, besides just tax levies and income taxes. Those sources range from federal and state grants to business grants and foundation awards. Raffles, dances, concerts and pancake breakfasts all are fundraisers that a department can undertake — if it really wants to purchase something.

Though the cost of a CAF system will be of major concern to department administrators, do these administrators truly have the best interests of their residents and firefighters in mind? Are these administrators the same ones that approve spending funds on “neat-to-have” items when purchasing fire apparatus that have little effect, if any, on the performance and functionality of the apparatus? After using CAF for nearly two years, I’m even a bigger believer in the importance of it and the role it should play in providing top quality performance, firefighter safety and customer service.

As fire officers, we must first educate our firefighters and ourselves, and then begin to educate our administrators regarding CAF. Start with the hundreds of videos that are available which demonstrate CAF operation — almost every pump manufacturer has a CAF video on its website. While there are many administrators who see the fire service as an evil and costly necessity, but the fire-extinguishment ability of CAF is not arguable. The improved safety benefits and reduction in water damage far outweigh the cost. One very important thing to remember is training. As with any new tool, everyone needs to understand its operation and how tactics and protocols need to be adjusted.

Firefighter safety is extremely important and is greatly enhanced when water usage is reduced. The savings in water is not achieved by reducing fire attack flow rates, but rather is a direct result of improved extinguishing capabilities — which are made possible by the use of compressed-air foam.

Timothy J. Paulus, OFE, serves as fire chief for two different fire departments in Portage County, Ohio: the Edinburg Township and Palmyra Township Fire Departments. He has more than 25 years experience in the fire service.

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