By Waterous Staff
While compressed-air foam systems (CAFS) have their roots in wildland fire operations, the technology has proved to be a revolutionary breakthrough in structural firefighting. What follows is a thumbnail sketch of the advantages found in deploying CAFS for the structure fire attack.
1. Improved Initial-Attack Capability
Using CAFS, the fire-stopping effectiveness of first-arriving fire scene resources—equipment, personnel, and water supply—increases up to five times. In some fire situations, this allows crews to turn a defensive operation into an offensive attack. The use of CAFS has reinvented the limits of what a given total water supply and/or water delivery rate can do. Rather than protecting exposures and letting a fire burn unhindered, CAFS often is successful in darkening the main body of a large fire.
2. Reduced Fire-Scene Cycle Time
Fire-scene cycle time (when the fire apparatus arrives on scene at a working fire to when the units return, available for the next fire) is more than an important statistic. For personnel who directly engage in fire combat, exposure to heat and toxic products of combustion is reduced, thereby lessening stress and risk of injury.
3. Reduced Time Tankers/Tenders Operate on Roadways
Since much less total water supply is required to extinguish a fire when applying compressed-air foam (CAF), tankers/tenders shuttling water from static supply sources in rural areas to the fire scene spend less time on the road. This reduces the risk of roadway fire apparatus accidents and injuries.
4. Reduced Water Use
Applying CAF, the total water supply (total gallons) required to extinguish a fire is reduced to as little as one third compared with applying water alone. This also carries through to exposure protection. CAF clings well to vertical fire exposures, which means less water is wasted from runoff during exposure-protection operations. In rural areas where water supplies are scarce, if exposure-protection applications are needed, more water remains available for offensive fire attack.
5. Increased Reach Equals Increased Safety
CAF streams have greater reach than water or nozzle-aspirated foam fire streams. This provides greater standoff distances from fire hazards and greater stream penetration into structures, which translates into increased crew safety. In addition, hoselines filled with CAF are filled with about 30 percent air by volume. This makes them lighter and easier to advance through a structure during an interior attack, reducing stress on the attack team.
6. Less Chance of “Fire at Your Back”
During aggressive interior attacks of preflashover fires, applying CAF absorbs more heat than water, lessening the chance of potentially deadly fire compartment flashover. As attack teams advance through dwelling interiors and move past rooms where flames have been knocked-down, the wetting and penetrating action of a foam blanket applied on room furnishings reduces the chance of a rekindle and “fire at their backs.”
7. Superior Moisture Penetration Equals Less Overhaul
During interior structure fire attack, CAF streams cling well to horizontal and vertical room furnishings. Moisture draining from the foam blanket starts to penetrate deep-seated fire and hot spots. This results in less “dig and pull” overhaul of an interior fuel load.
8. Reduced Smoke and Steam
During aggressive interior structure fire attacks, the application of CAF preserves the thermal balance and leaves minimal smoke and steam in the atmosphere. Interior visibility is excellent, and the attack team never loses sight inside the room. Firefighters are not driven to the floor by the moisture cloud penetrating their turnout gear, which they typically experience during conventional water application through a fog nozzle.
9. Effective Structure Protection
When severe wildland fires burn into populated areas, firefighters using CAFS can pre-treat the exterior of homes with a foam blanket prior to the arrival of the approaching fire. Applied on buildings with wood exteriors, the foam application raises the fuel’s moisture content. An effective exposure-protection and fire-prevention tactic, this allows time for the fire crew to egress from the area. This takes firefighters out of harm’s way before exposure to the flames and smoke normally found when using a conventional “defend-in-place” tactic.
10. Visible Application Reduces Waste
During wildland/urban-interface fire incidents, the application of CAF on trees, brush, and building exposures is highly visible. This prevents over-application of agent and water wastage. The foam blanket acts as a short-term thermal barrier. Once the foam blanket evaporates, the need for reapplication is evident to fire crews.
For more information, visit http://www.waterousco.com/cafs-systems.html.