Periodic performance checks must be made on the foam distribution systems of aircraft rescue and fire fighting (ARFF) vehicles to maintain mission readiness. During these checks, the vehicles discharge a fire-fighting agent known as Aqueous Film Forming Foam (AFFF) as run-off. The resistance of AFFF to biodegradation, the toxicity of its constituent butyl carbinol, and its extreme foaming activity pose environmental concerns. Therefore, after testing, the AFFF must be collected and treated at high cost, which has deterred some Department of Defense (DoD) fire departments from conducting the necessary performance checks. In this project, an external Universal Stationary/Mobile NoFoam Unit (USNOFU) containing a benign, surrogate fluid for testing the distribution system was demonstrated on ARFF vehicles at the following four DoD facilities: Marine Corps Air Facility Quantico, VA; Tyndall AFB, FL; Fort Benning, GA; and Naval Air Station Fallon, NV.
The NoFoam Unit hardware consists of piping, flow monitoring sensors and a control panel, which displays the discharge flow rate of the surrogate solution. The system is easily towed and can therefore be stationary or mobile. The ARFF vehicles are connected to the unit, the AFFF concentrate is isolated during the testing, and discharge of the AFFF foam to the environment is thereby eliminated. The longer amount of time required for system checks (i.e., 10-15 minutes) with the USNOFU is more than offset by the time that would be required for collection of AFFF run-off. Also, the firefighter gains added confidence in the flow distribution system because the surrogate test fluid is a visible dye-water solution, which can be observed as it discharges.
A minimum of six months of data was collected on nine of the ten ARFF platforms tested. All platforms reduced or eliminated the AFFF wastewater that would have been generated from weekly scheduled nozzle discharge checks. The NoFoam Unit did not malfunction or break down on any of the platforms. Previously unknown deficiencies in the AFFF foam distribution systems also were observed in nine of the ten platforms tested.
Eliminating the discharge of AFFF removes the environmental hazard, reduces AFFF purchase costs, and reduces the cost of waste disposal. Mission readiness is not jeopardized, and compliance with environmental regulations and attainment of waste minimization targets are facilitated. Annual disposal cost savings were estimated at $52,000 per ARFF vehicle, which translate to an annual savings of $62 million for the DoD's 1,200 ARFF vehicle inventory and a 2-3 month payback period on the required $22,000 capital investment for a NoFoam Unit with three retrofit modules. Two of the host DoD facilities retrofitted modules for their ARFF vehicles upon completion of the demonstrations. (Project Completed - 2004)