Compressed air foam (CAF) systems use low expansion foam concentrates to produce foam of substantially higher expansion ratios. The systems include a mixing and foam generating device which meters and combines the concentrate, water, and compressed air to produce CAF, which is then piped to proprietary nozzles for application to the hazard. Use of CAF reduces the water and concentrate required to extinguish flammable liquid fires, due to higher expansion and lower required application rates. CAF can both spread across horizontal surfaces and cling to vertical surfaces. Systems must be designed by the manufacturer for the specific application.