Foam-based Sprinkler Systems most commonly use the balanced pressure proportioning method for flammable liquid fire protection applications. They are designed to accurately control the flow of a foam liquid concentrate into a water stream over a wide range of flow rates and pressures. Two basic types, bladder tanks and pump systems, require the foam concentrate pressure to be balanced with the water pressure at the proportioner which meters the proper amount of foam concentrate into the water stream. The resulting foam solution is piped to discharge devices protecting the hazard area.
Foam liquid concentrates are suitable for use on fires involving ordinary hydrocarbon petroleum products, and some foam may also be suitable for use on fires involving polar solvent fuels. A Vanguard fire protection system designer first identifies the fuel load and selects the foam liquid concentrate according to its ability to be used for a given fuel load. Upon selecting the foam liquid concentrate, the designer then selects equipment, including discharge devices, based on listing/approval compatibility of the equipment with the concentrate.