The wide range proportioner accurately proportions foam concentrate into a water stream over a wide range of system flow rates and is configured to proportion foam concentrate at a 3% ratio. Wide range proportioners are an integral part of an approved foam system. In addition to the wide range proportioner, the main components of the approved foam system are specific foam concentrate(s), a foam storage tank, a concentrate control valve and foam discharge devices. The discharge devices most commonly used are closed head sprinklers but nozzles, monitors, grate nozzles, foam makers and foam chambers can also be used. The system must be designed so that the wide range proportioner can accurately proportion foam over the range of flow rates expected during the system operation. Intended for use primarily in wet pipe and preaction type systems, the wide range proportioner has the capability to accurately proportion foam concentrate into the water supply at low flow rates as required when only a small quantity of sprinkler heads have activated.