Foam Proportioner is a device for mixing foam concentrate with fire water to become a foam solution before sending to the discharge devices. Generally, this device utilize a fire water flow through venturi orifice to induce a negative pressure area which will draw foam concentrate from the container into the stream in the desired ratio. The ratio is controlled by the flow rate and pressure of the water flowing through the device and hence must be calculated on case by case basis to get the desired mixing ratio.