Stationary proportioners for extinguishing systems.


Many fire scenarios require foam for successful extinguishing. To produce these extinguishing agents, the foam agent must be admixed to the water flow at high precision. This is what makes the FireDos product concept outstanding: The specially designed water motors and proportioning pumps of the foam proportioners work flow-proportionally, allowing precise proportioning across a wide range of water flow rates and pressures. Furthermore, the proportioners allow a cost-saving and eco-friendly testing of the proportioning rate while no foam or premix is actually produced. Typical application fields are any place where flammable substances, particularly fluids, are produced, transported, stored or disposed of. This includes extinguishing systems for tank farms, jetties, hangars, high-rack warehouses or pump rooms.


The FireDos product concept has been optimised, resulting in GEN III, the latest generation of proportioning systems. GEN III is characterised, among others, by more compact dimensions, reduced pressure loss, improved cylinder cut-off and optimised delivery of highly viscous and pseudoplastic foam agents.

GEN III proportioning system


FireDos foam proportioners: purely mechanical, with a constant proportioning rate.

  • The water motor (1) is driven by the extinguishing water flow which passes through it.
  • In turn, the water motor drives the proportioning pump (2). This pump pulls in the foam agent and delivers it into the extinguishing water pipework.
  • Switching between actual proportioning of the foam agent and passing it back to the atmospheric storage tank is done by use of the ball valve (3).


  • Driven just by the water flow

    No electricity and no backup power supply required.

  • For all types of foam agents

    Also suitable for extremely high-viscous, alcohol-resistant and fluorine-free foam agents.

  • Precise and constant proportioning rate

    Maximum operating range, while maintaining the proportioning rate at all water flow rates and under all pressure conditions.

  • For all types of extinguishing systems

    Thanks to the wide operating range, the proportioners are qualified for all types of extinguishing systems like sprinkler, deluge, wet and dry extinguishing systems.

  • No water loss

    As the water motor is a closed system, no water is lost.

  • Quick installation and start-up

    The proportioner is supplied ready-to-install. Any further adjustment when starting up is neither necessary nor possible.

  • Cost-saving and eco-friendly

    Save costs, testing the proportioning rate in an eco-friendly way without generating foam or premix!

  • Minimal foam agent consumption

    Going easy on the foam agent, just letting the amount pass which is actually needed: no warming by circulation.

  • No time limits for fire-fighting

    The separate foam agent tank is unpressurised and can therefore be refilled whenever necessary.



Optional equipment.

Pressure-relief valve for the foam agent return line on site
The pressure-relief valve is permanently set to an opening pressure corresponding to the pressure of the extinguishing water line. This way, testing and measurement of the proportioning rate through the return line take place under live conditions equal to a real extinguishing operation.

Magnetic-inductive flow meter for the foam agent return line on site
Intended to measure the foam agent flow rate passed back to the tank through the on-site return line for testing purposes. If the water flow rate is measured at the same time, the proportioning rate then can be determined very easily.

Flow meter for the extinguishing water
Using a proximity switch at the FireDos proportioner, the water motor's number of revolutions is measured. The current water flow rate is calculated in litres/minute from the number of revolutions and shown on an LED display.

Switch for electric monitoring of the 3-way ball valves
Switch for integration into an on-site control system. The position of the manual ball valves to change between "Admixing/Returning" and "Flushing/Priming" is monitored by the electric switches.

Check valves in the proportioning line with a higher opening pressure.
The check valves installed in the flushing line and the proportioning line prevent both the proportioning pump and the tank, if placed higher than the proportioner, from running empty in case of a pressureless extinguishing water line.

They prevent unintended running-empty of the foam agent tank under particular extinguishing system conditions.

Variant for operating temperatures of up to 80 °C.
Using a special variant of rotor vanes in the water motor allows operating the unit at ambient temperatures of up to 80 °C.

Variant for static pressure >16 bar.
If in a static situation (no extinguishing water flow) the maximum allowed pressure of 16 bar is exceeded, modified seals for the water motor are available, suitable for static pressures of up to 25 bar.

Cylinder cut-off
Opening a ball valve at single cylinders of the proportioning pump leads to mere
circulation of the foam agent in these cylinders instead of further delivery through
the pump. Correspondingly, the proportioning rate is reduced.
Two different variants exist:

■ ⅓ of the initial proportioning rate by cutting off two of three cylinders.
Example: Instead of 3% → 1% and 3%
■ ⅔ of the initial proportioning rate by cutting off one of three cylinders.
Example: Instead of 3% → 2% and 3%

Variant suitable for seawater instead of freshwater.
With correspondingly adapted materials.

Control valves.
Various types of control valves made by Bermad and Inbal can be used for the following purposes:

  • To protect the water motor against overload.
  • To engage a second, parellel-installed proportioner and thus to extend the water flow range.

Please ask us!

Screwed flanges for water motors with male-threaded connections up to the type series FD2500. As from the FD4000 range, the flanges are provided as an integral part of the cast water motor housing. All flanges are available as DIN and ANSI versions.

Drain valves.
To protect the water motor, the proportioning pump and the connecting pipework from damage by frost.

Start-up flow reduction.
Allows reducing the minimum water flow rate from which the FireDos proportioner can be operated to approx. ⅓ of the amount without a start-up flow reduction.The water flow rate passing through the water motor is initially higher than the amount that actually leaves the extinguishing water line at its end: Downstream of the water motor, a constantly high differential water flow rate is passed back to the water tank or water supply.

Electric ball valves.
All ball valves of the proportioner are available as an electric version (24V DC or 230V AC) for integration into an on-site control system.

The following documents can be provided with FireDos proportioners if required:

  • Laminated DIN A3 brief instruction manual
  • Test/inspection report
  • Factory certificate 2.2 according to DIN EN 10204
  • Acceptance test/inspection certificate 3.1 according to DIN 10204 for a limited scope
    of parts
  • Nozzle Load Calculation for the water motor, possible from type series FD4000 upwards.


More than 12 000 FireDos Proportioners have been installed worldwide. You can find a small selection of them here. We will be pleased to provide you with further images or with references.

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