Proportioners which are referred to as 'Positive-pressure proportioning systems' according to the European standard EN16327 are used to generate fire extinguishing foam or surfactant water. Therefore, a foam or wetting agent must be admixed to the extinguishing water flow at a high rate of precision. The relief forces of municipal and voluntary fire brigades as well as factory fire departments need equipment to rely on for their demanding job. This was the focus when the FireDos proportioners were designed, which offer some great benefits for effective fire-fighting. This is what makes the FireDos product concept outstanding: The specially designed water motors and proportioning pumps work flow-proportionally, allowing precise proportioning across a wide range of water flow rates and pressures.


The DZ1000 portable proportioner has been developed, especially for different firefighting scenarios. Highly versatile for mobile use, the DZ1000 guarantees precise foam concentrate proportioning across the entire operating range, from 140 l/min to 1000 l/min. It takes only a few turns to switch between the proportioning rates of 3%, 1% and 0.3% during operation.

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FireDos foam proportioners for fire brigades: 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 the ball valve (3) between suction of the foam agent and flushing mode.
The following animation illustrates the proportioner's working principle as well as the testing mode where no foam or premix is generated. Please click ON and OFF to see.


  • Driven just by the water flow. No electricity is required, thus preventing additional load to the vehicle's power supply.

  • The specially designed pump allows keeping the proportioning rate at all water pressures, even if they vary.

  • The selected proportioning rate is instantly and precisely at hand whenever the next job starts. Here is why: The water motor's number of revolutions is determined directly by the current water flow rate. Whereas, an electric motor would have to adjust the number of revolutions first.

  • Flushing can be skipped: After operation, the foam/wetting agent can remain in the proportioning pump and is even supposed to do so. One more reason why the set proportioning rate is available instantly and precisely when operation is started again.

  • Course and length of the hose lines on-site play no role since the water pressure has no influence on the proportioning rate.

  • Perfectly suited for aerial/turntable ladder trucks: The height difference between proportioner and discharge device does not matter as the specially designed proportioning pump works independently of the backpressur.

  • Also suitable for alcohol-resistant and fluorine-free foam agents with a very high viscosity as we have dimensioned the proportioning pump especially for this challenge.

  • Suitable for all discharge devices:

    • Jet spray nozzles with/without a foam attachment.
    • Medium, heavy and adjustable foam nozzles.
    • High-expansion foam generators.
    • Monitors.


The type name starts with the maximum possible water flow rate in litres per minute, followed by the proportioning rate(s) or the proportioning range in percent.

Types for fixed installation in fire trucks or roll-off containers:

Series Water flow rate* Operating pressure Proportioning rates
FD500 ca. 60 – 500 l/min   Fixed proportioning rates:
FD1000 ca. 100 – 1000 l/min up to 16 bar 0.5%
FD1600 ca. 150 – 1600 l/min   1%
      3 / 3% (except FD500)
FD2500 ca. 250 – 2500 l/min   Stepwise adjustable proportioning rates:
FD4000 ca. 400 – 4000 l/min   0.2% / 0.3% / 0.5%
FD6000** ca. 500 – 6000 l/min up to 16 bar 0.3% / 0.7% / 1% 
FD8000** ca. 500 – 8000 l/min   1% / 2% / 3%
FD10000** ca. 600 – 10000 l/min   1% / 2% / 3% / 4% / 5% / 6% (except FD500)
FD15000** ca. 800 – 15000 l/min    
FD20000** ca. 800 – 20000 l/min   Stepless adjustable proportioning rates:
      0.05 - 0.5% up to FD10000
      0.1 - 1% up to FD10000
      0.3 - 3% up to FD4000
      0.6 - 6% up to FD2500
  *without the optional flow reduction
  ** Up from FD6000, upon request

Types for mobile use:

Series Water flow rate Operating pressure Proportioning rates
      Stepwise adjustable proportioning rates:
FD-DZ 5 ca. 60 – 500 l/min up to 16 bar 0.3% / 0.7% / 1%
      1% / 2% / 3%
      0.3% / 0.7% / 1%
FD-DZ 10 ca. 100 – 1000 l/min up to 16 bar 1% / 2% / 3%
      0.3% / 0.7% / 1% / 2% / 3%
      Fixed proportioning rates:
FD500 ca. 60 – 500 l/min   0.5%
FD1000 ca. 100 – 1000 l/min up to 16 bar 1%
FD1600 ca. 150 – 1600 l/min   3%
FD2500 ca. 250 – 2500 l/min   6%
      3 / 3% (except FD500)
      Stepwise adjustable proportioning rates:
      0.2% / 0.3% / 0.5%
      0.3% / 0.7% / 1% 
      1% / 2% / 3%
      1% / 2% / 3% / 4% / 5% / 6% (except FD500)
      Stepless adjustable proportioning rates:
      0.05 - 0.5% up to FD10000
      0.1 - 1% up to FD10000
      0.3 - 3% up to FD4000
      0.6 - 6% up to FD2500

Further proportioning rates are possible. Please ask us.

Special equipment options.

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 to the suction side of the fire pump.

As soon as the water consumption at the outlet of the extinguishing water line is sufficiently high, the start-up flow reduction must be switched off by using a ball valve.

Additional suction connection for a second, permanent foam agent tank installed in the vehicle.
Switching takes place by use of a ball valve.

Pneumatic ball valves.
For remote-controlled operation, all ball valves at the proportioner can be fitted with pneumatic drives for integration into an on-board control system.

Emergency operation of pneumatic ball valves.
In the case of malfunction of a pneumatic drive, it is still possible to operate the ball valve by turning the handle while pushing it down.

5/2-way magnetic valve.
The pneumatic drives of all ball valves are double-acting.To actuate the pneumatic drives, 5/2-way magnetic valves are available.

Electric adjustment of the control gear.
The stepless adjustment of the proportioning rate can take place by use of an electric 24V DC drive instead of manual operation, for integration into an existing control system. For position indication, a signal of 4...20 mA (two-wire technique) is available to show the proportioning rate on a vehicle-mounted display.

Measurement of the water flow rate.
The number of revolutions of the water motor is measured by a proximity switch. This figure is used to calculate the water flow rate in l/min, which is shown on a 24V DC display intended for installation at a suitable place in the vehicle.

Check valve in the flushing line:
If no shutoff device exists between the fire pump and the FireDos proportioner, this check valve must be fitted to conduct a proper dry suction test. In addition, the check valve prevents a foam agent tank placed higher than the FireDos proportioner from running empty.

Cylinder cut-off.
The proportioning pumps usually include three clinders. One or two of these cylinders can be cut off in order to reduce the proportionig rate or to extend the extinguishing rate range.
This enables the following additional proportioning rates:

  • instead of 1 % → 0.3 %, 1 % or 0.3 %, 0.7 %, 1 %
  • instead of 3 % → 1%, 3% or 1 %, 2 %, 3 %
  • instead of 3 % and 6 % → 1 %, 2 %, 3 %, 4 %, 5 %, 6 %
  • instead of 0.1 - 1 % → 0.03 – 1 %
  • instead of 0.3 – 3 % → 0.1 – 3 %

Compact version.
In the compact version, the proportioning pump is fitted on top of the control gear, instead of beside it, and is driven by a toothed belt. This makes the FireDos proportioner shorter and higher than in the standard stretched version.

Screwed flanges.
Up to type series FD2500, the water motors have male threaded connections which can be supplemented by screwed flanges. As from the FD4000 range, the flanges are provided as an integral part of the cast water motor housing.

Water drain valves
for water motor, proportioning pump and the connecting pipework in case of a risk of damage by frost.

Pipe elbow.
A pipe elbow is available for the FD1000 type series with a stepless adjustable proportioning rate to simplify the water motor's outlet connection. The pipeline then passes downward through the support frame.

Check valve in the proportioning line with a higher opening pressure.
For the proportioning line of type series FD500 and FD1000. If no shutoff device exists between the fire pump and the FireDos proportioner, this check valve must be fitted to conduct a proper dry suction test. Provided as a standard feature as from FD1600

Shaft extension for the control gear.
Extension of the shaft between the control gear and the adjusting wheel that is used for setting the proportioning rate. This extension brings the adjusting wheel closer to the operator.


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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