29 Nov 2022

For decades, aqueous film-forming foam compounds (AFFF) based on fluorosurfactants were used in firefighting. These ensure unsurpassed extinguishing results, especially in the case of liquid fires. However, they have recently come under criticism because of their effect on organisms.

Although fluorine-containing additives may currently still be sold and used in many countries, the mandatory disposal of contaminated fire-fighting water or residues in the soil makes them increasingly unattractive. In the medium term, a ban is also likely.

The goal: Results similar to AFFF

In AFFF use, both the formation of foam and the formation of a gas-tight water film ensure this separation

Water is and remains the most important extinguishing agent. In the case of liquid fires, however, it is necessary to create a stable separating layer between the liquid and the ambient oxygen. In AFFF use, both the formation of foam and the formation of a gas-tight water film ensure this separation.

However, with the current Rosenbauer use of fluorine-free foam compounds in practice, there is no water film formation. An insulating effect can only be achieved by forming a stable low expansion foam.

Use of fluorine-free foam compounds

Current foam test procedures require the use of a standardized low expansion foam nozzle for the certification tests. Fluorine-free foam compounds that meet the criteria of ICAO Level A, B or C can actually provide the required extinguishing performance under the conditions applied.

However, since AFFF extinguishing agents achieve this excellent extinguishing performance in both foamed and un-foamed states, many fire services have opted to use roof turrets without foam branch pipes in recent decades.

Rosenbauer offers the appropriate extinguishing technology

If a switch is made to the use of fluorine-free foam compounds, the extinguishing effect may lessen as the required foam expansion may not be achieved. However, with appropriate extinguishing technology, the enrichment with air can be significantly improved.

Rosenbauer offers the right technologies for this. In this way, both environmental protection and extinguishing efficiency requirements can be met.

How can Rosenbauer Customer Service help?

In CAFS systems, compressed air is introduced into the water-foam compound mixture

Basically, two technologies are available for this: foam branch pipes and compressed air foam systems (CAFS). Foam branch pipes for turrets suck in air and form low expansion foam. With the help of deflectors, a flat jet can optionally be formed from the full jet to achieve better area coverage. These foam branch pipes can be retrofitted by Rosenbauer Customer Service.

In CAFS systems, compressed air is introduced into the water-foam compound mixture, before it exits the water turret. Due to the expansion of the air component on discharge, the discharge velocity increases significantly.

High-performance CAFS systems

The result is a very straight throw pattern and a homogeneous and stable foam. This allows excellent throw ranges even at a low angle of attack, reducing the influence of the wind and making aiming easier. This ensures an even more efficient application of the limited extinguishing agent.

The prerequisite for this are high-performance CAFS systems, such as those from Rosenbauer, with which the required output volumes can be realized. Contact Rosenbauer Customer Service for questions concerning the installation of CAFS systems in existing vehicles.

Rosenbauer Customer Service

Rosenbauer service technicians are trained to the highest standards, are certified, and have in-depth and technical manufacturer know-how. Through its first-class service, Rosenbauer ensures that vehicles and equipment are always ready for operation to protect and save lives.