A Technological Analysis in the Context of the 2025 Record Season

In large-scale fire scenarios, particularly in remote areas lacking developed water supply infrastructure, the availability of water becomes the most critical limiting factor of the entire operation. The logistics of water supply, whether through kilometre-long hose lays from open water sources or via a continuous shuttle of water tenders, are resource-intensive and time-consuming. Every minute spent on water procurement is a minute in which the fire can advance unchecked. In this context, maximising the efficiency of every litre of water deployed is of the highest strategic importance. Water in its pure form, however, quickly reaches its physical limitations. Its high surface tension (a result of the strong hydrogen bonds between molecules) causes it to bead up and run off many surfaces, especially dense organic materials like humus, pine litter, or charred timber. It flows away superficially, often evaporating from the immense radiant heat before it even reaches the combustible material, and fails to penetrate deep-seated embers. These smouldering hotspots, often buried deep beneath the surface, are the primary cause of re-ignition and can cause a supposedly extinguished area to erupt into flames once more.

The physics-based solution to this problem lies in the targeted modification of the water's properties through the creation of wetting agent. By proportioning specific additives, such as multi-purpose foam concentrates or dedicated class A foam agents, into the water at very low concentrations, the hydrogen bonds are broken, and the surface tension is drastically reduced. This effect, which literally makes the water "wetter," enables deep penetration into porous materials. The modified extinguishing water no longer merely extinguishes the fire on the surface, but penetrates the burning material, cools it from the inside out and effectively smothers deep-seated embers.

The strategic importance of this method is significant: scientific studies and countless operational experiences confirm a reduction in water consumption of up to 50%. This is not a marginal gain but a potentially decisive operational advantage that can double the time on station, halve the logistical effort, and ultimately mean the difference between controlling a fire and its catastrophic escalation.

The success of this highly effective tactic, however, is inextricably linked to the precision of the proportioning technology employed. Wetting agents achieve their optimal effect within a very narrow concentration window, typically between 0.1% and 0.5%. Any deviation from this optimum has negative consequences: too low a concentration results in an insufficient reduction of surface tension, squandering the efficiency potential. Too high a concentration leads to the unnecessary waste of expensive concentrate and the unwanted creation of a light foam that lacks the desired deep-penetrating effect. A precise, reliable, and, above all, repeatable proportioning accuracy throughout the entire operational period is therefore an indispensable technical requirement for any modern fire appliance deployed in wildland firefighting.

To ensure this precision under the highly dynamic and often adverse conditions of a fire incident, purely mechanical, pressure-independent proportioning systems have established themselves as the technologically superior standard over older technologies in fire services worldwide. Whereas traditional Venturi inductors are highly dependent on inlet pressure and flow rate, with their performance becoming unpredictable during pressure fluctuations, the principle of an alternative purely mechanical system is based on a water motor driven directly by the fire water stream, which in turn drives a high-precision piston pump. Through this purely mechanical coupling, the ratio between the water- and concentrate flow rates is fixed and remains constant and exact across an extremely wide operating range. Regardless of pressure fluctuations caused by varying engine speeds of the fire pump, the opening and closing of nozzles (pulse-firefighting method), the quality of the extinguishing agent produced is always guaranteed. 

The strategic advantages of this technology in the context of wildland firefighting are manifold:

Guaranteed Precision and Reproducibility: Constant and repeatable proportioning rates enable reliable operational planning and the extinguishing water and foam agents are used in an economically and ecologically responsible manner.

Maximum Operational Reliability and Robustness: The deliberate avoidance of sensitive electronics, vulnerable sensors, or complex control loops for managing the proportioning process minimises the probability of failure in harsh operational environments. Heat, dust, vibrations, and moisture have little effect on such purely mechanical systems. This inherent robustness is a critical criterion for safety-critical equipment, where failure in the field can have catastrophic consequences.

High Tactical Flexibility: Modern systems allow personnel to switch between different pre-set proportioning rates at the push of a button or lever. This permits a split-second change in tactics, for example, from wetting agent (e.g., 0.3%) for the intensive attack on ground fires and embers, to the production of firefighting foam (e.g., 1% or 3%) for defensive measures such as creating firebreaks to protect buildings or critical infrastructure.

The greatest and least predictable danger for crews stems from direct confrontation with the fire front. Extreme radiant heat, which can cause severe burns even at distances of tens of metres, unpredictable wind changes that can redirect the fire in seconds, and eruptive fire phenomena such as fire whirls or flashovers make attacking with hand-held nozzles an extremely high-risk endeavour. The strategic necessity of keeping personnel and high-value vehicle assets out of the immediate danger zone while simultaneously delivering a massive, concentrated extinguishing effect inevitably leads to the use of remote-controlled, high-performance delivery systems.

Firefighting monitors, whose development was originally driven by the requirements of fixed fire protection in heavy industry, are now an indispensable tool on modern fire engines for firefighting.

Innovation for Maximum Reach and Efficiency: A critical factor for the strategic effectiveness of a monitor is its throw range. Advanced, flow-optimised designs, such as the "Oval-Flat-Design" developed by FireDos, minimise pressure losses within the monitor by specifically reducing turbulence. This results in a more cohesive, laminar water flow resulting in a significantly greater throw range for the same inlet pressure at the pump. For fire services, this means that targets can be reached from a greater, and therefore safer, distance. Alternatively, the same reach can be achieved with lower pump power and thus reduced fuel consumption, which extends the autonomous operational time of the vehicle on site.

System Integration as the Key to Reliability: A further, often underestimated strategic advantage lies in the integration of the monitor, its control system, and the vehicle (e.g., via a CAN bus interface) from a single source. Instead of relying on complex and potentially fallible interfaces between components from different manufacturers, vehicle bodybuilders and end-users receive a reliable, comprehensively tested system solution. This not only increases operational reliability but also simplifies operation, maintenance, and service over the entire lifecycle of the vehicle.

Scalable Performance Classes for Tailored Mobile Applications: For installation on fire engines, the following performance classes have become established in fire and rescue services in recent years:

•   Low flow (up to 2,000 l/min): The compact entry-level model, ideal as a front-mounted monitor on fire engines to massively increase their firepower and enable fast, targeted attacks or asset protection. An optional flat-spray nozzle is available, which produces a fan-shaped jet, perfect for extinguishing larger burning areas.
• Medium flow (up to 2,500 l/min): A high-performance all-rounder, perfectly suited as a roof-mounted monitor on fire engines, representing an optimal balance between dimensions and extinguishing power.
• High flow (up to 4,000 l/min): The powerhouse for medium to large tanker fire engines or hook-lift containers. With this capacity, wide fire fronts can be effectively knocked down, and large assets can be safely protected even from a considerable distance. 

In addition to the monitors listed, suppliers offer fire monitors for up to 60,000 and 80.000 l/min. These fire monitors are generally trailer mounted. Optionally fire monitors can be equipped with dry powder nozzles for use on fire engines in industrial facilities. In addition, as an example, FireDos monitors can be equipped with flexible AMPN multi-purpose nozzles, which allow for continuous adjustment of the jet pattern (hollow jet/spray jet) as well as adjustment of the flow rate during operation. Radio remote controls allow the operator to steer the monitor from a safe position with an optimal overview of the scene.