To extinguish a fire efficiently, larger water reach of surface area is a key factor due to faster evaporation and lower water damage in the fire scene. In other words, the smaller the water droplets can be made, the larger the surface area is to be formed. Undoubtedly droplet size matters, but it is only one of the supporting factors increasing the cooling effect yet reducing the chock effect.
What is crucial, let’s not forget, is the amount of water discharged per time unit. Water can absorb heat and energy from the fire. The more water is provided, the more energy is taken away from the fire in a certain time period, thus extinguishing the fire better and faster when the water is vaporized. In short, the amount of water is no less important than the droplet size to successfully extinguish the fire.
The droplet size contributes to better water evaporation while the pressure of the extinguishing system merely helps generate certain sizes of droplets. Higher pressure, however, does not necessarily means that fires can always be extinguished successfully.
Firefighters all over the world do wish that they could have an all-in-one extinguishing system for so many different types of fires and fire sizes. In this sense, how a fire department determines what types of extinguishing system to procure based on the potential dangers becomes the top priority and a perpetual concern.
Rosenbauer Group, one of the world’s three largest firefighting system manufactures, provides fire departments with a wide variety of extinguishing systems with the desired flow rates, extinguishing efficacy, and vehicle applications that are required for all classes of fires.
The high-pressure extinguishing system Rosenbauer invented in the 1950s is still in use today through continuous improvement and not the least outperformed by ultra-high pressure or compressed air foam counterparts. In fact, no single extinguishing system can be considered “only true” when there are normal pressure, high pressure, or compressed air foam systems for you to choose.
The type of extinguishing system that a fire department should choose depends on the type of potential risks it might face, which needs to be dealt with without any cognitive bias or stereotype. Up to now, Rosenbauer’s NH centrifugal pump has been a market-leading two-in-one firefighting product that combines both the normal pressure and high-pressure pumps on one pump shaft. The high-pressure pump features a 4-stage centrifugal pump with a high performance (400 l/min at 40 bar) and a flat pump curve, perfect for the parallel use of twin high-pressure nozzles.
In addition, the NH pump is well-designed to be integrated with an around-the-pump foam proportioning system at the high pressure (HP-FIXMIX) so that water and foam can be discharged simultaneously yet independently through the normal pressure pump and the high-pressure pump, respectively.
The quality of the high-pressure foam is still an open question because the foam discharged at a higher speed from the foam pipe nozzle turns out to be homogeneous and stable as compared to that from the normal pressure extinguishing systems. Moreover, the discharge distance is longer than that of its normal pressure counterparts.
After all, high-pressure foam can be competing on quality with compressed air foam (CAFS).
