How do trolley-mounted water-based fire extinguishers achieve rapid cooling and effectively suppress reignition?
Publish Time: 2025-11-10
In modern firefighting equipment systems, trolley-mounted water-based fire extinguishers, with their comprehensive performance of high efficiency, safety, and environmental friendliness, have become an important tool for dealing with Class A solid fires and Class B liquid fires. Their core advantage stems from the aqueous film-forming foam extinguishing agent they use. This agent, through a unique physicochemical mechanism, significantly reduces the risk of reignition while extinguishing flames. This process relies not only on the cooling effect of water but also on the synergistic effect of the isolation barrier formed by the foam and the water film, thus achieving triple protection of "rapid extinguishing, deep cooling, and prevention of reignition."
1. Water's high specific heat capacity enables rapid cooling
Water, as the main component of trolley-mounted water-based fire extinguishers, has an extremely high specific heat capacity. This means that a unit mass of water can absorb a large amount of heat while its own temperature rise is limited. When the extinguishing agent is sprayed onto the surface of the burning material, the water evaporates rapidly. Each kilogram of water vapor can absorb approximately 2260 kilojoules of latent heat, thus carrying away a large amount of heat energy from the fire in a very short time, rapidly lowering the temperature of the burning material below its ignition point. This highly efficient cooling capacity is particularly crucial for extinguishing Class A fires involving wood, paper, cotton, and linen, fundamentally interrupting the combustion chain reaction.
2. Foam Covering Isolates Oxygen, Blocking the Three Elements of Combustion
After passing through the nozzle foaming device, the aqueous film-forming foam extinguishing agent forms a large number of fine, stable foam clusters. These foams quickly spread and cover the surface of the burning liquid or solid, forming a dense covering layer. This foam layer, on the one hand, isolates oxygen from the air, suffocating the combustion zone due to oxygen deficiency; on the other hand, it blocks external heat transfer to the fuel surface, preventing the continuous generation of pyrolysis gases. Especially when extinguishing Class B fires involving gasoline, diesel, and methanol, foam covering effectively inhibits the volatilization of flammable vapors, cutting off the supply of combustible gases at the source and preventing deflagration or fire spread.
3. Water Film Formation: Key to Inhibiting Evaporation and Preventing Reignition
The unique feature of aqueous film-forming foam (AFCF) fire extinguishing agents lies in their fluorocarbon surfactants, which rapidly spread to form an ultra-thin water film on the surface of hydrocarbon fuels. This water film floats on the fuel, further isolating oxygen and, more importantly, significantly reducing the evaporation rate of flammable liquids. For example, the water film formed on gasoline can reduce its vapor pressure by more than 70%, greatly weakening the conditions for reignition. Even if the open flame has been extinguished, as long as the water film has not completely evaporated, the fuel is unlikely to reach a flammable concentration again, thus achieving a long-lasting effect against reignition. This characteristic gives water-based fire extinguishers an irreplaceable advantage in high-risk locations such as oil depots, gas stations, and chemical workshops.
4. Synergistic Effect Enhances Overall Fire Extinguishing Efficiency
Water and foam are not simply superimposed; rather, they work synergistically to produce a "1+1>2" fire extinguishing effect. Foam slows down moisture loss and prolongs cooling time; water maintains foam stability and enhances its fluidity, allowing it to cover large areas of fire more quickly. The trolley-mounted design further amplifies this advantage—large-capacity agent, high spray pressure, and long hose configuration allow a single person to continuously and intensely spray fires covering areas larger than 30 square meters. It offers wide coverage and strong extinguishing capabilities, making it particularly suitable for initial fire control in open areas such as warehouses, workshops, and parking lots.
5. Safe and Environmentally Friendly, Widely Applicable Scenarios
Trolley-mounted water-based fire extinguishers are non-toxic and non-corrosive. The residue after extinguishing the fire is biodegradable, making them friendly to personnel, equipment, and the environment. They possess certain electrical insulation properties, allowing them to be used near fires involving electrical equipment, provided a safe distance is maintained. Combined with ease of operation and low maintenance costs, they have become an ideal configuration for public places such as schools, shopping malls, and logistics centers.
The reason trolley-mounted water-based fire extinguishers have become a mainstay in modern fire protection systems lies in the ingenious synergy of their extinguishing agent's triple mechanisms of cooling, isolation, and film formation. It not only suppresses flames within seconds but also provides long-term protection through a water film, preventing reignition. In today's world, where fire prevention and control increasingly emphasize "early extinguishing, rapid control, and prevention of reignition," this fire extinguishing solution, which integrates scientific principles and engineering practicality, is continuously safeguarding the safety bottom line of countless places.
