Foam agent vs. water

Jun 23, 2021 | News

The latest issue of the Swedish Firefighters magazine mentions the advantages of the cutting extinguisher over the negative environmental impact of foam agent.

Besides cutting through virtually any known building materials, the droplet size is one of the first recognized advantages of the cutting extinguishing method. The reason is that there is an inverted exponential relation between the droplet size and the area of water exposed to heat in any given volume of water (Försth, 2012). This means that the smaller the droplets, the greater the surface exposed to heat, and the faster the water may evaporate.

The small droplets are produced at a low water flow rate and at ultra-high pressure, which generates much less water consumption than what is generated by a conventional spray nozzle. The cutting extinguisher uses about 60 litres of water per minute, while a conventional system uses about 300 litres of water per minute.

Since the water flow rate is drastically lower, the amount of water used in a fire is reduced. Hence the spreading of hazardous substances from water runoff will also be reduced.

As the article mentions, the usage of foam agents has a negative impact on the environment. The foam agent contains tensides that alter the surfactant capacity, which allows contaminated water runoff to reach our groundwater. The foam agent is also used to disperse vapours and leaching chemical substances formed during a fire, which means that the foam agent provides a higher concentration of various substances in the water runoff.

By using a water mist produced by ultra-high pressure, almost all the water will evaporate – resulting in very little, if any, water runoff.

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Sources

Sources

Read the article in Swedish Firefighters magazine (in Swedish)