Foam extinguishing principle

Four conditions required for combustion process:

1, combustible. 2, atmospheric oxygen. 3, to reach 4, fuel burning of combustible and quantitative atmospheric oxygen.

The above conditions are indispensable, otherwise it will not burn. In chemistry, combustion is fast fierce reaction between a fire caused by burning, and atmospheric oxygen.

In order to achieve the extinguishing effect, must be burning material with oxygen in the air or from the burning material cooling to the ignition of the following. Bubble is to achieve the extinguishing effect by this way. The following is used in the use of foam when the bubble:

Isolation effect

The foam layer can be closed combustion zone and the surrounding air isolation and continuous supply of oxygen to prevent burning.

Cooling effect

Precipitated from the bubble in the water in the top of the flame evaporation, evaporation and absorption heat of combustion zone, the combustion reaction rate between the object and the decrease of atmospheric oxygen. Foam in solution overflow water can reduce the combustion temperature of an object.

Inhibitory effect

The use of light or medium space, channel, a bubble into the workshop area in place, can inhibit the combustion of oxygen and combustible gas required in the air.

Covering effect

The foam layer sealed can cover the burning object, prevent combustion of combustible gas in fuel reburning continue to shine, to avoid. In the class B fire, airtight foam layer can prevent the leakage of combustible gas, avoid gas discharged harmful to the environment. At the same time, significantly reducing the risk of fire.

Insulation effect

Foam low thermal conductivity, can isolate unburned combustible material, and prevent the fuel has been extinguished by the influence of fire and heat radiation.

Polymer film

When the fire extinguished the polar solvent (such as alcohol, ketone, ester), polymer containing a bubble in the composition of the material on the formation of polymer film.Polymeric membrane as the isolation layer floating between flammable solvent and foam, foam to prevent liquid was destroyed. Only the gentle foam, polymer film to stable and continuous formation.

Water film (AFFF effect)

Bubble is a very thin water film in nonpolar hydrocarbons. In front of this film flow in the bubble, with excellent liquidity, fire resistance, can prevent fuel reburning.

Do not need to use inflatable foam solution will form a water film. If the sprinkler, spray gun, the use of foam solution in nozzle.

Foam composition

The proportion of mediation will concentrate a fixed number of foam with water and pour the mixture, produce foam solution. Then the machine will foam solution mixed with air bubbles in the manufacturing, the expansion of foam solution. If the air ratio is low, is to produce heavy "wet" bubble. If a high proportion of air, generating medium "wet" or "dry" lighter foam. In any case, the production of foam volume ratio of foam solution volume must be several times larger.

Mixing ratio

Said foam solution, the proportion of foam concentrate into the water. The proportion of 3% said 3 foam concentrate and 97 mixed water. In the actual process of fire, foam concentrate by proportional regulator or pre mixing pump add. The proportion of the range according to the material type, foam concentrate fire, burning in different types, 1%-6%. When using artificial foam concentrate as wetting agent, concentrated liquid proportion need to add 1%.

principle