Water and its properties

 Why water is used as extinguishing agent.

Water is used as extinguishing because it is easily and widely available to extinguish the fire and is very effective and inexpensive. water is transportable and can be pumped from source to fire scene.
Water comes in three states that are 1. solid 2. liquid 3. vapor(steam) .

Physical properties of water.

  1. at normal temperature water exist as stable liquid it viscosity remain same at temperature ranges from 34 to 210 Fahrenheit.
  2. It has high density due to which it can project from nozzle.
  3. Specific heat of water is 1btu per lb.
  4. Due to its high latent heat of evaporation it very effective in cooling agent.

Extinguishing properties of water.

Extinguishing by cooling-
Water is used to extinguish solid fire. as the water is introduced to fire it promotes heat loss due to which fire starts to extinguish and as its physical property water is effective in cooling due to its high latent heat of evaporation.

Extinguishing by smothering.
When the water is applied to the fire or hot surface the water in its liquid form transform into gaseous form that is vapor due to which the air around the fire gets diluted and due to not supply of proper oxygen fire got extinguish.

Extinguishing by emulsification
An emulsion is formed when immiscible liquids are agitated together and one of the liquids is dispersed throughout the others. Extinguishment by this process can be achieved by applying water to certain viscous flammable liquids, since the effect of cooling the surfaces of such liquids prevents the release of flammable vapors.

Extinguishing by dilution
Fires in water-soluble, flammable materials may, in some instances, be extinguished by dilution. The percentage of dilution necessary varies greatly, as does the volume of water and the time necessary for extinguishment.

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