These materials are composed of halogen elements such as fluorine, chlorine, bromine and iodine.
The halogen elements consist of:
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Fluorine, Chlorine and Bromine.
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Iodine: a solid black material fumes into a purple by heating. Methane has been used because the iodine solid and toxic.
How the hallon gases chemically extinguish fire:
The hallon is methane gas consisting of one carbon atom and four hydrogen atoms, where interdependence between carbon and hydrogen atoms is destroyed; and the fluorine, chlorine or bromine replace hydrogen. The atomic weight of the new composition is heavier than atomic weight of the first composition, thus the new composition stabilizes on the surface of fire owing to increased weight, which is followed by an increase in interdependence.
Types of halogens:
Species which are used to combat sensitive electrical appliances and aircraft fires:
A - Hallon (104), consisting of carbon tetrachloride trade name of Tetra (CTC) was used frequently in the past to fight electrical fires, but it is no longer used owing to toxic gas it produces if exposed to heat.
B - Hallon (1011) consists of chlorine Bromo-methane (CB) now is used in the Federal Republic of Germany against fires category (b) because it contains bromine (Br2), which removes oxygen or hydrogen from fire. In addition, it suppresses fire and cools it in same time. Moreover, the (BCF) does not cause rust or corrosion to most types of minerals; and does not convey electricity. It is quick and effective, and can be used for all types of fires; it evaporates at 4 centigrade; therefore, the liquid being discharged from the cylinder evaporates if released.