Halon Gases

Sprinkler and Halon systems are usually ceiling-mounted, fixed fire-fighting systems. One releases a deluge of water, the other a suppressive gas. Halon systems, which use a gas with the vendor name of Halon, are being phased out because Halon gases are damaging to the ozone layer. 

Instead, bromine compounds have found two other appHcations, both connected with fire. One is as a fire extinguisher. Organobromine compounds, halons, such as halon-1211 CBrClF and halon-1301 CBrFj, are used. Damage to the ozone layer caused by from halon gases has however been confirmed. For this reason, the Montreal Protocol forbids their use. 

Halon gas is immediately released into the drying chamber to suppress and smother the deflagration before it ruptures the chamber. For more information the reader should contact the suggested manufacturers in the reference list... 

Halons are gases, so a sudden discharge of a halon gas will deprive the fire of oxygen. 

Special consideration for fire protection shall be given to areas in which volatile organic liquids are stored and handled. A fire suppression system using halon gas (or an equivalent substitute) as the fire suppression agent shall be installed. An inert gas purging system may be considered for the liquid tanks. 

Carbon dioxide and certain halon compounds have a specialized application for fires in electrical equipment where a non-conducting medium is important. All are toxic to a degree, and operate either by smothering the fire or by a chemical reaction which inhibits combustion. Gas extinguishers must not be used in a confined space because of the toxic risk or the risk of asphyxiation. 

For gases and vapors, the amount absorbed is highly dependent on the partial pressure of the gas and the solubility of the gas in blood. Let s take the simple case of a gas that is not metabolized and is excreted by exhalation (e.g., an anesthetic gas or a Halon-type fire-extinguishing agent). At any given concentration (or partial pressure) in the atmosphere, the concentration in the blood will reach a steady state in the blood. Accordingly, prolonged exposure does not lead to continual buildup. 

A large number of observations, both remote and in situ, confirm this qualitative picture of the loss of ozone over Antarctica. The in situ data have come from instruments carried on small balloons and the NASA ER-2 high-altitude aircraft. Small-balloon measurements are of particle distributions and sizes, ozone, and water vapor (23, 33). ER-2 measurements, listed in Table I, are of particle size and composition atmospheric parameters such as temperature, pressure, lapse rate, and winds and trace gas abundances of 03, N20, NOy or NO, CIO and BrO, and stable gases, including CH4, chlorofluorocarbons, halons, and others (34-45). 

Whole-air sampler (C02, CH4, N20, CO, CFCs, and halons) pressurized canisters postflight analysis with gas chromatography 40... 

CADMIO (Spanish) or CADMIUM (7440-43-9) Cd Air exposure, especially of powdered form, may cause chemical to self-ignite. Finely divided material reacts violently with strong oxidizers, fused ammonium nitrate, bromine pentafluoride, lithium, nitryl fluoride, phosphorus trichloride, potassium chlorate carbon dioxide + heat, hydrozoic acid (possible explosion), nitric oxide, tellurium. Contact with acid forms explosive hydrogen gas. Contact with hexafluorobenzene forms a heat-sensitive explosive compound. May react with selenium, elemental sulfur, zinc. On small fires, use dry chemical powder (such as Puiple-K-Powder), foam, Halon, or CO2 extinguishers. 

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