Metal combustion

Portable fire extinguishers are classified according to appHcabiHty Class A for soHd combustibles Class B for flammable Hquids Class C for electrical fires that require a nonconducting agent and Class D for combustible metals. Water frequently is used for Class A extinguishers bicarbonates for Class B and Class BC carbon dioxide or Freon for Class C ammonium phosphate for Class ABC and powdered salt, sodium chloride, for Class D. 

Class D Fires. The last classification is reserved for fires occurring in combustible metals such as niagnesium, litliium, sodium, and aluminum. Class D fires require special e.xliiiguisliiiig metliods and agents, such as the grapliite-based type. 

Group E. Atmospheres containing combustible metal dusts, including aluminum, magnesium, and their commercial alloys, or other combustible dusts whose particle size, abrasiveness, and conductivity present similar hazards in the use of electrical equipment. 

Standard for Combustible Metals, Metal Powders, and Metal Dusts... 

On April 21, 1995, an explosion and fire at Napp Technologies in Lodi, New Jersey, killed five employees and destroyed the facility (Figure l).19 The plant was conducting a toll blending operation to produce a commercial gold precipitation agent. The chemicals involved were water reactive (i.e., aluminum powder, a combustible metal in the form of finely divided particles and sodium hydrosulfite, a combustible solid). 

Fires involving combustible metals, e.g., sodium used as a coolant or catalyst... 

Fires are classified based on the type of fuel involved. Fuels are typically placed into three classes ordinary combustibles (like wood and paper), flammable liquids, and combustible metals. For firefighting, a fourth fire class, electrical fires, is also considered. The four main classifications of fire are shown in Table B-1. 

Class D Fire in combustible metals Fires in combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium. 

Aluminum (Al) is a silver-colored light and soft metal used as a major component of aluminum alloys, which are used to construct aircraft and vehicles, similar to Mg alloys. However, Al is known as a readily combustible metal. Thus, Al particles are used as major fuel components of pyrolants. Al particles are mixed with ammonium perchlorate particles and polymeric materials to form solid propellants and underwater explosives. The reaction between aluminum powder and iron oxide is known as a high-temperature gasless reaction and is represented by ... 

The smoke characteristics of three types of pyrolants, namely nitropolymer pyrolants composed of NC-NG with and without a nickel catalyst, and a B-KNO3 pyrolant, have been examined in relation to the use of these pyrolants as igniters of rocket motors. Though nitropolymer pyrolants are fundamentally smokeless in nature, a large amount of black smoke is formed when they burn at low pressures below about 4 MPa due to incomplete combustion. Metallic nickel or organonickel compounds are known to catalyze the gas-phase reaction of nitropolymer pyrolants. 

Arfwedson and Gmelin tried in vain to isolate lithium metal After faffing to reduce the oxide by heating it with iron or carbon, they tried to electrolyze its salts, but their voltaic pile was not sufficiently powerful (14). W. T. Brande succeeded in decomposing Iithia with a powerful battery and obtained a white, combustible metal, and Davy also obtained a small amount of hthium in the same manner (14,15, 31, 32, 33). 

The increase in the deton vel of TNT-combustible metal (such as colloidal boron) mixtures at chge diams greater than 40mm showed that metals (in particular boron) can bum-up in the deton wave of condensed expls with the liberation of an additional amt of heat which leads to the growth of... 

P. Chereau, FrP 1318773 (1963) CA 58, 13702 (1963), claims rocket fuel or incendiary composed of a combustible metal, eg, Al, Mg, or Li or a liquid fuel such as kerosine, in fine grains or droplets encapsulated in situ by formation of a polymer skin. Thus, 0.18 of 2,4-tolylene diisocyanate is dissolved in 41.8g of paraffin oil. A portion (24.5g) of this mixt is added drop by drop to a stirred soln contg 2g of ethylene glycol in 250g water. Discrete spherical particles... 

Fires involving combustible metals such as magnesium are Class D fires. Special foam compounds are needed to extinguish these fires. 

Dry Powder A tenn applied to the extinguishing agent suitable for use on combustible metals. Dusts Solid particles generated by mechanical processes such as crushing and grinding, without any chemical change from the paren material. Their size range is typically between 0.1 and 100 microns. 

CA 71, 40929g(1969) [Nitrate-fuel-binder expl compns are described which were prepd from mixts of K, Ba, or org (aliphatic or guanidine) nitrate, a fuel (C, S, sugar, a combustible metal powder, or mixts), and a resinous binder. The binder consisted of a... 

Other combustible metal dusts, such as Mg and Be, could be incorporated with Al. Heats of combustion of some of these mixtures were given... 

Class D fires involve combustible metals, such as magnesium, titanium, potassium and sodium as well as pyrophoric organometallic reagents such as alkyllithiums, Grignards and diethylzinc. These materials burn at high temperatures and will react violently with water, air, and/or other chemicals. Handle with care ... 

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