Pyrotechnic devices

Pyrotechnics have been used for military purposes for many centuries as propellants, explosive charges, time fuses, and for illumination. There are still many uses of pyrotechnic devices in military appHcations, where they provide portability, storage stability, simplicity of operation, safety, and the reUability required for military scenarios. The devices must be capable of surviving rough handling, weather extremes, and extended storage, yet reUably perform when called on to function. 

Smoke-Generating Devices. Smoke generators are used by the military for daytime obscuration and signaling. For field use where portable stable systems ate requited, pyrotechnic devices are often employed. The primary composition since the 1940s has been HC smoke, which generates a cloud of zinc chloride, ZnCl, smoke by a series of reactions between hexachloroethane, C2Clg(HC), zinc oxide, and aluminum (3) (eq. 4—6). The zinc regenerated in... 

A delay element is a self-contained pyrotechnic device consisting of an initiator, delay column and an output charge or relay, ail assembled into a specially designed inert housing. It provides a predetermined inter/al between initiation and functioning of a device... 

In devices which can tolerate moderate ignition delay, further development of non-primary initiators (Refs 31, 77, 97 112) will extend the storability, the manufacturing safety, the electromagnetic Held and spark sensitivity and the high temp compatibility of pyrotechnic devices... 

Anon., Lab. Accid. Higher Educ., item 7, Barking, HSE, 1987 A pyrotechnic device was being prepared by loading 16 g of a mixture of 73% potassium chlorate, 24% gallic acid and 3% gum tragacanth into a 9 mm copper tube 280 mm long, when it exploded violently and caused shrapnel injuries. Such mixtures are very friction-sensitive. 

Mixtures of sulfur and potassium perchlorate, used in pyrotechnic devices, can be exploded by moderate impact. All other inorganic perchlorates form such impact-sensitive mixtures. 

Pine Bluff Arsenal in Arkansas was reported to be the major facility manufacturing smoke and pyrotechnic devices containing hexachloroethane for the military (Gordon et al. 1991). It was estimated that between 1966 and 1977 this facility used an average of 192,802 pounds of hexachloroethane annually (Kitchens et al. 1978). Data on quantities of hexachloroethane currently consumed for military and civilian uses were not located. 

Hexachloroethane is an industrial chemical which is not known to occur naturally. It is not produced for commercial distribution in the United States, but is imported for use in military smoke and pyrotechnic devices and as an intermediate in the organic chemicals industry. It is released to the environment from these uses, primarily to the atmosphere. 

Recent data reported to the TRI indicate that environmental releases of hexachloroethane from manufacture and industrial processing total about 51,088 pounds (TRI93 1995). However, these data do not include releases from the manufacture and use of military smoke and pyrotechnic devices, since federal facilities are not required to report releases to the TRI. 

Releases may also occur from the use of this chemical in smoke and pyrotechnic devices. Hexachloroethane content of the smoke devices is about 44.5-46% of the total solid material. The smoke device bums, producing smoke which is mainly zinc chloride, but contains some hexachloroethane. It was estimated that about 0.3-5% of the mass of the reagents in the device is released to air as hexachloroethane in the smoke, assuming a 70% bum efficiency (Katz et al. 1980 Novak et al. 1987). On this basis, it was estimated that during 1982-1984, a maximum of about 6,683 kg (14,700 pounds) of hexachloroethane was released to the atmosphere at Fort Irwin, California, a major military training facility (Novak et al. 1987). Hexachloroethane in smoke (aerosol) was measured in a wind tunnel at concentrations ranging from 0.64-1.26 mg/m3 (average 0.89 mg/m3) (Cataldo et al. 1989). 

Hexachloroethane may be released to soil by industrial sources and from hazardous waste sites at which this chemical has been detected. It may be also be released to soil from the use of hexachloroethane smoke and pyrotechnic devices via deposition of airborne particulates (see Section 5.3.1) (Cataldo et al. 1989) or ejection of partially reacted compounds from the canister by the force of combustion (Schaeffer et al. 1988). 

Workers in industrial facilities manufacturing or using hexachloroethane as an intermediate in the manufacture of other products may be exposed to the chemical by inhalation or dermal absorption. In addition, military or civilian personnel working with smoke or pyrotechnic devices may be exposed. Based on information collected for the National Occupational Exposure Survey, the National Institute for Occupational Safety and Health (NIOSH) estimates that 8,515 workers were potentially exposed to hexachloroethane (NOES 1991). 

Residents or workers near hazardous waste sites containing hexachloroethane wastes or military training areas using smoke or pyrotechnic devices containing hexachloroethane may be exposed to higher than ambient levels. 

Barium nitrate is used to produce green color in flares, pyrotechnic devices in green signal lights and in tracer bullets. 

Two basic audible effects are produced by explosive and pyrotechnic devices a loud explosive noise (called a "report" or "salute" in the fireworks industry) and a whistling sound. 

The items used for military purposes include those used for small arms ammunition, artillery ammunition, rocket ammunition, aircraft bombs, land sea mines, grenades, demolition devices and pyrotechnic devices. As some items (such as detonators, primers, etc) can be used in several kinds of ammunition our write-up might contain some repetitions... 

Pyrotechnic Devices. Items used for both military and nonmilitary purposes, such as producing bright lights for illumination, colored lights, or smoke for signalling purposes. These items are consumed in the process (Ref 40a, p 118 Ref 43, p A384-R)... 

Squib. 1) (General). Any of various small size pyrotechnic or explosive devices 2) (Specific). A small explosive device similar in appearance to a detonator, but loaded with low explosive, so that its output is primarily heat (flash). Usually electrically initiated, and provided to initiate action of burning type munitions, pyrotechnic devices and rocket propellants. An electrical squib consists essentially of a tube containing a flammable material, and a small charge of powder compressed around a fine resistance wire connected to electrical leads or terminals (Ref 40a, p 135)... 

These primers can be used not only in small arms but also in some pyrotechnic devices and fuzes. All simple primers are small in size, 0.21 to 0.31 inch in diam and 0.12 to 0.23 inches long for rifle ammunition and slightly Smaller for carbines. They contain only one small charge of primary expl or a mixture which must have sufficient sensitivity to be initiated either by the crushing or stab action of a firing pin... 

Fuzes used in pyrotechnic devices are of two kinds those which are an integral part of a device and those shipped separately for use with parachute flares. Only the fuzes which are shipped separately are described in TM 9-1370-200 (1966)... 

CA 66, 1995 (1967) (Pyrotechnic devices for use on sterilized spacecraft) [Biological sterilization is generally recognized as a requirement for a planetary landing vehicle. 

A literature survey of properties of the thousands of commercially available pyrotechnic devices showed tha t the majority of them would not stand sterilization. In other cases, there was insufficient information about them or their cost was unreasonably high. This eliminated all but about two dozen of commercial devices, which might prove to be suitable if the test described... 

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