Smoke for screening

Members of NDRC Division 10 carried out the perfection of absorbents in gas masks, both activated carbon and filters, which supplied protection for United States troops far superior to that of the enemy forces and also oil smokes for screening large areas. Division 8 developed a new method for producing RDX and made other major improvements... 

Without doubt, the gas-cloud method of attack directed attention to the possibilities of smoke for screening parts of the battlefield from enemy observation. The dense clouds produced in damp weather by the release of chlorine served to mask the advance of the German infantry which follow ed behind them, to demonstrate clearly the tactical advan-t e of concealment during the offensive. 

Obscuring Power of White Smokes. The total obscuring power, TOP, of a white smoke agent used for screening purposes, is obtained by multiplying the product of volume, in cubic ft or smoke produced per lb of material, and the reciprocal of the smoke layer, in ft, necessary to obscure the filament of a 40-watt Mazda lamp. The TOP for some white smoke agents, at low altitudes where atm constituents are plentiful, is given in Table 1... 

WP was largely used by the Allies in WWI for screening smokes in hand grenades and mortars. 

The pyrotechnic generation of smoke is almost exclusively a military device for screening and signaling. While first encountered on a significant scale in WWI, its importance was not realized until early in WW1I when the bulk of the presently known data were collected. In the last 30 years studies of smoke have continued at a reduced rate... 

Hexachloroethane is a solid crystalline material that has entered the environment as a result of its use in militaiy pyrotechnics and as a component of smoke-producing devices used for screening or signaling purposes. It is an intermediate in the production of fluorocarbons, cleaning agents, and refrigerants and was... 

Smoke (a) Signals (b) Screening (a) For signaling and observation. (b) For screening/masking. 

In the initial stages of development of smoke formulations, HCE-Zn dust-based formulations were in use for screening purposes. But as this formulation is very sensitive to moisture and accidents were reported, zinc dust was replaced by zinc oxide. 

The screening smoke formulations based on HCE-ZnO have some drawbacks like poor screening property at low relative humidity (RH) as the metal halide smoke particles need atmospheric moisture to react and form a smoke screen. However, such smokes are well known for screening purposes and have been found to have IR characteristics also which make them useful in modern day warfare. 

The TOP values of some well-known smokes given in the literature [28] suggest that the phosphorus class of smokes are most effective for screening and hence are used during military operations. 

Krone, U. (1990) A non-toxic pyrotechnic screening smoke for training purposes. Proc. 15th Inti. Pyrotech. Sem.,... 

Under the term of "chemical agents are also understood items used for starting fires in enemy installations, houses, ships, or vehicles(see under INCENDIARY WARFARE) as well as substances producing smokes serving for screening movements of troops, ships, trains, or vehicles(See under SMOKES IN WARFARE)... 

The principal use for the tetrachloride is in pyrots as a smoke agent (called FM ), Ref 5 reports that the tetrachloride. . is extremely reactive resulting in the formation of hydrated oxides, or with atmospheric moisture and, when used for screening, is often disseminated from aircraft spray tanks. Its reaction with water vapor is relatively complex. First, the titanium tetrachloride is hydrated. This reaction is followed by further hydrolysis yielding, finally, titanium hydroxide and HC1. The smoke consists of a mixture of fine particles of solid titanium hydroxide, Ti(0H)4 the hydrated oxide, Ti02-H20 intermediate hydroxychlorides of titanium and dilute HC1 droplets. The sequence of reaction is ... 

Cone calorimetry according to the ASTM E1354138 or ISO 5660139 standards are commonly used in the laboratory to screen flammability of materials by measuring heat release characteristics of the compound.116140 This device is similar to FPA but does not have the versatility of FPA. The cone calorimeter can determine the ignitability, heat release rates, effective heat of combustion, visible smoke, and C02 and CO development of cable materials. This test has been used extensively for wire and cable material evaluation. The microscale combustion calorimeter (MCC), also known as pyrolysis combustion flow calorimeter (PCFC), was recently introduced to the industry for screening heat release characteristics of FR materials.141142 This device only requires milligram quantities of test specimen to measure the heat release capacity (maximum heat release potential). Cone calorimetry and MCC have been used in product development for flammability screening of wire and cable compounds.118... 

Uses Powerful incendiary burning pieces adhere to skin and clothes and have a limited casualty effect. Was largely used by Allies in World War 1 for screening smokes in hand grenades and mortars. It is now also extensively used for incendiary purposes, in shells, bombs, and incendiary leaves, P5. 

During the World War obscuring smoke proved its tactical value on land and sea and won for itself an assured place as a military weapon, ffince the war the development of air forces has still further enhanced tin value of obscuring smoke, for not only are airplanes a means par excellence for putting down smoke screens on the field of battle, but their power of observation has greatly increased the need for obscuration. So greatly has aircraft increased the facility of obser dng enemy dispositions and... 

The wide range of uses for screening smokes indicates that different and varying populations may be exposed and, as discussed below, this has implications for health-hazard assessments and advising on the protective and precautionary measures that may be needed. 

White phosphoms has been used for the production of a screening smoke for signaling and for... 

Mineral oils, including the older preparations of fog oil, can produce cutaneous malignant neoplasms because of the presence of PAHs. In view of this, the military (army) altered the specification for screening smoke fog oil, requiring that it be solvent-treated or hydrotreated to remove potential carcinogenic hydrocarbons and analyzed to confirm the absence of such materials (NRC, 1997). 

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