Smoke generators development

Rauchgase (sichtbarer Qualm) smoke generation (development of smoke)... 

These materials are developed from the polyetherimides introduced by General Electric (see also Section 18.14.2). At the time of writing one grade, Ultem Siltem STM 1500, is being offered. It is of particular interest as a material for wire and cable insulation, as it not only has excellent flame resistance coupled with low smoke generation but also avoids possible toxic and corrosion hazards of halogenated polymers. This can be of importance where there are possible escape problems in the event of a fire, such as in tunnels, aircraft and marine (particularly submarine) vessels. 

Polymers with an aromatic group in the main chain, however, such as polysulphones, polycarbonates and poly(phenylene oxides) proved to be intermediate in their smoke generation, possibly due to their considerable charring tendency. Also the unexpected drop in smoke density observed when poly(vinyl chloride) is partially chlorinated may be attributed to the high char yield. Einhom et al. (1968) concluded that smoke development decreases with increasing amount of chlorine- and phosphorus-containing additives, and with increasing cross-link density. 

The cone calorimeter was developed in the early 1980s by NIST [11]. This method uses 10 by 10 cm specimens that may be up to 5 cm thick. A cone-shaped heater applies a heat flux of up to 100kW/m2 to the top of the sample. Parameters that can be measured include peak and total heat release rate, mass loss and smoke generation. The data obtained from cone calorimetry can be used for engineering purposes. 

Numerous special chemical de ices such as land mines, toxic smoke candles, smoke generators on tanks, etc., have also been developed during the postwar period by many of the principal world powers. 

This defensive work included improvements to many First World War weapons, including gas shells, mortar bombs, the Livens Projector and toxic smoke generators and the development of apparatus for mustard gas spray from aircraft, bombs of many types, airburst mustard gas shell, gas grenades and weapons for attacking tanks . The various inventions were tested in north Wales, Scotland, and in installations scattered throughout the Empire, notably northern India, Australia and the Middle East. 

Toxic smoke, usually an arsenical compound, could penetrate gas masks— which were quite effective by 1918 because smoke is not a gas and the smoke particles would not be absorbed by the charcoal or lime in the mask canisters. Moreover, America had developed a thick felt that would filter out the smoke particles even with Brownian motion operating. This felt was simply wrapped around existing mask canisters. Also, the small size of bombs and projectiles made candles and smoke generators particularly attractive. 

By carefully adjusting block size and comonomer composition, J. Celia at General Electric developed a series of thermoplastic silicone-polyimides (7) with excellent electrical and thermal properties as well as low smoke generation [29], These materials are marketed under the name Siltem as wire coatings and enamels, and can be found in a variety of aerospace applications including passenger aircraft. 

The XP-2 chamber was further developed by the US National Bureau of Standard (NBS). This NBS chamber as standardized in ASTM E 662-1979 has become the most wide-spread test apparatus in the United States. In this method, the light transmittance is again measured for calculating the specific optical density of the smoke generated on the following theoretical basis ... 

Phenolic resin foam is an interesting material for the cellular insulation industry because of its high temperature resistance, fire resistance, and very low smoke generation [16]. The aqueous resole is crosslinked in the presence of a surfactant and a low boiling liquid, that volatizes during the increase ofviscosity or plasticity of the mixture. The surfectant is necessary to develop a uniform fine cellular foam stracture [1,6], Carbonization of phenolic foams yields carbon foams with an excellent thermal resistance, that are applied as high temperature insulation materials for the production of filters for corrosive agents and catalyst supports [1]. 

The smoke generation characteristic of polymers during fire propagation is expressed by a smoke development index (SDI) [21, 22,40, 83]. The SDI concept... 

White P served as a smoke generator and as an incendiary agent in both world wars. More sophisticated versions of these weapons have now been developed (Section 12.16). 

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