Off-gassing of materials

Off-gassing of materials The liberation of volatile organic compounds (VOC) and other gases from building products or from a manufacturing process. 

OFF-GASSING OF MATERIAL PROPERTIES Heated Freon will off-gas. Hydrofluoric acid gas is one hazardous by-product... 

The third category of metallic artifacts includes collections of a most different provenance—such as scientific instruments, fine arts, historic pieces, ethnographic specimens, etc., which are usually kept in museums. Contrary to the belief that an object is safe once it enters a museum, certain storage or display conditions may lead to corrosive reactions that are different from those found in the natural environment [264, 265]. Some of these dangers come from off-gassing from materials used to build display cases and rooms, as well as air pollution introduced by visitors. 

This is needed to make up for air removed by exhaust fans to pressurize buildings so as to reduce the infiltration of unwanted hot, cold, moist, or dirty outdoor air to dilute exhaled carbon dioxide, off-gassing of plastic materials, tobacco smoke, and body odors and to replenish... 

Hospital staff working in an enclosed area can be secondarily contaminated by cyanide vapor off-gassing from heavily soaked clothing or skin, or from toxic vomit. Avoid dermal contact with cyanide-contaminated victims or with gastric contents of persons who may have ingested cyanide-containing materials (patients do not usually pose secondary contamination risks after contaminated clothing is removed and the skin is washed. 

Some VOCs can be malodorous pollutants, sensory irritants, or hazardous air pollutants. Hazardous VOC air pollutants include acetaldehyde, benzene, carbon tetrachloride, chloroform, ethylbenzene, formaldehyde, hexane, methylene chloride, naphthalene, paradichlorobenzene, pesticides (biocides), styrene, tetrachloroethylene, toluene, trichloroethylene, and xylenes. They are found in essentially all indoor locations, released by off gassing from numerous sources, such as construction and decorating materials, consumer products, paints, paint removers, furnishings, carpets, and from combustion of wood, kerosene, and tobacco. While more than 500 VOCs have... 

Small Areas Ventilation. In heavily contaminated areas, decontamination with a fresh solution of HTH pool bleach in denatured alcohol (approximately 9 percent by weight) followed by decontamination with copious amounts of aqueous sodium hydroxide solution (a minimum of 10 percent by weight). Vigorous off-gassing may occur during this process. Removal of porous material, including painted surfaces, that may have absorbed Nerve Agent vapor may be required as these materials could continue to re-release vapor after exposure has ceased. 

Polyester putty emissions are again application- and technique-related, and they are typically very high in VOC emissions (around 224 g/L). New, lower VOC technologies are available, but the levels are still not reduced considerably. The use of these materials is very application-dependent, and off-gassing is also a matter of concern. 

The choice of insulator is as important for analytical performance and practical reasons as the conductor for the same reasons chemical reactivity, physical integrity, cost, and convenience of manufacture. In addition, plastics and other materials are prone to off-gassing with increases in temperature through impurities or small oligomers retained from the production process or through decomposition of the polymer. Another property of the insulator is electrical conductivity, which should be in megaohms per centimeter. 

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