Fire resistance toxicity

Petroleum (qv) products dominate lubricant production with a 98% share of the market for lubricating oils and greases. While lower cost leads to first consideration of these petroleum lubricants, production of various synthetic lubricants covered later has been expanding to take advantage of special properties such as stability at extreme temperatures, chemical inertness, fire resistance, low toxicity, and environmental compatibility. 

Plant Fireproofing. There is a growing practice in the chemical industry of locating principal equipment out of doors and to enclose only a control room where all instmments and control equipment are centered. The control room should be resistant to potential explosion, fire, and toxicity ha2ards of processes in the vicinity. Prompt and ordedy shutdown of processes following a serious incident is essential in order to minimise personnel-injury and property-loss ha2ards (65,66). 

Toxicity is defined as the quality, state, or degree of being toxic or poisonous. Some liquids contain chemicals that are a serious toxic hazard. These toxic or poisonous chemicals may enter the body through inhalation, by absorption through the skin, or through the eyes or the mouth. The result is sickness and, in some cases, death. Manufacturers of hydraulic liquids strive to produce suitable liquids that contain no toxic chemicals and, as a result, most hydraulic liquids are free of harmful chemicals. Some fire-resistant liquids are toxic, and suitable protection and care in handling must be provided. 

Poly(aryloxyphosphazene) elastomers offer outstanding fire resistance without the presence of halogen. In a fire these elastomers produce low levels of smoke as well as low toxicity and non-corrosive off-gases. 

Fire Resistant Elastomers. The poly(aryloxyphosphazene) elastomers offer excellent fire resistance without incorporating halogen in the polymer or as an additive. These polymers are self-extinguishing in air and generate only moderate non-corrosive smoke and a minimum of toxic combustion products upon combustion (50-53). The poly(aryloxyphosphazene) elastomers (APN ) have excellent potential for applications such as... 

Electrical conductors are normally insulated for protection and avoidance of electrical shorting. Typical insulating materials are plastics that can readily bum with toxic vapors. The NEC specifies certain fire resistant rating to electrical cables to lessen the possibility of cable insulation ignitability and fire spread. 

Fire resistance is naturally excellent but perfluorinated thermoplastics release corrosive and toxic fumes. Oxygen indices are at least 95 and UL94 rating is VO. 

PVF films are appreciated for weatherability, good chemical and staining resistance good non-stick properties, easy-to-clean properties low permeability good behaviour at low temperature good electrical insulating properties even in hot and wet environments fire resistance (but beware of toxic fumes). 

Polychlorinated biphenyls (PCBs) are colorless toxic organic substances that cause cancer and birth defects. There are more than 200 different types of PCBs, ranging in consistency from heavy, oily liquids to waxy solids, and each type further varying in the number and location of chlorine atoms attached to its molecular carbon rings. They are fire resistant and do not conduct heat or electricity well. Accordingly they have numerous commercial applications as insulation in electrical systems, for example, for transformers. 

Plastic pipe or tubing may be used for a wide variety of services. As with all nonmetallic materials, code restrictions limit the applications in which their use is permitted. In general, their use in flammable or toxic service is limited. Plastic tubing of various types may be used for instrument air-signal connections however, as is the case with all nonmetallic applications, the need for fire resistance must be considered. When used)in specialized applications such as potable water or underground fire water, care should be taken to ensure that the specified products are certified by appropriate agencies such as the National Sanitation Foundation and Factory Mutual. 

Significant properties of insulation (Table 1) include thermal conductivity, fire resistance, and minimal production of toxic gases primarily during combustion. Other criteria include water-vapor permeability, resistance to water absorption, and dimensional stability over prolonged periods of submission to extreme environments. 

ISO TC92 fire safety (with subcommittees on fire initiation and growth, fire containment (or fire resistance), fire threat to people and the environment (or smoke toxicity), and fire-safety engineering)... 

Several classes of synthetic oils, such as phosphoric acid esters, polyglycols and silicones, are used as hydraulic lubricants. They are mostly used as fire-resistant lubricants, of importance for coal mines, steel mills and foundries, especially when hydraulic systems operate close to hot areas, e.g. furnaces. Polychlorinated biphenyls, PCBs, are the most fire resistant but are no longer used because of their high and persistent toxicity. Silicones have very poor lubricity and are very expensive, whereas polyglycols with high flash points do not fiilly meet more stringent fire-resistant requirements. At present, therefore, synthetic hydraulic lubricants are almost exclusively based on trialkyl or triaryl phosphates, or their mixtures, available with a wide range of viscosities and adequate low-temperature properties required for hydraulic lubricants. 

Polyglycols were the first basestocks to be formulated into biodegradable fluids and they are still used widely as fire-resistant lubricants and also in food processing. However, polyglycols lack the required biodegradability performance and are potentially toxic in water when mixed with lubricating additives. 

In recent years there has been an effort to eliminate chlorine from all flame retardant compounds. Thus, there is a tendency to avoid the use of two of the most used additive flame retardants for fabrication of fire resistant PU TCEP and TCPP. This ban is dictated by the toxic and corrosive gases formed during combustion and from ecological point of view. 

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