Foams flammability

Flammability Acrolein is very flammable its flash point is <0° C, but a toxic vapor cloud will develop before a flammable one. The flammable limits in air are 2.8% and 31.0% lower and upper explosive limits, respectively by volume. Acrolein is only partly soluble in water and will cause a floating fire, so alcohol type foam should be used in firefighting. The vapors are heavier than air and can travel along the ground and flash back from an ignition source. 

Aryl Phosphates. Aryl phosphates were introduced into commercial use early in the twentieth century for flammable plastics such as cellulose nitrate and later for cellulose acetate. CeUulosics are a significant area of use but are exceeded now by plastici2ed vinyls (93—95). Principal appHcations are in wire and cable insulation, coimectors, automotive interiors, vinyl moisture barriers, plastic greenhouses (Japan), furniture upholstery, conveyer belts (especially in mining), and vinyl foams. 

Flammability. The results of small-scale laboratory tests of plastic foams have been recognized as not predictive of their tme behavior in other fire situations (205). Work aimed at developing tests to evaluate the performance of plastic foams in actual fire situations continues. All plastic foams are combustible, some burning more readily than others when exposed to fire. Some additives (131,135), when added in small quantities to the polymer, markedly improve the behavior of the foam in the presence of small fire sources. Plastic foams must be used properly following the manufacturers recommendations and any appHcable regulations. 

Flammability. Plastic foams are organic ia aature and, therefore, are combustible. They vary ia their respoase to small sources of ignitioa because of composition and/or additives (255). AH plastic foams should be handled, transported, and used according to manufacturers recommendations as weU as appHcable local and national codes and regulations. 

Diketene is a flammable Hquid with a flash point of 33°C and an autoignition temperature of 275°C. It decomposes rapidly above 98°C with slow decomposition occurring even at RT. The vapors are denser than air (relative density 2.9, air air = 1). The explosive limits in air are 2—11.7 vol % (135). In case of fire, water mist, light and stabilized foam, as well as powder of the potassium or ammonium sulfate-type should be used. Do not use basic extinguisher powders and do not add water to a closed container. 

Because of thek flash pokits, nitroparaftins are classified as flammable Hquids under DOT regulations (ha2ard class 3, PG III). Nitromethane and nitroethane tires can be extinguished with water, CO2, foam, or class ABC dry chemical extinguishers. Nitroparaftins should not be exposed to dry caustic soda, lye, or similar alkaline materials. 

Table 10. Physical and Flammability Properties of Silicone Foam Rubber ...

Special additives are often included in a carrier formulation to provide specific properties such as foam control, stabiUty, and fiber lubrication during dyeing. Most important are the solvents used to solubilize the soHd carrier-active chemicals. These often contribute to the general carrier activity of the finished product. For example, chlorinated benzenes and aromatic esters are good solvents for biphenyls and phenylphenols. Flammable compounds (flash point below 60°C) should be avoided. 

The surface area of a spill should be minimized for materials that are highly toxic and have a significant vapor pressure at ambient conditions, such as acrylonitrile or chlorine. This will make it easier and more practical to collect vapor from a spill or to suppress vapor release with foam. This may require a deeper nondrained dike area than normal or some other design that wilfminimize surface area, in order to contain the required volume. It is usually not desirable to cover a diked area to restric t loss of vapor if the spill consists of a flammable or combustible material. 

Provide adequate fixed fire protection for tanks and vessels containing flammable, unstable or reactive materials. This can include fire loops with hydrants and monitors in the storage area, foam systems for individual tanks, and deluge spray systems to keep the exposed surfaces of tanks cool in case of fire in an adjacent tank. 

Provide safe separation distances Install fixed fire protection and alarms, water sprays (deluge), and/or foam systems activated by flammable gas, flame, and/or smoke detection devices... 

The law requires nonessential products releasing Class 1 chemicals to be banned within 2 years of enactment. In 1994 a ban wiU go into effect for aerosols and non-insulating foam using Class II chemicals, with exemptions for flammability and safety. Regulations for this purpose will be required within one year of enactment, to become effective tv o vears afterwards. 

The rate of evolution of a toxie or flammable vapour from a liquid (e.g. in an open vessel, from a spillage or as a spray) is direetly related to the exposed area. Therefore, the rate of vapour formation from solvent-impregnated rag, from solvent-based films spread over a large area, from foams or from mists ean be many times greater than that from bulk liquid. 

The penetration and eooling aetion of water is required with Class A fires, e.g. those involving paper, wood, textiles, refuse. Water is applied in the form of a jet or spray foam or multi-purpose powder extinguishers are alternatives. Extinguishment of a Class B fire ean be aehieved by the smothering aetion of dry ehemieal, earbon dioxide or foam. Most flammable liquids will float on water (refer to Table 6.1 under Speeifie gravity ), so that water as a jet is unsuitable a mist may, however, be effeetive. Water is also widely used to proteet equipment exposed to heat. Dry powders are effeetive on flammable liquid or eleetrieal fires. 

Foam is a proportioned mixture of water and foam eoneentrate aspirated with air to eause expansion, e.g. from 6 to 10 times the volume (low expansion foam) up to >100 times (high expansion foam). It transports water to the surfaee of flammable liquids and enables it to float and extinguish the fire. An effeetive system depends upon ... 

The type of flammable liquid - determines the type of foam, e.g. standard or aleohol-resistant grade. Aqueous film-forming foam may be used for rapid knoek-down . 

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