Foaming sodium bicarbonate

Potassium bicarbonate (Purple K) dry chemical agent in cartridge-type or pressurized extinguishers is compatible with foam. Sodium bicarbonate agent may be used where potassium bicarbonate is not available or approved for general... 

Materials/characteristics Physical blowing agents low-boil hydrocarbons. Chemical blowing agents fluorocarbons (for polyurethane and PS foams) sodium bicarbonate/citric acid or azo compounds, etc., for moulded structural foams. 

Lignosulfonate has been reported to increase foam stabihty and function as a sacrificial adsorption agent (175). Addition of sodium carbonate or sodium bicarbonate to the surfactant solution reduces surfactant adsorption by increasing the aqueous-phase pH (176). 

Other sources of sodium ion that are used to make sodium citrate are sodium carbonate and sodium bicarbonate. These reactions evolve large volumes of carbon dioxide gas, resulting in much foaming but less exotherm. 

Sodium bicarbonate (baking soda) is added for taste and mouth feel. It combines with acids to release carbon dioxide gas, adding to the foam produced by brushing. It is a mild abrasive. It may reduce the numbers of acid-loving bacteria in the mouth, although this effect lasts only as long as the mouth stays alkaline. 

Sodium bicarbonate- and borax bicarbonate-based dry chemicals were among the first dry agents used in portable fire extinguishers. About 1960, the sodium bicarbonate dry chemical was modified to make it compatible with protein-based, low-expansion foam to create a dual agent extinguishing system. Shortly thereafter, the more effective Purple K based extinguishers replaced sodium bicarbonate extinguishers. 

Potassium bicarbonate has greater extinguishing capability on Class B fires than sodium bicarbonate and is usually foam compatible. This characteristic permits emergency response personnel to fight fire more effectively. 

The efficiency of azodicarbonamide and sodium bicarbonate blowing agents for PE foams was considered (253). These systems, which generate GO2 gas, are more suitable for compression moulding of foams. Blends of the blowing agents have a reduced exotherm, so are more suitable for polymer systems that are temperature sensitive, such as ethylene copolymers. 

Class B Fires. These are fires in flammable liquids (oils, gasoline, solvents, etc.), where a blanketing or smothering effect is essential to put the fire out. This effect keeps oxygen away from the fuel, and can be obtained with carbon dioxide, dry chemical (essentially sodium bicarbonate), foam, or a vaporizing-liquid type of extinguishing agent. Water is most effective when used as a fine spray or mist... 

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