History of Fire Fighting Foams
Water has long been a universal agent for suppressing fires, but is not best in all cases. For example, water is typically ineffective on an oil fire, and can be dangerous. Fire-fighting foams were a positive development in extinguishing oil fires.
In 1902, a method of extinguishing flammable liquid fires by blanketing them with foam was introduced by the Russian engineer and chemist Aleksandr Loran. Loran was a teacher in a school in Baku, which was the main center of the Russian oil industry at that time. Impressed by the terrible and hardly extinguishable oil fires that he had seen there, Loran tried to find such a liquid substance that could deal effectively with the problem. So he invented fire-fighting foam, which was successfully tested in several experiments in 1902-1903. In 1904 Loran patented his invention, and developed the first foam extinguisher the same year.
The original foam was a mixture of two powders and water produced in a foam generator. It was called chemical foam because of the chemical action to create it. In general, the powders used were sodium bicarbonate and aluminium sulfate, with small amounts of saponin or liquorice added to stabilise the bubbles. Hand-held foam extinguishers used the same two chemicals in solution: To actuate the extinguisher, a seal was broken and the unit inverted, allowing the liquids to mix and react. Chemical foam is a stable solution of small bubbles containing carbon dioxide with lower density than oil or water, and exhibits persistence for covering flat surfaces. Because it is lighter than the burning liquid, it flows freely over the liquid surface and extinguishes the fire by a smothering(smothering is removal/prevention of oxygen) action. Chemical foam is considered obsolete today because of the many containers of powder required, even for small fires.
In the 1940s, Percy Lavon Julian developed an improved type of foam called Aerofoam. Using mechanical action, a liquid protein-based concentrate, made from soy protein, was mixed with water in either a proportioner or an aerating nozzle to form air bubbles with the free-flowing action. Its expansion ratio and ease of handling made it popular. Protein foam is easily contaminated by some flammable liquids, so care should be used so that the foam is applied only above the burning liquid. Protein foam has slow knockdown characteristics, but it is economical for post-fire security.
In the early 1950s, high-expansion foam was conceived by Herbert Eisner in England at the Safety in Mines Research Establishment (now the Health & Safety Laboratory) to fight coal mine fires. Will B. Jamison, a Pennsylvania Mining Engineer, read about the proposed foam in 1952, requested more information about the idea, and proceeded to work with the US Bureau of Mines on the idea, testing 400 formulas until a suitable compound was found. In 1964, Walter Kidde & Company (now Kidde) bought the patents for high expansion foam.
In the 1960s, National Foam, Inc. developed fluoroprotein foam. Its active agent is a fluorinated surfactant that provides an oil-rejecting property to prevent contamination. In general, it is better than protein foam because its longer blanket life provides better safety when entry is required for rescue. Fluoroprotein foam has fast knockdown characteristics and it can also be used together with dry chemicals that destroy protein foam.
In the mid-1960s, the US Navy developed aqueous film-forming foam (AFFF) . This synthetic foam has a low viscosity and spreads rapidly across the surface of most hydrocarbon fuels. A water film forms beneath the foam, which cools the liquid fuel, which stops the formation of flammable vapors. This provides dramatic fire knockdown, an important factor in crash rescue fire fighting.
In the early 1970s, National Foam, Inc. invented Alcohol-Resistant AFFF technology. AR-AFFF is a synthetic foam developed for both hydrocarbon and polar-solvent materials. Polar solvents are combustible liquids that destroy conventional fire-fighting foam. These solvents extract the water contained in the foam, breaking down the foam blanket. Therefore, these fuels require an alcohol- or polar-solvent-resistant foam. Alcohol-resistant foam must be bounced off of a surface and allowed to flow down and over the liquid to form its membrane, compared to standard AFFF that can be sprayed directly onto the fire.
Read more about this topic: Fire Fighting Foam
Famous quotes containing the words history of, history, fire, fighting and/or foams:
“I am not a literary man.... I am a man of science, and I am interested in that branch of Anthropology which deals with the history of human speech.”
—J.A.H. (James Augustus Henry)
“History does nothing; it does not possess immense riches, it does not fight battles. It is men, real, living, who do all this.... It is not “history” which uses men as a means of achieving—as if it were an individual person—its own ends. History is nothing but the activity of men in pursuit of their ends.”
—Karl Marx (1818–1883)
“The most stringent protection of free speech would not protect a man in falsely shouting fire in a theater and causing a panic.”
—Oliver Wendell Holmes, Jr. (1841–1935)
“Armies, for the most part, are made up of men drawn from simple and peaceful lives. In time of war they suddenly find themselves living under conditions of violence, requiring new rules of conduct that are in direct contrast to the conditions they lived under as civilians. They learn to accept this to perform their duties as fighting men.”
—Gil Doud, U.S. screenwriter, and Jesse Hibbs. Walter Bedell Smith (Himself)
“This fantastic state of mind, of a humanity that has outrun its ideas, is matched by a political scene in the grotesque style, with Salvation Army methods, hallelujahs and bell-ringing and dervishlike repetition of monotonous catchwords, until everybody foams at the mouth. Fanaticism turns into a means of salvation, enthusiasm into epileptic ecstacy, politics becomes an opiate for the masses, a proletarian eschatology; and reason veils her face.”
—Thomas Mann (1875–1955)