Firefighting foam
Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, thus achieving suppression of the combustion.
There are 2 main application techniques[7] of applying foam onto a fire, recognized by the European (EN1568) and international (ISO7203) standards: Sweep (roll-on) method - Use only on a pool of flammable product on open ground.
Bankshot (bankdown) method - Firefighter uses an object to deflect the foam stream so it flows down the burning surface.
Might not be effective if wind conditions are unfavorable Water has long been a universal agent for suppressing fires, but is not best in all cases.
In 1902, a method of extinguishing flammable liquid fires by blanketing them with foam was introduced by Russian engineer and chemist Aleksandr Loran.
Impressed by large, difficult-to-extinguish oil fires that he had seen there, Loran tried to find a liquid substance that could deal effectively with them.
In general, the powders used were sodium bicarbonate and aluminium sulfate, with small amounts of saponin or liquorice added to stabilise the bubbles.
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.
Chemical foam is considered obsolete today because of the many containers of powder required, even for small fires.
Will B. Jamison, a Pennsylvania Mining Engineer, read about the proposed foam in 1952, requested more information about the idea.
He proceeded to work with the US Bureau of Mines on the idea, testing 400 formulas until a suitable compound was found.
In general, it is better than protein foam because its longer blanket life provides better safety when entry is required for rescue.
A water film forms beneath the foam, which cools the liquid fuel, stopping the formation of flammable vapors.
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.
Carol Browner, the USEPA Administrator in 1998, described Pyrocool as the "Technology for the Third Millennium: The Development and Commercial Introduction of an Environmentally Responsible Fire Extinguishment and Cooling Agent".
Their environmental challenge has been to convince their customers to choose their new generation of green products, which are 100% fluorine free, and have proven to be effective.
[20][21] In Australia, in 2015 a public safety announcement was issued by the New South Wales Environment Protection Authority following a water source contamination near RAAF Base Williamtown.
Surface water, groundwater, and fish were reported to contain chemicals from firefighting foams that had been released by the local Royal Australian Air Force base prior to training protocol changes in 2008.
[23] The discovery led to the banning of all forms of fishing in the waters of Fullerton Cove until the beginning of October 2016.
[24][25] As of 2017, the Australian Department of Defence was dealing with two class-action suits brought by those affected by contamination at Williamtown and at Army Aviation Centre Oakey.
