fire class A fire class is a system of categorizing fire with regard to the type of material and fuel for combustion. Class letters are often assigned to the different types of fire, but these differ between territories. There are separate standards for th ...

es, a Class B fire is a

fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition ...

flammable liquid A flammable liquid is a liquid which can be easily ignited in air at ambient temperatures, i.e. it has a flash point at or below nominal threshold temperatures defined by a number of national and international standards organisations. The Occupat ...

s or flammable gases,

petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...

greases,

tar Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black bit ...

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

oil-based paint Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnis ...

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

lacquer Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity. Asian lacquerware, which may be ca ...

s, or

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

s. For example,

propane Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used a ...

natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...

and

kerosene Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...

fires are types of Class B fires.James R. Gillespie & Frank Flanders, ''Modern Livestock & Poultry Production'', 8th ed. (Centgage Learning: 2009), p. 76.

International Association of Fire Chiefs The International Association of Fire Chiefs (IAFC) is a network of more than 12,000 fire chiefs and emergency officers.

National Fire Protection Association The National Fire Protection Association (NFPA) is an international nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards. As of 2018, the NFPA claims to have 50,000 mem ...

, ''Fire Inspector: Principles and Practice'' (

Jones and Bartlett Publishers Jones & Bartlett Learning, a division of Ascend Learning, is a scholarly publisher. The name comes from Donald W. Jones, the company's founder, and Arthur Bartlett, the first editor. History In 1988, the company was named by ''New England Busines ...

, 2012), pp. 204-06. The use of lighter fluid on a

charcoal grill A barbecue grill or barbeque grill (known as a barbecue or barbie in Australia and New Zealand) is a device that cooks food by applying heat from below. There are several varieties of grills, with most falling into one of three categories: gas-f ...

, for example, creates a Class B fire. Some

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

s are also Class B fire materials. Class B fires are distinguished from the other fire classes: Class A fires ("ordinary combustibles" such as

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed ...

, or

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

); Class C fires (in which the burning material is energized electrical equipment) and Class D fires (in which the burning material is combustible

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

s). The less-commonly-used Class F (known in the United States as Class K) refers to fires involving cooking oil or fat; these materials are technically part of Class B.JB Crippin, "Types of Fires" in ''Forensic Chemistry'' (ed. Max M. Houck:

Academic Press Academic Press (AP) is an academic book publisher founded in 1941. It was acquired by Harcourt, Brace & World in 1969. Reed Elsevier bought Harcourt in 2000, and Academic Press is now an imprint of Elsevier. Academic Press publishes reference ...

, 2015), p. 219. Fires are classified by the proper extinguishing agent. While water is used on Class A fires, using water on a Class B fire (such as a grease fire) is extremely dangerous. This is because Class B fires typically have a fuel with a lower density than water (causing it to rise) and burning grease is hotter than the

boiling point The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding envir ...

of water (212 degrees

Fahrenheit The Fahrenheit scale () is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined his ...

or 100 degrees

Celsius The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The ...

); when water is placed on grease, it creates steam which expands rapidly and splatters, causing burns and spreading the fire. Because of this, Class A

fire extinguisher A fire extinguisher is a handheld active fire protection device usually filled with a dry or wet chemical used to extinguish or control small fires, often in emergencies. It is not intended for use on an out-of-control fire, such as one which ha ...

s use water, while Class B fire extinguishers use dry chemicals (foam or powder), such as aqueous film-forming foam, multi-purpose dry chemicals such as

ammonium phosphate Ammonium phosphate is the inorganic compound with the formula (NH4)3PO4. It is the ammonium salt of orthophosphoric acid. A related "double salt", (NH4)3PO4.(NH4)2HPO4 is also recognized but is impractical use. Both triammonium salts evolve ammoni ...

, and

halogenated In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polyme ...

agents (such as

Halon 1301 Bromotrifluoromethane, commonly known as Halon 1301, R13B1, Halon 13B1 or BTM, is an organic halide with the chemical formula C Br F3. It is used for gaseous fire suppression as a far less toxic alternative to bromochloromethane. Table of physi ...

and

Halon 1211 Bromochlorodifluoromethane (BCF), also referred to by the code numbers Halon 1211 and Freon 12B1, is a haloalkane with the chemical formula carbon, Cfluorine, F2chlorine, Clbromine, Br. It is used for fire suppression, especially for expensive eq ...

)Lon H. Ferguson & Christopher A. Janicak
Fundamentals of Fire Protection for the Safety Professional
(2d ed. 2015), pp. 203-04. or highly pressurized

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

. Some fire extinguishers contain chemicals designed to fight both Class A and Class B fires. Grease and

cooking oil Cooking oil is plant, animal, or synthetic liquid fat used in frying, baking, and other types of cooking. It is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips, and may be called edible oil. ...

fires pose a greater safety risk. One ten-year study, examining the years 1976 to 1985, found that 4.7% of hospitalized burn patients suffered burns from hot grease or oil, with 78% of such injuries occurring in the home. According to the

, between 2010 and 2014, nearly half (46%) of home structure fires reported to fire departments in the United States involved cooking; over the same time period, cooking equipment was implicated in 19% of home fire deaths, 44% of home fire injuries, and 17% of total direct property damage. Grease fires are an object of study in

food science Food science is the basic science and applied science of food; its scope starts at overlap with agricultural science and nutritional science and leads through the scientific aspects of food safety and food processing, informing the developm ...

.Ingolf Gruen
Out of the Frying Pan and into the Grease Fire: A Case Study in Food Science
National Center for Case Study Teaching in Science,

University at Buffalo The State University of New York at Buffalo, commonly called the University at Buffalo (UB) and sometimes called SUNY Buffalo, is a public research university with campuses in Buffalo and Amherst, New York. The university was founded in 1846 ...

(May 31, 2003). File:Class B fire square.svg, Class B fire icon File:Fire Liquid.png, Combustible materials fire symbol File:Fire type B.svg, Other combustible materials fire symbol

References

External links

* Types of fire {{Firefighting-stub

See also

References

External links