Class B fire

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Attempts to extinguish a grease fire during a demonstration A volunteer attempts to extinguish a grease fire during a demonstration as part of Fire Prevention Week hosted by the 4th Civil Engineer Squadron at Seymour Johnson Air Force Base, N.C. Oct. 11, 2013 131011-F-JH807-080.jpg
Attempts to extinguish a grease fire during a demonstration

In fire classes, a Class B fire is a fire in flammable liquids or flammable gases, petroleum greases, tars, oils, oil-based paints, solvents, lacquers, or alcohols. [1] For example, propane, natural gas, gasoline and kerosene fires are types of Class B fires. [2] [3] The use of lighter fluid on a charcoal grill, for example, creates a Class B fire. [4] Some plastics are also Class B fire materials. [3]

Contents

Class B fires are distinguished from the other fire classes: Class A fires ("ordinary combustibles" such as wood, paper, or rubber); Class C fires (in which the burning material is energized electrical equipment) and Class D fires (in which the burning material is combustible metals). [3] 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. [5]

Fires are classified by the proper extinguishing agent. While water is used on Class A fires, using water on a Class B fire (e.g., a grease fire) is extremely dangerous. [3] [5] This is because Class B fires typically have a fuel with a lower density than water (causing it to rise) and the burning fluid is hotter than the boiling point of water (212  °F or 100  °C). The resulting sudden rising of a column of flames together with droplets of boiling fuel and water is generally known as a slopover. [6] [7] For example, when water is placed on grease, it creates steam which expands rapidly and splatters burning droplets in a phenomenon causing burns and spreading the fire. [3] Because of this, Class A fire extinguishers use water, while Class B fire extinguishers use dry chemicals (foam or powder), [5] such as aqueous film-forming foam, multi-purpose dry chemicals such as ammonium phosphate, and halogenated agents (such as Halon 1301 and Halon 1211) [8] or highly pressurized carbon dioxide. [5] Some fire extinguishers contain chemicals designed to fight both Class A and Class B fires. [8]

Grease and cooking 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. [9] According to the National Fire Protection Association, 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. [10] Grease fires are an object of study in food science. [11]


See also

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<span class="mw-page-title-main">Fire extinguisher</span> Active fire protection device

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References

  1. ↑ NFPA's Illustrated Dictionary of Fire Service Terms, p. 23 (National Fire Protection Association/Jones and Bartlett Publishers: 2006).
  2. ↑ James R. Gillespie & Frank Flanders, Modern Livestock & Poultry Production, 8th ed. (Centgage Learning: 2009), p. 76.
  3. 1 2 3 4 5 International Association of Fire Chiefs/National Fire Protection Association, Fire Inspector: Principles and Practice (Jones and Bartlett Publishers, 2012), pp. 204-06.
  4. ↑ Robert H. Hill, Jr. & David C. Finster, Laboratory Safety for Chemistry Students (2d ed.: John Wiley & Sons, 2016).
  5. 1 2 3 4 JB Crippin, "Types of Fires" in Forensic Chemistry (ed. Max M. Houck: Academic Press, 2015), p. 219.
  6. ↑ API (1991). Fighting Fires in and Around Flammable and Combustible Liquid Atmospheric Storage Tanks. API Publication 2021 (3rd ed.). Washington, D.C.: American Petroleum Institute. p. 29.
  7. ↑ NFPA (2018). Flammable and Combustible Liquids Code. NFPA 30 (2018 ed.). Quincy, Mass.: National Fire Protection Association. p. 102. ISBN   978-145591661-0.
  8. 1 2 Lon H. Ferguson & Christopher A. Janicak, Fundamentals of Fire Protection for the Safety Professional (2d ed. 2015), pp. 203-04.
  9. ↑ Schubert, Warren; Ahrenholz, David H.; Solem, Lynn D. (1990). "Burns from Hot Oil and Grease: A Public Health Hazard". Journal of Burn Care & Rehabilitation. 11 (6): 558–62. doi:10.1097/00004630-199011000-00014. PMID   2286612.
  10. ↑ Marty Ahrens, Home Fires Involving Cooking Equipment, National Fire Protection Association (November 2016).
  11. ↑ 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 (May 31, 2003).


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