fire extinguisher

fire extinguisher
a portable container, usually filled with special chemicals for putting out a fire.
[1830-40]

* * *

      portable or movable apparatus used to put out a small fire by directing onto it a substance that cools the burning material, deprives the flame of oxygen, or interferes with the chemical reactions occurring in the flame. water performs two of these functions: its conversion to steam absorbs heat, and the steam displaces the air from the vicinity of the flame. Many simple fire extinguishers, therefore, are small tanks equipped with hand pumps or sources of compressed gas to propel water through a nozzle. The water may contain a wetting agent to make it more effective against fires in upholstery, an additive to produce a stable foam that acts as a barrier against oxygen, or an antifreeze. carbon dioxide is a common propellant, brought into play by removing the locking pin of the cylinder valve containing the liquefied gas; this method has superseded the process, used in the soda-acid fire extinguisher, of generating carbon dioxide by mixing sulfuric acid with a solution of sodium bicarbonate.

      Numerous agents besides water are used; the selection of the most appropriate one depends primarily on the nature of the materials that are burning. Secondary considerations include cost, stability, toxicity, ease of cleanup, and the presence of electrical hazard.

      Small fires are classified according to the nature of the burning material. Class A fires involve wood, paper, and the like; Class B fires involve flammable liquids, such as cooking fats and paint thinners; Class C fires are those in electrical equipment; Class D fires involve highly reactive metals, such as sodium and magnesium. Water is suitable for putting out fires of only one of these classes (A), though these are the most common. Fires of classes A, B, and C can be controlled by carbon dioxide, halogenated hydrocarbons such as halons (q.v.), or dry chemicals such as sodium bicarbonate or ammonium dihydrogen phosphate. Class D fires ordinarily are combated with dry chemicals.

* * *


Universalium. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Fire extinguisher — Extinguisher redirects here. Extinguisher may also refer to a candle snuffer. A stored pressure fire extinguisher …   Wikipedia

  • fire extinguisher — Extinguisher Ex*tin guish*er, n. One who, or that which, extinguishes; esp., a hollow cone or other device for extinguishing a flame, as of a torch or candle. [1913 Webster] {fire extinguisher} a portable device designed to deliver chemicals,… …   The Collaborative International Dictionary of English

  • fire extinguisher — UK US noun [C] (also extinguisher) ► WORKPLACE a piece of equipment that contains a substance that can be put onto a small fire to stop it burning: »Decorations must not obstruct fire escape signage, fire extinguishers, and emergency lighting …   Financial and business terms

  • fire extinguisher — fire extinguishers also fire extinguisher N COUNT A fire extinguisher is a metal cylinder which contains water or chemicals at high pressure which can put out fires …   English dictionary

  • fire extinguisher — ► NOUN ▪ a portable device that discharges a jet of liquid, foam, or gas to extinguish a fire …   English terms dictionary

  • fire extinguisher — n. a portable device containing chemicals that can be sprayed on a fire to put it out …   English World dictionary

  • fire extinguisher — n. 1) to train a fire extinguisher (on a fire) 2) to operate a fire extinguisher 3) to recharge a fire extinguisher * * * to operate a fire extinguisher to recharge a fire extinguisher to train a fire extinguisher (on a fire) …   Combinatory dictionary

  • fire extinguisher — UK / US noun [countable] Word forms fire extinguisher : singular fire extinguisher plural fire extinguishers a metal container filled with water or a chemical that you pour onto a fire to stop it burning …   English dictionary

  • fire-extinguisher — gesintuvas statusas T sritis chemija apibrėžtis Įtaisas gaisrui gesinti. atitikmenys: angl. extinguisher; fire extinguisher; fireextinguisher rus. гаситель; огнетушитель …   Chemijos terminų aiškinamasis žodynas

  • fire extinguisher — np A chaperone. Priscilla was so hot, she could never go out without a fire extinguisher. 1920s …   Historical dictionary of American slang

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”