Fire Extinguishing Agents – Overview of Types, Uses, and Mechanisms

Fires are classified according to their: - ANS-- fuel To be effective and safe, the extinguisher being used must match the _________ to be extinguished - ANS-- class of fire Combustible cooking media is one type of fire where a __________ extinguisher should not be used. - ANS-- water A short circuit could occur if a stream of water is discharged onto - ANS-- Live electrical equipment . ____________ rate fire extinguishers according to the type of fires they can safely extinguish - ANS-- Independent testing laboratories Listed extinguishers have been: - ANS-- tested, approved Fires involving live electrical equipment can best be extinguished using a ____________ fire extinguisher. - ANS-- Class C Fires involving vegetable oil or animal fats can best be extinguished using a _____________ fire extinguisher - ANS-- Class K Fires involving combustible metal alloys can best be extinguished using a _____________ fire extinguisher. - ANS-- Class D . Fires involving rubber and fabrics can best be extinguished using a ______________ fire extinguisher. - ANS-- Class A . Fires involving oils, paint, and lacquer can best be extinguished using a _____________ fire extinguisher. - ANS-- Class K Which class of fire includes natural fibers and may be extinguished using water? - ANS-- Class A . Which class of fire includes magnesium and zirconium and will require specifically designed chemical extinguishing agents to put out? - ANS-- Class D Which class of fire involves energized electrical equipment and can be extinguished by using carbon dioxide? - ANS-- Class C All portable fire extinguishers use __________ to expel the extinguishing agent - ANS-- Pressure . Some fire extinguishers store the pressurizing gas externally using a: - ANS-- Separate cylinder Carbon dioxide is an example of an extinguishing agent that: - ANS-- Creates its own pressure The majority of fire extinguishers consist of the following six basic parts: cylinder, handle, lever, nozzle or horn, pressure indicator, and: - ANS-- locking mechanism Which type of extinguisher keeps the agent and the pressurizing gas together in the cylinder? - ANS-- Stored pressure To discharge the extinguishing agent, which part of handle is depressed? - ANS-- lever . The purpose of the ___________________ is to prevent accidental discharge. - ANS-- locking mechanism .As an extinguishing agent, water is best suited for ____________ fires. - ANS-- Class A Water extinguishes fires by: - ANS-- Water extinguishes fires by: An extinguishing agent that creates bubbles that form a film when breaking, creating a film on the surface of the fuel to prevent the escape of vapors, best describes: - ANS-- aqueous film-forming foam An extinguishing agent that works best against fires involving polar solvents is: - ANS-- alcohol type aqueous film-forming foam Film-forming fluoroprotein (FFFP) foam is similar to aqueous film-forming foam (AFFF) in that it: - ANS-- forms a film over a flammable liquid surface. Wet chemical agents are specifically designed for which class of fire? - ANS-- Class K 8. When using wet chemical, the reaction in which a soapy foam forms on top of the burning material of the cooking medium is known as: - ANS-- saponification To be successfully extinguished, cooking medium fires must be: - ANS-- cooled below their ignition temperature This type of extinguisher discharges a fine spray and is designed as an alternative to halon: - ANS-- water-mist extinguisher The water-mist extinguisher may be used on Class C fires. - ANS-- True Which class of fires requires the process of saponification to occur in order to extinguish a fire? - ANS-- Class K Which class of fires includes ignitable lubricants and may be extinguished using dry chemical extinguishing agents? - ANS-- Class B Purple K, ABC, Super K, and Monnex are all examples of this type of extinguishing agent: - ANS-- Dry Chemical Why is dry chemical not recommended for fires in delicate electrical equipment? - ANS-- It may damage the equipment beyond repair Sodium bicarbonate is also known as: - ANS-- regular dry chemical and BC Why are regular dry chemical extinguishers not recommended for Class A fires? - ANS-- They have no effect on deep-seated fires . Purple K uses a _________________extinguishing agent: - ANS-- potassium bicarbonate Monoammonium phosphate dry chemical is more commonly known as: - ANS-- ABC ABC dry chemical extinguishes ordinary combustible fires by creating a _____________ on the surface of the burning material. - ANS-- Molten residue Burning lithium is an example of a Class ______ fire. - ANS-- D Class D agents work by excluding oxygen and by - ANS-- absorbing thermal energy The Class D extinguishing agent graphite is best applied using a: - ANS-- dry scoop or shovel Halogenated extinguishing agents suppress fires by interrupting the ________________________of the fire. - ANS-- chemical chain reaction The primary advantage of halogenated agents has been: - ANS-- lack of cleanup required FE-36 and halotron are examples of: - ANS-- Extinguisher applied halon alternatives FE-36 and Halotron extinguish fires primarily through: - ANS-- cooling Because a violent reaction could occur, these types of extinguishers should not be used on fires involving oxidizers: - ANS-- ABC dry chemical, Halon 1211, and Halotron I . During Class A fire tests, the minimum allowable discharge time for extinguishers rated 2A and higher is: - ANS-- 13 seconds For an extinguisher to be classified for Class C fires, the extinguisher test consists of - ANS-- he extinguishing agent only needing to be tested for electrical nonconductivity The minimum rate at which the agent must be applied to the fire, usually expressed in a ratio of quantity of agent per area unit per time unit, is called the: - ANS-- critical application rate The disadvantages of using higher flow rates include: - ANS-- wasting chemicals and having less discharge time Theoretically, two operators applying dry chemical at the same time can ___________ the flow rate of their extinguishers. - ANS-- double When operating a fire extinguisher, the acronym PASS stands for: - ANS-- pull, aim, squeeze, sweep The most important aspect of any fire extinguisher application technique is: - ANS-- operator safety With regard to protection against radiant heat, foam streams: - ANS-- do not give good protection When applying foam to a fire, it should be applied: - ANS-- gently with minimal disturbance to the fuel surface If water-miscible fuels are involved in the fire, a/an _____________ must be used. - ANS-- alcohol type foam Because dry chemical uses a ________________ action to extinguish a Class B fire, no physical properties of the fire are affected. - ANS-- chain-breaking Flammable liquid contained in a certain area by a vessel, berm, or dike is considered to be: - ANS-- fuel in depth When fighting in-depth flammable liquid fires with dry chemical extinguishers, the sweep of the extinguisher should be ______ inches past the edge of the burning fuel. - ANS-- 6 Three-dimensional Class B fires involve flammable liquids: - ANS-- in motion When attacking a three dimensional flammable liquids fire, the point of attack should begin with the: - ANS-- ground fire One of the most successful ways of combating fires with extinguishers is by: - ANS-- working in teams For fires involving flammable liquids under pressure, fast-flow equipment with high flow rates must be used because: - ANS-- The dry chemical flow rate must match the escaping fuel flow rate. When used in conjunction with water hoselines on fog patterns, dry chemical can be applied to fires with: - ANS-- great success When applying dry powder to Class D fires, the operator should be careful that _________________ is present in the surrounding area. - ANS-- no moisture Fire extinguishers shall be inspected at a minimum of: - ANS-- 30-day intervals The test in which the extinguisher cylinder is subjected to pressure applied by water or other noncompressible fluid is known as a __________________ test. - ANS-- hydrostatic test . Carbon dioxide extinguishers need to hydrostatically tested every _______ years. - ANS-- 5 Extinguishers requiring 12-year hydrostatic tests shall be emptied and subject to a thorough examination of mechanical parts every _______ years. - ANS-- 6 Stored-pressure water extinguishers with fiberglass shells, vaporizing liquid, and cartridgeoperated loaded stream extinguishers, are examples of extinguishers that are: - ANS-- obsolete