Chapter 7

PASS Method

**Alway approach the fire from the windward side-wind always to your back -P:pull the pin breaking the thin wire or plastic seal -A:aim the nozzle at the base of the fire -S:squeeze the handles together to release the agent -S:sweep the nozzle back and forth to cover the burning material **if extinguishment is not achieved after an entire extinguisher has been discharged onto the fire, withdraw and reassess the situation

3 Factors determining value of a fire extinguisher

*Inspect at lease once a year to make sure they are accessible and operable -serviceability -accessibility -simplicity of operation

How to select the proper fire extinguisher

-classification or the burning fuel -rating of the extinguisher -hazards to be protected -size and intensity of the fire -atmospheric conditions -availability of trained personnel -ease of handling extinguisher -any life hazard or operational concerns

Inspecting fire extinguishers

-external condition:no apparent damage -hose/nozzle:in place -weight:feels as though it contains agent -pressure gauge(if available): in operable range

Fire extinguishers mechanisms

-manual pump: operator physically applies pressure to a pump that increases pressure within the container, forcing the agent out a nozzle at the end of a hose -stored pressure: compressed air or inert gas within the container forces the agent out a nozzle at the end of a hose when the operator presses the handle -pressure cartridge: Compressed inert gas is contained in a separate cartridge on the side of the container. When operator punctures the cartridge, the expellant enters the container forcing the agent out a nozzle on the end of a hose

Care and Store fire extinguisher

-never drop or throw a portable fire extinguisher -depending on size and weight, carry it diagonally across the body with one hand on the handle and the other on the bottom edge -do not remove the safety pin until you are ready to use it -store the extinguisher securely in its apparatus or mounting bracket -lay empty extinguishers on their sides to indicate that they are out of service -do not store or stack items in front of wall mounted extinguishers -shake dry chemical extinguishers monthly to loosen agent and prevent settling

Common portable fire extinguishers include:

-pump type water extinguishers -stored pressure water extinguishers -water mist stored pressure extinguishers -wet-chemical stored pressure extinguishers -aqueous film forming foam (AFFF) extinguishers -clean agent extinguishers -carbon dioxide extinguisher -dry chemical extinguishers -dry powder extinguishers

To be qualified as Firefighter 1 you must:

-select appropriate extinguisher for size and type of fire -safely carry portable fire extinguishers -approach fire with portable fire extinguishers -operate portable fire extinguishers

Extinguishing agents use following methods to put fires out

-smothering:excluding oxygen from the burning process -cooling: reducing the burning material below its ignition temperature -chain breaking: interrupting the chemical chain reaction in the burning process -saponification: forming an oxygen-excluding soapy foam surface

Saponification

A phenomenon that occurs when mixtures of alkaline based chemicals and certain cooking oils come into contact resulting in the formation of a soapy film.

Extinguishing Agent

Any substance used for the purpose of controlling or extinguishing a fire.

Dry Powder Extinguishers

Are used on Class D fires. They form a solid crust over the burning metal. Most common powder used is sodium chloride.

Carbon Dioxide Extinguishers

Both handheld and wheeled. Most effective in extinguishing Class B and C fires. Because their discharge is in the form of a gas, they have a limited reach and the gas can be dispersed by wind. They do not require freeze protection. Stored under its own pressure, discharge is usually accompanied by dry ice crystals or 'snow'. The CO2 displaces the oxygen and smothers the fire. No cooling effect or vapor suppressing film. CAUTION: When CO2 is discharged, a static electrical charge builds up on the discharge horn. Touching the horn before the charge has dissipated can result in shock.

Halogenated Extinguishing Agents

Chemical compounds (halogenated hydrocarbons) that contain carbon plus one or more elements from the halogen series. Halon 1301 and Halon 1211 are most commonly used as extinguishing agents for Class B and Class C fires. Also known as Halogenated Hydrocarbons.

Dry powder

Extinguishing agent suitable for use on combustible metal fires.

Wet Chemical System

Extinguishing system that uses a wet-chemical solution as the primary extinguishing agent; usually installed in range hoods and associated ducting where grease may accumulate.

Air-Aspirating Foam Nozzle

Foam nozzle especially designed to provide the aeration required to make the highest quality foam possible; most effective appliance for the generation of low-expansion foam.

Water-mist

In the fire service, water mist is associated with a fire extinguisher capable of atomizing water through a special applicator. Water-mist fire extinguishers use distilled water, while back-pump type water-mist extinguishers use ordinary water.

Class K Fire

Involve combustible cooking oils and fats in kitchens. Wet chemical system an portable fire extinguishers are used to control and extinguish the fire

Class D Fires

Involve combustible metals such as magnesium, lithium, potassium or sodium. Identified by bright white sparks and emissions from combustion process. Special Class D Dry Chemical agents are used, however, do not confuse these agents with standard dry chemicals that are used on Class B and C fires. They will not work.

Class K Ratings

Must be capable of saponifying(converting the fatty acids or fats to foam or soap) vegetable oil, peanut oil, canola oil, other oils with little or no fatty acids.

Class A Rating

On water extinguishers is primarily based on on the amount of extinguishing agent and the duration and range of the discharge used in extinguishing test fires

Fire extinguisher

Portable fire fighting device designed to combat incipient fires.

Class B Rating

Ratings ranging from 1-B through 640-B. Nonexpert operator can extinguish using one full extinguisher

Fire extinguisher Maintenance

Should be removed from service for annual maintenance. This includes a thorough inspection and disassembly of the unit. Every 6 years the dry chemical extinguishing agent should be emptied and the extinguisher refilled

Wet Chemical Stored-Pressure Extinguishers

Similar in appearance to standard stored-pressure water extinguishers as well. These Class K units are specifically designed to control and extinguish fires in deep fryers. They contain a special potassium-based, low-pH agent formulated to cool and suppress fires in unsaturated cooking oils.

Water-Mist Stored-Pressure Extinguishers

Similar in appearance to standard stored-pressure water extinguishers, water-mist extinguishers use deionized water as the agent and nozzles that produce a fine spray instead of a solid stream. Because it is the impurities in water that make it electrically conductive, the deionized water also makes these Class A extinguishers safe to use on energized electrical equipment fires (Class C). The fine spray also enhances the cooling characteristics of water.

Class C Rating

Since electricity does not burn, extinguishers for use on Class C fires receive a letter rating because Class C fires are essentially Class A or Class B fires involving energized electrical equipment

Aqueous Film Forming Foam (AFFF) Extinguishers

Suitable for use on Class A and Class B fires. particularly useful in combating fires in or suppressing vapors from small liquid fuel spills. Different from stored-pressure extinguishers in two ways: Contains a specific amount of AFFF concentrate mixed with water, and has an air-aspirating nozzle that aerates the foam solution, producing a better-quality foam than a standard extinguisher nozzle. When the AFFF and water are mixed, the resulting finished foam floats on the surface of fuels that are lighter than water. The vapor seal created by the film of water extinguishes the flame and prevents re-ignition. Not suitable for fires in Class C or D fuels, 3-D fires such as in fuel flowing down from an elevated point and fuel under pressure that is spraying from a leaking object. Most effective on static pools of liquids.

Dry Chemical Extinguishers

Used for Class A, B and C fires or Class B and C. Types are 1-regular B:C rated and 2-multipurpose and A:B:C rated. Typically use Sodium Bicarbonate, Potassium Bicarbonate, Urea-Potassium Bicarbonate, Potassium Chloride or Monoammonium Phosphate. do not use with foam.

Class B Fires

Usually involve flammable liquids and grease and typically start in kitchens and maintenance areas. Agents used to extinguish special hazard class B fires are carbon dioxide, dry chemical, and class B foam

Class D Ratings

Vary with the type of combustible metal being testing. Remember these factors during each test: -reactions between the metal and the agent -toxicity of the agent -toxicity of the fumes produced and the products of combustion -Time to allow metal burn completely without fire suppression compared to the time to extinguish the fire using the extinguisher

Deionized water

Water from which ionic salts, minerals, and impurities have been removed by ion-exchange.

Stored-pressure fire extinguisher

also called air-pressurized water or pressurized water extinguishers are useful for all types of small class A fires. often used for extinguishing confined hot spots during overhaul operations

Corrosive

capable of destroying or eating away by chemical action

Dry Chemicals

extinguishing system that uses dry chemical as the primary extinguishing agent; often used to protect areas containing volatile flammable liquids

pump type water extinguisher

intended primarily for use on ground cover fires bu may also be used for small class A fires. Nozzle produces a straight stream, fog, or water-mist pattern

Class C Fire

involve energized electrical equipment. Water and water based agent will conduct electrical current they cannot be used until the electrical energy has been eliminated. Class C extinguishing agents will not conduct electricity making them suitable for electrical fires. Once power supply has been disconnected or turned off fire can be treated as a Class A or B fire

Class A Fire

involve ordinary combustibles such as textiles, paper, plastics, rubber, and wood. Can easily be extinguished with water, water based agents such as class A foam or dry chemicals