Chapter 8

Portable Fire Extinguishers

Introduction

• Portable fire extinguishers designed to fight:– Small fires– Unusual fires– Fires that cannot be reached quickly

with hoselines

• Fire extinguishers are a valuable tool

8.2

Introduction (cont’d.)

• Four basic PASS steps– P: Pull the pin– A: Aim the nozzle– S: Squeeze the handle– S: Sweep the base of the fire

• Fire extinguishers come in a variety of types and sizes

8.3

Fire Classification and Risk• Type of material burning defines

class of fire• Different classes of fire used to

identify type of extinguishers and agents used

• Four traditional classes of fire– Additional class added in the past few

years

• Have a pre-incident plan for fuel types and locations

8.4

Class A

• Involves ordinary combustibles• Can be extinguished with:

– Water– Water-based agents– Foam– Multipurpose dry chemicals

• Water usually the agent used

8.5

Class B• Flammable and combustible

liquids, gases, and greases• Special hazards: situations where

fire extinguishers have not been tested

• Common extinguishing agents:– Carbon dioxide– Regular and multipurpose dry

chemical– Foam

8.6

Class C• Involves energized electrical equipment• Water-based agents cannot be used• Turn off electrical power and use

appropriate extinguisher• Categorized with another class of

extinguisher: BC or ABC• Agents include:

– Carbon dioxide– Regular and multipurpose dry chemicals

8.7

Class D• Involves combustible metals and alloys• Can have erratic behavior• Water and other agents can react violently

when applied to burning combustible metals– Appear to explode when water applied

• No universal Class D extinguisher for all metals

• Class D agents called dry powders– Not to be confused with dry chemicals

8.8

Class K

• New classification as of 1998• Fires in combustible cooking fuels• Agents are usually wet chemicals• Agents usually used in fixed systems

8.9

8.10

Figure 8-1 Class K equipment.

Types of Fire Extinguishers

• Many types available• Factors for selecting an

extinguisher:– Type and amount of fuel– Person using extinguisher– Type of building construction and

occupancy– Type of equipment protected

• Main objective is extinguishing the fire

8.11

8.12

Figure 8-2 Various types of fire extinguishers.

Types of Extinguishing Agents• Water is the basic agent for class A

materials• Loaded stream extinguisher • Water-based foam extinguishers have

either:– Aqueous Film-Forming Foam (AFFF)– Film-Forming Fluoroprotein Foam (FFFP)

• Carbon dioxide: inert gas stored under pressure as a liquid capable of being self-expelled

• Dry chemical agents: particles propelled by gaseous medium

8.13

Kinds of Extinguishers• Many types are in use today:

– Small and handheld– Large and require a wheeled cart

• Pump-type extinguishers are hand-pumped devices of two designs

• Stored pressure extinguishers expel gas to propel agent

• Cartridge-operated extinguishers have expelled gas stored in cartridge on side of container

8.14

8.15

Figure 8-3 (A) Older versions of fire extinguishers are labeled with colored geometrical shapes with letter designations. (B) Newer fire extinguishers are labeled with a picture label system. (C) Many fire extinguishers can be used to fight more than one type of fire.

(A) (B) (C)

Rating Systems forPortable Extinguishers

• Each class of fuel is subjected to a separate type of extinguisher test for its class

• Usually conducted by independent testing agency

• Appropriate ratings and symbols are noted on label of extinguisher

8.16

Class A

• Testing utilizes wood cribbing• Extinguisher should extinguish

about 1 cubic foot of wood cribbing• Ratings increase as amount of fire

suppressed increases– Class 2-A extinguisher puts out twice

the fire of 1-A

8.17

Class B

• Test involves igniting a pan of flammable liquid, allowing a pre-burn period, and attacking the fire

• Size of pan determines rating– 4-square-foot pan yields rating of 4-B

• Ratings based on inexperienced extinguisher operator

• Larger fires require more agent per area than smaller ones

8.18

Class C

• Testing tests only the conductivity of:– Agent– Nozzle– Hose– Nozzle combination

• No actual fire test• No numbers are assigned with

Class C rating

8.19

8.20

Figure 8-20 Class C test for electrical conductivity of agent.

Limitations of PortableExtinguishers

• Exceeding capabilities can cause damage and injury

• Designed for specific purposes• First-aid method for fire extinguishment• Usually best to pick the larger size• Wrong class extinguisher may not do the

job– May cause a reaction or electrical shock

8.21

Portable ExtinguisherOperation

• PASS outlines four simple steps for extinguisher use:– P: Pull the pin– A: Aim the nozzle– S: Squeeze the handle– S: Sweep the base of the fire

8.22

Care and Maintenance ofPortable Extinguishers• Simple inspections and careful

storage prevent most problems• Vehicle operators should

periodically move unit from its bracket to hand test weight and do visual check

8.23

Care and Maintenance ofPortable Extinguishers (cont’d.)

• Recharging water extinguisher is a simple process– Performed at fire station by any

firefighter• Unscrew and remove the top• Add the manufacturers recommendation

of water• Add foam, if required• Replace the top• Charge the extinguisher with the

manufacturers recommendation of air8.24

8.25

Figure 8-21 (A) Unscrew and remove the top. (B) Add the manufacturer’s recommendation of water. (C) Add foam, if required.

(A)

(B)(C)

8.26

Figure 8-21 (cont’d.) (D) Replace the top. (E) Charge the extinguisher with the manufacturer’s recommendation of air.

(D) (E)

Inspection Requirements• Many popular fire extinguishers of

the past are now obsolete• Inspection of fire extinguishers is

usually a visual inspection• If something does not look right,

extinguisher should be removed and replaced

• Extinguishers returned to service should be examined prior to their placement on apparatus

8.27

Lessons Learned• Fire extinguishers can be used as:

– Initial response tools– To fight fires in special situations

• Firefighters classify fires by their fuels– Ordinary combustibles– Flammable liquids and gases– Energized electrical equipment

• Four-step process for using an extinguisher: PASS

8.28