Chapter 12

Copyright © 2006 Thomson Delmar Learning

Introduction to Fire Protection 3rd EditionRobert Klinoff

Introduction to Fire Protection3rd Edition



Chapter 12

Fire Protection Systems and Equipment



Objectives

• Describe the components of a water supply system

• Explain the importance of a dependable water supply system

• Describe the components and importance of a fire department water supply program

• Describe fire detection systems and their components



Objectives (con’t.)

• Describe different types of extinguishing systems and their components

• Describe the different types of extinguishing agents

• Explain how the various types of extinguishment agents work



Introduction

• Water is most common extinguishing agent• Over the years, water systems have been

become dependable and readily available• Additives are added to water to increase

effectiveness• Other extinguishing agents have been

developed for cases in which water causes damage or is ineffective



Public Water Companies

• Water is one of the single most important factor in municipal fire protection– Water companies formed to provide adequate

water supplies

– Fire or building department determines required fire flow for structures

– Water company may have to boost pressure to provide for flow at large fires



Private Water Companies

• Usually established to address industrial or commercial needs

• Maintain own distribution and storage

• Should be checked periodically by fire department



Water Supply Systems

• Storage capacity and redundancy of system• Factors for determining required system

capacity– Frequency and duration of drought

– Danger to system from natural disaster



Water Supply Systems (con’t.)

• Types of supply systems– Gravity fed systems

– Direct pumping systems

– Underground storage systems

– Combination systems

• Requires duplication of equipment to prevent shutdowns







Water Supply Systems (con’t.)

• Adequacy criteria– Average daily consumption

– Maximum daily consumption

– Peak hourly consumption

• Minimum recognized water supply system for fire protection– 250 gpm for 2 hours (30,000 gallons)



Distribution System

• From storage to treatment to consumer• Water mains

– Underground piping of differing sizes

– Largest are called primary feeders

– Widely spaced throughout system

– Best when laid in grid pattern• Looped to prevent dead ends and pressure

drops



Distribution System (con’t.)

• Secondary feeders– Reinforce grid

– Concentrate supply in high demand areas

• Distributors– Serve individual hydrants and blocks of

consumers









Fire Hydrants

• Two basic types (see Figure 12-5)– Wet barrel

• Contains water• May have more than one valve• Common fitting sizes: 2 ½, 4, and 4 ½ inch

– Dry barrel• Is dry to prevent freezing• Valve located underground







Fire Hydrants (con’t.)

• Special hydrant types– Airport taxiway/runway

• Totally underground

– Dry hydrant• Drafting source from static water supply• Facilitates drafting operations

• Hydrant spacing is specified by local ordinance



DRY HYDRANT WALL HYDRANT




• Hydrant maintenance program– Inspect, clean, and lubricate all parts

– Clear weeds and other obstructions

– Flush when necessary• Notify water company first• Open and close valves slowly• Water hammer may occur if valves are closed too

quickly, especially at high flows or pressures




• Hydrant testing– Performed on new systems to assess flow rates

– Performed on old systems to assess condition of system

• Hydrant painting– Painted for visibility

– Color coded to identify flow rates (developed by NFPA)



NFPA Coding System

• 1,000 GPM + Green Caps and Bonnet

• 500 to 999 Orange Caps

• 499 or less Red Caps

• Dead-end mains one cap black

• Out of service Bonnet painted white



PITOT TUBE

PITOT TUBE MEASURES FLOW.





Water Systems Program

• Used to promote cooperation between fire department and water companies– Letter of working agreement

– Water system map

– Hydrant records

• Maintaining water system familiarizes personnel with the location of hydrants



Auxiliary Sources of Water Supply

• In areas with lack of an adequate water supply system, especially rural areas

• Water available from static sources– Cisterns, reservoirs

– Canals, creeks, rivers

– Tanks, swimming pools, etc.

• Preplan your area and identify sources





Private Fire Protection Systems

• Designed to protect individual properties from fire

• Uses detection devices• Has two main purposes

– Alert building occupants

– Notify fire department



Detection Devices

• Smoke detectors– For public education purposes, the NFPA

prefers the term “smoke alarm”

• A working smoke alarm in the home doubles a person’s chances of surviving a fire– Change your clock

– Change your battery

– Test your alarm monthly







Detection Devices (con’t.)

• Smoke/flame detector types– Ionization chamber

– Flame or light detector

– Visible smoke detector

– Rate of rise detector

– Fixed temperature detector



Detection Devices (con’t.)

• Alarm system activation– Manual pull stations (see Figure 12-14)

– Water flow switch or excess flow switch

• Many systems have combinations of smoke/heat detectors and other devices



Extinguishing Agents

• Water– Most commonly used agent

– High specific heat• One gallon absorbs 1,280 BTU when temperature

raised from 62 degrees to 212 degrees• Additional 8,080 BTU absorbed when going from

212 degrees water to 212 degrees steam

– Volume expands 1,700 times when converted to steam



Extinguishing Agents (con’t.)

• Foam– Consists of concentrate added to water

– Extinguishes three ways• Cools surface• Cuts off vapor production• Insulates surface from radiated heat




• Types of foam– Chemical

• Combination of two agents• Chemical reaction creates bubbles

– Mechanical• Concentrate added to hose stream through

inductor• Nozzle adds air to create bubbles






• Types of mechanical foam (Class B)– AFFF

– AFFF ATC

– Protein

– Fluorinated protein

– High expansion




• Class A foam– When used with CAFS, will stick to vertical

surfaces to form fire resistive protection layer

– Acts as wetting agent

– Reduces surface tension of water

– Helps it soak into fuel/reduces runoff

• Do not mix foam types– Use the right type for the classification of fire




• Wetting agents– Reduce surface tension of water and allow it to

soak into fuel at faster rate

– Water does not evaporate as fast

– Less water is needed for job

– Deep seated embers are extinguished more quickly




• Fire retardant– Short term

• Depends on wetness to suppress fire• Uses class A foam and wetting agents• Applied by air or ground-based units

– Long term• Depends on chemical reaction with fuel• Contains pigment to remain visible from air• Applied by aircraft




• Other agents– Carbon dioxide (CO2) dilutes oxygen to smother

fire

– Halogenated agents break chemical chain reaction

– Clean agents act like halogenated agents and do not damage ozone layer




• Other agents (con’t.)– Dry chemical

• Breaks chemical chain reaction• Used for A, B, and C fires• Can be used along with water• Must be followed up with water to ensure deep-

seated embers are extinguished




• Other agents (con’t.)– Dry powder

• Used for class D fires • Used on flammable metals• May just be dry sand in a pail

Safety Note: Water may react violently with some

combustible metals, causing an

explosion of hot metal particles



Extinguishing Systems

• Automatic sprinklers– Proven 96% effective– Failures are primarily due to

• Improper maintenance• Inadequate or shut off water supply• Incorrect installation or design• Obstructions



Residential Sprinklers

• Less expensive than commercial systems• Less complicated• Proven effective, but not commonly installed

due to:– Added cost

– Misconception that operation results in water damage



Commercial and Industrial Sprinkler Systems

• Basic components– Fire department connection

– Open screw and yoke (OS&Y) valves

– Post indicator (PI) valves

– Backflow prevention

– Main control valve



Wet Pipe System

• Used where freezing is not a concern• Water remains behind sprinkler heads at all

time• Clapper in control valve keeps water pressure

constant in system• Alarm valve actuates when flow is detected• Retard chamber prevents false alarms due to

pressure fluctuations



Example Wet Pipe System



Post Indicator ValvesRiser And Loop





Dry Pipe System

• Used where freezing is a concern• Compressed air in system keeps water below

clapper in main control valve• Head opening releases air pressure and water

enters system• System may cause delay in water discharge at

head



Dry Pipe System (con’t.)

• Fire department connection – Attached to riser

– For boosting system pressure with fire department apparatus

– May be several in high rise or other large structures

– Know which ones to connect to

• Preplan your systems and mark if possible




• Path of water through system– Water main

– PI valve and OS&Y (may have back flow preventer)

– Through main valve mounted on riser

– Feed mains

– Cross mains

– Branch lines

– Sprinkler heads




• Deluge system– All sprinkler heads open at all times

– Sensor system releases water into sprinkler system

– Used where flooding amounts of water are required

– Systems are used in LPG storage, lumber operations, etc.




• Preaction system– Closed sprinkler heads

– Preaction valve opens on activation

– Allows water into piping

– Water is discharged when heat is sufficient to open sprinkler head



Sprinkler Heads

• Include deflector to divide flow into droplets• Various types for differing applications

– Pendant: head down

– Upright: head upright

– Sidewall: head horizontal

Note: Types are not interchangeable and should

only be used as designed









Standpipe Systems

• Usually found in stairwells• Prevent having to lay hose to upper floors

– Class I: 2 ½ inch hose connection for Fire Department use

– Class II: 1 ½ inch hose connection with hose for occupant use

– Class III: 2 ½ and 1 ½ inch connection for occupant and fire department use

• Watch out for pressure-reducing devices





Foam Systems

• Can create foam in several ways– Eduction: draws concentrate into hose stream

through Venturi action

– Injection: injects concentrate into system before or after main pump

– Batch mixing: pours concentrate into tank

– Premixing: concentrate and water stored as mixture





Gas Extinguishing Systems

• Used when water will cause excessive damage to stock or electrical installations

• Carbon dioxide– Stored in large tanks/cylinders

– Plumbed to nozzles

– Alarm evacuates area before discharge

– Release delayed to allow evacuation



Dry Chemical Systems

• Powder stored in a container• Common fire extinguisher• May have expellant gas in container with

powder or in remote reservoir• Can handle rough service• Requires little maintenance



Wet Chemical Extinguishing Systems

• Used for combustible cooking• Installed hood system or portable extinguishers• Reduces temperature of liquid and applies

extinguishing agent



Fire Pumps

• Boosts pressure in fixed systems• Diesel and/or electric powered

– System may have both

• Centrifugal pumps• Vertical turbine pumps



Fire Extinguishers

• From very small to very large• Found in all types of applications• Different types for all classifications of fires• Not for use on all classifications of fire at the

same time• Check the label before using



EXTINGUISHER LABELS

Class A

• Green Triangle

• Picture of Trash Can

• Picture of Wood

• Flames



EXTINGUISHER LABELS

Class B

• Red Square

• Gas Can with Flames



EXTINGUISHER LABELS

Class C

• Blue Circle

• Picture of Electric Plug and Receptacle

• Flames



EXTINGUISHER LABELS

Class D

• Gold Star

D



Extinguisher Labels

• Class K

• Picture of a Frying Pan with Flames



Obsolete Agents

• Some obsolete extinguishers are still in use– Soda acid, carbon tetrachloride

• If encountered– Remove these from service

– Handle carefully ad dispose properly

• If unsure of extinguisher type, ask local extinguishing service to assist



Pressure-Reducing Devices

• Used to reduce pressure on lower floors of high-rise buildings

• Used to reduce pressure in standpipe systems• May require special nozzles to provide effective

firefighting hose stream• Preplan the location and types of systems for

safety



Summary

• Fire department should maintain close relationship with local water company

• Firefighters must: – Be familiar all types of extinguishing agents– Be aware of the hazards of agents– Know how to operate all agent systems– Stay informed of new agents and systems– Be able to pick the best option available at an

incident

Education

Chapter 12