Chapter 12

Introduction to Fire Protection 3rd 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 (CO 2 ) 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 Valves Riser 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

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
Summary

Chapter 12

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Chapter 12

by Joe

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Chapter 12 Presentation Transcript

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