Fire detection, alarm, and suppression systems are installed to:

Fire detection, alarm, and suppression

systems are installed to:

Fire fighters must understand the

various types of fire protection

systems which may be encountered

in different occupancies and

How these

systems

function

P

P

F

A

S

LOCAL FIRE ALARM SYSTEM

TYPES OF ALARM SYSTEMS

Designed to be

initiated manually

by pull stations

Designed to only alert the building's occupants Does not notify the fire department

Automatic detection devices may be added to the system to detect a fire and initiate the

Respond to the

thermal energy

of a fire

Slowest type of

system to

activate

Activate at a predetermined

Used in areas

unoccupied or

environmentally

unsuitable for

application of

smoke

detectors

Activate when heated to the

rated temperature, usually 135

F

or higher

In a large area, a

fire could burn for

some time without

activating a

fixed-temperature

Operate identically to

fusible links or frangible

bulbs used in automatic

sprinkler systems

Many of these devices are still in service,

however, they are no longer

manufactured

To restore a fusible

device/frangible bulb

detector, the entire

A fusible device is held in place with solder

with known melting

temperature

When the temperature rises

to the fusing temperature, the

solder melts, a spring closes

the contact points and

One type is a cable

with a conductive

metal inner core

sheathed in stainless

steel tubing

The core and sheathing are separated by an insulating material

At a predetermined temperature, the insulation loses some of its electrical resistance

Another system

uses two

insulated wires

with an outer

covering

When the rated temperature is reached,

the insulation melts and the wires touch

The circuit is then completed and the

Uses two metals with

different heat expansion rates

When heated, one metal

expands faster, causing the strip to bend

The deflection makes or breaks the circuit causing alarm activation

Operates on the

assumption that the

temperature from a fire

will increase faster than

normal atmospheric

heating

Designed to operate when the temperature

rise exceeds 12

F to 15

F in one minute

Most are reliable and not subject to false

activations

Most common type of rate-of-rise detector used

Consists of a dome-shaped air chamber with a flexible metal diaphragm in the base

During a fire, the air in the chamber expands faster than it can escape

The expansion causes the pressure in the chamber to increase and forces the metal

Consists of an outer

metallic sleeve

housing two bowed

struts with slower

expansion rates than

the sleeve

When heated rapidly, the outer sleeve

expands in length

Typically installed in

nonresidential and multifamily occupancies

Detects smoke and transmits a signal to another device that sounds the alarm

A beam of light

is focused onto

a photoelectric

cell which

converts the

beam into an

electric current

When smoke obscures the light beam, the

amount of current is reduced and an

A light beam passes through a small

chamber away from the light source

When smoke enters the

chamber, the light beam is refracted in all directions and strikes the photocell, activating the alarm

The light does not strike the photocell and no

Tiny particles and

aerosols are

produced during

combustion

These particles can be detected by

devices using a small amount of

radioactive material to ionize air

molecules as they enter the detector

The ionized air

particles allow an

electrical current to

flow between plates in

the ionization chamber

When smoke enters the chamber, its

particles attach to the air ions making the air

less conductive

Reacts the fastest to fire

Prone to activation by sunlight, welding and other bright lights Usually positioned where other light sources are unlikely

Must have an unobstructed view of the protected area

Used where immediate reaction is necessary such as

Virtually insensitive to sunlight

Not suitable when arc welding is done

Sensitive to sunlight and usually installed in fully enclosed areas

Most are designed to

Used to detect the gases

produced by a fire in a

confined space

The gases produced will vary depending on

the chemical makeup of the burning fuel

Will initiate an alarm more quickly than a

heat detector but slower than a smoke

detector

Combination detectors: makes detectors more responsive to fire conditions

Fire department response to alarm calls

Normally a full structure fire

response is dispatched to the

location of a activated smoke

or heat alarm

If there are no signs of

smoke or fire when they

arrive, a fire fighter with a

portable radio should go to

the alarm control panel to

Fire department response to alarm calls

The system must

not be reset or

turned off until fire

fighters determine

the cause of the

alarm

The individual assigned to the alarm panel

must remain and monitor the panel in case

of another alarm

If a second alarm sounds, the Incident

AUTOMATIC ALARM SIGNALING SYSTEMS

Auxiliary systems

Local energy systems: used

only in communities with

municipal fire alarm box

systems

An occupancy's alarm system

is directly connected to the

AUTOMATIC ALARM SIGNALING SYSTEMS

Auxiliary systems

Shunt systems where the

municipal alarm circuit extends (“is shunted”) into the protected property

Parallel telephone systems

Not connected to the municipal alarm system

Transmits the alarm over municipally controlled

R

EMOTE

S

TATION

S

YSTEM

Protected Properties

AUTOMATIC ALARM SIGNALING SYSTEMS

R

EMOTE

S

TATION

S

YSTEM

AUTOMATIC ALARM SIGNALING SYSTEMS

P

ROPRIETARY

S

YSTEM

Used for large commercial and industrial buildings, high rises, and commonly owned facilities in a single location (campus or industrial complex)

Alarms are transmitted to a supervising stations where operators can call the fire department or the fire

AUTOMATIC ALARM SIGNALING SYSTEMS

Typically a company that sells alarm services to individual customers at different properties

AUTOMATIC ALARM SIGNALING SYSTEMS

C

ENTRAL

S

TATION

A

LARM

S

YSTEM

When an alarm is received, central station employees initiate an appropriate emergency

AUTOMATIC ALARM SIGNALING SYSTEMS

C

ENTRAL

S

TATION

A

LARM

S

YSTEM

Protected Properties

Fire alarm systems are designed to be

self-supervising

A distinct trouble signal is generated anytime the

system is not operating normally, such as when:

A utility power

outage occurs and the system switches to battery power

Older systems use closed, supervised

circuits where a tiny current always flows

Newer systems

microprocessors do

an internal diagnostic

system test at

specified intervals

Alarm signals must

be distinctively

Alarm systems must also be

“addressable,” indicating the location

of an activated detector or pull station

Consists of a series of sprinkler heads

arranged to automatically apply water

directly on a fire to either extinguish it

Complete system: protects

an entire building

Factors affecting sprinkler system reliability and performance:

Partially or completely closed valves Poor or improper maintenance

Improper design

Hazards of the occupancy Distribution obstructions Deficient water supply

Partial sprinkler protection Frozen or broken pipes

Properly operating

sprinkler systems:

Improve the life safety of a building's

occupants by applying water when a fire is

relatively small

Prevent vertical fire spread in multistory buildings

Protect occupants in

Sprinklers alone may

not be as effective if:

Fires are too small to

activate the sprinkler

system

Smoke reaches the

occupants before the

system activates

Sleeping,

intoxicated, or

SPRINKLER SYSTEM

COMPONENTS

Water Supply

Supply Main Branch lines: piping on which

sprinkler heads are installed Cross Main

SPRINKLER SYSTEM BASIC PIPING

Riser:

larger vertical

135

to 170

: uncolored or black

175

to 200

: white

250

to 300

: blue

325

to 375

: red

Temperature ratings: Frangible bulbs

135

to 170

: orange or red glass bulb

175

to 200

: yellow or green bulb

250

to 300

: blue bulb

Fusible Link

Frangible Bulb

Two lever arms press against the frame

arms and valve cap to hold back the

water

The fusible link holds the levers together

The link melts or fuses when exposed to heat and the water pushes the levers and cap out of the way

Water strikes the deflector and becomes a spray

F

B

O

The bulb filled with

liquid and a bubble

holds the orifice

shut

Heat expands the liquid until the bubble is

absorbed by the liquid

The increase in internal pressure shatters the

bulb and the orifice opens

S

H

P

Sidewall

Extends from the

side of the pipe and has a special

A storage

cabinet for

extra heads

and a wrench

should be

installed near

the sprinkler

system

Located between water source and

sprinkler system to shut off water supply

Visually show if opened or closed

C

ONTROL

I

NDICATOR

V

ALVES

Has a yoke on the outside with

a threaded stem which

controls the valve gate

C

I

V

Post Indicator Valve (PIV)

Valve stem inside of

C

I

V

Wall Post Indicator

Valve (WPIV)

Similar to PIV but

extends through

wall

Has a sight area that is open when the valve is open

Alarm test valve: simulates activation of the system

OPERATING VALVES

Inspector's test valve:

equipped with a same size

opening as a sprinkler head to simulate activation of a head

Main drain valve: to drain water from the

W

F

A

To alert occupants

and a passerby that

water is flowing

through the system

W

F

A

Alerts occupants

and transmits an

alarm that water is

flowing through the

system

Usually a clappered

siamese with

at least two

2½” female

connections

F

IRE

D

EPARTMENT

C

ONNECTION

(FDC)

F

D

S

A minimum of two

2

/

” or larger lines

should be attached to

the FDC

Most sprinkler

systems are

supplied at 150 psi

Wet Pipe Systems

Sprinkler heads discharge

water immediately on

activation

Usually equipped with an

alarm check valve on the

main riser

Used in locations not

subject to freezing

Newer systems may have a

backflow prevention check

valve and electronic flow

alarm instead of an alarm

check valve

(“straight stick systems”)

Maybe equipped with a

retard chamber to catch

excess water that may

come through the alarm

valve in a water

pressure surge

Newer systems may have a

backflow prevention check

valve and electronic flow

alarm instead of an alarm

check valve

Wet Pipe Systems

Gauges

Installed above and below each alarm check valve

Riser pressure gauge showing pressure in system

Owner or owner's

representative should check and record

Used in areas subject

to freezing

Dry Pipe Systems

Dry Pipe Systems

One on water side and another on the air side of dry pipe valve and at the air pump supplying air Owner should check and record gauge

readings weekly to ensure normal air

Used in properties to

prevent water damage,

even if pipes are broken

Uses a deluge type valve, fire detection

devices, and closed sprinkler heads

Sprinkler heads open only from functioning

of fusible links

System pipes are dry until

water is released into

R

S

Used to prevent fire

involvement in area of

origin and allow

occupants to escape

Typically equipped with

quick-response sprinkler

heads

Whenever possible,

pumpers supplying

hose streams should

operate from mains

other than that

supplying system

Control valves should

not be closed until fire

has been extinguished

unless the incident

C

O

W

F

F

S

Remove sprinkler wedge or clamp

from apparatus

Raise ladder under

activated head

Insert wedge or

clamp into flowing

head

Class I

For use by fire fighting personnel Have 21_/ 2-inch hose connections attached to standpipe risers

Class II

Have 11/2-inch single jacket

hose with a lightweight nozzle attached

Designed for use by

building occupants with no fire training

Class I

For use by fire fighting personnel

Have 21_/

2-inch hose

Class III

Have 2

/

-inch hose

connections and

1

/

-inch single

jacket linen hose

with a lightweight

nozzle attached

Designed for use

by building