services for fire

FIRE
K . K E D H E E S WA R A N M . A r c h 1

Fire fighting can be defined in three separate categories:
Fire protection, by design features in the construction of the
building and subsequent control of human behaviour
Fire Detection, using artificial systems or human senses.
Fire suppression using a number of fixed or portable
systems.
K.KEDHEESWARAN M.Arch 2

All fire fighting starts with the idea of what is needed for FIRE

All fire fighting breaks the triangle
REMOVAL
Or
STOPPAGE
Reduce
to less
than
10%
Oxygen

Fire Detection and Alarm Systems
A key aspect of fire protection is to identify a developing fire emergency in
a timely manner, and to alert the building's occupants and fire emergency
organizations.
This is the role of fire detection and alarm systems. Depending on the
anticipated fire scenario, building and use type, number and type of
occupants and criticality of contents and mission, these systems can
provide several main functions:
First, they provide a means to identify a developing fire through either
manual or automatic methods.
Second, they alert building occupants to a fire condition and the need to
evacuate.
Another common function is the transmission of an alarm notification
signal to the fire department or other emergency response organization.
They may also shut down electrical, air handling equipment or special
process operations, and they may be used to initiate automatic
suppression systems.

A fire detection system consists of the following
elements:
Human observation
Manual fire alarms
Automatic Fire detectors-smoke, flame, heat (gas,
H2S)
Combinations of the above
For reference purposes Fire detection system
requirements are detailed in SOLAS CHAPTER II-2
FIRE DETECTION

Fire Detection Principles
Manual Fire Detection - Pull Stations
Manual fire detection is the oldest method of detection. In the simplest
form, a person yelling can provide fire warning. In buildings, however, a
person's voice may not always transmit throughout the structure. For this
reason, manual alarm stations are installed. The general design
philosophy is to place stations within reach along paths of escape. It is
for this reason that they can usually be found near exit doors in corridors
and large rooms.
The advantage of manual alarm stations is that, upon discovering the
fire, they provide occupants with a readily identifiable means to activate
the building fire alarm system. The alarm system can then serve in lieu of
the shouting person's voice. They are simple devices, and can be highly
reliable when the building is occupied. The key disadvantage of manual
stations is that they will not work when the building is unoccupied. They
may also be used for malicious alarm activations. Nonetheless, they are
an important component in any fire alarm system.

Fire Detection Principles
Automatic Detectors – Spot type
Spot Type Detector. A device in which the detecting Element is concentrated at a
particular location. Typical examples are Bimetallic detectors, fusible alloy
detectors, certain pneumatic rate-of-rise Detectors, certain smoke detectors, and
thermoelectric detectors.

Automatic Detectors – Photoelectric
Light Scattering Smoke Detection. The principle of using a light source and a
photosensitive sensor arranged so that the rays from the light source do not normally
fall onto the photosensitive sensor. When smoke particles inter the light path, some
of the light is scattered by reflection and refraction onto the sensor. The light signal
is processed and used to convey an alarm condition when it meets preset criteria.

A – Light Source
B – Photo Sensor
In the normal case, the light from the light source on the left shoots straight
across and misses the sensor.
When smoke enters the chamber, however, the smoke particles scatter the light
and some amount of light hits the sensor.
Automatic Detectors – Photoelectric

Photoelectric Smoke Detectors:
Light Obscuration Type
• In a projected Beam
Detector, alarms are
generated by diffusing
the projected light beam
by a specified
percentage of
obscuration.
• Total beam blockage
generally results in a
trouble signal.

Automatic Detectors – Flame
Due to their fast detection capabilities, flame detectors are generally used
only in high-hazard areas, such as fuel-loading platforms, industrial process areas,
hyperbaric chambers, high-ceiling areas, and atmospheres in which explosions or
very rapid fires may occur. Because flame detectors must be able to 'see' the fire,
they must not be blocked by objects placed in front of them. The infrared-type
detector, however, has some capability for detecting radiation reflected from walls.

Automatic Detectors – Air Sampling
Air Sampling-Type Detector. A detector that consists of a piping or tubing distribution network
that runs from the detector to the area(s) to be protected. An aspiration fan in the detector
draws air form the protected area back to the detector through air sampling ports, piping, or
tubing. At the detector, the air is analyzed for fire products.

Automatic Detectors – Fixed Temp.
Fixed-Temperature Detector. A device that responds when its operating
element becomes heated to a predetermined level.
Fixed-temperature heat detectors are designed to alarm when the temperature of the
operating elements reaches a specific point. The air temperature at the time of alarm is
usually considerably higher than the rated temperature because it takes time for the air to
raise the temperature of the operating element to its set point. This condition is called
thermal lag. Fixed-temperature heat detectors are available to cover a wide range of
operating temperatures - from about 135'F (57'C) and higher. Higher temperatures
detectors are also necessary so that detection can be provided in areas normally subject
to high ambient temperatures, or in areas zoned so that only detectors in the immediate
fire area operate.

Automatic Detectors – Ionization
Ionization smoke detectors use an ionization chamber and a source of ionizing
radiation to detect smoke. This type of smoke detector is more common because it is
inexpensive and better at detecting the smaller amounts of smoke produced by
flaming fires.
An ionization chamber is very simple. It consists of two plates with a voltage
across them, along with a radioactive source of ionizing radiation.
IONIZATION SMOKE DETECTION. The principle of using a small amount of
radioactive material to ionize the air between two differentially charged electrodes
to sense the presence of smoke particles. Smoke Particles entering the ionization
volume decrease the conductance of the air by reducing ion mobility. The reduced
conductance signal is processed and used to convey an alarm condition when it
meets preset criteria.

Automatic Detectors – Rate-of-Rise
Rate-of-Rise Detector. A device that responds when the temperature rises at
a rate exceeding a predetermined value
One effect that flaming fire has on the surrounding area is to rapidly increase air
temperature in the space above the fire. Fixed-temperature heat detectors will not initiate
an alarm until the air temperature near the ceiling exceeds the design operating point. The
rate-of-rise detector, however, will function when the rate of temperature increase
exceeds a predetermined value, typically around 12 to 15'F (7 to 8'C) per minute. Rate-of-
rise detectors are designed to compensate for the normal changes in ambient
temperature that are expected under non-fire conditions.

Automatic Detectors – Combination
Combination Detector. A device that either responds to more than one of the fire phenomena
or employs more than one operating principle to sense one of these phenomena. Typical
examples are a combination of a heat detector with a smoke detector or a combination of rate-of-
rise and fixed temperature heat detector. This device has listings for each sensing method
employed.
Combination detectors contain more than one element which responds to fire. These
detectors may be designed to respond from either element, or from the combined partial or
complete response of both elements. An example of the former is a heat detector that operates
on both the rate-of-raise and fixed-temperature principles. Its advantage is that the rate-of-rise
element will respond quickly to rapidly developing fire, while the fixed-temperature element will
respond to a slowly developing fire when the detecting element reaches its set point
temperature. The most common combination detector uses a vented air chamber and a flexible
diaphragm for the rate-of-rise function, while the fixed-temperature element is usually leaf-spring
restrained by a eutectic metal. When the fixed-temperature element reaches its designated
operating temperature, the eutectic metal fuses and releases the spring, which closes the
contact.

Duct Detectors
• Photoelectric detector
mounted in housing
outside the ductwork
that has probes that
extend into the duct to
sample the air inside the
duct.
• Primarily used as a
smoke control device to
control the flow of air in
ductwork.

Notification Appliances Types
• Audible - Horns, Bells, Sounders, Sirens,
Chimes, Speakers
• Visual - Strobes
• Physical - Bed shakers
• Olfactory - Smell

Audible Devices
• Bells: Used if they are only for fire, or have a
distinctive sound from other bell signaling
devices. Often used as an external gong to
indicate the flow of water in the sprinkler
system.
• Horns: Loud and distinctive output. Often
used in high-noise environments, such as
manufacturing plants.

• Sounders: Electronic or mechanical audible
devices, which are capable of producing a
variety of tones. Often, the tone is selectable
during installation of the device.
• Chimes: Soft-toned appliances used where
loud noises could be disruptive to other
operations. Generally used where qualified
personnel are continuously in attendance.
Audible Devices

• Sirens: Extremely loud devices
generally limited in use to outdoor
or heavy industrial areas.
• Speakers: Audible devices used in
conjunction with voice evacuation
messages. Life-Safety speakers are
not generally associated with Muzak
systems.
Audible Devices

Visual Signaling Appliances
• Visual signaling appliances are used in high-noise
environments, in areas occupied by hearing-impaired
individuals, or in areas where audible devices may not be
desired.
Speaker/
Strobe
Chime/Strobe
Horn/S
trobe
Strobe

The Fire Alarm Systems
Conventional “Hard Wired” System
• Simplest type of control unit.
• Generally, a single circuit board contains power supply,
control, initiating and notification circuitry.
• Some models use auxiliary circuit boards to perform
special functions.
• Input/output devices connect to dedicated circuits.
• Designated outputs occur when initiating signals are
received.
• Limited special functions and capabilities.

Conventional “Programmable” System
• Basic “Designed System”
• Components selected by the designer to meet
the direct needs of the customer.
• Initiating circuits are programmable for fire,
waterflow, supervisory service, etc.
• Output circuits are programmable for code
selection and silenceability.
• On some systems, input-to-output CIRCUIT (not
device) mapping.

Addressable System
• Each device (detector, pull station…) has a unique
number assigned to it called the address for reporting
alarms and troubles.
• Employs a Signaling Line Circuit (SLC) Loop along which
all addressable input and output devices are connected
to the fire alarm control panel.
• Addressable devices transmit an electronic message
back to the Control Unit representing their state
(Normal, Alarm, Trouble) when polled by the Control
Unit.

Analog System
• Always an Addressable System.
• Processes detailed, analog data from
detectors about smoke levels.
• Can provide sensitivity data for each
detector.
• Employs Drift Compensation (self
calibration) in its detectors.

Sprinkler Systems

2 major different types of water sprinkler systems
 Wet pipe system
 Dry pipe system
Wet-pipe Systems
Dry pipe system

Location and spacing of sprinklers
Spacing depends on the class of
hazard of occupancy and the type of
ceiling construction
Light hazard - 15' maximum
between sprinklers
Ordinary hazard - 12-15' ft.
depending on use of area
Extra hazard - 12' maximum

Location and spacing of sprinklers
Sprinklers must also be spaced so that each sprinkler does not
protect more than a specified area:
Light hazard occupancy—floor area/sprinkler maximum
of 130-200 square feet, depending on type of ceiling
Ordinary hazard occupancy--max. area per sprinkler 100-130 square
feet, depending on use of space
Extra hazard occupancy--90 square feet sprinkler maximum
Extra High
Hazard
90 ft2

SPRINKLER PIPING
tank
(or natural water
supply
public water supply - 8” – 12”
yard main
6” – 8”
always below freeze
line
cross
main
branch lines feed
main
sprinkler
head
post indicator valve
“open” or
“closed”
should be
“open”
pad lock
unlock to
close valve
riser
(alarms, water flow
valve, sprinkler
valve)

Sprinkler Valves
The purpose of a sprinkler valve is to
retain & control flow of water and to
isolate individual risers.

TYPES OF CONTROL VALVES
OS&Y (Outside
Screw and
Yoke)
PIV (Post
Indicator Valve)
WPIV (Wall Post
Indicator Valve)

Type based on position
SPRINKLER HEADS
The different colours denote different operating
temperatures, but the alcohol is the same, only the size of
the air bubble changes.

HEAD is
pressurised by
Fresh water
BULB
keeps
valve
closed.
Heat causes alcohol inside bulb to expand, shatter bulb
and water flows.
RELEASING MECHANISMS

RELEASING MECHANISMS
Fusible
Link
(Standard)
Chemical
Pellet
Frangible
Bulb
Fusible Link
(Quick
Response)

SPRINKLER DESIGNS
Pendant
Sidewall
Upright

HIGH FOG
A single stage low pressure centrifugal pump, with a screw
inducer fitted in the eye takes suction direct from the
domestic fresh water tank.

Non-Colored  Ordinary  135-1700F
White  Intermediate  175-2250F
Blue  High  250-3000F
Red  Extra High  325-3750F
Green  Very High  400-4750F
Orange  Ultra High  500-6500F
TEMPERATURE RATING OF SPRINKLER HEADS

CARBON DIOXIDE EXTINGUISHING SYSTEMS
Types of fixed systems
Total flooding
Local application
Total flooding
apply to an entire room or
confined area
Local application
applying CO2 over the surface
of the tank local
application
Acid Pickling Tank

Dry Chemical Fire Extinguishing Systems
DRY CHEMICAL POWDER TOTAL FLOODING SYSTEM
Dry chemical fixed pipe fire suppression systems are
self contained units, designed by factory trained personnel,
consisting of a pressure vessel constructed to ASME
standards, nitrogen cylinders , automatic detection devices
and electric/pneumatic manual actuation devices.
POWDER BASE SYSTEMS

FM-200® Fire Suppression agent was the first environmentally acceptable
replacement for Halon 1301.
FM-200® has zero ozone depleting potential, a low global warming potential and a
short atmospheric lifetime. It is particularly useful where an environmentally acceptable agent
is essential, where clean up of other media presents a problem, where weight versus
suppression potential is a factor, where an electrically non-conductive medium is needed, and
people compatibility an overriding factor.
FM-200® is a colorless, liquefied compressed gas. It is stored as a liquid and
dispensed into the hazard as a colorless, eclectically non-conductive vapour that is clear and
does
Gas Extinguishing

Fire Fighting Foam Principles and Ethanol-Blended Fuel
Production of ethanol large & likely to continue to
increase
Predominate danger from tanker trucks & rail cars
carrying large amounts of ethanol, manufacturing
facilities, & storage facilities
Responders need to be prepared for large-scale
emergencies & prepared with most effective techniques
& extinguishing media

WHAT IS FOAM?
―…an aggregate of air-filled bubbles formed from aqueous
solutions which is lower in density than flammable liquids.
It is used principally to form a cohesive floating blanket on
flammable and combustible liquids, and prevents or extinguishes fire by
excluding air and cooling the fuel. It also prevents re-ignition by suppressing
formation of flammable vapors.
It has the property of adhering to surfaces, which provides a degree
of exposure protection from adjacent fires‖
Why use foam?
 Only agent capable of suppressing vapors & providing visible proof of
security
 Foam blanket on un-ignited spill can prevent fire
 Suppression of vapors prevents them from finding ignition source
 Can provide post-fire security by protecting hazard until it can be
secured / removed
 Can provide protection from flammable liquids for fire & rescue
personnel during emergency operations

Basic Foam Principles
• How foam works:
– Foam can:
• Exclude oxygen from fuel vapors
• Cool fuel surface with water content of foam
• Prevent release of flammable vapors from fuel surface
• Emulsify fuel
• How foam works:
– Foam tetrahedron:
• Before being used must be
proportioned & aerated
• 4 elements:
– Foam concentrate
– Water
– Air
– Aeration

What is foam not effective on?
Foam is not effective on Class C electrical fires:
Foam contains 94–97% water & water conducts
electricity
Class C fires can be extinguished using nonconductive
extinguishing agents
What is foam not effective on?
Foam is not effective on 3-dimensional fires
Recommended to first control spill fire
Extinguish flowing fire using dry chemical agent
TYPES OF FOAM:
Protein foam
Fluoroprotein foams
AFFF
FFFP
AR foam

Foam characteristics:
 Knockdown
 Heat resistance
 Fuel tolerance
 Vapor suppression
 Alcohol tolerance

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