Presentation about fire fighting systems, including detection and different fire suppression systems.

1. Fire Fighting Systems
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2. Fire Fighting Systems
Are installations or equipment
manufactured, used or designed to be
used for the purpose of extinguishing,
attacking, preventing, limiting or
giving warning of fire.
They may be fixed or portable, and
either automatic or manual in
operation.
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3. Common components of fire
fighting system :
Fire detection system
Fire alarm system
Fire suppression systems
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4. Fire alarm and detection
 Fire alarm mainly services :
 To protect life
 Prevent property loss
 Fire alarm main parts :
 Signal initiation
 Signal processing
 Alarm indication
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5.  For automatic fire alarm systems, the signal initiation
can be actuated by fire and smoke detectors and/or
water flow switches.
 The alarm signal is processed by some sort of control
equipment, which in turn activates audible and visible
alarms and in some cases, alerts a central fire station.
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6. Manual Alarm Detection
 Bells, gongs, and flashing lights are manually activated
by a switch (Fig 01).
 To avoid accidental operation of the switch, the
station is usually designed so that a person must break
a glass panel or glass rod or must perform other
preliminary actions before the alarm can be operated.
Fig 01 Manual Alarm
system
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7. Thermal Detectors
 1) Fixed-temperature type:
This sensor consists of normally open contact (shown in fig
02) held by bimetallic elements that will close the contacts
when the ambient temperature reaches a fixed setting. The
setting is generally designed for operation at 57℃, 88℃, or
94℃.
Fig 02, Fixed temperature fire
detector 7

8. Cont. Thermal Detectors
 2) Rate-of-rise (ROR) type:
This sensor (shown in fig 03) reacts to the rate at which the
temperature rises. It contains a sealed but slightly vented air chamber
which expands quickly when the temperature near the device rises
quickly. When the air chamber expands faster than it can be vented,
electrical contacts attached to the chamber begin to close and thus
initiate an alarm.
 3) Combination type:
This device reacts to both a fixed temperature and a rate of rise.
Fig 03, Rate of rise fire
detector
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9. Smoke Detectors
 Smoke detectors (Fig. 04) are quicker to respond than
thermal detectors.
 Photoelectric type
 Ionization type
Fig. 04 smoke detectors
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10. Photoelectric type
 This type operates on the principle of the scattering of
light (Fig 05).
 Photoelectric detectors are not so sensitive.
Fig 05 Photoelectric sensor
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11. Ionization Type
 Ionization type This type operates on the principle of
changing conductivity of air within the detector chamber.
 The ionization detector can detect even invisible
combustion gases produced by an open flame and will
therefore respond slightly faster to an open flame fire than
a photo-electric detector. (Fig 06)
Fig 06 Ionization type
smoke detector
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12. Flame Detectors
 Flame detectors are used to detect the direct radiation
of a flame in the visible, infrared, and ultraviolet
ranges of the spectrum.
 Typical applications for optical flame detectors are :
-Whenever highly combustible materials are in volved.
-where there is a need for instantaneous response time.
-wherever unsupervised areas require automated fire
protection
-where there is a large capital investment to be protected.
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13. Infrared single frequency flame detector
 The detector is sensitive to a narrow band of radiation
around the 4.4 micron range which is predominant
emission band for hydrocarbon fuelled fires.
 Strengths of single frequency IR detectors:
-Highly immune to optical contamination like oil, dirt and
dust.
-High speed response under 30 ms for some brands.
-insensitive to solar welding, lightening, x-rays, sparks,
arcs and corona.
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14. Infrared single frequency flame detector (Cont.)
 Limitation of single frequency IR flame detector :
-generally not suitable for non carbon fires.
-some brands will respond to modulated infra red
sources.
-rain, ice and water vapor on the detector lens will
inhibit detection.
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15. IR multi spectrum flame detectors
 Principle of operation : the detector (Fig 07) has three
sensors each sensitive to a different frequency of
radiation, the IR radiation emitted by a typical
hydrocarbon fire is more intense at the wavelength
accepted by one sensor than the other two.
 Strengths of multi spectrum IR detectors :
-Virtually immune to false alarm.
-Long detection range 50 m for some fires.
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16. IR multi spectrum flame detectors (Cont.)
 Limitation of multi spectrum IR detectors :
-Typical response time is longer when compared to
single frequency detector.
Fig 07 Multi IR detector
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17. UV flame detector
 UV flame detector (Fig 08) uses a sensor tube that
detects radiation emitted in the 1000 to 3000
angstrom, it is important to notice that Ultraviolet
radiation that reaches the earth, starts at 2800
angstrom, if the detector has a wide range it will be
triggered by the sun rays, which means it is only
suitable for indoor use.
 These sensors are available for range from 1800 to 2500
angstrom.
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18. UV flame detectors
 Advantages:
- Unaffected by solar radiation
- Respond to hydrocarbon, hydrogen and metal fires.
- High speed response under 10 ms.
 Disadvantages:
- Subject to false alarms from UV sources (arc welding,
electrical sparks, halogen lamps).
- Blinded by thick smoke, vapors, grease and oil
deposits on the detector’s window
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19. UV flame detector
Fig. 08 UV flame detector
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20. Classification of Fires ( according to NFPA, U.S.A.)
 Class A: Fires of ordinary combustible materials such
as wood, cloth, paper, rubber, and many plastics.
 Class B: Fires in flammable liquids, oils, greases, tar,
oil-base paints, lacquers, and flammable gases.
 Class C - Fires that involve energized electrical
equipment. Extinguishing medium must not be a
conductor of electricity.
 Class D: Fires of combustible metals, such as
magnesium, titanium, zirconium, sodium, lithium,
and potassium.
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21. Fire Suppression Systems
 Fire suppression is achieved by cooling the
combustible material to below its ignition temperature
or by preventing oxygen from reacting with the
combustible material.
 Suppression systems may be wet or dry and composed
of extinguishing agents, including water, chemical,
gas, liquid, powder, or a combination. The most
important thing to determine is which system will be
most effective against the hazard being protected
against.
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22. Sprinklers
 Sprinkler system is defined as a system of water pipes
fitted with sprinkler heads at suitable intervals and
heights and designed to control or extinguish a fire by
the discharge of water.
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23. Sprinklers advantages
 They detect and extinguish.
 They have immediate action.
 They are always ready, attack the seat of fire, restrict
fire growth, reduce smoke spread.
 They require no human intervention during
operation.
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24. Sprinklers system components :
 Fire pumps, main alarm valves, distribution pipe works and
sprinkler heads.
 Sprinkler heads are classified based on degree of hazards :
 extra light hazard (XLH).
 ordinary hazard (OH) .
 extra high hazard (XHH).
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25. Sprinkler head types (Fusible link Type)
 The fusible link (Fig. 09) type of heat detector is
constructed of certain alloy which melt at a
specific temperature rather than gradually
softening. When the link temperature reaches its
melting point, the link is pulled apart by the water
pressure and opens nozzle
Fig. 09 fusible link type
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26. Sprinkler head types (Frangible Bulb type)
 The frangible bulb type (Fig. 10) of detector contains a
glass bulb partially filled with a liquid that expands
with temperature. At the rated temperature, the liquid
will shatter the bulb and open the nozzle.
Fig. 10 frangible bulb types
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27. Sprinkler head components
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28. Sprinkler bulb temperature ratings
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29. Standard vs. Quick Response
 The main physical difference between standard
response and quick response fire sprinklers is the size
of the bulb. Quick response sprinklers have a smaller
bulb, leading to a slightly faster response time.
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30. Pendent Sprinkler Head
 The most common type of fire sprinkler head is the
pendent (Fig. 11). A pendent fire sprinkler protrudes
and hangs down from the ceiling.
 Once water is expelled onto a pendent fire sprinkler's
deflector, it sprays in a circular pattern providing the
most coverage of any fire sprinkler. The deflector is
curved downward, which helps to direct the water out
into a cone pattern. Commercial pendent fire
sprinklers are bet used in offices, hotels, factories, etc.
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31. Pendent Sprinkler Head
Fig . 11 Pendent sprinkler head
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32. Upright Sprinkler Head
 Upright fire sprinklers (Fig. 12) are suited for areas
that are difficult to access, like around beams, ducts,
and other ceiling obstructions, or in ceilings without a
finish (eg., no drop ceiling or drywall).
 These sprinklers are commonly found in buildings
with exposed ceilings, like many chic restaurants or
mechanical rooms. It may be useful to think of an
upright fire sprinkler like an upside down pendent fire
sprinkler, only with a concave deflector.
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33. Upright Sprinkler Head
Fig. 12 Upright sprinkler head
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34. Sidewall Sprinkler
 Sidewall sprinklers (Fig. 13) protrude through the wall
and basically only have half of a deflector, which
sprays water in a half circle or crescent shape.
 They're designed to protect small rooms, hallways, and
other areas where sprinkler pipes are running up walls
but not in the ceiling
 As they are designed to be installed on the wall,
instead of in the ceiling, along or under a beam.
However, sidewall sprinklers perform the same basic
functions as other fire sprinklers.
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35. Sidewall Sprinkler
Fig. 13 Sidewall sprinkler head
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36. Concealed Sprinkler Head
 Concealed fire sprinklers (Fig. 14) are somewhat like
pendent fire sprinklers; however, they're located
within the ceiling and they're hidden by a cover plate.
 The cover plate will fall off at a temperature about 20
degrees lower than the fire sprinkler, allowing the
deflector of the concealed sprinkler to drop and be
exposed to the heat from the fire.
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37. Concealed Sprinkler Head
Fig.14 Concealed sprinkler head
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38. Types of Automatic sprinkler systems
Wet pipe by far the most common.
Dry-pipe where water freezing is possible.
Deluge for high hazard applications.
Pre-Action where concerns over water damage.
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39. Wet pipe system.
 Wet-pipe sprinkler systems employ automatic
sprinklers attached to a piping system containing
water and connected to a water supply so that water
discharges immediately from sprinklers opened by a
fire (Fig 15).
 This type is the most reliable and simple of all
sprinkler systems since no equipment other than the
sprinklers themselves need to operate.
 Only those sprinklers which have been operated by
heat over the fire will discharge water.
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40. Wet pipe system (Cont.)
 Water flows through opened sprinkles heads until
shutoff .
 The opened sprinkler heads are changed and the
system is reset.
 An alarm check valve detects water flow and activates
the alarm system.
 Restoration of the System;
- shut down any water source supplying the system.
- the sprinkler head(s) are replaced with an identical one.
- re-open any closed control valves.
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41. Fig. 15 Wet pipe sprinkler
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42. Dry pipe system
 Dry-pipe sprinkler systems employ automatic
sprinkler attached to a piping system containing air or
nitrogen under pressure (Fig 16).
 When sprinklers are open by a fire, the gas is released
and the dry pipe valve is open by the water pressure.
The water then flows into the piping system and
discharges only from those sprinklers which have been
open by heat over the fire.
 Dry-pipe systems are installed in lieu of wet-pipe
systems where piping is subject to freezing
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43. Dry pipe system
 Water flows until shut off, where opened sprinklers are
to be replaced to reset the system.
 Pipes in protected space are filled with air or inert gas;
an opening sprinkler head, triggers the system by
releasing the air or gas, which allows water to flow into
the pipes and then out through the open sprinkler
head,
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44. 44
Fig .16 Dry pipe sprinkler

45. Deluge System
 Pipes are not filled with water (or gas), and all
sprinkler heads are pre-opened.
 A signal from a detection device mechanically opens a
water valve :
- water fills the pipes and flows from all heads.
- water flows until shut off.
- system is reset.
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46. Deluge system (Cont.)
 Primarily installed in special hazard areas that have
fast spreading fire, ( i.e. petroleum facilities,
hazardous materials), also used to apply foams.
 Activation will cause great quantities of water or foam
to flow, so usually requires several detectors to activate
before discharging.
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47. Pre- action system
 Pipes are not filled with water, and all sprinkler heads
are of the standard type (they are closed), when a
detection device opens a water valve, water fills the
pipes, but only flows from a sprinkler head if it is
opened by heat from a fire.
 Water flows until shut off and system is reset.
 Used primarily to protect property where water could
severely damage facilities or equipment, (historical
items).
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48. Pre- action system.
 Similar to dry-pipe and deluge system;
- closed piping.
- little or no air/gas pressure.
- water does not flow to the sprinkler heads until
detector activates.
- water on fire after sprinkler head fuses.
 Turns into a wet system, but allows personnel to
check/fight fire before head fuses.
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49. Finally,
 Sprinkler systems save lives. They have been around
for over one hundred years and have an impeccable
record for saving lives and property. NFPA reports that
there has never been a multiple loss-of-life fire in a
fully sprinkled building.
Note: NFPA considers multiple loss of life to be greater than three
persons.
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50. References
 Robert Burke, Fire protection systems and response,
2008.
 Albert Ting-pat So, Intelligent Building Systems, 1st
edition, 1999.
 Truman C. Surbrook, Jonathan R. Althouse,
Interpreting the national electrical code, 8th edition.
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