2. • Introduction
• Classification of Fire and Construction Hazards
• Planning for Fire Protection
• Influence Of Materials
• Fire Safety Design
• Fire Detection and Signalling Devices
• Fire Alarm Systems
• Fire Suppression Equipment's & Systems
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3. • Fire protection is the study and practice of mitigating the unwanted effects of
potentially destructive fires.
• A fire protection system includes: devices, wiring, piping, equipment, and controls
to detect fire or smoke, to actuate signal, and to suppress the fire or smoke.
• Objectives of fire protection
1) Primary objectives: to save lives and protect property.
2) Secondary objective: to minimize interruptions of service due to a fire.
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INTRODUCTION
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Current trends in building design and modern lifestyles contributing to serious fire hazards:
1) High-rise buildings: Buildings become taller and more densely situated.
2) Architectural design: Larger areas and open spaces. Less separation walls.
3) Controlled indoor environment: Constructed of fixed glass windows instead of operable
windows in order to mechanically control temperature, humidity and air quality and to minimize
a stack effect.
4) Increased use of combustible materials: Furnishings, equipment, and decorative finishes
made of materials such as plastic and synthetics are a source of toxic gas and smoke during a
fire.
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CLASSIFICATION OF FIRE AND CONSTRUCTION
HAZARDS
Classification of Fires
Fire load
Classification of Hazards
Use or Occupancy
Type of Construction
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FIRE LOAD
• Fire load is the amount of heat in kilocalories (kcal) which is liberated per square meter of floor area of
any compartment by the combustion of the contents of the building and any combustible part of the
building itself. This amount of heat is used as the basis of grading of occupancy's
• The fire load is determined by multiplying the weight of all combustible materials by their calorific
value and dividing the floor area under consideration
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• 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.
Classification of Fires ( according to NFPA, U.S.A.)
• Light (low) hazard: Locations where the total amount of Class A combustible materials is minor.
>275000 kcal/m
• Ordinary (moderate) hazard: Locations where Class A combustibles and Class B flammables are
present in greater amounts than expected under light hazard occupancies. >550000 kcal/m
• Extra (high) hazard: Locations with large quantities of highly combustible materials and
conditions are such that fires could develop quickly with high heat release.> 1100000 kcal/m
Classification of Hazards
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Use or Occupancy
• Group A: Assembly. Occupied by more than 1000 people (A-1), less than 1000 people , and other
situations (A-3, A-4, and A-5).
• Group B: Business. Used for offices, professions or service-type transactions.
• Group E: Educational. Elementary schools (E-1, E-2), day care (E-3).
• Group F: Factory. Moderate hazard (F-1), low Hazard (F-2).
• Group H: Hazard. Group H-1 through H-7, depending on the hazardous material being handled or
stored.
• Group I: Institutional. Nurseries, hospital, nursing homes (I-1), others (I-2, I-3).
• Group M: Mercantile- display, storage and sale of merchandise.
• Group R: Residential
- Hotels, motels, or boarding houses (R-1)
- Multifamily dwellings (R-2)
- One-family or two family dwellings (R-3) child care (R-4)
• Group S: Storage
- Moderate hazard (S-1)
- Low hazard (S-1)
- Repair garage(S-3)
- Open parking garage (S-4)
- Aircraft (S-5)
• Group U: Utility. Buildings not covered by the above groups
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• Building construction is divided into types 1 through 5.
• Type 1: (Fire-Resistive) structures are high-rises, and they’re the stoutest of all construction types when
exposed to fire. High-rises are usually defined as buildings more than 75 feet tall. Type 1 structures are
constructed of concrete and protected steel .
• Type 2: (Non-Combustible) construction is typically found in new buildings and remodels of commercial
structures. The walls and roofs are constructed of non-combustible materials. Specifically, walls are
usually reinforced masonry or tilt slab.
• Type 3: (Ordinary) buildings can be of either new or old construction, and they have non-combustible
walls and a wood roof. Older construction buildings may consist of unreinforced masonry and have a
conventionally framed roof, while newer buildings will have lightweight roof systems supported by
reinforced masonry or tilt slab.
• Type 4: (Heavy Timber) construction is found in older buildings and utilizes large dimensional lumber for
structural members and interior elements. These buildings hold up well under fire conditions, but it’s
critical that firefighters not feel a false sense of security
• Type 5: (Wood-Framed) construction is found in many modern homes. The walls and roofs are made of
combustible materials—most commonly wood. If the walls are wood-framed, the roof usually is as well.
Type of Construction
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FIRE SAFETY REQUIREMENTS FOR BUILDINGS
1. All buildings more than one storey shall provided with liberally designed and safe fireproof exits or escapes
2. The exits shall be so placed that they are always immediately accessible and each is capable of taking all
persons on that floor as alternative escape routes may be rendered and unusable and unsafe due to fire.
3. Escape routes shall be well ventilated as persons using the escapes are likely to be overcome by smoke and
fumes which may enter from the fire.
4. Fire proof doors shall confirm rigidly to the fire safety requirements.
5. Where fire resisting doors are employed as cut off or fire breaks they shall be maintained in good working
order so that they may be readily opened to allow quick escapes of person trapped in that section of the
building and also, when necessary prompt rescue work can be expeditiously carried out.
6. Electrical and mechanical lifts while reliable under normal conditions may not always relied on for escape
purposes in the event of a fire, as the electrical supplied to the building itself may be cut off or otherwise
interrupted, or those relying as mechanical drive may not have the driving powder available.
7. Lift shafts and stairways invariably served as flues or tunnels thus increasing the fire by increased drought
and their design shall be such as to reduce or avoid this possibility and consequent spread of fire.
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8. False ceiling, either for sound effects or air conditioning or other similour purpose shall be so
constructed as to prevent either total or early collapsed in the event of fire so that person underneath
are not fatally traped before they have the time to reach the exits, shall apply to cinema theaters and
other public or private buildings where many people congregate.
9. Whatever be the class or purpose of the building the design and construction shall embody the fire
retardent for ceilings and roofs.
10. Floors are required to withstand the effect of fire for the full period stated for particular grading. The
design and construction of floors shall be of such a standard that shall obviate any replacement, partial
or otherwise, because experience shows that certain type of construction stand up satisfactorily
against collapse and suffer when may first be considered as negligible damage, but in practise later
involve complete stripping down and either total or major replacement. This consideration shall also be
applied to other elements of structure where necessary.
11. Roofs for the various fire grades of the building shall be designed and constructed to withstand the
effect of fire for the maximum period for the particular grading and this requires concrete or equivalent
construction. It is however important that maximum endurance is provided.
12. Basements. Where basements are necessary for a building where such basements are used for storage,
provision shall be made for the escape of any heat arising due to fire and for liberating and smoke may
be caused. It is essential that fire resistant of the basement shall confirmed to the highest order and all
column for supporting upper structures shall have a grading not less than laid down in types 1 to 3.
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13. Smoke extraction from basements. The following requirements shall be provided for smoke extraction :
❖ Unobstructed smoke extracts having direct communications with the open air shall be
provided in or adjoining the external wall and in positions easily accessible for firemen
in an emergency.
❖ The area of smoke extracts shall be distributed as far as possible, around the perimeter
of encourage flow of smoke and gases where it is impractical to provide a few large
extracts for eg:- not less than 3 m2 in area, a number of small extracts having the same
gross area shall be provided.
❖ Covers to the smoke extracts shall, where practicable, be provided in the stall board
and pavement light at pavement level, and be constructed of light cast iron frame or
other construction which may be readily broken by fireman in emergency. The covers
shall be suitably marked.
❖ When they pass through fire resisting separations, smoke extracts shall inall cases be
completely separated from other compartments in the building by enclosures of the
appropriate grade of fire resistance. In other cases, steel metal duct may be provided.
❖ Where these are sub basements, the position od the smoke extracts from sub
basements and basements shall be suitably indicted and distinguished on the externals
faces of the building
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In fire resistant construction, the design should be such that the components can withstand fire
as an integral member of structure , for the desired period. We shall consider the construction of
the following components:
• Walls and columns
• Floors and roofs
• Wall openings
• Escape elements
• Strong room construction
FIRE RESISTANT CONSTRUCTION
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WALLS AND COLOUMN
1. Walls and columns: the following points should be observed for making walls and columns fire –
resistant :
• Masonry walls and columns should be made of thicker section so that these can resist fire for longer
time and can also act as barrier against spread of fIre to the adjoining areas.
• In case of solid load bearing walls , bricks should be preferred to stones
• If walls are to be made of stones, granite and lime stones should be avoided.
• In the case of building with framed structure, R.C.C. should be preferred to steel
• If steel is used for the framed structure, the steel structure components should be properly enclosed
or embedded into concrete, terracotta, brick, gypsum plaster board, or any other suitable material as
illustrated in fig
• If the frame work is of R.C.C.., thicker cover should be used so that the members can resist fire for
longer time. It is recommended to use 40 to 50 mm cover for columns, 35 to 40 mm cover for beam
and long span slabs and 25 mm for short span slabs
• Partition walls should be fire resistant material such as R.C.C , reinforced brick work , hollow concrete
block , burnt clay tiles reinforced glass, asbestos cement boards
• Clay wall construction has better fire resistance.
• All walls, whether load bearing or non load bearing, should be plastered with fire resistive mortar.
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• Floors and roofs: The following points are not worthy for fire resistant floor and roofs:
• For better fire resistance, slab roof is preferred to sloping or pitched roofs.
• If it is essential to provide sloping roof, trusses should either be of R.C.C or of protects rigid steel with fire
proof covering.
• For better fire resistance the floor should be either of rcc or of hollow tiled ribed floor or of concrete jack
arch floor with joists embedded on concrete.
• If the floor is made of timber thicker joists at a greater spacing should be used and the fire stops or barriers
should be provided at suitable interval.
• The flooring materials like concrete tiles ceramic tiles, bricks, etc. are more suitable for fire resistance.
• If cast iron, wrought iron, core carpet, rubber tiles etc are to be used, these should be protected by a
covering of insulating materials like ceramic tiles plaster terracota brick etc.
• Ceiling, directly suspended from floor joist should be of the fire resistant materials like aspestos cement
boards fibre boards metal lath with plaster etc.
FLOORS AND ROOFS
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• From the point of view of fire spread, openings in the wall should be a bare minimum.
• Openings serve means of escape. Hence these should be properly protected by suitable
arrangements in the case of fire.
• Doors and windows should be made of steel. Fire resistant door can be obtained by fixing steel
plates of both the sides of the door.
• Wire glass panels are preffered for windows.
• Rolling shutter doors should be used for garages, godowns, shops, etc.
• In case of timber door minimum thickness of the door leaf should be 4 cm and that of door frame as
8-10 cm
• All escape doors should be such as to provide free circulation to the persons in passages, lobbies,
corridors, stairs, etc and should be made of fire proofing materials.
Wall opening
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• All escape elements such as staircases corridors, lobbies, entrance,etc. should be constructed of
fire resistant materials.
• The escape elements should be fire proof.
• Doors to this escape should be fire proof.
• Staircases should be located next to the outerwall and should be accessible from any floor in the
direction of flow towards the exit from the building.
• Fire proof doors to the emergency staircases should be fixed in such a way as to make them
close from inside only.
• Lift shafts connecting various floors should be surrounded with the enclosure walls of fire
resisting material.
• Lift shafts should be vented from the top to permit escape of smoke and hot gases.
• An emergeny ladder should be provided in fire resisting building. This ladder should be atleast 90
cm wide and should be constructed with fire resisting materials.
• All escape routes over roofs should be protected with railings balustrades or parapets not less
than 1m height.
ESCAPE ELEMENTS
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SIGNALLING
SUPPRESSION
DETECTION
PLANNING FOR FIRE PROTECTION
The presence of a fire is
detected manually or
automatically
The building’s management,
its occupants and the fire
department are notified of
the presence of the fire.
Manual or automatic fire suppression equipment and systems are
used to extinguish the fire and remove the smoke
• (INITIAL EFFORT): Potable and manual firefighting equipment, such as fire extinguishers, fans, and a first-aid
fire hose, are used to extinguish the fire and to remove smoke by dilution or exhaustion.
• (MAIN EFFORT): Fire suppression systems, such as automatic sprinklers, fire hoses, and other systems, are
used to extinguish the fire. Smoke control systems are activated to remove or confine the spread of smoke.
• (LAST EFFORT): The fire department takes over the firefighting effort when all previous efforts are ineffective
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Thermal detectors are temperature-activated sensors to initiate an alarm.
• Fixed-temperature type: This sensor consists of normally open contact 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℃.
• Rate-of-rise (ROR) type: This sensor 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.
THERMAL DETECTORS
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BIMETALLIC ELEMENTS
A bimetallic strip is used to convert a temperature change into mechanical displacement. The strip
consists of two strips of different metals which expand at different rates as they are heated, usually
steel and copper, or in some cases steel and brass. The strips are joined together throughout their
length by riveting, brazing or welding. The different expansions force the flat strip to bend one way
if heated, and in the opposite direction if cooled below its initial temperature. The metal with the
higher coefficient of thermal expansion is on the outer side of the curve when the strip is heated
and on the inner side when cooled.
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▪ Smoke detectors are quicker to respond than thermal detectors.
I. Photoelectric type
II. Ionization type
SMOKE DETECTOR
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This type operates on the principle of the scattering of light. Photoelectric detector detect the presence of
visible particles (larger than 3 microns) in the air. Inside the detector, there is a light emitting diode (LED)
that directs a narrow beam of infrared light across the detection chamber. When smoke or particles enter the
chamber, the infrared light beam is scattered. A photodiode or photo detector, usually placed 90 degrees to
the beam, will sense the scattered infrared light and when a present amount of light is detected, the alarm
will sound. Photoelectric detectors are not as sensitive and are designed to detect cool or slow-moving
(smouldering) fires that produce a lot of smoke.
PHOTOELECTRIC TYPE
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This type operates on the principle of changing conductivity of air within the detector chamber. The
ionization detector uses a small amount of radioactive material to make the air within a sensing
chamber conduct electricity. When smoke particles or combustion gases enter the sensing chamber
they interfere with the conduction of electricity, reducing the current and triggering an alarm. 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.
IONIZATION TYPE
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FLAME DETECTORS
• ▪ Flame detectors are used to detect the direct radiation of a flame in the visible, infrared, and
ultraviolet ranges of the spectrum.
• ▪ Flame detectors are used mostly in industrial processes for the protection of combustion equipment.
Thermal or smoke detectors would be unreliable and generate false alarms in these environment.
Here are four basic types:
o Infrared detector
o Ultraviolet detector
o Photoelectric detector
o flame flicker detector
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Fire alarm systems are an integral part of a fire protection plan. They are basically electrical systems that
are specially designed to announce the presence of fire or smoke. They are not intended to suppressor
extinguish a fire.
FIRE ALARM SYSTEMS
SIGNALLING
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• Bells, gongs, and flashing lights are manually activated by a switch.
• 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
MANUAL ALARM STATION
FLASH LIGHT ALARM FLASH LIGHT + ALARM
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SUPPRESSION
• Fire suppression is achieved by cooling the combustible material to below its ignition temperature or
by preventing oxygen from reacting with the combustible material.
• Fire suppression system must be designed by considering the class of fire and the type of building
occupancy.
• Fire suppression system may be classified in several ways.
o According to the fire suppression medium – water, foam, chemical,
gas, etc.
o According to the action of the device – a portable extinguisher,
standpipe and hose , automatic sprinkler, etc.
o According to the method of operation of the device – manual or
automatic.
SUPPRESSION
MEDIUM
WATER FOAMCHEMICALGAS
ACTION OF
DEVICE
PORTABLE
STANDPIPE
AND HOSE
AUTOMATIC
SPINGLERS
METHOD OF
OPERATION
MANUAL AUTOMATIC
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PORTABLE FIRE EXTINGUISHERS
• Portable fire extinguishers are used as the first line of fire protection.
• They are normally pre-charged with water or chemicals and are hand-operated.
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WATER SYSTEM
• Water is W e s the universal firefighting medium.
• It is readily available in large quantities and, in general, is more economical than any other
firefighting medium.
• It is most effectively for CLASS A cases.
• For fire protection purposes, the water supply should be separated from a building’s domestic water
system, even though the two are connected to the same public water main.
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FOAM SYSTEM
• Foam systems are most effective for Class B fires caused by liquid, oil, grease, paint, etc.
• The foam is made by generators, which mix water with detergent or other chemicals to
produce as much as 1000 gallons of foam for each gallon of water.
• This systems suppress fire by separating the fuel from the air (oxygen).
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GASEOUS FIRE SUPPRESSION SYSTEMS
• Gaseous systems are most effective for Class C fires caused by electrical equipment.
• All these gases are stored in liquid state under high pressure.
• There are three varieties in agent gases:
o The carbon dioxide: CO2
o Halogenated gas : fluorine, chlorine, bromine, or iodine
o Atmospheric gas: mixture of argon, carbon dioxide, and nitrogen. The gas mixture is nontoxic,
with zero ozone depletion potential (ODP) and zero global-warming potential (GWP).
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DRY CHEMICALS
Dry chemicals are used especially for Class D fires caused by combustible metals.
• Examples of such metals include sodium, titanium, magnesium, potassium, uranium, lithium,
plutonium, and calcium. Magnesium and titanium fires are common.
• When one of these combustible metals ignites, it can easily and rapidly spread to surrounding
ordinary combustible materials.
• Most of the dry chemicals contain bicarbonates, chlorides, phosphates, andother proprietary
compounds.
• The use of water should be avoided on burning metals, since hot metal extracts oxygen from
water, promotes combustion, and at the same time liberates hydrogen, which ignites readily
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STANDPIPE-AND– HOSE SYSTEMS (STANDPIPE SYSTEMS)
• Standpipe systems consist of piping, valves, hose connections, and nozzles to provide streams
of water for fire suppression.
I. Wet system
II. Dry system
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WET SYSTEM
• A "wet" standpipe is filled with water and is pressurized at all times.
• Whenever the system is activated, water will charge into the connected hose immediately.
• Wet standpipes can be used by building occupants.
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DRY SYSTEM
• A “Dry” standpipe is NOT filled with water.
• The intakes of dry standpipes are usually located near a road or driveway so that a fire engine can
supply water to the system.
• This system can be used only by firefighters.
• Regulations in many countries require that standpipe systems be charged by hoses from two
different pump trucks, which can be accomplished by using both sides of a Siamese connection.
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AUTOMATIC SPRINKLER SYSTEMS
• Automatic sprinkler systems are integrated fire suppression systems consisting of a water supply
and a network of pipes, sprinkler heads, and other components to provide automatic fire
suppression in areas of a building.
• This system is the most effective for suppressing a Class A fires in buildings containing ordinary
combustible materials, such as wood, paper, and plastics.
• The design and installation of the system are strictly regulated by insurance companies and in
accordance with fire codes.
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SPRINKLERS
• The major component of an automatic sprinkler system is the sprinkler, which discharge water
in specific pattern for extinguishing or controlling a fire.
• A sprinkler head consists of three major components:
1. Nozzle
2. Detector: Fusible link type / Frangible bulb type
3. Water spray pattern deflector
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• The fusible link type of heat detector is constructed of a “eutectic 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
• The frangible bulb type 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.
• The temperature rating of heat detectors is divided into seven groups.
• Sprinklers are color-coded for ease of identification.
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TYPES OF AUTOMATIC SPRINKLER SYSTEMS
(WET-PIPE AND DRY-PIPE)
• Wet-pipe system
o 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.
o This type is the most reliable and simple of all sprinkler systems since no equipment
other than the sprinklers themselves need to operate.
o Only those sprinklers which have been operated by heat over the fire will discharge water
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o Dry-pipe sprinkler systems employ automatic sprinkler attached to a piping system containing
air or nitrogen under pressure.
o 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.
o Dry-pipe systems are installed in lieu of wet-pipe systems where piping is subject to freezing
• DRY PIPE SYSYEM
