PROTECTION, PREVENTION,

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PROTECTION, PREVENTION, EXTINCTION
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O Agni, help us to gain prosperity by leading us
on the righteous, redeem us from all our
sins and actions. We bow before you with
gratitude. -Rig Veda
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RPL - JAMNAGAR Fire accident ( 26.10.2006 )
Property Damage of Rs.25 Cr
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ONGC BOMBAY HIGH ON SHORE RIG Fire accident (
21.04.2004 )
Claimed 6 lives with pre mature closure of
the Countrys prestigious On shore oil platform
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HPCL VIZAG Fire accident (Sep15 1997 )
Claimed 51 lives incurred a loss of about Rs
600 cr
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And now a construction Site
Can u Access the Lives lost ????
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• TOPICS
• CHEMISTRY OF FIRE
• HOW TO PREVENT FIRES.  
• EXOTHERMIC ENDOTHERMIC REACTIONS.  
• HOW FIRES ARE INITIATED.  
• KINDS OF FIRES AND ITS CLASSIFICATION.
• MECHANISM OF EXTINGUISHING FIRES.  
• FIRE EXTINGUISHING MEDIUMS.  

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CHEMISTRY OF FIRE COMBUSTION Fire is
combustion, a chemical reaction in which heat and
light are produced. The rate it precedes is fast,
because more energy is generated than can escape
into the surrounding medium. This results in
rapid acceleration of the reaction because of the
build up of heat energy.
OXIDATION When the rate of reaction is very
slow only heat is produced and slow oxidation
occurs, such as rusting. Combustion is rapid
oxidation.
FLAME Most combustion processes produce flame,
which has the ability to spread through an
atmosphere with the emission of heat and light.
The flame front is a transition region separating
burnt from un burnt gases, and light is given out
from this region.   A fuel oxidation mixture,
which liberates enough energy on combustion to
allow flame to spread through the unignited
region of the mixture, is called flammable.  
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EXPLOSION The transmission from combustion to
explosion is due to an acceleration of the
reaction, caused either by the rise in
temperature (thermal explosion). Generally
explosions are of a chain/thermal nature that is
a combination of the two causes where both heat
accumulation and chain auto-acceleration
contribute to the explosion.
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THE FIRE TRIANGLE
Combustion will continue as long as these three
factors are present in the correct proportions.
Removal of any one leads to the collapse of the
triangle, combustion stops and it is the basic
principle of fire prevention.
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Fuel - SOLIDS, LIQUIDS AND GASES. The common
solid and liquid fuels must emit vapor or gas
before they can burn to produce a
flame.   Oxygen- Generally in the form of air.
Air comprises approximately 79
Nitrogen. 20.7 Oxygen. 0.3 Carbon
dioxide.   Heat - Causing vaporization of the
fuel providing a source of ignition from,
sparks, arcs, naked flames, static
electricity, sun, lighting a hot surface or a
sufficient high temperature for spontaneous
ignition.
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DIFFERENT STAGES OF FIRE INCIPIENT STAGE No
visible smoke, flame, no significant
heat  SMOULDERING STAGE Combustion increases
develops smoke still no flame - heat
also FLAME STAGE Fire develops further ignition
occurs and flame starts HEAT STAGE Large
amount of Heat, Flame smoke toxic gases
produced
Please Refer the Chain Reaction, which is the
fourth factor in the tetrahedron
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THE FIRE TETRAHEDRON
FUEL
CHAIN REACTION
OXYGEN
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EXOTHERMIC AND ENDOTHERMIC REACTIONS OF
FIRE   Exothermic Reaction   A Chemical
reaction, which gives out heat in the process, is
called exothermic reaction. Ex. When carbon is
glowing a red heat, the combination of reaction
of carbon with O2 is taking place.   The process
is depicted by the chemical reaction.   C O2
CO2 10,890 British thermal unit for 12 oz of
carbon.   That is one atom of carbon and one
molecule containing two atoms of O2 combines or
reacts to form the molecule of CO2.The process is
accompanied by liberation of a large quantity of
heat.
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Endothermic reaction.  But when CO2 is passed
over glowing carbon a chemical reaction takes
place whereby, two atoms of CO2 are shared
between two atoms of carbon to give a new gas
Carbon monoxide (2CO), which is poisonous and
flammable. This is represented by the chemical
equation.
C CO2 2CO 4,360 British thermal unit
ABSORBED for 12 oz of carbon       Further
enormous quantity of heat is also absorbed in the
process to an extent of 4360 British thermal
unit for 12 oz carbon.   This is called
Endothermic reaction.       C CO2 2CO 4,360
British thermal unit absorbed for 12 oz of
carbon.
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PYROLYSIS Decomposition brought about by heat.
Common fuels must vaporize to burn, when heated
they decompose to smaller molecules with greater
volatility and flammability, and to carbon. It is
vapor given off in the heating and decomposition
process that burns.   Because a certain amount of
heat is necessary to vaporize a fuel, individual
fuels have critical temperature relative to the
ignition processes.
IGNITION TEMPERATURES Flash Point - The lowest
temperature at which a hydrocarbon liquid
vaporizes and on application of ignition will
ignite but not necessarily support
combustion.   Fire Point - The lowest temperature
for a fuel at which sufficient Vapor is given
off which on application of ignition will
ignite and support combustion.
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  Spontaneous - The temperature at which a fuel
will automatically Combustion ignites without
an independent source of ignition.   Automatic
- The temperature at which a hydrocarbon liquid
is Ignition heated and will automatically
ignite without applying a source of ignition.
EXPLOSIVE LIMITS The explosive limits are the
proportions of fuel vapor and oxygen coming
together, necessary for a fire or explosion to
occur. The Lower Explosive Limit (LEL), and
Upper Explosive Limit (UEL), are expressed as
percentages by volumes of flammable vapors in
air.
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TRANSMISSION OF FIRE
CONTACT CONDUCTION CONVECTION RADIATION
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FIRE SPREAD   Fire can spread by   Conduction -
Heat traveling along or through conductive
material eg. Unprotected steel
girders.   Convection - Fire spread by rising hot
gases and smoke eg. Stair and lift
wells.   Radiation - Materials ignited when
placed too close to a source of radiated heat
eg. Electric fires.   Direct burning- Combustible
materials giving off sufficient vapor to
encourage combustion and continue burning
when coming into contact with a naked flame,
eg.Chair or mattress being exposed to lighted
cigarette.
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CLASSIFICATIONS OF FIRES
A
CLASS
Solid Combustible Materials such as WOOD, PAPER,
FABRICS-CARD BOARDS (QUENCHING-COOLING)
B
CLASS
Flammable oil such as COAL, OIL, GAS, GREASE,
CHEMICALS LNG, LPG (BLANKETING-SMOTHERING)
C
CLASS
ELECTRICAL (NON-CONDUCTING)
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PRINCIPLES OF EXTINGUISHMENT   Removal of one
or more of the factors of the Triangle of Fire is
the basic principles of fire prevention   Starvat
ion - Removal of the fuel from the
fire.   Smothering - Limitation of oxygen from
the fire.   Cooling - Limitation of the heat
below the ignition temperature.
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FIRE EXTINGUISHERS   Most fires are relatively
small and can be easily extinguished.   It is
important that all employees are familiar with
fire extinguisher distributed about the premises
and the principles underlying their design,
maintenance and use.   Hand fire extinguishers
are designed for small fires and therefore are
used close to the burning material.
Dry Chemical Powders   The basis of most chemical
powders is sodium bicarbonate, with the addition
of a metal striate as water proofing agent, is
widely used, not only in portable /wheeled
extinguishers but also for general application in
large quantities in DCP Fire Tenders.
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Properties   Principle base chemical Sodium
bicarbonate   Additive mixed with the powder
Metallic striates Tricalcium to prevent
caking Phosphate hydrofobic
Silicones.   Particle size of the powder 20 to
25 microns.   Characteristics a) Free
Flowing b) Non-toxic and unlikely
to give any environmental
Problem c) Water repellent d)
Non-conductor of Electricity   Extinguishes Fire
By 1) Smothering 2) Cooling 3)
Shielding Radiation of heat.
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Dry Chemical Powder Extinguishers This
Consists of two types   1) Gas Cartridge
type   The Powder is expelled by pressure
released into the body of the extinguisher from a
CO2 gas cartridge   2) Stored Pressure
type   The powder is expelled by pressure
maintained in the body of the extinguisher by
nitrogen or air.
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DRY CHEMICAL POWDER EXTINGUISHER
SAFETY CLIP
Co2 CATRIDGE (INNER CONTAINER)
RUBBER HOSE
DRY CHEMICAL POWDER
OUTER CONTAINER
NOZZEL
TO OPERATEE KEEP EXTINGUISHER UPRIGHT. REMOVE
SAFETY CLIP STRIKE KNOB. DIRECT THE POWDER AT
THE BASE OF FIRE
RECHARGE IMMEDIATELY
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DRY CHEMICAL
HAND TYPES
PIN
CO2 CARTRIDGE
NOZZLE
VALVE
VALVE
NOZZLE VALVE
BICARB. SODA POWDER TREATED TOMAKE WATERPROOF
WHEEL TYPES
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CARBON DIOXIDE FIRE EXTINGUISHERS
CO2 LIQUID UNDER PRESSURE
HOSE
VALVE
PIN
HANDLE
2.5 LBS
CYLINDER
20 LBS
HORN
CO2 Extinguishers In this type of extinguisher,
the liquid CO2 is contained in a pressure
cylinder and is released by a squeeze trigger
mechanism through a horn type applicator.
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CARBON DI-OXIDE (CO2) AS EXTINGUISHING MEDIA
Properties
Appearance Colourless / Odorless Gas (White
Cloudy smoky appearance) Molecular
Weight 44 Density 1.52 Vapour
Pressure at 25OC 58.24 bar Critical
Temperature 31.0OC Critical Pressure
72.85 atm Boiling Point (Sublimes)
-78OC Latent Heat of Vaporization 0.121
KJ/Kg
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Foam Extinguishers   In this type of
extinguisher, foam is produced from a foam
solution. The foam concentrate is stored either
as a solution or in water within the body of the
extinguisher, or separately in a sealed inner
container.   When the extinguisher is activated
foam solution is expelled. Foam is produced in a
miniature, self-aspirating foam branch at the end
of the discharge hose. The types of concentrate
which may be used are   

• Protein
• Fluoroprotein
• Fluorochemical (AFFF)
•  
• The foam solution is expelled by pressure
  released into the body of the extinguisher from a
  CO2 cartridge (gas cartridge).
• The foam solution is expelled by pressure
  maintained in the body of the
• extinguisher by air or nitrogen (stored
  pressure).

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FOAM TYPE EXTINGUISHER
PLUNGER
NOZZLE
ALLUMINIUM SULPHATE SOLUTION ( INSIDE CONTAINER )
LEVEL INDICATOR
SODIUM BICARBONATE SOLUTION ( OUTSIDE CONTAINER )
TO OPERATE
1. TAKE IT NEAR FIRE. 2. PULL THE KNOB AND TURN
IT RIGHT AND LET IT REST ON THE CAP. 3. INVERT
AND DIRECT STREAM TO FALL GENTLY ON FIRE.
TO CHARGE
1. RECHARGE IMMEDIATELY AFTER USE. 2. AFTER
DISCHARGE THIS EXTINGUISHER MUST BE WASHED OUT
WITH FRESH WATER USING ATLEAST TWO
CHANGES. 3. RECHARGE AT LEAST EVERY TWO YEARS.
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• FOAM AND ITS LIMITATIONS FOR USE ON LIQUID FIRES
• Foam are not suitable for fires involving gases
  and light ends.
•  
• 2. Foam should not be used on materials, which
  are susceptible to water damage, and also
  materials like Sodium and Potassium reacts
  violently with water.
•  
•  
• 3. Foam is a conductor and should not be used on
  energized electrical equipment fires.
•  
•  
• 4. Foam is not effective on flowing liquid fires.
•  
•  
• On hot oil/burning asphalt (which are above the
  boiling point of water) applying
• foam may cause violent frothing and foaming over.

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water as extinguishing media   Water Water is
still the most efficient, cheapest and most
readily available medium for extinguishing fires
of general nature. Techno-logical developments
have produced additives to increase the
efficiency of water as a fire extinguishing for
specialized applications.  Water is a Colorless
Liquid   Source Easily available, cheap,
relatively stable and heavy liquid can be
transported easily from one place to
another place.   Specific Heat 180
btu/lb   Latent heat of Vaporization of
Water 970 btu/lb   At ordinary pressure
water expands 1700 times  Water extinguishes
fire by 1) Cooling 2) Smothering 3)
Emulsification 4) Dilution
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Aquamist and MicroDrop uses a range of droplet
sizes to maximize penetration of the fire plume,
and hence extinguishing performance. Large
Droplets have the momentum to penetrate the fire
plume, and will drag the smallest droplets into
the combustion zone. Smaller Droplets surround
the fire, and are pulled into the base of the
fire as it draws in oxygen. The Smallest droplets
cool the gases in the room, strip smoke from the
air, and block the transfer of radiant heat. The
end result is extinguishments, using considerably
less water than a traditional water spray system.
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ANNEXURE-1    SOURCES OF IGNITION
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HOW TO USE A PORTABLE FIRE EXTINGUISHER
  Remember the acronym, "P.A.S.S."     P - Pull
the Pin.   A - Aim extinguisher nozzle at the
base of the flames.   S - Squeeze trigger while
holding the extinguisher upright.   S - Sweep
the extinguisher from side to side, covering the
area of the fire with the
extinguishing agent.  
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THANK U ALL