prepared by: 4.7 basic fire fighting · pdf file04.05.2012 · fire precautions...
TRANSCRIPT
Learning Objectives
To describe the Principle of Fire Extinguishment.
To illustrate and explain the triangle of three elements that influence ignition.
To differentiate the classification of fire.
To understand how to extinguish a fire using a fire fighting media and action to be taken in the event of fire.
• Fires and explosions
can be the greatest
potential hazard in a
building etc
• Leads to: property
damage, explosion
• Five main hazards:
oxygen depletion,
flame/heat, smoke,
gaseous and structural
failure of buildings.
The theory of
combustion and fire
should be:
1. Fire precautions
2. Fire prevention
3. Fire protection
Fire precautions
measures taken in the provision of the
fire protection in a building
minimize the risk to the occupants,
contents and structure from an outbreak
of fire.
Fire prevention
preventing outbreaks of fire
reducing the risk of fire spreading
avoiding danger to persons and
property from fire.
Fire protection
design features, systems or equipment in
a building
reduce the danger to persons
property by detecting, extinguishing
or containing fires.
LEGAL REQUIREMENTS
In Malaysia major provisions are contained :
Fire Services Act 1988
Fire Services Regulations July 2005
Factory and Machinery (Safety, Health and
Welfare) Regulations 1970
Uniform Building By-Laws 1984
CHEMISTRY OF FIRE
Three main ingredients: fuel, oxygen & an
ignition source/ a sufficiently high temperature.
Combustion: a heat-generating process, is the
chemical reaction between oxygen and fuel
Flammable liquids and gases cannot cause fire
by themselves
The misuse of flammable liquid alone is
responsible for 15% to 18% of industrial fire
losses.
HEAT OXYGEN FUEL
Heat can be transferred
from one place to
another.
Four categories:
Conduction
Radiation
Convection
Direct Burning /
Physical
Transport
HIGH temperature to a
region of LOW
temperature.
An essential
component of any
combustion reaction.
The degree of oxygen
supply determines: the
efficiency of the fire
and the nature of the
combustion product
formed.
The main source of
oxygen:
-Air contains 21% oxygen
and combustion
needs only 16% of
oxygen.
-Oxidising agents
-Combustible substances
A fuel is a necessary
component of all
combustion reactions.
Almost all organic
chemicals are potential
fuels.
Examples: wood,
plastic, fibres, petrol,
oil, LPG
Most but not all
inorganic substances
are not flammable.
CLASSIFICATION OF FIRES
Four categories :
Class A
Normally: an organic nature
Examples: wood, paper, coal and natural fibres.
Extinguisher agent is water either as a jet or spray
Class B
Class B (i): involving liquids which are soluble in
water such as methanol and acetone.
Extinguished with water spray, alcohol-resistant foam,
carbon dioxide and dry powder.
Class B (ii): involving liquids which do not dissolve in
water such as petrol oil, fats and waxes.
Extinguished by foam, carbon dioxide and dry
powder.
Class C
Involving gases or liquefied gases in the from of
liquid gas spillage or gas leaks
Extinguished by either isolating the supply
or by inert gas injection.
Class D
Involving metals, such as magnesium and
aluminium.
Special dry powder must be used and no other
extinguishers; these include powdered
graphite,
soda, ash, limestone and dry sand.
FIRE FIGHTING
Principle of Fire Extinguishment
Cooling – cooling of fuel to the point where
combustion
vapors are no longer produced, e.g. water
Smothering – the removal of oxygen to the point
where
combustion ceases, e.g. fire blanket, foam or
sand
Starving – the removal of fuel to the point where
there is nothing remaining to burn e.g. turning
off valves
Inhibiting the Flame Chain Reaction – by
arresting the
chemical chain reaction in the flame zone,
combustion
process is terminated, e.g. introduce a dry
chemical
extinguisher
FIRE FIGHTING SYSTEMS
A) Fixed
- sprinklers or deluge
- fixed extinguishers –
halons or CO2
- hydrants / hose reels
- early detection or
suppression
B) Portable
- fire extinguishers
- fire blankets
- dry extinguisher
agents
Fire fighting systems can be divided into 2 types:
Example of Fire Fighting Systems
Hydrants:
It is a statutory requirement that all manned
installations have a fire water.
The main is fed continuously from the fire
pumps.
Fire Hose:
Should be maintained and cared for as follows:
-cleaned after use
-stowed correctly
-stored in a clean and dry condition
-not dragged over ground unnecessarily
Branches and Nozzles:
To increase the velocity, to project and direct the
flow
of water onto a fire.
Hose Reels:
Advantages of Hose Reels:
simple to use
endless supply of water
more effective jet
has nozzle control
operator doesn’t need to carry a
heavy extinguisher
cost effective – no recharging required
Foam :
• Foam is a mixture of foam concentrate, water
and air
• To float on the burning liquid and create the
barrier
between the vapour and the air and
thus extinguish the flames
stability – foam retains its liquid content
expansion – by passing through special aspiration
nozzles, foam will increase it’s surface area coverage
burn-back – provides security against re-ignition by
remaining intact
flow – will flow across the liquid to be extinguished
or protected
contamination resistance – foam has the ability to
resist
contamination by the flammable liquid leading to
foam destruction
Types of Portable Extinguishers and Their Uses :
Water Type Extinguishers
Contents - 9 litres of water pressurized with
air
Duration - 1.5 to 2 minutes
Stream - 8 meters
Types of Portable Extinguishers and Their Uses :
Water Type Extinguishers:
Operation
check gauge
carry extinguisher to the fire by the carry handle
release safety pin
test operation
direct at base of fire
can be used intermittently
extinguishes by cooling
Use on – A Class Fires
Types of Portable Extinguishers and Their Uses :
Foam Type Extinguishers:
Contents - 8.5 liters water 0.5 AFFF
Duration - 30 to 90 seconds
Stream - 6 meters
Types of Portable Extinguishers and Their Uses :
Foam Type Extinguishers:
Operation:
check gauge
carry extinguisher to the fire by the carry handle
release safety pin
test operation
direct stream at wall of container or over surface
of fire
can be used intermittently
extinguishes fire by smothering and cooling
Use on – B Class Fires
Dry-Chemical Type Extinguishers:
Contents - Sodium Bicarbonate 0.9kg to 14 kg
Duration - 90 seconds upwards for 9 kg
Stream - 1.8 to 4 meters
Dry-Chemical Type Extinguishers:
Operation:
check gauge
carry extinguisher to the fire by the carry handle
release safety pin
test operation
direct at vapor space in a sweeping motion
can be used intermittently
extinguishes by inhibiting flame chain reaction
Use on – Small B Class Fires
Carbon Dioxide Type Extinguishers :
Contents - liquid CO2 1 kg to 5.5 kg
Duration - 20 seconds upwards
Stream - 1 to 2.5 meters
Carbon Dioxide Type Extinguishers :
Operation:
check gauge
carry extinguisher to the fire by the carry handle
release safety pin
test operation
direct close to fire in sweeping motion
can be used intermittently
extinguishes fire by smothering
Use on – Small B Class Fires
ESCAPE IN CASE OF FIRE :
Means of escape in buildings other than those
with
only a ground floor generally consists of 3
distinct areas:
• Any point on a floor to a staircase
• The route down a staircase
• The route from the foot of the staircase to the
open
air, clear of the building
Types of means of escape will be determined by:
• Occupancy characteristics – numbers,
• Building uses – residential commercial,
manufacturing,
entertainment etc
• Construction characteristics of the building
• Evacuation times
• Occupant movements
ACTION TO BE TAKEN IN THE EVENT OF
FIRE:
F Find: Locate the area of the fire
I Inform: Raise the alarm either manually,
automatically or by voice
R Restrict: Large, small or confined, remove
the source
of fuel
E Extinguish: If fire is small enough, attempt to
extinguish,
otherwise evacuate the area and raise
alarm
TRAINING IN FIRE FIGHTING
In the FMA (Safety, health and welfare)
REGULATION 1970 – Regulation 21 (4) stated
that:
“The occupier of every factory shall ensure that
all persons employed are familiar with the
means
of escape in case of fire, the use of such
means and
the routine to be followed in case of fire.”