5. 1.1 What is Fire ?
Fire is a chemical reaction called combustion resulting in the release
of heat and light.
To initiate and maintain this chemical reaction, there are three factors
which must be present at the same time in order for a fire to occur.
They are the following;
Fuel Combustion substance either solid, liquid or gas.
Oxygen Air containing approx. 21% oxygen.
Heat The attainment of a certain temperature (a fire
normally maintains its own heat supply).
FIRE FIGHTING COURSE
6. FIRE FIGHTING COURSE
1.2 THE FIRE TRIANGLE
Fire will exist when all 3 elements of the fire triangle are present.
7. 1.3 Spreading’s ways of the Fire
There are three ways for the fire for spreading:
1. Radiation
2. Conduction
3. Convection
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9. 1.3.3 RADIATION
Combustible materials can be ignited if they are situated close to a
radiation source.
The heat energy is transferred from the source to the combustible
material by means of electro-magnetic radiation.
Electric fire.
Sun's rays magnified through glass.
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11. 1.3 HOW FIRE SPREAD
1.3.1 CONDUCTION
Heat applied to a solid is conducted through the material to heat up its
entire area.
The heat energy is transferred from one molecule to the next
throughout the entire area of the solid.
Steel supporting beams which can transfer heat to numerous locations
in a building. Contact between the beam and combustiblematerial at
any point could start a fire.
Pipework for heating systems in a building.
Electrical wiring.
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13. 1.3.2 CONVECTION
Convection helps to spread fire from one location to another. This is
done by means of thermal air currents.
Fire heats up the air causing it to expand and become less dense. The
hot air rises and move away from the fire. At the same time, more
cooler air is drawn towards to fire to aid combustion and it is heated up
in the same way causing the process to continue.
The result is a circulation and spreading of heat, hot gasses and
possibly burning embers.
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14. 1.4 FIRE CLASSIFICATION
There are four main classes for fire:
A - B - C - D
These classifications depend on the nature of the material which is
burning.
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15. Class A Solid materials: free burning combustibles such as wood,
paper, fabric, plastic, etc...
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16. Class B Flammable liquids: oils, petrol, alcohol, greases,
paint, varnishes, etc.
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17. Class C Flammable gases: propane, butane, acetylene, etc…
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18. Class D Combustible metals: magnesium, titanium, zirconium,
aluminium powder, lithium, pothasium for which
special consideration has to be given to the method of
application, appliance and extinguisher media.
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19. Class E Electrical Fire: normally is produced by the heat
generated by a short circuit or an electrical
socket overcharged.
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20. 1.5 FIRES INVOLVING ELECTRICAL RISKS
One's personal safety is of paramount importance. Electric shock must
be avoided.
The electric supply must be disconnected, then the fire can be treated
and extinguished according to its classification. In most cases it will be
a class A fire.
If the electric supply cannot be disconnected, a non conductive
extinguishing agent such as CO2, vaporising liquids or dry powder
must be used.
Never use water or foam on electric fire !!!
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21. To extinguish a fire we need to remove just ONE of the elements. We
must remove each element of the fire triangle by different means
Heat Removed by cooling.
Oxygen Removed by smothering.
Fuel Removed by starving.
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FIRE EXTINCTION
22. Fire will cease to exist when the heat is removed (cooling)
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23. COOLING
Cooling absorbs sufficient heat in the fire (as the water turns to steam)
so as to reduce the temperature below the fire point.
There is not enough heat left to maintain combustion.
Water is the most effective way to cool a fire
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24. Fire will cease to exist when the oxygen is removed (smothering)
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25. SMOTHERING
At least 21% oxygen in the atmosphere is required to maintain
combustion. This supply can be blocked off by smothering so as
to extinguish the fire.
Methods used to cut off the oxygen supply
Blanketing the fire with dry powder.
Use of a fire blanket to cover the fire (e.g. a chip pan fire).
Application of foam on a liquid fire (which spreads over the
surface of the burning liquid and gradually cuts off the oxygen
supply).
Displacing the oxygen
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26. Fire will cease to exist when the fuel is removed (starvation)
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27. STARVING
This method is to extinguish the fire through starvation by removal of
the fuel.
Examples
Removal of surrounding combustible materials.
Turning off a gas supply.
Blanking of a pipeline.
FIRE FIGHTING COURSE
30. FIRE FIGHTING COURSE
Classes Substance Extinguishing
methods
Water Foam CO2 Dry
Powder
A Solid
materials
Cooling;
smothering
X X X
B Flammable
liquids
Smothering X X X
C Flammable
gases
Starving X X
Electrical
hazards
Cut off electric
supply
X X
Vehicles Smothering X X
36. 4.1 THE CONTROL OF FUELS
The fuel side of the fire triangle can result from uncontrolled usage or
storage of combustible materials.
Combustible fuels (solid, liquid or gas) must be controlled in usage
and storage in order to reduce or eliminate the risk of fire occurring.
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37. 4.1.1 SOLIDS
Uncontrolled usage and storage of large quantities of paper, furnishings,
fittings may result in the initial ignition of a fire or supply sufficient fuel for
the development of a serious fire following ignition.
All managers and supervisors should ensure that:
Paper and files should be stored in presses (ideally non combustible metal
cupboards) away from sources of ignition.
Unwanted stocks of paper, boxes or any unwanted fittings / furnishings are
be removed and disposed.
Paper does not accumulate on floors or in rooms with electronic
equipment, computers, battery charging equipment, etc…
No unapproved storage area is used to store solid combustibles.
Regular cleaning of all areas under supervision is carried out and that
rubbish removed is disposed of safely.
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38. 4.1.2 LIQUIDS
The ability of flammable liquids, such as petrol, to ignite at ambient
temperatures requires strict control regarding storage and use.
All managers and supervisors should ensure that:
Petrol or its by-products are only transported in approved metal
containers.
Petrol or its by-products are only stored in approved metal containers
at a safe distance from any camp set up.
Cleaning sprays or liquids labelled as 'highly flammable' are kept
to the minimum quantity necessary, and stored in metal presses or
approved cupboards out of direct sunlight.
Cooking oils are only used in approved areas (kitchens) and
heated up only by competent persons under supervision.
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39. 4.1.3 GASES
Fire or explosions involving the storage or use may result from the
ignition of leaking gas or following the heating of cylinders under fire
conditions.
All managers and supervisors should ensure that:
Cylinders are not stored in buildings or vehicles overnight.
Cylinders are securely stored in approved cages or compounds
when not in use.
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40. Cylinders containing oxygen or air are stored separately from
combustible gases such as propane or butane.
Damaged or defective cylinders are returned to the supplier.
Staff using LPG or other combustible gases should ensure that:
Hoses and connections are in sound condition.
Only approved connections are used in conjunction with cylinders.
Cylinders are kept upright at all times during transportation,
storage and use.
Cylinders are stored in approved locations only.
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41. 4.2 THE CONTROL OF SOURCES OF IGNITION
The heat or ignition side of the fire triangle can result from a number
of sources which are readily available in the workplace or home.
Frequent causes of fire :
Electrical apparatus or wiring.
Smoking.
Gas and LPG equipment.
Cutting and welding equipment.
Rubbish burning.
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42. 4.2.1 ELECTRICAL EQUIPMENT AND WIRING
Electrical equipment may cause a fire :
Arcing due to overload, earth faults or loose connections.
Overheating due to overload capacity.
Accidental ignition from apparatus designed to run hot in normal
use (heaters, cookers, soldering irons, etc.).
Accidental overheating of apparatus not designed to run hot in
normal use.
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43. Prevention and Control
All electrical maintenance and repair should be carried out by
qualified staff.
Equipment and apparatus should be protected by correctly rated
fuses and earthed in accordance with relevant standards.
All apparatus and equipment should be unplugged at the end of
the working day.
Cookers and cooking equipment should be constantly supervised
when in use and switched off when not in use.
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44. Never overload sockets by the over use of adapters.
Electrical switching, battery charging and generator locations should
be kept free of material at all times and never used for the storage of
combustible items.
Soldering irons should only be used by competent staff and never
left unsupervised when connected to a power source. Approved
stands should always be provided for soldering irons.
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45. Do Check for signs of damage to cables and leads.
Do Report and defective equipment immediately.
Do Switch off unnecessary equipment at the end of the day.
Don’t Overload circuits.
Don’t Cover or place articles over heating appliances.
Don’t Leave heat emitting apparatus such as cookers or
soldering irons unattended.
Don’t Tamper with electrical apparatus.
Don’t Attach any combustible materials to light fittings.
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46. Don’t Overload circuits.
Don’t Cover or place articles over heating appliances.
Don’t Leave heat emitting apparatus such as cookers or
soldering irons unattended.
Don’t Tamper with electrical apparatus.
Don’t Attach any combustible materials to light fittings.
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47. 4.2.2 SMOKING
Only strict prohibition of smoking in key areas can prevent the risk of
ignition of combustible items from discarded cigarettes or matches.
Smoking should be prohibited in the following areas:
Storage areas.
Mechanics' workshop areas.
LPG storage areas.
Flammable liquid stores.
Petrol or diesel bowsers.
Offices and computer rooms.
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48. Do Provide a sufficient number of ash trays in
designated smoking areas.
Do Check that smoking materials are correctly
extinguished.
Do Erect 'no smoking' signs in all non-smoking areas.
Do Enforce the no-smoking rule.
Don’t Discard smoking materials irresponsibly.
Don’t Smoke in prohibited areas.
Don’t Disregard breaches of the no-smoking rule.
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49. 4.2.3 GAS AND L.P.G. EQUIPMENT
All LPG cylinders should be stored in the approved cage or
compound at the end of the working day.
Hoses and connections should be checked for signs of leaks.
The connection of valves, regulators or hoses to cylinders should
only be carried out in the open air.
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50. Do Exercise caution when handling LPG cylinders.
Do Check hoses for signs of leaks.
Do Keep cylinders away from sources of heat.
Do Keep cylinders under shade in direct sunlight.
Don’t Store cylinders indoors overnight.
Don’t Use portable LPG appliances for heating purposes.
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51. 4.2.4 CUTTING AND WELDING EQUIPMENT
Extremely high temperatures are produced locally in operations
involving oxy-propane, oxy-acetylene or arc welding.
Flame, sparks, molten metals or heat transmitted through materials
being welded or cut, can ignite combustible items.
Lack of knowledge of the working environment by outside
contractors increases the risk.
Ideally, cutting and welding operations should be subject to a permit
to work system supervised by the department head.
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52. Do Ensure that all cutting and welding equipment is in safe
operating condition.
Do Ensure that only trained authorised persons carry out
welding and cutting operations.
Do Remove all combustibles from the work area and cover
fixed combustible items with a fire blanket.
Do Store oxygen, propane and acetylene cylinders securely in
separate compounds outside and in an upright position
with all valves turned off.
Don’t Allow contractors to use welding and cutting equipment
unsupervised.
Don’t Store welding gases overnight indoors.
Don’t Allow untrained staff to use welding or cutting equipment.
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53. 4.2.5 RUBBISH BURNING
Rubbish should only be incinerated at a designated site which is in a
safe location and operated by competent persons.
Do Ensure that rubbish is collected daily in rubbish
bins.
Don’t Burn rubbish anywhere except in the approved
incineration area.
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55. If fire occurs Set on the fire alarm.
Shout Fire ! Fire ! Fire !.
Attack the fire if possible.
If in danger Don't take risk.
Evacuate to the fire assembly
point.
When the fire alarm sounds Leave your location.
Report to the assembly point.
Don't stop for personal belongings.
Do not return until the all clear is
given.
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