Fire protection built in merchant ship.ppt

Fire protection designed for ship

1. FIRE PROTECTION BUILTIN
SHIPS

2. CHEMISTRY OF FIRE
Fire is an oxidation process
It is exothermic
Oxidation
It is a chemical process in which substances combine
with oxygen Giving off HEAT
Conditions of fire
The presence of material such as gas or liquid which
act as a fuel
A source of ignition e.g. chemical physical or
biological
The presence of oxygen and as air or from oxidizing
agents

3. For a substance to oxidise its molecules have to be
surrounded by oxygen
All matters exist in one of the three states.
Solids
Molecules & Atoms bound tightly to each other.
Liquids
Molecules & atoms bound loosely together
Gases
Molecules & atoms are not bound at all.
It is easier only for vapours to oxidise

4. Fire triangle
OXYGEN, HEAT & FUEL are
needed to start a fire.
If any one is cut-off then the fire
can be put off.
For the fire to sustain,
continuous availability of fuel is
required.
The availability of fuel
continuously makes it as a chain
reaction.

5. FIRE TETRAHEDRON
To move into a slightly more advanced theory
of fires, there is a fourth ingredient necessary
for fire, and the "fire tetrahedron" more
accurately demonstrates the combustion
process.
A tetrahedron is a solid figure with four
triangular faces.

7. FIRE TETRAHEDRON
It contains the four things required for
combustion.
Fuel (to vaporize and burn),
oxygen (to combine with the fuel vapor),
Heat (to raise the vapor to its ignition point)
Chain reaction (the chemical reaction among the
fuel, oxygen and heat).
Remove any of these four and you have no fire

8. Fighting fire
If any one side of the fire triangle is removed, the fire
will be extinguished.
Four methods of fighting fire are:
Smothering: Removing of air
Starving : Removing of burning material from
surrounding
Cooling : Removing of heat
Inhibiting : Checking / stopping the exothermic chemical
reaction of substance containing oxygen within themselves

9. Removal of Oxygen
Except in those substances that contain their own
oxygen the removal of sufficient oxygen will extinguish
a fire.
Small fires can be smothered with sand from a fire
bucket, and a rug or blanket can be used to smother
flames from a person’s clothes.
It is imperative to ensure the door is properly closed
when leaving a fire to burn in a compartment or room.

10. Removal of Oxygen
Fires in cargo holds can be starved of oxygen by
closing hatches and blanking-off ventilators.
In all spaces affected by fire, ventilating fans
should be shut down and doors and other
openings dosed.
In galley fat fires, a wet towel or purpose-made
blanket can be applied after disconnecting the
power source.

11. Removal of Oxygen
In fire extinguishing operations, oxygen is
excluded by smothering the fire with a layer of
foam.
Oxygen is also cut off during the operation of
portable and semi-portable carbon dioxide
extinguishers and, to some extent, during the
operation of dry powder extinguishers.

12. Removal of Oxygen
However, in the instances of carbon dioxide and
dry powder, the removal of oxygen is temporary
and unless the fuel is cooled, re-ignition may
occur.
In total flooding fixed fire extinguishing systems
for ships holds, pump rooms and machinery
spaces, carbon dioxide gas displaces the air to such
an extent that there is insufficient air for
combustion.

13. Removal of Oxygen
Use of Inert Gas
Although it is a fire prevention measure and not a
fire extinguishing technique, inerting plays an
important role in oil and chemical tanker
operations.
It involves maintaining an atmosphere of such low
oxygen content that fire or explosions cannot
occur. In oil tanker operation, either suitably
treated funnel gases or gases from an inert gas
generator are pumped into the cargo and slop
tanks

14. Removal of Oxygen
In chemical tankers, depending on the type of cargo,
an inert atmosphere is maintained by gases from an
inert gas generator or from an inert gas (e.g. nitrogen)
supply.

15. Removal of Heat
To achieve this level of effectiveness the water has
to be applied as a fine spray.
Coincidentally, a degree of smothering can also be
achieved from the steam generated.
Heat can also be absorbed by the decomposition of
dry powders.
The source of power should be cut off in electrical
insulation and galley fires.

16. The removal of fuel is not always possible.
However, in the case of liquid fuel fires caused by
leaking pipes or fittings, the fuel supply should be
closed.
It may also be possible to drain fuel from a
burning tank.
It is particularly important to shut off the supply in
a gas fire.
However, gas could also be left burning in a
controlled manner to exhaust itself.
Removal of fuel

17. Removal of Fuel
For instance, halogenated hydrocarbons (Halons)
and dry powders attack the structure of the species
and prevent their reaction by killing the flame -
sometimes in less than one-hundredth of a
second.
On some occasions, it may be prudent to dump
burning or potentially dangerous material
overboard.

18. Breaking the Chain Reaction
For instance, halogenated hydrocarbons (Halons)
and dry powders attack the structure of the species
and prevent their reaction by killing the flame -
sometimes in less than one-hundredth of a second.
This extinction takes place without any appreciable
removal of heat, fuel or oxygen.
However, the remaining three sides of the
tetrahedron will still be present and, unless the heat
is removed, there is a danger of re-ignition if the
concentration of extinguishing agent is not
maintained.

19. The main sources of fire onboard a ship are:
1.Smoking
2.Faulty electrical installations / faulty circuits
3.Attitude of personnel onboard
4.Improper storage of materials
5.People from ashore (Ignorance)
6.Galley
7.Welding and Hot work.

20. Sources of fire in the engine room are:
1.Smoking
2.Faulty electric circuits(Overload, faulty/poor
quality materials)
3.Improper storage
4.Oily rags
5.Scavenge fires
6.Oily mist / Crankcase explosions
7.Boiler uptake fires
8.Leaking/splashing from pumps
9.Poor housekeeping