The resulting chemical reaction
produces carbon dioxide gas which pressurises the space above the
liquid forcing it out through the internal pipe to the nozzle. This
extinguisher is used for Class A fires and will be found in
Fig:Soda acid portable fire extinguisher
Maintenance and testing
All portable extinguishers are pressure vessels and must therefore be
The dry powder
extinguisher is tested to 35 bar once every four years.
Most extinguishers should be tested by discharge over a period of one
to five years, depending on the extinguisher type,
Where practicable the operating mechanisms of portable extinguishers
should be examined every three months.
Any plunger should be checked for free movement, vent holes should
be clear and cap threads lightly greased. Most extinguishers with
screw-on caps have a number of holes in the threaded region. These are
provided to release pressure before the cap is taken off: they should be
checked to be clear.
The type, number and locations of portable and semi-portable extinguishers are supplied to cargo vessels according to SOLAS, Flag and Classification requirements. All fire fighting equipment must be in a constant state of readiness and be regularly and properly maintained. Any valves in these systems are to be operated and proved free every month.
Any defects with the equipment are to be reported to the Company immediately and rectified on an urgent basis.
It is essential that when fire-fighting equipment is landed ashore for service or maintenance, sufficient quantities remain onboard to cope with an emergency situation. If required, equipment may be hired as a temporary replacement for the ship’s own equipment.
Types of portable fire extinguisher
There are four principal types of portable extinguisher usually found on
board ship. These are the soda-acid, foam, dry powder and carbon dioxide
extinguishers. Details as below :
Fixed fire extinguishing installations
- Soda acid portable fire extinguisher
The container of this extinguisher holds a sodium bicarbonate solution.
The screw-on cap contains a plunger mechanism covered by a safety
- Foam type portable fire extinguisher
The main container is filled with sodium bicarbonate solution and a long
inner polythene container is filled with aluminium sulphate
- Dry powder fire extinguishers
The outer container contains sodium bicarbonate powder. A capsule of
carbon dioxide gas is located beneath a plunger mechanism in the
- CO2 portable fire extinguisher
A very strong container is used to store liquid carbon dioxide under
A variety of different fixed fire fighting installations exist, some of
which are specifically designed for certain types of ship. A selection of
the more general installations will now be outlined.
Other important fire & safety equipments
- Fire main system for cargo ships
An outbreak of fire requires a source of ignition, the presence of combustible material and ample oxygen. Of the three factors, oxygen is provided in large quantities in machinery spaces, accommodation, dry cargo holds and tanker pumprooms by ventilation fans. Air supply trunkings are not only a source for a supply of oxygen to feed the fire but also have potential for carrying smoke from one area to another....
- Automatic water spray & water mist system for machinery protected area
The automatic spray or sprinker system provides a network of sprinkler heads throughout the protected spaces. This system may be used in accommodation areas, and in machinery spaces with certain variations in the equipment used and the method of operation. ....
- Automatic foam induction system for machinery space fire
Foam spreading systems are designed to suit the particular ship's requirements with regard to quantity of foam, areas to be protected, etc. Mechanical foam is the usual substance used, being produced by mixing foam making liquid with large quantities of water. Violent agitation of the mixture in air creates air bubbles in the foam. ...
- CO2 fire extinguishing installations for machinery spaces
Fire extinguishing installations employing CO 2 stored under pressure at ambient temperature are extensively used to protect ships' cargo compartments, boiler rooms and machinery spaces. When released the CO 2 is distributed throughout the compartment, so diminishing the relative oxygen content and rendering the atmosphere inert....
- Inert gas systems, inert gas generator
Inert gases are those which do not support combustion and are largely nitrogen and carbon dioxide. Large quantities suitable for fire extinguishing can be obtained by burning fuel in carefully measured amounts or by cleaning the exhaust gases from a boiler. ....
- Fire fighting Halon system
A Halon storage system would be very similar to one using carbon dioxide except that fewer cylinders would be required. The liquefied Halon is usually pressurised in the cylinders with nitrogen in order to increase the speed of discharge. ....
Marine machineries - Useful tags
Marine diesel engines
- Use of Breathing apparatus
Compressed air cylinders are of various sizes, usually of either 9 or 6 litre water capacity.
The fully charged pressure of cylinders also varies. Some types are charged to as high as 300 bar (4500 p.s.i.). The maximum charging pressure is always stamped on either the neck or the shoulder of a cylinder.
- Emergency Fire pump cargo ships machinery spaces
Two independently powered pumps must be provided in all cargo ships of 1000 tons gross and over and in passenger ships of less than 4000 tons gross. Larger passenger vessels and passenger ferries must have three such pumps.
- Foam adapter for machinery space fire
Foam branch pipes which operate in a similar manner to those used in deck installations for tankers, are fitted for use with the hydrants in some machinery spaces and in particular for passenger ferry car decks.
- Various fire detectors working principle
The main function of a fire detector is to detect a fire
as quickly as possible; it must also be reliable and require a minimum of
- Fire detection system
The fire detection system is to be classed as Critical Equipment and must be maintained in good working order.
- Fire fighting strategy for cargo ships
A basic strategy should be followed in all fire fighting situations. This
will involve four distinct aspects, which are locating, informing, containing
and finally extinguishing a fire.
||Steam generating plant
||Air conditioning system
||Emergency power supply
||Exhaust gas heat exchangers
||Feed extraction pump
|| Four stroke engines
|| Fuel injector
|| Fuel oil system
|| Fuel oil treatment
Lub oil filters
MAN B&W engine
Oily water separator
Overspeed protection devices
Piston & piston rings
Sewage treatment plant
Starting air system
Two stroke engines
Drydocking & major repairs
Deck machineries & cargo gears
|| Control and instrumentation
||Engine room safety