marine engineering

Home page||Fire protection||


Ship fire protection systems

Fire protection on ships is provided by detection and fire-fighting equipment together with structural features which are intended to contain an outbreak of fire and the employment when required of non-combustible materials to prevent its spread.
For reference purposes fires may be grouped in three classes:

1 This ciass covers fires in solid materials such as wood and soft furnishings. Fires in this class may be extinguished by quenching or cooling with a water.

2. This class covers fires in fluids, such as petrol, lubricating oil and grease. It is dangerous to attempt to extinguish such fires with a jet of water, A small slug of water projected beneath the surface of hot, burning oil can erupt into steam so rapidly that burning oil is thrown in all directions.

A very fine water spray, used with care, can be beneficial for fighting oil fires or as a heat screen. These fires may be extinguished by smothering, i.e. being deprived of oxygen.

3. This class covers fires in electrical equipment and any extinguishing agents must be non-conductive.

Sources of ignition & Preventive measures against fire -Safety precautions


Fire aboard a general cargo vessel can be disastrous. Common causes are:

i) faulty electrical appliances/circuitry
ii) overloading of electrical circuitry
iii) careless disposal of cigarette ends
iv) spontaneous combustion of dirty waste/ rags especially if contaminated with oil
v) damp storage of linen/materials
vi) oil spillage/leakage in machinery spaces
vii) galley fires due to overheating of cooking oils
viii) carelessness with hand pressing irons
ix) incorrect methods of drying laundry

The prevention of fire on board ship is of utmost importance. Below is outlined all probable sources of ignition and how to take preventive measures.




Smoking

Conspicuous warning notices should be displayed in any part of the ship where smoking is forbidden (permanently or temporarily) and observance of them should be strictly enforced. Ashtrays or other suitable containers should be provided and used at places where smoking is authorised.


Electrical and other fittings

All electrical appliances should be firmly secured and served by permanent connections whenever possible.
Flexible leads should be as short as practicable and so arranged as to prevent their being chafed or cut in service.
Makeshift plugs, sockets and fuses should not be used.
Circuits should not be overloaded since this causes the wires to overheat, destroying insulation and thus resulting in a possible short-circuit which could start a fire. Notices should be displayed warning that approval should be obtained from a responsible officer to connect any personal electrical appliances to the ship's supply.

All portable electrical appliances, lights etc should have insulation readings taken before use, and should be isolated from the mains after use.

Electrical equipment which is to be used in any cargo area should be of an approved design.

It is important that all fixed electric heaters are fitted with suitable guards securely attached to the heater and that the guards are maintained in position at all times. Drying clothing on or above the heaters should not be permitted and suitably designed equipment should be supplied, or areas designated.

When using drying cabinets or similar appliances, the ventilation apertures should not be obscured by overfilling of the drying space. Any screens or fine mesh covers around the ventilation apertures should be regularly inspected and cleaned, so that they do not become blocked by accumulated fluff from clothing.

The use of portable heaters should be avoided wherever possible. However, if they are required while the ship is in port (as temporary heating during repairs and as additional heating during inclement weather), a protective sheet of a non-combustible material should be provided to stand them on to protect wooden floors or bulkheads, carpets or linoleum. Portable heaters should be provided with suitable guards and should not be positioned close to furniture or other fittings. These heaters should never be used for drying clothes etc.

Personal portable space-heating appliances of any sort should not be used at sea and notices to this effect should be displayed.

The construction and installation of electric heaters should always be carried out in accordance with the relevant regulations and instructions or guidance supplied by the manufacturer.


Spontaneous combustion

Dirty waste, rags, sawdust and other rubbish - especially if contaminated with oil - may generate heat spontaneously which may be sufficient to ignite flammable mixtures or may set the rubbish itself on fire. Such waste and rubbish should therefore be properly stored until it can be safely disposed of.

Materials in ship's stores, including linen, blankets and similar absorbent materials are also liable to ignite by spontaneous combustion if damp or contaminated by oil. Strict vigilance, careful stowage and suitable ventilation are necessary to guard against such a possibility. If such materials become damp, they should be dried before being stowed away. If oil has soaked into them, they should be cleaned and dried, or destroyed. They should not be stowed in close proximity to oil or paints, or on or near to steam pipes.


Machinery spaces

All personnel should be made fully aware of the precautions necessary to prevent fire in machinery spaces - in particular, the maintenance of clean conditions, the prevention of oil leakage and the removal of all combustible materials from vulnerable positions

. Suitable metal containers should be provided for the storage of cotton waste, cleaning rags or similar materials after use. Such containers should be emptied at frequent intervals and the contents safely disposed of.

Wood, paints, spirits and tins of oil should not be kept in boiler rooms or machinery spaces including steering gear compartments.

All electric wiring should be well maintained and kept clean and dry. The rated load capacity of the wires and fuses should never be exceeded.


Galleys

Galleys and pantries present particular fire risks . Care should be taken in particular to avoid overheating or spilling fat or oil and to ensure that burners or heating plates are shut off when cooking is finished. Extractor flues and ranges etc should always be kept clean.

Means to smother fat or cooking oil fires, such as a fire blanket, should be readily available close to stoves. Remote cut-offs and stops should be conspicuously marked and known to galley staff.


Preventing engine room fire

The majority of serious engine room fires are fuelled by oil. In the event of fire, the primary source of fuel must be rapidly isolated and the operation of quick-closing valves, either locally or remotely, is often the only way of achieving this. United States Coastguard inspections have revealed that these valves are sometimes intentionally blocked, modified or poorly maintained, thus preventing them from operating as designed in an emergency. The apparent disregard for an essential safety item could lead to more detailed focus in other areas from any Port State Control authorities. Defects are likely to result in a vessel's detention.

Portable fire extinguishers

The first line of defence against fire in any area of the ship, is the portable fire extinguisher. Some common portable extinguishers that have been used at sea are described below.
  1. Soda-acid extinguisher (discharges water)

    2. The main body of the Soda acid extinguisher contains sodium bicarbonate, an alkaline solution. The extinguisher must be kept upright when in use. The operator strikes the pin at the top to break the acid phial so that acid and alkali mix, to form carbon dioxide which forces the water (with the chemical remains) out of the discharge. The device must be held upright in use. .....more

  2. Foam portable extinguisher

    3. Mechanical Foam extinguisher is filled with water and contains an inner container with a small metal bottle of liquid carbon dioxide, surrounded by a plastic bag of foam making compound. .....more

  3. CO2 portable fire extinguisher

    4. While carbon dioxide is used in some extinguishers as an inert propellant the gas is also used extensively as a blanketing agent. The carbon dioxide is in liquid form and is at a pressure of 6 bar at 20 deg C necessitating a strong container. This type of extinguisher can only be recharged ashore. .....more

  4. Dry powder portable extinguisher

    5. This type of extinguisher contains sodium bicarbonate powder with a water proofing agent such as magnesium stearate to prevent caking. The container shown holds a cartridge containing liquid carbon dioxide. On piercing its seal with the plunger pin, the gas is delivered through a tube to the bottom of the casing where it entrains the dry powder and carries it up through the discharge tube. .....more

    Portable halon extinguisher The use of halon in portable extinguishers should be discontinued when suitable alternatives are available because of the high ozone depletion potential.



Summarized below more fire protection equipments & guideline:
  1. Fire main system & related mechanism

    2. The fire main extends to the full length of the ship and from the machinery spaces to the highest levels. Hydrants served by the main, are situated so that with suitable hoses any area on the ship can be reached. .....more

  2. CO2 fire extinguishing installation

    3. Fire extinguishing installations employing CO2 stored under pressure at ambient temperature are extensively used to protect ships' cargo compartments, boiler rooms and machinery spaces. When released the CO2 is distributed throughout the compartment, so diminishing the relative oxygen content and rendering the atmosphere inert. ...... more

  3. Fire fighting equipments

    4. 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. The pumps are fitted with non-return valves if they are of the centrifugal type, to prevent loss of water back through open valves when not running. ..... more

  4. Details of fire detectors

    5. A variety of devices are available for detecting fire in unmanned machinery spaces but each has an ability to detect basically only one aspect. Thus, smoke detectors based on the ionization chamber are able to recognize combustion products but will not register radiation from a flame or heat. .....more

  5. Machinery space fire & use of Walter Kidde CO2 system

    6. Walter Kidde CO2 system employs pilot CO2 cylinders to open the distribution system main stop valve and subsequently the valves on the individual CO2 cylinders. .....more

  6. Fire protection system for cargo holds

    7. Holds for general cargo, have been protected against fire by fixed installations which deliver inert gas from an inert gas generator based on combustion of fuel (similar to the system available for inerting oil tankers) and halon systems. .....more

  7. Low pressure CO2 storage

    8. In some installations, the CO2 is stored in low pressure refrigerated tanks. The cylindrical storage vessels are fabricated to the pressure vessel requirements of the authorities. The tanks are of low temperature steel, fully tested and stress relieved. They are mounted on supports designed to withstand shock from collision. ..... more

  8. Halon system

    9. Halon 1301 has the chemical formula CF3 Br being known as bromo-trifluoromethane. It is a colourless, odourless gas with a density five times that of air and extinguishes fire by breaking the combustion chain reaction. .....more

  9. Multi-spray system for the machinery spaces

    10. This system is similar to the sprinkler used in accommodation areas but the spray heads are not operated automatically. The section control valves (Figure 14.20) are opened by hand to supply water to the heads in one or more areas. Ready to use hoses can also be supplied. Fresh water is used for the initial charging and the system is brought to working pressure by means of the compressed air connection. .....more

  10. Automatic sprinkler system

    11. A network of sprinkler heads is arranged throughout the spaces to be protected. Each sprinkler head is normally kept closed by a quartzoid bulb which is almost filled with a liquid having a high expansion ratio. .....more

  11. Details various portable extinguishers & how to use ?

    12. The first line of defence against fire in any area of the ship, is the portable fire extinguisher. Some common portable extinguishers that have been used at sea are described. .....more



Home page||Cooling ||Machinery||Services ||Valves ||Pumps ||Auxiliary Power ||Propeller shaft ||Steering gears ||Ship stabilizers||Refrigeration||Air conditioning ||Deck machinery||Fire protection||Ship design ||Home ||


General Cargo Ship.com provide information on cargo ships various machinery systems -handling procedures, on board safety measures and some basic knowledge of cargo ships that might be useful for people working on board and those who working in the terminal. For any remarks please Contact us


Copyright © 2010-2016 General Cargo Ship.com All rights reserved.
Terms and conditions of use
Read our privacy policy|| Home page||