marine engineering

Home page||Fire protection||


Multi-spray system for the machinery spaces

Air supply: 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.

Emergency stops must be fitted so that ventilation fans can be stopped from a position external to the space served. Trunkings are provided with flaps which can be used to isolate various areas as necessary. Provision should be made so that all openings which could admit air can be closed off from a safe position external to the space or from the deck.

Multi-spray system for the machinery spaces

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. The air bottle provides a cushion and prevents cut-in of the pump due to any slight leakage of the water. The pump is automatically operated by pressure drop in the system when the control valve to one section is opened.



The pump must have either an independent drive or an electric motor with a supply via the emergency generator switchboard. It must be able to maintain working pressure when supplying all the sections simultaneously in one compartment. It is installed outside the compartment it serves.

Spray nozzles are designed to give the correct droplet size for fires in flammable liquids such as fuels and lubricating oils, when working at the correct pressure. They are located so as to give adequate water distribution over the tank top and all fire risk areas.

Multi-spray and drencher system (R, C, Dean)
Figure 14.20 Multi-spray and drencher system (R, C, Dean)

Water spray is a potentially good fire-fighting medium because (a) it produces a large quantity of steam which has a smothering action; (b) in producing the steam, a large amount of heat is required (latent heat) and this gives a cooling effect; (c) the spray will protect personnel in the compartment; (d) water is readily available.

Corrosion of the system is minimized by keeping it charged with fresh water. After operation, the pipework is drained of salt water and refilled with fresh water after washing through. Damage to any electrical equipment by the salt water is dealt with by washing with hot fresh water before drying out. The multi-spray, sprinkler or drencher systems, can be connected through a cross connection which is normally locked shut. A car deck drencher system is included in the sketch.



Summarized below general cargo ship 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||