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APPENDIX
SUPPLEMENT TO THE INTERPRETATIONS
1 Clarification on Protected Area
For typical diesel engines, the detail of the area on top of the engine including fuel oil injection pumps and turbo chargers is shown in the followings.
Length: Between both ends on top of cylinders. Where turbo charger(s) is installed at either end of the engine, the turbo charger should be included.
Breadth: Between inlets of exhaust gas chamber(s) and the fuel oil injection pumps.
Height: Between the top of cylinders and the fuel oil injection pumps.
2 Operational capabilities of the systems - Action Procedures for the use of the systems in case of local fire
(1) In case of manned machinery spaces *1
Act.1 Detect a local fire by watch in the machinery space.
Act.2 Shutdown fuel oil for the object. In case of the fire on the running generator engine, shutdown may be taken place after transferring the power supply to the stand-by generator. Where blackout has occurred*2 before the completion of the transfer, the automatic start of a stand-by generator should be confirmed.
Act.3 Activate the system*2 by manual operation for suppression of the fire (activation alarms work), then the main fire-extinguishing system may be activated if necessary.
Note: Act.2 may be omitted depend on the scale of the fire.
(2) In case of unmanned machinery spaces (fire recognized in early stage)
Act.1 Detect a local fire by a fire detection system*3 and alarm to manned stations.
Act.2 Confirm the fire in the machinery space and judge the position of the fire.
Act.3 Follow the Act.2 in the above-mentioned case (1). (After the Act.2 in case (1), the system will be activated automatically*4 by the 2nd fire detection.)
(3) In case of unmanned machinery spaces (fire not recognized in early stage)
Act.1 Detect a local fire by a fire detection system*3 and alarm to manned stations.
Act.2 The 2nd fire detection activates the system automatically*4. (activation alarms work)
Act.3 Confirm a fire in the machinery space and judge the position of the fire.
Act.4 Shutdown fuel oil for the object. In case of the fire on the running generator engine, shutdown may be taken place after transferring of the power supply to the stand-by generator. Where blackout has occurred*2 before the completion of the transfer, the automatic start of a stand-by generator should be confirmed.
Act.5 The main fire-extinguishing system may be activated, if necessary, and the system may be stopped, if appropriate.
*1 In case of manned machinery spaces, an automatic release system, if provided, should be cut off.
*2 Where blackout has occurred after the activation of the systems, the systems should be re-activated when the stand-by generator comes to run.
*3 An automatic release system should be achieved by the combined fire detecting system consisting of fire detectors provided in accordance with the requirements of regulation II-2/7.4.1 of the Convention and additional flame type fire detectors dedicated to each protected area for detecting the specific fire immediately and for preventing an accidental release. First fire detection (may be achieved by a flame type fire detector) provides only the fire alarm (and starts the stand-by generator, if possible), then, 2nd fire detection by any one of conventional detectors in the machinery space provides the system activation and its alarm. In this context, these two detections of fire alarms need not to be distinct from each other.
*4 Manual operation should be available to override the automatic release system.
3 Influence of water mist on electrical equipment
Considerations should be given to the influence of water mist on the electrical equipment essential for the ship's operation in the area covered by the water mist which is considered relatively larger than the effective area assigned by MSC/Circ.913. Generator engines should be so arranged as to prevent the loss of electrical power supply by isolating them each other. Due to the difficulty of such isolation especially in small ships, the generators should be provided with some effective protections to complement the incomplete isolation. The protection of IP44 and above is considered effective against water mist. Lower ratings of IP grade combined with small alternations on the generator casings such as extended air inlet hoods and air filters may be acceptable providing that it is verified by an endurance test of 20 minutes carried out under the simulated condition.
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