Section 6 Ship safety systems

6.1.1 The electrical power required for power-operated sliding watertight doors is to be separate from any other power circuit and supplied from the emergency switchboard either directly or by a dedicated distribution board situated above the vertical limit of watertight integrity. The associated control, indication and alarm circuits are to be supplied from the emergency switchboard either directly or by a dedicated distribution board situated above the vertical limit of watertight integrity and be capable of being automatically supplied by the transitional source of emergency electrical power required by Vol 2, Pt 9, Ch 2, 5.2 Emergency source of electrical power 5.2.6 in the event of failure of either the main or emergency source of electrical power.

6.1.2 Watertight doors actuated by electric motors are to be capable of being automatically supplied from the transitional source of emergency electrical power or be provided with an independent temporary source of stored energy.

6.1.3 A single failure in the power operating or control system of power-operated sliding watertight doors shall not result in a closed door opening or prevent the hand operation of any door.

6.1.4 Availability of the power supply is to be continuously monitored at a point in the electrical circuit adjacent to the door operating equipment, including hydraulic power units where applicable. Loss of any such power supply is to activate an audible and visual alarm at the navigating bridge and main machinery control station.

6.1.5 Electrical power, control, indication and alarm circuits are to be protected against fault in such a way that a failure in one door circuit will not cause a failure in any other door circuit. Short circuits or other faults in the alarm or indicator circuits of a door are not to result in a loss of power operation of the door. Arrangements are to be such that leakage of water into the electrical equipment located below the vertical limit of watertight integrity will not cause the door to open.

6.1.6 The enclosures of electrical components necessarily situated below the vertical limit of watertight integrity are to provide suitable protection against the ingress of water with ratings as defined in IEC 60529: Degrees of protection provided by enclosures (IP Code) or an acceptable and relevant National Standard, as follows:

1. Electrical motors, associated circuits and control components, protected to IPX7 standard.

2. Door position indicators and associated circuit components protected to IPX8 standard, where the water pressure testing of the enclosures is to be based on the pressure that may occur at the location of the component during flooding for a period of 36 hours.

3. Door movement warning signals, protected to IPX6 standard.

6.1.7 Watertight door electrical controls including their electric cables are to be kept as close as is practicable to the bulkhead in which the doors are fitted and so arranged that the likelihood of them being involved in any damage which the ship may sustain is minimised.

6.1.8 An audible alarm, distinct from any other alarm in the area, is to sound whenever the door is closed remotely by power and sound for at least five seconds but no more than ten seconds before the door begins to move and is to continue sounding until the door is completely closed. The audible alarm is to be supplemented by an intermittent, highly visible, visual signal at the door.

6.1.9 The door is to have, as far as is practically achievable, a uniform rate of closure under power. The closure time, from the time the door begins to move to the time it reaches the completely closed position, shall in no case be less than 20 seconds or more than 40 seconds with the ship in the upright position.

6.1.10 Sliding watertight doors are to be capable of being remotely closed from the navigation bridge and are also to be operable locally from each side of the bulkhead. Indicators are to be provided at the respective control positions showing whether the doors are open or closed, and an audible alarm and intermittent visual signal is to be provided at the door closure.

6.1.11 A central operating console is to be fitted on the navigation bridge or main machinery control station and is to be provided with a ‘master-mode’ switch having:

1. an ‘in port’ mode, which is to allow any door to be locally opened and locally closed after use without automatic closure; and

2. an ‘at sea’ mode, which is to allow any door that is opened to be automatically closed whilst still permitting any doors to be locally opened but with automatic reclosure upon release of the local control mechanism.

6.1.12 The ‘master-mode’ switch is to be arranged to be normally in the ‘at sea’ mode position, be clearly marked as to its function, and be Type Approved in accordance with LR’s Procedure for Type Approved Products.

6.1.13 The central operating console is to be provided with a diagram showing the location of each door, with visual indicators to show whether each door is open or closed. A red light is to indicate a door is fully open and a green light a door fully closed. When the door is closed remotely, a red light is to indicate the intermediate position by flashing. The indicating circuit is to be independent of the control circuit for each door.

6.1.14 The arrangements are to be such that it is not possible to remotely open any door from the central operating console.

6.1.15 The requirements of Vol 2, Pt 9, Ch 9, 6.1 Watertight doors and hatches 6.1.1 to Vol 2, Pt 9, Ch 9, 6.1 Watertight doors and hatches 6.1.14 shall be applied to any electrically controlled, actuated door or hatch forming part of a watertight subdivision boundary.

6.2.1 Where it is required by Vol 1, Pt 4, Ch 3 Special Features that indicators be provided for bow, stern and shell doors, loading doors and other closing appliances, which are, intended to ensure the watertight integrity of the ships structure in which they are located, the indicator system is to be designed on the fail-safe principle. The system is to indicate if any of the doors or closing appliances are open or are not fully closed or secured.

6.2.2 Where such doors and appliances are to be operated at sea, the requirements of Vol 2, Pt 9, Ch 9, 6.1 Watertight doors and hatches are to be complied with as far as is practicable.

6.2.3 The electrical power supply for the indicator system is to be independent of any electrical power supply for operating and securing the doors.

6.3.1 A flooding detection system is to be fitted for watertight spaces below the damage control deck that:

1. have a volume, in cubic metres, that is more than the ship’s moulded displacement per centimetre immersion at the deep draught; or
2. have a volume more than 30 cubic metres, whichever is the greater.

6.3.2 Any watertight spaces that are individually equipped with a liquid level monitoring system (such as fresh water, ballast water, fuel, etc.), including an indicator panel or other means of monitoring at the bridge, or ships command centre are excluded from the requirements of this sub-Section.

6.3.4 Where a watertight space extends in height over more than one deck, there is to be at least one flooding detection sensor at each deck level. This provision is not applicable in cases where a continuous flood level monitoring system is installed.

6.3.5 Consideration may be given to the number and location of flooding detection sensors in watertight spaces with unusual arrangements or in other cases where these requirements would not achieve the intended purpose.

6.3.6 Each flooding detection system is to give an audible and visual alarm at the navigation bridge and the main machinery control station, if located in a separate space from the navigation bridge. These alarms are to indicate which watertight space is flooding. For watertight spaces with unusual arrangements consideration should be given to providing separate indications for different areas of the compartment.

6.3.7 The alarm system is to conform to the requirements of Vol 2, Pt 9, Ch 7 Control, Alerts and Safety Systems.

6.3.8 Sensor cabling and junction boxes are to be suitably rated and protected to ensure operability of the detection system in a flooded condition.

6.3.9 Flooding detection system sensors and equipment are to be installed where they are accessible for testing, maintenance and repair.

6.3.10 Flooding detection sensors shall be protected from mechanical and physical damage. Protective guards shall be provided if sensors are in a located in a vulnerable position where damage could occur. The guards shall not impair the operation of the sensor.

6.3.11 The flooding detection system is to be capable of being functionally tested using either direct or indirect methods.