4.15 Openings in Watertight Bulkheads below the Bulkhead Deck:

(1) The number of openings in watertight bulkheads shall be reduced to the minimum compatible with the design and proper working of the ship, satisfactory means shall be provided for closing these openings.

(2) Watertight bulkhead integrity shall be maintained in accordance with the following provisions-

• (a) where pipes, scuppers, electric cables, etc., are carried through watertight bulkheads, arrangements shall be made to ensure the watertight integrity of the bulkheads;

• (b) valves not forming part of a piping system shall not be permitted in watertight bulkheads; and

• (c) lead or other heat sensitive materials shall not be used in systems which penetrate watertight bulkheads, where deterioration of such systems in the event of fire would impair the watertight integrity of the bulkheads.

(3) No doors, manholes, or access openings are permitted in watertight transverse bulkheads dividing a storage space from an adjoining storage space, except as provided in section 4.15(9).

(4) Subject to section 4.15(10)-

• (a) not more than one door, apart from the doors to shaft tunnels, may be fitted in each watertight bulkhead within spaces containing the main and auxiliary propulsion machinery including boilers serving the needs of propulsion;

• (b) where two or more shafts are fitted, the tunnels shall be connected by an intercommunicating passage;

• (c) there shall be only one door between the machinery space and the tunnel spaces where two shafts are fitted and only two doors where there are more than two shafts;

• (d) all these doors shall be of the sliding type and shall be so located as to have their sills as high as practicable; and

• (e) the hand gear for operating these doors from above the bulkhead deck shall be situated outside the spaces containing the machinery.

(5) Watertight doors shall comply with the following general provisions-

• (a) watertight doors, except as provided in section 4.15(9), shall be power-operated sliding doors complying with the requirements of section 4.15(7) capable of being closed simultaneously from the central operating console at the navigation bridge in not more than 60 seconds with the ship in the upright position; and

• (b) the means of operation whether by power or by hand of any power-operated sliding watertight door shall be capable of closing the door with the ship listed to 15° either way and consideration shall also be given to the forces which may act on either side of the door as may be experienced when water is flowing through the opening applying a static head equivalent to a water height of at least 1 metre above the sill on the centreline of the door;

• (c) watertight doors and their controls, including hydraulic piping and electric cables shall comply with the following provisions

  • (iv) the controls shall be kept as close as practicable to the bulkhead in which the doors are fitted, in order to minimise the likelihood of them being involved in any damage which the ship may sustain; and

  • (v) the positioning of watertight doors and their controls shall be such that if the ship sustains damage within one fifth of the breadth of the ship, as defined in section 1.3 such distance being measured at right angles to the centreline at the level of the deepest subdivision draught, the operation of the watertight doors clear of the damaged portion of the ship is not impaired.

(6) All power-operated sliding watertight doors shall-

• (a) be provided with means of indication which will show at all remote operating positions whether the doors are open or closed; and

• (b) have their remote operating positions only at the navigation bridge as required by section 4.15(7)(a)(v) and at the location where hand operation above the bulkhead deck is required by section 4.15(7)(a)(iv).

(7) Watertight doors shall comply with the following provisions-

• (a) Each power-operated sliding watertight door shall-

  • (i) have a vertical or horizontal motion;

  • (ii) subject to section 4.15(10), be normally limited to a maximum clear opening width of 1.2 metres; provided that the Administration may permit larger doors only to the extent considered necessary for the effective operation of the ship provided that other safety measures, including the following, are taken into consideration-

    • (ba) special consideration shall be given to the strength of the door and its closing appliances in order to prevent leakages; and

    • (bb) the door shall be located inboard the damage zone B/5;

  • (iii) be fitted with the necessary equipment to open and close the door using electric power, hydraulic power, or any other form of power that is acceptable to the Administration;

  • (iv) be provided with an individual hand-operated mechanism such that it shall be possible to open and close the door by hand at the door itself from either side, and in addition, close the door from an accessible position above the bulkhead deck with an all round crank motion or some other movement providing the same degree of safety acceptable to the Administration and the direction of rotation or other movement is to be clearly indicated at all operating positions; the time necessary for the complete closure of the door, when operating by hand gear, shall not exceed 90 seconds with the ship in the upright position;

  • (v) be provided with controls for opening and closing the door by power from both sides of the door and also for closing the door by power from the central operating console at the navigation bridge;

  • (vi) be provided with an audible alarm in accordance with the following provisions-

    • (ba) it shall be distinct from any other alarm in the area;

    • (bb) it shall sound whenever the door is closed remotely by power and shall sound for at least 5 seconds but no more than 10 seconds before the door begins to move and shall continue sounding until the door is completely closed; provided that in the case of remote hand operation it is sufficient for the audible alarm to sound only when the door is moving; and

    • (bc) additionally, in passenger areas and areas of high ambient noise the Administration may require the audible alarm to be supplemented by an intermittent visual signal at the door;

  • (vii) have an approximately uniform rate of closure under power and 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;

• (b) The electrical power required for-

  • (i) power-operated sliding watertight doors shall be supplied from the emergency switchboard either directly or by a dedicated distribution board situated above the bulkhead deck;

  • (ii) the associated control, indication and alarm circuits shall be supplied from the emergency switchboard either directly or by a dedicated distribution board situated above the bulkhead deck and be capable of being automatically supplied by the transitional source of emergency electrical power required by Regulation 42 of Chapter II-1 D of SOLAS, in accordance with Chapter 5 of this Code, in the event of failure of either the main or emergency source of electrical power.

• (c) Power-operated sliding watertight doors shall have either-

  • (i) a centralised hydraulic system complying with the following provisions-

    • (ba) two independent power sources each consisting of a motor and pump capable of simultaneously closing all doors;

    • (bb) having, for the whole installation, hydraulic accumulators of sufficient capacity to operate all the doors at least three times, i.e. closed-open-closed, against an adverse list of 15º;

    • (bc) the operating cycle referred to in sub-subparagraph (bb) above shall be capable of being carried out when the accumulator is at the pump cut-in pressure;

    • (bd) the fluid used in the system shall be chosen considering the temperatures liable to be encountered by the installation during its service;

    • (be) the power operating system shall be designed to minimise the possibility of having a single failure in the hydraulic piping adversely affect the operation of more than one door;

    • (bf) the hydraulic system shall be provided with a low-level alarm for hydraulic fluid reservoirs serving the power-operated system and a low gas pressure alarm or other effective means of monitoring loss of stored energy in hydraulic accumulators; and

    • (bg) the alarm referred to in sub-subparagraph (bf) above is to be audible and visual and shall be situated on the central operating console at the navigation bridge;

  • OR

  • (ii) an independent hydraulic system for each door complying with the following provisions-

    • (ba) each power source shall consist of a motor and pump capable of opening and closing the door;

    • (bb) in addition, there shall be a hydraulic accumulator of sufficient capacity to operate the door at least three times, i.e. closed-open-closed, against an adverse list of 15º and this operating cycle shall be capable of being carried out when the accumulator is at the pump cut-in pressure;

    • (bc) the fluid used shall be chosen considering the temperatures liable to be encountered by the installation during its service;

    • (bd) a low gas pressure group alarm or other effective means of monitoring loss of stored energy in hydraulic accumulators shall be provided at the central operating console on the navigation bridge; and

    • (be) loss of stored energy indication at each local operating position shall also be provided;

  • OR

  • (iii) an independent electrical system and motor for each door complying with the following provisions-

    • (ba) each power source shall consist of a motor capable of opening and closing the door;

    • (bb) the power source shall be capable of being automatically supplied by the transitional source of emergency electrical power as required by Regulation 42 of Chapter II-1 D of SOLAS, in accordance with Chapter 5 of this Code, in the event of failure of either the main or emergency source of electrical power and with sufficient capacity to operate the door at least three times, i.e. closed-open-closed, against an adverse list of 15º,

  • (iv) For the systems specified in sections 4.15(7)(c)(i), 4.15(7)(c)((ii) and 4.15(7)(c)(iii), provision should be made as follows-

    • (ba) power systems for power-operated watertight sliding doors shall be separate from any other power system; and

    • (bb) a single failure in the electric or hydraulic power-operated systems excluding the hydraulic actuator shall not prevent the hand operation of any door.

• (d) control handles shall be provided at each side of the bulkhead at a minimum height of 1.6 metres above the floor and shall be so arranged as to enable persons passing through the doorway to hold both handles in the open position without being able to set the power closing mechanism in operation accidentally and the direction of movement of the handles in opening and closing the door shall be in the direction of door movement and shall be clearly indicated

• (e) as far as practicable, electrical equipment and components for watertight doors shall be situated above the bulkhead deck and outside hazardous areas and spaces.

• (f) the enclosures of electrical components necessarily situated below the bulkhead deck shall provide suitable protection against the ingress of water¹.

• (g) electric power, control, indication and alarm circuits shall 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 shall not result in a loss of power operation of that door and arrangements shall be such that leakage of water into the electrical equipment located below the bulkhead deck will not cause the door to open.

• (h) the power operating or control system of a power-operated sliding watertight door shall comply with the following provisions-

  • (i) a single electrical failure in the power operating or control system of a power-operated sliding watertight door shall not result in a closed door opening;

  • (ii) the availability of the power supply should be continuously monitored at a point in the electrical circuit as near as practicable to each of the motors required by section 4.15(7); and

  • (iii) the loss of any such power supply should activate an audible and visual alarm at the central operating console at the navigation bridge.

(8) The central operating console at the navigation bridge shall comply with the following provisions-

• (a) it shall have a "master mode" switch with two modes of control as follows-

  • (i) a "local control" mode which shall allow any door to be locally opened and locally closed after use without automatic closure; and

  • (ii) a "doors closed" mode which shall automatically close any door that is open;

• (b) the "doors closed" mode shall-automatically close any door that is open and permit doors to be opened locally and shall automatically re-close the doors upon release of the local control mechanism.

• (c) the "master mode" switch shall normally be in the "local control" mode.

• (d) the "doors closed" mode shall only be used in an emergency or for testing purposes; and

• (e) special consideration shall be given to the reliability of the "master mode" switch.

• (f) the console shall be-

  • (i) be provided with a diagram showing the location of each door, with visual indicators to show whether each door is open or closed;

  • (ii) be fitted with a red light indicating that a door is fully open and a green light indicating that door is fully closed and when a door is closed remotely the red indicating light shall indicate the intermediate position by flashing,

• (g) the indicating circuit shall be independent of the control circuit for each door; and

• (h) it shall not be possible to remotely open any door from the central operating console.

(9) If the Administration is satisfied that the fitting of watertight doors in watertight bulkheads dividing storage between deck spaces is essential then such doors, of satisfactory construction, may be fitted in accordance with the following provisions-

• (a) such doors may be hinged, rolling or sliding doors but shall not be remotely controlled;

• (b) they shall be fitted at the highest level and as far from the shell plating as practicable, but in no case shall the outboard vertical edges be situated at a distance from the shell plating which is less than one fifth of the breadth of the ship, as defined in section 1.3, such distance being measured at right angles to the centreline at the level of the deepest subdivision draught;

• (c) should any such doors be accessible during the voyage, they shall be fitted with a device which prevents unauthorised opening; and

• (d) when it is proposed to fit such doors, the number and arrangements shall receive the special consideration of the Administration.

(10) Portable plates on bulkheads shall not be permitted except in machinery spaces and where they are permitted shall be subject to the following conditions-

• (a) the Administration may permit not more than one power-operated sliding watertight door in each watertight bulkhead larger than those specified in section 4.15(7)(a)(ii) to be substituted for these portable plates, provided these doors are intended to remain closed during navigation except in case of urgent necessity at the discretion of the master; and

• (b) such doors need not meet the requirements of section 4.15(7)(a)(iv) regarding complete closure by hand-operated gear in 90 seconds.

(11) Where trunkways or tunnels for access from crew accommodation to other spaces, for piping, or for any other purpose are carried through watertight bulkheads, they shall be comply with the following provisions-

• (a) they shall watertight and in accordance with the requirements of section 4.18;

• (b) the access to at least one end of each such tunnel or trunkway, if used as a passage at sea, shall be through a trunk extending watertight to a height sufficient to permit access above the bulkhead deck;

• (c) the access to the other end of the trunkway or tunnel may be through a watertight door of the type required by its location in the ship;

• (d) such trunkways or tunnels shall not extend through the first subdivision bulkhead abaft the collision bulkhead;

• (e) where it is proposed to fit tunnels piercing watertight bulkheads, these shall receive the special consideration of the Administration; and

• (f) where trunkways in connection with refrigerated spaces and ventilation or forced draught trunks are carried through more than one watertight bulkhead, the means of closure at such openings shall be operated by power and be capable of being closed from a central position situated above the bulkhead deck.