Doors in Watertight Bulkheads of Passenger Ships and Cargo Ships

 For the purpose of this interpretation the following definitions apply:

  1.1 Watertight: Capable of preventing the passage of water in any direction under a design head. The design head for any part of a structure should be determined by reference to its location relative to the bulkhead deck or freeboard deck, as applicable, or to the most unfavourable equilibrium/intermediate waterplane, in accordance with the applicable subdivision and damage stability regulations, whichever is the greater. A watertight door is thus one that will maintain the watertight integrity of the subdivision bulkhead in which it is located.

  1.2 Equilibrium waterplane: The waterplane in still water when, taking account of flooding due to an assumed damage, the weight and buoyancy forces acting on a ship are in balance. This relates to the final condition when no further flooding takes place or after cross flooding is completed.

  1.3 Intermediate waterplane: The waterplane in still water, which represents the instantaneous floating position of a ship at some intermediate stage between commencement and completion of flooding when, taking account of the assumed instantaneous state of flooding, the weight and buoyancy forces acting on a ship are in balance.

  1.4 Sliding door or rolling door: A door having a horizontal or vertical motion generally parallel to the plane of the door.

  1.5 Hinged door: A door having a pivoting motion about one vertical or horizontal edge.

 Doors and their frames should be of approved design and substantial construction in accordance with the requirements of the Administration and should preserve the strength of the subdivision bulkheads in which they are fitted.

 Doors should be fitted in accordance with all requirements regarding their operation mode, location and outfitting, i.e. provision of controls, means of indication, etc., as shown in table 1 below. This table should be read in conjunction with paragraphs 3.1 to 5.4 below.

  3.1 Frequency of use whilst at sea

  3.1.1 Normally closed: Kept closed at sea but may be used if authorized. To be closed again after use.

  3.1.2 Permanently closed: The time of opening such doors in port and of closing them before the ship leaves port should be entered in the logbook. Should such doors be accessible during the voyage, they should be fitted with a device to prevent unauthorized opening.

  3.1.3 Normally open: May be left open provided it is always ready to be immediately closed.

  3.1.4 Used: In regular use, may be left open provided it is ready to be immediately closed.

  3.2 Type

  3.3 Control

  3.3.1 Local

  3.3.1.1 All doors, except those which should be permanently closed at sea, should be capable of being opened and closed by hand locally^footnote, from both sides of the doors, with the ship listed to either side.

  3.3.1.2 For passenger ships, the angle of list at which operation by hand should be possible is 15º or 20º if the ship is allowed to heel up to 20º during intermediate stages of flooding.

  3.3.1.3 For cargo ships, the angle of list at which operation by hand should be possible is 30º.

  3.3.2 Remote

 Where indicated in table 1, doors should be capable of being remotely closed by power from the bridge^footnote. Where it is necessary to start the power unit for operation of the watertight door, means to start the power unit is also to be provided at remote control stations. The operation of such remote control should be in accordance with SOLAS regulations II-1/13.8.1 to 13.8.3.

  3.4 Indication

  3.4.1 Where shown in table 1, position indicators should be provided at all remote operating positions^footnote as well as locally, on both sides of the doors^footnote, to show whether the doors are open or closed and, if applicable, with all dogs/cleats fully and properly engaged.

  3.4.2 The door position indicating system should be of self-monitoring type and the means for testing of the indicating system should be provided at the position where the indicators are fitted.

  3.4.3 An indication (i.e. red light) should be placed locally showing that the door is in remote control mode ("doors closed mode"). Refer also to SOLAS regulation II-1/15-8.1. Special care should be taken in order to avoid potential danger when passing through the door. Signboard/instructions should be placed in way of the door advising how to act when the door is in "doors closed" mode.

  3.5 Alarms

  3.5.1 Doors which should be capable of being remotely closed should be provided with an audible alarm, distinct from any other alarm in the area, which will sound whenever such a door is remotely closed. For passenger ships the alarm should sound for at least 5 s but not more than 10 s before the door begins to move and should continue sounding until the door is completely closed. In the case of remote closure by hand operation, an alarm is required to sound only while the door is actually moving.

  3.5.2 In passenger areas and areas of high ambient noise, the audible alarms should be supplemented by visual signals at both sides of the doors.

  3.6 Notices

 As shown in table 1, doors which are normally closed at sea, but are not provided with means of remote closure, should have notices fixed to both sides of the doors stating: "To be kept closed at sea". Doors which should be permanently closed at sea should have notices fixed to both sides stating: "Not to be opened at sea".

  3.7 Location

 For passenger ships the watertight doors and their controls should be located in compliance with SOLAS regulations II-1/13.5.3 and II-1/13.7.1.2.2.

  4.1 Watertight doors may also serve as fire doors but need not be fire tested when intended for use below the bulkhead deck. Where such doors are used at locations above the bulkhead deck they should, in addition to complying with the provisions applicable to fire doors at the same locations, also comply with means of escape provisions of SOLAS regulation II-2/13.

  4.2 Where a watertight door is located adjacent to a fire door, both doors should be capable of independent operation, remotely if required by SOLAS regulations II-1/15.8.1 to 15.8.3 and from both sides of each door.

  5.1 Doors which become immersed by an equilibrium or intermediate waterplane or are below the freeboard or bulkhead deck should be subjected to a hydrostatic pressure test.

  5.2 For large doors intended for use in the watertight subdivision boundaries of cargo spaces, structural analysis may be accepted in lieu of pressure testing. Where such doors utilize gasket seals, a prototype pressure test to confirm that the compression of the gasket material is capable of accommodating any deflection, revealed by the structural analysis, should be carried out.

  5.3 Doors above freeboard or bulkhead deck, which are not immersed by an equilibrium or intermediate waterplane but become intermittently immersed at angles of heel in the required range of positive stability beyond the equilibrium position should be hose tested.

  5.4 Pressure testing

  5.4.1 The head of water used for the pressure test should correspond at least to the head measured from the lower edge of the door opening, at the location in which the door should be fitted in the ship, to the bulkhead deck or freeboard deck, as applicable, or to the most unfavourable damage waterplane, if that be greater. Testing may be carried out at the factory or other shore-based testing facility prior to installation in the ship.

  5.4.2 Leakage criteria

  5.4.2.1 The following acceptable leakage criteria should apply:

  5.4.2.2 Limited leakage may be accepted for pressure tests on large doors located in cargo spaces employing gasket seals or guillotine doors located in conveyor tunnels, in accordance with the following^footnote:

  5.4.2.3 However, in the case of doors where the water head taken for the determination of the scantling does not exceed 6.1 m, the leakage rate may be taken equal to 0.375 l/min if this value is greater than that calculated by the above-mentioned formula.

  5.4.3 For doors of passenger ships which are normally open and used at sea and which become submerged by the equilibrium or intermediate waterplane, a prototype test should be conducted, on each side of the door, to check the satisfactory closing of the door against a force equivalent to a water height of at least 1 m above the sill on the centre line of the door^footnote.

  5.5 Hose testing after installation

 All watertight doors should be subject to a hose test^footnote after installation in a ship. Hose testing should be carried out from each side of a door unless, for a specific application, exposure to floodwater is anticipated only from one side. Where a hose test is not practicable because of possible damage to machinery, electrical equipment insulation, or outfitting items, it may be replaced by means such as an ultrasonic leak test or an equivalent test.