Regulation 22 - Scuppers, inlets and discharges
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Conventions - Load Lines, 1966/1988 - International Convention on Load Lines, 1966, as Amended by the Protocol of 1988 - Annex I - Regulations for Determining Load Lines - Chapter II - Conditions of Assignment of Freeboard - Regulation 22 - Scuppers, inlets and discharges

Regulation 22 - Scuppers, inlets and discharges

  (1)

  • (a) Discharges led through the shell either from spaces below the freeboard deck or from within superstructures and deckhouses on the freeboard deck fitted with doors complying with the requirements of regulation 12 shall, except as provided in paragraph (2), be fitted with efficient and accessible means for preventing water from passing inboard. Normally each separate discharge shall have one automatic non-return valve with a positive means of closing it from a position above the freeboard deck. Where the inboard end of the discharge pipe is located at least 0.01L above the Summer Load Line, the discharge may have two automatic non-return valves without positive means of closing. Where that vertical distance exceeds 0.02L, a single automatic non-return valve without positive means of closing may be accepted. The means for operating the positive action valve shall be readily accessible and provided with an indicator showing whether the valve is open or closed.

  • (b) One automatic non-return valve and one sluice valve controlled from above the freeboard deck instead of one automatic non-return valve with a positive means of closing from a position above the freeboard deck, is acceptable.

  • (c) Where two automatic non-return valves are required, the inboard valve shall always be accessible for examination under service conditions (i.e., the inboard valve shall be above the level of the Tropical Load Line). If this is not practicable, the inboard valve need not be located above the Tropical Load Line, provided that a locally controlled sluice valve is fitted between the two automatic non-return valves.

  • (d) Where sanitary discharges and scuppers lead overboard through the shell in way of machinery spaces, a locally operated positive closing valve at the shell, together with a non-return valve inboard, is acceptable. The controls of the valves shall be in an easily accessible position.

  • (e) The position of the inboard end of discharges shall be related to the Summer Timber Load Line when a timber freeboard is assigned.

  • (f) The requirements for non-return valves are applicable only to those discharges which remain open during the normal operation of a ship. For discharges which are to be kept closed at sea, a single screw down valve operated from the deck is acceptable.

  • (g) Table 22.1 provides the acceptable arrangements of scuppers, inlets and discharges.

Table 22.1

  (2) Scuppers led through the shell from enclosed superstructures used for the carriage of cargo shall be permitted only where the edge of the freeboard deck is not immersed when the ship heels 5 either way. In other cases the drainage shall be led inboard in accordance with the requirements of the International Convention for the Safety of Life at Sea in force.

  (3) In manned machinery spaces, main and auxiliary sea inlets and discharges in connection with the operation of machinery may be controlled locally. The controls shall be readily accessible and shall be provided with indicators showing whether the valves are open or closed.

  (4) Scuppers and discharge pipes originating at any level and penetrating the shell either more than 450 mm below the freeboard deck or less than 600 mm above the Summer Load Line shall be provided with a non-return valve at the shell. This valve, unless required by paragraph (1), may be omitted if the piping is of substantial thickness (see paragraph (7) below).

  (5) Scuppers leading from superstructures or deckhouses not fitted with doors complying with the requirements of regulation 12 shall be led overboard.

  (6) All shell fittings and the valves required by this regulation shall be of steel, bronze or other approved ductile material. Valves of ordinary cast iron or similar material are not acceptable. All pipes to which this regulation refers shall be of steel or other equivalent material to the satisfaction of the Administration.

  (7) Scupper and discharge pipes:

  • (a) For scupper and discharge pipes, where substantial thickness is not required:

    • (i) for pipes having an external diameter equal to or less than 155 mm, the thickness shall not be less than 4.5 mm;

    • (ii) for pipes having an external diameter equal to or more than 230 mm, the thickness shall not be less than 6 mm.

  • Intermediate sizes shall be determined by linear interpolation.

  • (b) For scupper and discharge pipes, where substantial thickness is required:

    • (i) for pipes having an external diameter equal to or less than 80 mm, the thickness shall not be less than 7 mm;

    • (ii) for pipes having an external diameter of 180 mm, the thickness shall not be less than 10 mm;

    • (iii) for pipes having an external diameter equal to or more than 220 mm, the thickness shall not be less than 12.5 mm.

  • Intermediate sizes shall be determined by linear interpolation.


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