6.6 Draining of dry spaces other than cargo holds and machinery spaces

6.6.1 General

1. Except where otherwise specified, bilge suctions are to be branch bilge suctions, i.e. suctions connected to a bilge main.
2. Draining arrangements of tanks are to comply with the provisions of [7].

6.6.2 Draining of cofferdams

1. All cofferdams are to be provided with suction pipes led to the bilge main.
2. Where cofferdams are divided by longitudinal watertight bulkheads or girders into two or more parts, a single suction pipe led to the aft end of each part is acceptable.

6.6.3 Draining of fore and aft peaks

1. Where the peaks are not used as tanks and bilge suctions are not fitted, drainage of both peaks may be effected by hand pump suction provided that the suction lift is well within the capacity of the pump and in no case exceeds 7,3 m.
2. Except where permitted in [5.3.3], the collision bulkhead is not to be pierced below the freeboard deck.
3. For tankers, see Pt E, Ch 7, Sec 4, [2.1.4].
4. For bulk carriers, the water level detector giving an audible and visual alarm located on the navigation bridge, shall be fitted:
   • In any ballast tank forward of the collision bulkhead, indicating when the liquid in the tank reaches a level not exceeding 10% of the tank capacity. An alarm overriding device may be installed to be activated when the tank is in use.
   • In any dry or void space other than a chain cable locker and any part of which extends forward of the foremost cargo hold, bulkhead shall be fitted with the water level detector giving the alarm at a water level of 0,1 m above the deck. Such alarms need not be provided in enclosed spaces the volume of which does not exceed 0,1% of the ship's maximum displacement volume.
5. On bulk carriers, the bilge of dry spaces any part of which extends forward of the foremost cargo hold, as well as the means for draining and pumping ballast tanks forward of the collision bulkhead, shall be capable of being brought into operation from a readily accessible enclosed space, the location of which is accessible from the navigation bridge or propulsion machinery control position without traversing exposed freeboard or superstructure decks.
   The capacity of the dewatering system is to be designed to remove water from the forward spaces at a rate of not less than (320A) m³/h, where A is the cross-sectional area, in m², of the largest air pipe or ventilator pipe connected from the exposed deck to a closed forward space that is required to be dewatered by these arrangements.
   Where pipes serving such tanks or bilge pierce the collision bulkhead, valve operation by means of remotely operated actuators may be accepted as an alternative to the valve control specified in [5.3.3], provided that the location of such valve controls complies with this regulation. For that purpose, following shall be fulfilled:
   • The valve specified in [5.3.3] is to be capable of being controlled from the navigation bridge, the propulsion machinery control position or enclosed space which is readily accessible from the navigation bridge or the propulsion machinery control position without travelling exposed freeboard or superstructure decks. In this context, a position which is accessible via an under deck passage, a pipe trunk or other similar means of access is not to be taken as being in the accessible enclosed space
   • The valve is not to move from the demanded position in the case of failure of the control system power or actuator power
   • Positive indication is to be provided at the remote control station to show that the valve is fully open or closed
   • In addition, the local hand powered valve operation from above the freeboard deck is also to be provided
   • The drainage arrangements are to be such that any accumulated water can be drained directly by a pump or eductor
   • The drainage arrangements are to be such that when they are in operation, other systems essential for the safety of the ship including fire-fighting and bilge systems remain available and ready for immediate use. The systems for normal operation of electric power supplies, propulsion and steering should not be affected by the operation of the drainage systems. It must also be possible to immediately start fire pumps and have a ready available supply of fire-fighting water and to be able to configure and use bilge system for any compartment when the drainage system is in operation
   • Bilge wells are to be provided with gratings or strainers that will prevent blockage of the drainage system with debris
   • The spaces where availability of pumping systems is required should be the same watertight spaces where water level detectors are required in d)
   • Where the piping arrangements for drainage of closed dry spaces are connected to the piping arrangements for the drainage of water ballast tanks, two non-return valves are to be provided to prevent the ingress of water into dry spaces from those intended for the carriage of water ballast. One of these non-return valves is to be fitted with shut-off isolation arrangement
   • The non-return valves are to be located in readily accessible positions
   • The shut-off isolation arrangement is to be capable of being controlled from the navigation bridge, the propulsion machinery control position or enclosed space which is readily accessible from the navigation bridge or the propulsion machinery control position without travelling exposed freeboard or superstructure decks. In this context, a position which is accessible via an under deck passage, a pipe trunk or other similar means of access is not to be taken as being in the accessible enclosed space.
   The above specified requirement does not apply to the enclosed spaces the volume of which does not exceed 0,1% of the ship maximum displacement volume and to the chain locker.

6.6.4 Draining of spaces above fore and aft peaks

1. Provision is to be made for the drainage of the chain lockers and watertight compartments above the fore peak tank by hand or power pump suctions.
2. Steering gear compartments or other small enclosed spaces situated above the aft peak tank are to be provided with suitable means of drainage, either by hand or power pump bilge suctions. However, in the case of rudder stock glands located below the summer load line, the bilge suctions of the steering gear compartment are to be connected to the main bilge system.
3. If the compartments referred to in b) are adequately isolated from the adjacent "tweendecks, they may be drained by scuppers discharging to the tunnel (or machinery space in the case of ships with machinery aft) and fitted with self-closing cocks situated in well-lighted and visible positions.
   Note 1 : This arrangement is not applicable to ships required to comply with [5.5], and in particular to passenger ships, unless they are specially approved in relation to subdivision.

6.6.5 Draining of tunnels

1. Tunnels are to be drained by means of suctions connected to the main bilge system. Such suctions are generally to be located in wells at the aft end of the tunnels.
2. Where the top of the double bottom, in the tunnel, slopes down from aft to forward, an additional suction is to be provided at the forward end of this space.

6.6.6 Draining of refrigerated spaces
Provision is to be made for the continuous drainage of condensate in refrigerated and air cooler spaces. To this end, valves capable of blanking off the water draining lines of such spaces are not to be fitted, unless they are operable from an easily accessible place located above the load waterline.