Section 7 Pipe systems and their fittings

7.1.1 The arrangement of valves, cocks and their connections is to be such as to prevent the possibility of one watertight compartment being placed in communication with another or machinery spaces or other dry compartments being placed in communication with the sea or with tanks. For this purpose, screw-down non-return valves are to be provided in the following fittings:

• Bilge and dewatering valve distribution chests.
• Bilge suction hose connections, whether fitted direct to the pump or on the main suction line.
• Direct bilge and dewatering suctions and bilge pump or eductor connections to main suction lines.

7.1.2 The valves and controls required for the drainage arrangements necessary for complying with Vol 2, Pt 7, Ch 2, 3.1 General 3.1.2 and Vol 2, Pt 7, Ch 2, 4.1 General 4.1.2 are to be capable of being operated from the damage control deck.

7.1.3 All valves and cocks mentioned in Vol 2, Pt 7, Ch 2, 7.1 Prevention of communication between compartments 7.1.1 and Vol 2, Pt 7, Ch 2, 7.1 Prevention of communication between compartments 7.1.1 which can be operated from the damage control deck are to have their controls at their place of operation clearly marked and provided with means to indicate whether they are open or closed.

7.2.1 Bilge and dewatering pipes which are required for draining machinery spaces are to be entirely distinct from sea inlet pipes or from pipes which may be used for filling or emptying spaces where water or oil is carried.

7.3.1 Suctions for bilge drainage and dewatering in machinery spaces and tunnels, other than emergency suctions, are to be led from easily accessible mud boxes fitted with straight tail pipes to the suction wells and having covers secured in such a manner as to permit their being expeditiously opened or closed. Strum boxes are not to be fitted to the lower ends of these tail pipes or to the emergency drainage suctions.

7.4.1 The open ends of bilge and dewatering suctions in compartments outside machinery spaces and tunnels, such as cofferdams and tanks other than those permanently arranged for the carriage of fresh water, water ballast or fuel oil and for which other efficient means of pumping are provided, are to be enclosed in strum boxes having perforations of not more than 10 mm diameter, whose combined area is not less than twice that required for the suction pipe. The boxes are to be so constructed that they can be cleared without breaking any joint of the suction pipe.

7.5.1 The distance between the foot of all bilge and dewatering tail pipes and the bottom of the suction well is to be adequate to allow a full flow of water and to facilitate cleaning.

7.6.1 Bilge and dewatering valves, cocks and mud boxes are to be fitted at, or above, the machinery space and tunnel platforms.

7.6.2 Provision is to be made to prevent the compartment served by any bilge or dewatering suction pipe being flooded in the event of the pipe being severed, or otherwise damaged by collision or grounding in any other compartment. For this purpose, a non-return valve is to be fitted to the pipe in the compartment containing the open end.

7.6.3 Where relief valves are fitted to pumps having sea connections, these valves are to be fitted in readily visible positions above the platform. The arrangements are to be such that any discharge from the relief valves will also be readily visible.

7.7.1 Bilge and dewatering suction pipes are not to led through double bottom or deep tanks if it is possible avoid doing so.

7.7.2 Expansion bends, not glands, are to be fitted to these pipes within the tanks, and the pipes are to be tested, after installation, to the same pressure as the tanks through which they pass.

7.8.1 Where non-return valves are fitted to the open ends of bilge or dewatering suction pipes in order to decrease the risk of flooding, they are to be of an approved type which does not offer undue obstruction to the flow of water.