5.3.9 Cargo Spaces Intended to Carry Dangerous Goods
The following requirements apply to cargo spaces intended to carry dangerous goods as defined in 4-7-1/11.25.
5.3.9(a) Independent bilge system. A bilge system, independent of the bilge system of the machinery space and located outside the machinery space, is to be provided for cargo spaces intended to carry flammable liquids with a flash point of less than 23°C or toxic liquids. The independent bilge system is to comply with the provisions of 4-6-4/3, including the provision of at least two bilge pumps. The space containing the independent bilge pumps is to be independently ventilated, giving at least six air changes per hour. This, however, does not apply to eductors located in cargo space.
5.3.9(b) Combined bilge system. As an alternative to 4-6-4/5.3.9(a) above, the cargo spaces may be served by the bilge system of the machinery space and an alternative bilge system. The alternative bilge system is to be independent of or capable of being segregated from the machinery space bilge system. The capacity of the alternative bilge system is to be at least 10 m3/h per cargo space served, but need not exceed 25 m3/h. This alternative bilge system need not be provided with redundant pumps. Whenever flammable liquids with flash point of less than 23°C or toxic liquids are carried in the cargo spaces, the bilge lines leading into the machinery space are to be blanked off or closed off by lockable valves. In addition, a warning notice to this effect is to be displayed at the location.
5.3.9(c) Gravity drain system. If the cargo spaces are drained by gravity, the drainage is to be led directly overboard or into a closed drain tank located outside machinery spaces. The drain tank is to be vented to a safe location on the open deck. Drainage from a cargo space to the bilge well of a lower cargo space is permitted only if both spaces satisfy the same requirements.