Section 3 System arrangements

3.1.1 The installation and arrangements of systems and equipment are to recognise the manufacturer's recommendations for the effective functioning of waste systems.

3.1.2 The arrangements for waste systems are to be such that they are capable of operating under all normal angles of heel and trim.

Normal angles of heel and trim are to be taken as:

1. Ship on an even keel or has a list of not more than 5°.

2. Ship on even trim or is trimmed not more than 5° for a ship up to 100 m in length. Where the length of the ship exceeds 100 m, the maximum trim may be taken as 500/L degrees where L = length of ship, in metres.

3. The angles of heel and trim may occur simultaneously.

3.1.3 The piping system design for waste systems is to incorporate adequate fall and flow arrangements which exclude traps unless specifically required for system operation/cleaning. The determination of adequacy of fall and flow is to be made with reference to a suitable and proven design standard.

3.1.4 The piping system arrangements are to be such that they are capable of being cleaned and unblocked.

3.1.5 The processing/storage capacity of waste systems is to take into account the operational profile of the ship and its complement. For example, the ship may spend a prolonged period of time in littoral waters where sewage discharge overboard, treated or untreated, is prohibited by the relevant national authority and, therefore, adequate holding capacity may need to be provided.

3.1.6 The waste systems are to be of sufficient capacity to handle peak flows in addition to an average flow. Typically, peak flows can be three times the average hourly flow but this should be confirmed during the design stage.

3.1.7 Variations in the complement of the ship are to be taken into account but the system must be capable of satisfactory operation with the minimum number of persons on board when the ship is at sea.

3.1.8 If only one sewage treatment plant is fitted then arrangements are to be provided to allow essential maintenance work to be undertaken on this plant whilst retaining full use of the remainder of the sewage and waste water system.

3.1.9 Drains from medical facilities are to be led to the black water side of the sewage treatment plants or holding tanks.

3.1.10 Vents from wastes systems are to terminate outside the vessel. However, where a vessel is required to be capable of operating within an CBRN threat area, then these vents are to be capable of being reconfigured to vent inside the citadel via charcoal filters.

3.1.11 Overboard discharges are to be arranged such that they are clear of accommodation ladders, areas where boats are loaded/unloaded, etc.

3.1.12 Arrangements are to be made for the disposal of oily wastes stemming from food preparation in galleys. Systems intended for the disposal of such oily wastes are to be separate from other waste systems. Suitable notices are to be provided advising that oily wastes are not to be disposed of.