ISO 15749-4:2004 - Overview
ISO 15749-4:2004 is the International Standard that specifies requirements for the design of sewage disposal pipes as part of sanitary drainage systems on ships and marine structures. It focuses on routing, fittings and closing devices for wastewater disposal - including discharge overboard, discharge via storage units (collector tanks, sewage treatment plants, vacuum units), bypass lines and shore connections. For planning and basic sanitary drainage requirements, the standard refers to ISO 15749-1.
Key topics and technical requirements
- Scope of disposal methods: distinguishes disposal via storage units (pressure lines) and direct gravity discharge over the side.
- Disposal piping design: disposal lines from storage units are treated as pressure lines and must include appropriate pumps and non-return devices.
- Closing devices at the shell: requirements for screw-down non-return valves, gate/shutoff valves, self-closing non-return fittings and remote-operable closures with position indicators. Closing devices must be certified by classification societies.
- Location-dependent arrangements: specific configurations depend on vertical distance F (drain inner opening) relative to ship length L; different arrangements are specified for ranges of F (e.g., up to 0.01L, 0.01–0.02L, over 0.02L).
- Passenger ship rules & list considerations: additional safeguards apply (e.g., when lowest openings are less than 200 mm above summer loadline under a 5° list, or when drains lie at or below waterline). Pipe loops with crest heights (≥ 200 mm above waterline) can be used as second non-return fittings.
- Bypass lines: gravity system bypass lines must include shutoff gate valves and additional closing devices; they should feed into disposal pipes as close to shell closing fittings as possible.
- Shore discharge: wastewater discharge connections must use the international wastewater shore connection (MARPOL flange). Type N steel pipe wall thickness is acceptable for disposal piping.
- Pipework and materials: references and material specifications are provided via normative references (e.g., ISO 4200, ISO 9329-1, ISO 9330-1).
Practical applications and users
Who uses ISO 15749-4:
- Naval architects and ship designers specifying sanitary drainage and sewage disposal pipes
- Marine engineers and shipyards installing pipework and closing devices
- Classification societies and surveyors verifying compliance
- Ship operators and operators of marine structures ensuring safe wastewater discharge and MARPOL compatibility
Practical benefits:
- Prevents backflow and flooding from wastewater outlets
- Ensures safe overboard discharge and shore-transfer compatibility
- Supports design choices that meet stability, safety and regulatory requirements
Related standards
Keywords: ISO 15749-4, sanitary drainage, sewage disposal pipes, ships and marine technology, wastewater disposal, marine structures, MARPOL flange, non-return valve, bypass line, closing devices.
Open preview (PDF)Ships and marine technology — Drainage systems on ships and marine structures — Part 4: Sanitary drainage, sewage disposal pipes
