Overview
ISO 8099-2:2020 - Small craft - Waste systems - Part 2: Sewage treatment systems defines requirements for the design, construction and installation of sewage treatment systems on small craft (recreational boats and similar craft up to 24 m). The standard focuses on onboard sewage treatment units and their associated plumbing, labelling and documentation. It explicitly does not cover waste retention systems, accidental pollutant (e.g. oil, fuel) discharge prevention, or specific legal discharge limits (which are subject to international and national regulations).
Key topics and technical requirements
The standard sets practical, testable requirements for marine sewage treatment systems and related components, including:
- General performance
- Operability across ambient temperatures: +1 °C to +50 °C (storage −40 °C to +60 °C).
- Operation when heeled: discharge must function at up to 20° heel for monohull sailing craft and 7° for other craft.
- Back-siphon prevention to specified heel/trim angles (30°/10° monohull; 20°/10° other craft).
- Mechanical integrity and testing
- System pressure test: 20 kPa for 5 minutes without leaking (positive and, if applicable, negative pressure).
- Materials and durability
- Materials in contact with sewage must resist a list of substances (sewage, disinfectants, bleach, engine oil, detergents, ethylene glycol, etc.) and fuel/solvent immersion tests.
- Plumbing and venting
- Hoses/pipes: smooth inner surface, securely restrained, visually accessible; toilet-to-unit piping minimum 38 mm internal diameter if manufacturer does not specify.
- Seacocks for overboard discharge to conform to ISO 9093:2020.
- Vent system: odour mitigation, self‑draining, exterior termination, and water ingress prevention.
- Safety, controls and labeling
- Visible or audible alarm for unit malfunction.
- Readily accessible means to disable discharge and secure it closed.
- Mandatory labelling: manufacturer, model/serial, “ISO 8099-2”, power, capacities, pressure/head limits, manufacture date, etc.
- Documentation
- Detailed installation, operation and maintenance manual; owner’s manual with locations of controls, seacocks, bypass valves and warnings.
- Testing and certification
- Sewage treatment units to be tested by a recognised laboratory (e.g. ISO/IEC 17025) against manufacturer-declared discharge limits.
Applications and users
ISO 8099-2:2020 is intended for:
- Manufacturers of sewage treatment systems and marine sanitation devices
- Boat builders and naval architects specifying onboard waste systems
- Marine systems installers and maintenance technicians
- Regulatory bodies, marinas and owners evaluating system compliance and safety
- Testing laboratories certifying performance vs. declared limits
Practical benefits include safer, more reliable onboard sewage handling, reduced odours and environmental compliance support when combined with applicable discharge regulations.
Related standards and references
- ISO 8099-1:2018 (Waste water retention)
- ISO 9093:2020 (Seacocks and through‑hull fittings)
- ISO 13297:2020 (Electrical systems)
- ISO/IEC 17025 (Testing laboratory competence)
- IMO MEPC resolutions, EU MED 2014/90/EU, USCG 33 CFR Part 159 (discharge limits and marine sanitation device requirements)