Overview
ISO 8099-1:2018 - Small craft - Waste systems - Part 1: Waste water retention - specifies requirements for the design, construction and installation of temporary sewage retention systems on small craft (length of hull up to 24 m). The standard focuses on holding tanks, plumbing, vents, fittings and testing for safe, odor- and leak‑free retention and subsequent disposal. It does not address waste water treatment systems.
Key topics and technical requirements
- Scope and definitions: Applies to small craft up to 24 m LH; defines retention system, sewage, holding tank and portable holding tank.
- System layout: Every toilet must connect solely to a holding tank; Y‑valves between toilet and tank are not permitted.
- Materials: Components must resist sewage, fresh/salt/brackish water (including impurities and bilge oil), disinfectants, deodorants, antifreeze and recommended cleaning agents.
- Plumbing and hoses:
- Pipes and hoses should be smooth (no convolutions) and securely fastened.
- Minimum inside diameter between toilet and tank: manufacturer’s recommendation or 38 mm if unspecified.
- Through‑hull fittings for overboard discharge require seacocks compliant with ISO 9093‑1/2 and must be able to be secured closed.
- Vent system:
- Venting to exterior must function at heel angles up to 20° (at 90% tank capacity).
- Fittings’ inside diameters must be at least 75% of the vent pipe’s diameter.
- Venting must minimize clogging and resist a negative pressure of 20 kPa.
- Vent size rules: rigid tanks <400 L - min 19 mm (or smaller with relief valve meeting area requirements); rigid tanks ≥400 L - min 38 mm (or equivalent multiple vents or relief valve).
- Holding tanks:
- Secure fastening independent of piping.
- Level indication (observable at 3/4 full) or equivalent.
- Tanks >40 L require an accessible, sealable 75 mm minimum opening for cleaning.
- Tanks must not share walls with fuel or potable water tanks.
- Permanently installed tanks must allow removal of at least 90% of contents via pump‑out fitting; baffles must permit free flow.
- Performance and testing:
- Retention systems must operate from +1 °C to +60 °C and withstand –40 °C to +60 °C when empty.
- Pressure test: 20 kPa for 5 minutes without leaks; tanks must withstand –20 kPa for 5 minutes without permanent deformation.
- Electrical requirements: Conform to ISO 10133 and ISO 13297 where applicable.
Applications and users
ISO 8099-1:2018 is intended for:
- Boat designers and naval architects specifying sewage retention on small craft
- Manufacturers of holding tanks, toilets, hoses, seacocks and pump‑out fittings
- Installers, boatyards and surveyors evaluating compliance and safe installation
- Marinas and reception facilities implementing compatible pump‑out interfaces
Practical uses include design validation, compliance checking, component selection, and preparing owner’s manuals and maintenance procedures.
Related standards
Keywords: ISO 8099-1:2018, small craft waste systems, waste water retention, holding tanks, venting, pump-out fitting, seacock, marine sewage standards.