Glossary Term
AFFF Foam System
An AFFF foam system is a firefighting system that uses aqueous film-forming foam concentrate mixed with water to produce foam for flammable-liquid fire protection. IMO foam guidance defines aqueous film-forming foam concentrate as a mixture based on hydrocarbon and fluorinated surface active agents, and the FSS Code framework treats foam concentrates, proportioning, discharge equipment, compatibility, testing, and sampling as integral parts of the system rather than separate accessories.
On yachts, the term is most likely to appear around machinery-space protection, fuel-handling risks, helideck arrangements on applicable vessels, or portable and semi-fixed firefighting packages discussed in older specifications. The key technical points are proportioning accuracy, approved concentrate type, material compatibility, flushing and sampling arrangements, and whether the installed system was tested and approved with the foam actually carried on board. Different concentrate types are not meant to be mixed casually, and foam quality control is part of the maintenance burden.
There is also a current replacement issue. DNV and LR state that, from 1 January 2026, SOLAS amendments prohibit the use or storage of fire-extinguishing media containing PFOS, including firefighting foams, with compliance tied to delivery for new ships and to the first relevant survey for existing ships after that date. So on older yachts, an “AFFF foam system” may now trigger a compatibility and compliance review rather than a simple refill.