Definition(s)
High-Expansion Foam Fire-Extinguishing Systems
High-expansion foam fire-extinguishing systems are fixed total flooding extinguishing systems that use either inside air or outside air for aeration of the foam solution. A high-expansion foam system consists of both the foam generators and the dedicated foam concentrate approved during the fire testing specified in 3.1.3. <fixed foam fire-extinguishing systems>.
Source: IMO Resolution MSC.327(90), amendments to the International Code for Fire Safety Systems, 25 May 2012, International Maritime Organization. Regulatory Guidance