The principal extinguishing agent should be: a) a foam meeting the minimum performance level A; or b) a foam meeting the minimum performance level B; or c) a foam meeting the minimum performance level C; or d) a combination of these agents.
Both principal and complementary agents should normally be provided at an airport. Principal agents produce a permanent control, i.e. for a period of several minutes or longer. Complementary agents have rapid fire suppression capability but offer a “transient” control which is usually only available during application.
