(2) Low-velocity fog. Using a 4-foot low-velocity water fog applicator, the fire fighter can reach over or around
obstructions to apply a cooling, smothering blanket of fog on the fire. The all-purpose nozzle, when equipped with the
applicator and fog-head, projects (FIGURE 6-4) a fog having the maximum of diffusion. The fog pattern from the fog-
head is at its most effective dimensions 5 or 6 feet from the tip of the applicator. It also precipitates and dissolves smoke
and fire products while providing a cool path advancing on the fire.
Using water in the form of low-velocity fog to put out electrically caused fires is acceptable when two portable
extinguishers have not put out the fire. It is assumed that an effort has been made to deenerqize electrical equipment;
however, research has not revealed any cases of electrocution due to the application of a low-velocity fog on shipboard
electrical fires. The primary concern when using water on an electrical fire is damage to equipment by sea water. Using
the low-velocity fog applicator speeds extinguishment, decreases the amount of water used, and minimizes the water
damage to equipment not involved in the fire.
Water in the form of a solid stream is not a preferred method of water use on board ships. It is not as efficient as fog and
can add large quantities of water to an area which must eventually be pumped out. The splashing effect of the solid
stream also tends to cause damage to surrounding equipment.
FIGURE 6-4. All-Purpose Nozzle.