Variations
Fog nozzles come in many in different styles and sizes, but there are three types which encompass most: automatic, selectable, and manually adjustable. All contain an adjustable baffle that, like a thumb placed on the end of a garden hose, keeps their flow rates and stream reaches steady and finely adjustable despite variations in water pressure at the nozzle. To adjust the flow, the first two types use a control handle, or 'bale' located at the top of nozzle; however, selectable nozzles have a fixed set of flow rates (e.g., 60, 95, and 125 GPM) that are chosen with a ring or bezel located at their tips. It is important to note that selectable nozzles will only flow if the pump pressure exceeds the nozzle pressure. Moreover, the selectable nozzle will change its nozzle pressure and reach as the handle is moved, but the automatic nozzle will automatically re-adjust its opening as the firefighter adjusts its flow rate in order to maintain the correct pressure.
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