Water Pressure Flow Indicator : A device installed on a sprinkler system to indicate a pressure drop resulting from the flow of water in the system, thereby giving a water flow alarm. See: Pressure Switch
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}