1.1 These requirements cover vane type waterflow indicators intended for use in fire protective signaling systems to be employed in ordinary indoor locations, in accordance with the National Fire Alarm Code, NFPA 72.

1.2 Waterflow indicators covered by these requirements include sizes 3/4 inch and larger. The indicator sizes refer to the nominal inside diameter of the main sprinkler pipe or tubing on which they are installed.

1.3 A vane type waterflow indicator is an assembly of a mechanism having electrical contacts arranged to transmit a coded or noncoded signal when the vane, located in the supply pipe (riser) of a sprinkler system, is moved by the flow of water in the pipe. This flow is normally caused by the opening of one or more sprinkler heads resulting from a fire condition. The signaling contacts are intended to be connected to circuits of private fire protective signaling systems.

1.4 These requirements do not cover pressure-operated waterflow indicators.