UL 346:2019 PDF Download

The UL 346:2019 standard outlines requirements for vane type waterflow indicators used in fire protective signaling systems. These indicators are intended for installation in ordinary indoor locations, in accordance with the National Fire Alarm Code, NFPA 72.

The standard covers waterflow indicators of sizes 3/4 inch and larger, with the size referring to the nominal inside diameter of the main sprinkler pipe or tubing on which they are installed. These indicators are vane type, meaning they have a mechanism with electrical contacts that transmit a coded or noncoded signal when a vane, located in the supply pipe (riser) of a sprinkler system, is moved by the flow of water. This flow is typically initiated by the opening of one or more sprinkler heads in response to a fire condition. The signaling contacts of these indicators are designed to be connected to circuits of private fire protective signaling systems.

It is important to note that the standard does not cover pressure-operated waterflow indicators.