Butterfly Valves

Wafer, Lug or Grooved: Picking the Right Butterfly Valve

A butterfly valve closes a line with a disc that turns a quarter of the way around on a central stem, so a lever moves it from open to shut in one motion. That makes the body shorter and lighter than a gate or globe valve of the same size, which is why these valves show up on chilled water mains, process lines and fire loops where space and weight matter.

The body style decides how it mounts. Wafer valves sit between two flanges and are held by the line bolts, while lug valves carry threaded ears so one side of the pipe can be disconnected with the other still under pressure; the KITZ ductile iron lug valve is rated 250 PSI. Grooved valves, including Gruvlok, Lansdale and Tyco models, clamp straight onto grooved pipe with couplings, and some carry a tamper switch for supervised fire protection valve service.

Sizes run from 2" up to 12". Lever handles suit the smaller sizes, while gear operators take over on larger diameters where hand force would be too much. For corrosive or chemical lines, Spears PVC and CPVC butterfly valves are Schedule 80 with EPDM seats.