Fouress specialized Butterfly valves are installed to protect hydro-electric installations against the possibility of penstock rupture. These valves are designed to close against turbine runaway during an emergency condition. These valves act as isolating devices for inspection of penstock without dewatering entire head race tunnel.

Another important application of Fouress Butterfly valves is for large water supply schemes fed from reservoirs through long pipelines, failure of which can cause disastrous floods. Fouress valves, by virtue of their design and robust construction, close down automatically and instantaneously in the event of the downstream pipeline failure. These valves close during over velocity condition occurring due to turbine trip or runaway condition. Further, these special design Butterfly Valves can also be used for turbine inlet application also.

Spherical Valves are used for the same application when high heads are encountered