Widely Fitment Hot tapping machine kit works for piping, fittings and valves with NPT threads. Branch connections from 3/4″ to 4″ valve size on any appropriately sized mainline for most piping materials up to 300 psi. Product Parameters Valve Size: 3/4″ to 4″. Maximum Pressure: Chilled Water and Hot Water Systems 300 psi, Steam 15 psi. Maximum Operating Water Temperature: 250 degrees F. Pipe Materials: Mild Steel, Galvanized Steel, Stainless Steel, Copper, Brass, and Aluminum pipe. .