All gate valves within paved areas and all butterfly valves shall be constructed within an I.D.O.T. Type A valve vault with steps. Valve vaults on butterfly valves shall have offset cones. Frames shall be heavy duty Type 1 and shall be embossed with the word "Water". The Director of Public Works may require the installation of a one-inch corporation cock within certain valve vaults on the water mains for purposes of future flow gauging.