What type of valve is specially designed gate valve used to connect a new water main to an existing main under pressure?

• A. Globe valve
• B. Check valve
• C. Ball valve
• D. Tapping valve

Answer: (D)

When adding a new main to an existing pressurized water main, you need a valve that is designed for live tapping. A tapping valve is built to be installed on a live, under-pressure line and used with a tapping device to create a branch off the main without shutting it down. It allows a controlled piercing or connection to the existing pipe, enabling the new line to be extended while the system remains pressurized and isolated as needed after the connection is made.

Other valves serve different primary purposes: a globe valve mainly regulates flow, a check valve prevents backflow, and a ball valve provides a quick shutoff without facilitating the tapping operation. The tapping valve specifically enables the connection to a live main, which is why it is the correct choice.