Item #4 on Drawing 1 is a ______ valve.

Item #4 on Drawing 1 is a ______ valve.

• A. Main line
• B. Riser
• C. Service
• D. In-line shutoff

Answer: (C)

The main idea is recognizing valve types by where they sit in the medical gas distribution. A service valve is placed on the branch that feeds a specific service or department and is used to isolate that service without shutting down the entire system. In the drawing, the valve shown is on the branch feeding a particular service line rather than on the main supply or on a vertical riser, so it functions as a service valve. This allows maintenance or repair to that service line while leaving the rest of the system pressurized and active. By contrast, a main line valve would shut off the whole system, a riser valve would be on the vertical feeder between floors, and an in-line shutoff would be located within a run to isolate a segment of piping rather than a branch.

The main idea is recognizing valve types by where they sit in the medical gas distribution. A service valve is placed on the branch that feeds a specific service or department and is used to isolate that service without shutting down the entire system. In the drawing, the valve shown is on the branch feeding a particular service line rather than on the main supply or on a vertical riser, so it functions as a service valve. This allows maintenance or repair to that service line while leaving the rest of the system pressurized and active. By contrast, a main line valve would shut off the whole system, a riser valve would be on the vertical feeder between floors, and an in-line shutoff would be located within a run to isolate a segment of piping rather than a branch.