In the diagram referenced, valves #5, 6, and 13 are which type of valve?

• A. Zone valves
• B. Isolation valves
• C. Service valves
• D. Riser valves

Answer: (A)

Controlling flow to a defined area is the main idea behind zone valves. These valves are placed on the distribution lines that feed specific zones of a building, allowing you to shut off or regulate gas to that zone without affecting others. That capability is exactly what the diagram is showing for valves that serve individual zones, making them zone valves.

The other types have different roles: isolation valves are general shutoffs for larger sections, service valves provide access for testing or servicing, and riser valves regulate flow on vertical runs between floors. So they wouldn’t be used to manage per-zone distribution the way zone valves are.