What type of valve is used on a hydro test tree to maintain test pressure after the hydro has reached its required pressure?

• A. Gate
• B. Ball
• C. Check
• D. Globe

Answer: (C)

The essential idea is one-way flow control to keep the test pressure from dropping once the target hydro pressure is reached. A check valve does exactly that: it allows fluid to flow into the test line to build pressure, then automatically closes to stop flow in the reverse direction. That prevents the test fluid from leaking back through the hydro test tree, so the system can hold the required pressure with minimal leakage.

Gate valves and globe valves are better for isolating or throttling flow, but they don’t inherently prevent backflow, which is why they’re not used to maintain the pressure in this scenario. A ball valve provides quick shut-off but isn’t designed to maintain a pressurized condition over time.