Which valve type is commonly used for main isolation due to low leakage?

Which valve type is commonly used for main isolation due to low leakage?

• A. Ball valve.
• B. Globe valve.
• C. Butterfly valve.
• D. Gate valve.

Answer: (D)

When you need to isolate a main line, the priority is a tight shutoff with minimal leakage. Gate valves achieve this by moving a solid gate straight into the seats, creating a strong seal that blocks the flow path when fully closed. This design provides very low leakage under pressure and is well-suited for large-diameter, high-pressure piping typical of main isolation. They are not meant for throttling, so once closed, they maintain a reliable, tight seal. In contrast, throttling-focused designs like globe valves leave paths for leakage even when shut, and butterfly valves and ball valves, while capable of tight shutoffs, are not as routinely used for large main isolation in naval systems.

When you need to isolate a main line, the priority is a tight shutoff with minimal leakage. Gate valves achieve this by moving a solid gate straight into the seats, creating a strong seal that blocks the flow path when fully closed. This design provides very low leakage under pressure and is well-suited for large-diameter, high-pressure piping typical of main isolation. They are not meant for throttling, so once closed, they maintain a reliable, tight seal. In contrast, throttling-focused designs like globe valves leave paths for leakage even when shut, and butterfly valves and ball valves, while capable of tight shutoffs, are not as routinely used for large main isolation in naval systems.