A blank valve is used to relieve pressure in hose line after the discharge gates are closed.

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

Answer: (B)

Relieving pressure in a charged hose line after the discharge gates are closed is done with a drain valve. This valve provides a direct path for the water in the hose to flow out to atmosphere, allowing residual pressure to drop to zero. By opening the drain valve at the low point of the line, water drains away and the line becomes safe to handle and disconnect without sudden pressure or hose whip.

A check valve, in contrast, is meant to prevent backflow and does not drain the line. A ball valve is a shutoff that blocks or allows flow, not specifically for relieving pressure. A globe valve is used for regulating flow, not primarily for venting and draining a charged hose. Hence, the drain valve is the appropriate device for relieving pressure in this situation.