Gate Valve (OS&Y, PN16)

Gate valves are used to isolate sections of the hydrant network and pump lines. In fire systems, OS&Y (outside screw and yoke) valves are preferred because the rising stem provides a clear visual indication of open/closed status.

These valves provide full-bore flow with minimal pressure loss, making them reliable for critical fire mains. Typical installations include the main incoming supply, pump suction and discharge lines, and sectional isolations for floors or zones.

Cast iron or gunmetal bodies with corrosion-resistant trims are designed for PN10/PN16 service, and valves are cycled periodically to prevent seizing. In yards, post-indicator valves (PIV) are also used to show status from outside.