Gate Valves for Waterworks

Gate valves in water distribution systems act as the critical “cut-off” points along water mains, service connections, and pipelines leading to treatment plants. Their main function is to provide a reliable, on/off mechanism to completely isolate sections of the network for maintenance, repairs, or system modifications without disrupting the overall pressure and flow in the remaining network.

40″ (DN 1000) PN10 ductile iron flanged NRS gate valves, gear operation, EPDM seated, BS 5163/EN 1074-2, supplied to Umm Qasr, Iraq.

When a gate valve is fully open, its design—featuring a full-bore passage—ensures an almost unobstructed flow, which means there is minimal pressure drop. This is essential for efficient water distribution because it maintains consistent pressure across the system. In contrast, these valves are not meant for throttling or modulating flow; using them in a partially open state can lead to turbulence, vibrations, and eventual wear of the sealing surfaces.

Metal seated ductile iron gate valves made to BS 5150 & MSS SP 70 for water treatment systems, 8″ PN16, non-rising stem, flanged.

In many installations, especially where space is at a premium (like underground or buried pipelines), non‐rising stem gate valves are preferred. With a non‐rising stem, the operating mechanism remains compact because the stem stays within the valve body rather than extending vertically. Although you lose the immediate visual indication of the valve’s position (which rising stem designs provide), position indicators or markings are used to confirm whether the valve is open or closed.

Brass seated gate valves for improved corrosion & erosion resistance: Both the body and gate are weld overlaid by brass to form metal-to-metal seating surfaces.

To ensure these valves perform reliably over long service lives, Metalsin design them according to a series of rigorous international standards.

• AWWA C515 & AWWA C509: These American Water Works Association standards set performance and design criteria for resilient‐seated gate valves used in water supply systems. AWWA C515 applies to ductile iron valves with improved sealing and thinner walls validated by finite element analysis, while AWWA C509 traditionally covers resilient-seated valves made from gray cast iron.
• MSS SP 70: The Manufacturers Standardization Society’s SP 70 standard defines the construction and performance requirements for waterworks valves, ensuring that gate valves can meet the hydraulic and mechanical demands of water distribution.

Ductile iron gate valve for underground water service with a telescopic extended stem, 3″ PN10, designed to DIN 3352 F4, non-rising stem & resilient seated.

• European, BS & DIN Standards (EN 1171, EN 1074-2, BS 5163, BS 5150, DIN 3352): These standards cover aspects such as material quality, construction tolerances, and pressure ratings for gate valves in European and UK water systems. Compliance ensures that valves are manufactured to precise specifications that help maintain a leak-tight and durable design.
• AS 2638.2 & SANS 664: These standards guide the design and testing of resilient-seated gate valves for water distribution in Australia and South Africa, respectively, ensuring they can handle local environmental conditions and hydraulic loads.

Adhering to these standards guarantees that gate valves are built to withstand the cyclic stresses of isolation and reactivation, maintain a tight seal when closed, and minimize pressure loss when open. As such, these valves are indispensable in waterworks systems, ensuring that entire sections of the network can be safely isolated for maintenance or emergency response without negatively impacting system-wide operations.