OS&Y Gate Valve for Fire Protection
OS&Y Fire Protection · DN50–DN300 · PN16 · Fire Service Duty
Fire systems rely on OS&Y gate valves as sectional control valves — the rising stem and lockable handwheel prove the line is open.
We supply fire-service bodies with signal options for sprinkler and hydrant networks. They are not UL or FM listed — if your specification or the fire authority requires a UL/FM listed valve, tell us at enquiry stage and we will confirm in writing what can be documented.
Key Features
Tight Isolation
Wedge-to-seat geometry gives reliable shutoff with minimal leakage.
Low Pressure Loss
Straight-through bore keeps pressure drop near zero in open position.
Rising / Non-Rising Stem
OS&Y rising stem shows open/closed at a glance; NRS suits buried service.
Resilient or Metal Seat
EPDM/NBR for water; SS316/Stellite for steam and slurry.
Bi-Directional
Wedge disc seals in both flow directions for flexible installation.
Actuator Ready
Top flange accepts gearbox, pneumatic or electric actuators.
Technical Specifications
| Parameter | Specification |
|---|---|
| Body Material | WCB / SS304 / SS316 / Ductile Iron GGG50 |
| Wedge / Disc | Solid Wedge / Flexible Wedge / Parallel Slide |
| Seat Material | Resilient (EPDM / NBR) / Metal (SS316 / Stellite) |
| Size Range | DN40 – DN1200 (1.5" – 48") |
| Pressure Rating | PN10 / PN16 (ANSI 150 / 300) |
| End Connection | Flanged (ISO 7005-2 / ASME B16.5) / Butt-Weld |
| Stem Type | Rising Stem (OS&Y) / Non-Rising Stem |
| Operation | Handwheel / Gearbox / Pneumatic / Electric |
| Temperature | Resilient: -10→+80°C ; Metal: -40→+425°C |
| Leakage | Tight shutoff, bubble-tight with resilient seat |
| Standards | Design reference: API 600 / GB/T 12234 / EN 1171 — no API monogram held (API 609 applies to butterfly valves, not gate valves) |
| Certification | ISO 9001:2015, MTC available |
How to Specify a How to Specify a OS&Y Gate Valve for Fire Protection
In fire protection the gate valve is a life-safety component. The requirements are visual position indication, a defined pressure class, and documented testing.
OS&Y is a code requirement, not a preference
Fire protection systems generally require outside-screw-and-yoke valves so the open or closed position is visible from the floor without operating the valve. A non-rising stem valve does not satisfy that intent.
Confirm the pressure class the system needs
Fire mains are typically rated higher than domestic water. State the system working pressure and whether the authority having jurisdiction requires a specific listing.
Tamper switch or supervisory signal
Where the valve supervises a system, a tamper switch reports an unauthorised closure to the fire panel. It is a separate item from the valve and should be asked for explicitly.
Raised-face or grooved ends
Fire systems use both. The valve must match the system, and the flange drilling must be stated.
Documentation is part of the product
Fire authorities ask for pressure test records and material certificates. Ask for them at order stage, not after installation.
Installation & Maintenance
Leave the stem clear of obstructions
OS&Y needs vertical clearance for the rising stem. A valve installed under a beam cannot indicate position.
Set the tamper switch after the valve is installed
Calibrating the switch before final assembly guarantees a false supervisory alarm.
Record the as-found position at commissioning
Fire systems are normally left fully open. The commissioning record is what proves it.
Schedule and log the annual test
Fire valves are exercised on a statutory cycle. A valve that has not moved in five years is a maintenance finding waiting to happen.
Common Specification Mistakes
Using a non-rising stem valve where indication is required
It does not show position and may not be accepted.
Forgetting the tamper switch
Then the fire panel cannot tell whether the system is isolated.
No test documentation
The fire authority asks, and there is nothing to show.
Frequently Asked Questions
When should I use a rising-stem (OS&Y) gate valve?
Use OS&Y where you need visual confirmation of open/closed position — typical for fire protection and above-ground piping. Non-rising stem suits buried or space-limited installs.
Resilient seated or metal seated?
Resilient (EPDM/NBR) seats give bubble-tight shutoff for clean water up to +80°C. Metal seats handle steam, slurry and temperatures up to +425°C.
Why choose a knife gate valve?
Knife gate valves have a sharpened disc that cuts through slurry, pulp and viscous media — ideal for mining, wastewater and bulk solids.
Applications & Use Cases
Water & Wastewater
Resilient-seated gate valves for mains, hydrants and treatment plants.
Fire Protection
OS&Y gate valves for sprinkler and hydrant systems.
Power & Steam
Metal-seated wedge gates for high-temperature steam lines.
Mining & Slurry
Knife gate valves for abrasive and viscous process streams.
