When are OS&Y Valves Required?
OS&Y gate valve are required by NYC plumbing code on all water lines that provide fire protection meaning, any dedicated sprinkler line or combined water line (domestic & sprinkler in one pipe) must have one installed for new and existing projects. All domestic water lines 3″ or larger must have an OS&Y valve installed as well.
In addition to visual inspection, NYC code also requires that all handles and visual standpipe (sprinkler line) must be color coded
- All valve handles must be the following:
- Dedicated standpipe valve handles must be painted red
- Combination standpipe valve handles must be painted yellow
- Dedicated sprinkler valve handles must be painted green
- All Visible standpipe must be painted red
What is the key difference between an OS&Y and a Gate Valve?
OS&Y valves visibly show whether the valve is opened or closed which differs from a domestic water service where you can simply turn on the shower or sink to test its functionality. When the stem of the OS&Y is raised out of the body you know the water is on. With other gate valves, visual inspections will not determine if the valve is opened or closed.
What is an OS&Y Valve & how does it function?
An OS&Y gate Valve (outside screw & yoke) functions by opening and closing via a gate, which lowers both in and out of the valve. When the handle is turned clockwise the gate will close preventing any water from traveling through the valve. When the handle is turned counter clockwise, the gate will open allowing the water to flow through freely. The screws of the valve are held by a yolk on the outer portion of the valve, a wheel in the valve is attached to the nut which turns, allowing the shaft to lower or rise from the lower portion of the valve.