About Stop Valves
A stop valve is a miniature valve, which can be found in any residential home or commercial institution. The valve is most commonly installed in accessible locations near a plumbing fixture or an appliance and performs a simple shut-off function, allowing to temporary terminate water flow to the fixture to perform maintenance or repairs. They are suitable for both hot and cold water and are manufactured in a large variety of types and sizes for easy integration into any plumbing system.
Stop valves are installed in combination with flexible connectors or rigid copper risers and are typically complimented with escutcheons for a clean finished look.
Stop Valve Types
By flow pattern
To simplify the installation process, stop valves are manufactured in either angle or straight flow patterns. Angle stops have inlet and outlet connections perpendicular to each other and are best suited for projects where piping stubs out from the wall. Straight stops have both connections in a straight line and are used where piping stubs out from the floor.
Outlet connections on all supply stop valves are generally the same - 1/4" or 3/8" OD compression (most popular), compatible with flexible supply connectors or risers, both rigid, such as copper risers, and soft such as PEX risers.
Inlet connection types and sizes vary greatly, but most valves are designed for installation on either 1/2" PEX pipe or 1/2" copper pipe, and therefore come in PEX, compression, sweat, push-fit or threaded connections.
The original stop valve design, introduced decades ago and still used today is the multi-turn design. It incorporates a shut-off mechanism where valve stem with a washer is gradually moved to or from a round opening inside the valve, by rotating the handle, providing smooth closing and opening, while simultaneously negating the water hammer effect.
1/4-turn stop valve design is similar to that of the miniature ball valve, where closing and opening are performed by a metallic ball with a round straight-through opening, which is mechanically connected to and turned by the valve handle. 1/4-turn stop valves are easier to operate then multi-turn and are considered to be more reliable, but may require installing water hammer arrestors and are not allowed by code in some localities.
Frequently Asked Questions:
Q: 1/4-turn or Multi-Turn stop valve - which is better?
A: While both types are equally popular, 1/4-turn stop valves are often a preferred option. They are easier to operate, provide a visual shut-off confirmation and lack the packing nuts, washers and plastics stems, which are among the primary reasons for a leaking stop valve.
Q: Compression vs. Sweat vs. Threaded - which connection is better?
A: Compression connection is the most popular among all 4 since it does not require soldering, makes it easy to replace a valve and provides the most aesthetically pleasing appearance. Sweat stop valves ensure the most reliable connection of all, but are harder to replace and require experience and tools for soldering. Threaded stop valves are the least popular and are generally installed in conjunction with the older threaded brass pipes which stub out form the wall.
Q: Are 5/8" OD compression valves compatible with 1/2" copper pipes?
A: Yes. Any type of regular 1/2" copper pipe (US ASTM standard B88), whether K, L or M has an OD (Outside Diameter) of 5/8" and is therefore compatible with stop valves which have a 5/8" OD compression inlet.
Q: How to connect a stop valve to the fixture?
A: Use flexible braided or rigid copper connectors, such as the ones manufactured by BrassCraft.