Types of Building Water Shutoff Valves
The type of water shutoff valve used in your building may not be something you’ve given a lot of thought to, but it can become important when you least expect it. Using the wrong type of valve can leave you with leaks, flooding, low water volume, and blockages. The right valve gives you a simple and reliable way to control the water flow to your building in exactly the way you want.
Ball Valves
A ball valve contains a metal ball with a hole through the center. When the valve is open and the handle aligns with the pipe, the hole in the ball aligns with the sides of the pipe, allowing water to flow through. When the valve is closed and the handle is at a 90 degree angle to the pipe, the hole faces the sides of the pipe so the flow of water is blocked.
Ball valves are ideal for water systems in commercial buildings. They’re all but leak-proof, open and close quickly, and stand up well to high temperatures and pressures. As an added benefit, they’re compact and lightweight.
On the downside, they shouldn’t be used to adjust the flow of water or for permanent throttling. For good water volume, choose a full-port (full-bore) valve. In these valves, the whole in the ball is the same size as the interior of the pipe.
Globe Valves
These devices are also known as stop valves. Inside is a baffle water must pass over to leave the pipe. Above the baffle is a stopper than can be lowered to seal the baffle and stop the flow of water. The stopper is raised and lowered by turning a wheel.
These valves can work well for commercial water systems in some situations, but not all. This is largely because the baffle always restricts the water flow somewhat. Globe valves are best suited to situations in which you need to adjust the water flow frequently, but where the flow never has to be completely on full.
Diaphragm Valves
This type of water shutoff valve contains a rubber diaphragm and a stem above the diaphragm. Turning the valve wheel lowers the stem, which depresses the diaphragm and stops the flow of water. These valves provide a good seal and also work well for throttling the water flow.
In a weir-type diaphragm valve, the diaphragm closes against a weir beneath it. The weir always limits water flow somewhat. A full-bore diaphragm valve contains no weir, so it interferes with water flow less. If you plan to use a diaphragm valve as a hot water shutoff valve, keep in mind they have temperature limits that depend on the material used for the diaphragm.
Gate Valves
This valve contains a gate that can be raised and lowered to stop or start the water flow. It’s not designed to make minor adjustments to the flow, however, so it should be either open or closed completely.
Decades ago, gate valves were the preferred type of water shutoff valve, so you’ll still find them in many older commercial buildings. More recently, however, they’ve fallen out of favor for a number of reasons. Unlike the handle of a ball valve, the wheel of a gate valve doesn’t show you at a glance whether the valve is open or closed. What’s more, gate valves wear out quickly and are prone to corrosion, which can leave you with a valve that’s stuck open or closed.
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