Excessive sunlight exposure. | When the sun beats down on unprotected PVC pipe for an extended period of time, bad things can happen. The sun’s ultraviolet rays can break down the structure of the material and make it brittle. If you have to run PVC above ground for any reason, it’s recommended you take measures to protect the pipe from excessive sun exposure – either by painting the pipe or providing a covering. You should also choose a supplier who stores PVC in a covered warehouse so your pipe isn’t exposed to the elements before you even get it.
Water velocity. | If water travels through PVC too quickly, conditions such as water hammer and surge pressure can develop. Both of these can do a great deal of damage to PVC, regardless of how durable the material may be. If you are using PVC when installing an irrigation system, you need to be aware of flow velocity. A certain amount of water may flow smoothly through a one-inch diameter pipe but cause problems in a half-inch pipe. Take a close look at the pounds per square inch (psi) a pipe is designed to tolerate. Class 200 pipe, for example, will work properly at a flow rate of up to 200 psi.
Soil and debris. | Underground debris and rocks can lead to friction, which in turn can result in PVC pipe damage. That’s why it’s so important that contractors remove as much debris as possible before installing a plumbing system. When soil is especially rocky, it may be necessary to use a tool called a chain trencher to pulverize rocks. In many instances, a contractor will take out all the debris-filled soil from a plumbing line and replace it with sand. Soil movement is another major reason PVC pipes fail. While PVC is more flexible than a number of other pipe materials, it does have a breaking point. Freezing and thawing can cause soil to shift and wreak havoc on a plumbing system, which is why it’s usually recommended that PVC lines be installed at least a foot or two below ground to protect against freeze/thaw cycles.
Installation issues. | If a plumbing system is not properly planned, underground pipes can fail no matter what material they’re made of — this is especially the case when solvent cement is used to bond PVC to its fittings. PVC is extremely porous, and can break down when too much cement is applied. But it’s just as bad to not use enough cement because bonds will be too weak. When pipe cutting is required, the contractor needs to be careful to remove any type of debris such as burrs or anything else that can lead to the accumulation of residue. The outer edges need to be as smooth as possible so that joints can come together completely and the cement can bond properly. If they aren’t, leaks can occur. Another common installation error is known as “short insertion.” This occurs when a worker fails to push a pipe all the way into a fitting. The ensuing gap can cause the pipe system to fail due to the accumulation of contaminants.

PVC pipe is an extremely reliable, durable material, but it’s not infallible. If PVC is not properly installed, it can fail — and when that happens, major damage can take place.

Most PVC pipe failures can be prevented through proper installation. However, should a problem occur, it is very important to treat the root cause, not just the symptom to reduce the risk of future issues.

Above are some of the more common reasons pipe breaks happen and what can be done to prevent them.

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