Understanding Expansion & Contraction in FlowGuard® Plus CPVC water pipe

When installing a new CPVC water pipe system, it’s important to remember that changes in temperature will cause any material to expand or contract. This means at warmer temperatures, the pipe will increase in length, while at relatively cooler temperatures, the pipe will get shorter.

It’s important to consider expansion and contraction when installing FlowGuard Plus CPVC pipes water system. If the system doesn’t allow for thermal expansion, these changes in length can put stress on the pipes or fittings, increasing the risk of a failure in future years.

Expansion and Contraction Explained

FlowGuard® Plus will expand about 1 inch per 50 feet of straight pipe for every 10°C increase in temperature. The most important factor in determining how much expansion or contraction will occur in a FlowGuard Plus system is the temperature of the pipe at the time of installation. If the pipe is installed in unusually cold weather the pipe will be shorter at installation than it will when it is in service. This can be a major factor in hot water lines where a 50-foot long run of pipe installed at -6.7ºC would expand up to 2” when in service at 49ºC.

While hot water lines are most likely to be affected by expansion and contraction, cold water lines can also be affected when the installation was done at unusually high or low temperatures.

When not properly accounted for, thermal expansion can place excess stress on the system. In the example above, a 38ºC change in temperature on a 50-foot run would be the equivalent of about 545 Kg per square inch of compressive stress on the pipe or fitting.

This force can lead to problems such as cracked fittings and distorted or cracked pipes. In many cases, these problems can take years to develop because the system will withstand the excessive stress for some period of time before failing.

Expansion and Contraction Solutions

To avoid these problems, always allow for expansion and contraction by following these simple best practices:

• Do not restrict the natural movement of the pipe in the direction of expansion and contraction.
• Always leave adequate spacing between elbows and hangers/restraints.
• Never butt-up elbows against studs which restrict their ability to move freely.
• Ensure all holes and grommets used for pipe penetrations allow for lateral movement of the pipe without abrasion.
• Read and follow the manufacturer’s installation instructions.

Normal changes in direction will often be enough to accommodate expansion and contraction. Use loops or offsets to allow for changes in length in long, straight runs. Address expansion and contraction in under-slab installations, by snaking the pipe slightly.

There are many CPVC manufacturers in the country, so choosing the right CPVC is furthermore important as all CPVC pipes may not deliver the above.

FlowGuard® Plus is a registered brand name of Lubrizol and is licensed to manufacturers around the world. In India, Ashirvad Pipes Pvt Limited and Prince CPVC Pipes & fittings Limited manufacture and sell it through their vast retail channel all over the country.

Use CPVC Piping systems ask for FlowGuard® Plus….