Can I Use Plastic Tubular on My Kitchen Sink?

Basics

• CPVC is designed to handle hot and cold water in sinks and other indoor plumbing. You can buy CPVC pipes in diameters of ½ inch through 2 inches plus the fittings that go with them, including sink connections designed for iron or copper pipes. CPVC is elastic. When the temperature rises 100 degrees Fahrenheit, it will expand about 4 inches per 100 feet. CPVC pipes all but eliminate the noise called “water hammer” found in metal pipes.

Cost

• The Plastic Pipe and Fittings Association estimates that the cost and material for installing CPVC pipes is about 30 percent cheaper than copper or iron pipes. Differences in thermal conductivity between copper pipes and CPVC pipes mean that hot water will stay hot longer in a CPVC pipe, resulting in lower heating expenses.

Installation

• You can cut CPVC with a fine-toothed saw or with a circular tube cutter with a special blade for cutting plastic. If you use a ratchet cutter when the temperature is below 50 degrees, you risk cracking the pipe wall. Use nonstick-coated tape on the threads when you install CPVC plumbing.

Special Considerations

• If you plan to run a CPVC pipe under a slab on its way to your sink, test the system before you pour the slab. There should be no rocks or debris in the backfill, and you should apply 1-inch insulation sleeve at construction joints -- changes in direction and where the pipe emerges from the slab. Insulation enables a pipe to shift slightly when it carries hot water. If your pipe passes through metal studs on its way to or from your sink, use an insulator or rubber grommets to protect it from cuts and reduce noise. One-step solvent cements are marketed for use on CPVC pipes. Some building codes require purple primer and orange solvent cement to help plumbing inspectors. If your pipe should freeze on its way to or from your sink, wrap it in a hot cloth or use a hair dryer or low-wattage blower on the frozen area.