Working with CPVC and Plastic Supplies

Intro

Check local codes before installing plastic supply piping; many building codes do not permit it for interior use.

CPVC and other types of plastic pipe are often used for irrigation systems and other outdoor work. Because plastic pipe can be broken when hit, some codes allow it only for underground installations and require metal pipe above ground.

Often rigid plastic supply pipe is used with flexible tubing such as PEX, both for outdoor and interior installations. In a typical irrigation system, rigid pipe is used for long runs and flexible tubing is used for shorter runs leading to sprinkler heads.

Checklist

Time
About an hour to cut and join five or six pieces of pipe and fittings

Tools
Felt-tip marker, PVC pipe cutter or plastic-pipe saw and miter box, deburring tool, groove-joint pliers

Skills
Cutting, measuring, cementing

Prep
Cut holes behind walls or under floors to clear a path for the supply pipes.

Materials
Plastic supply pipe approved by local codes, appropriate primer and cement, damp rag, flexible pipe, compression fittings

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Step 1

Measure for the desired length and mark the pipe with a felt-tip marker. Cut small-diameter plastic pipe with a PVC pipe cutter (shown) or a saw and miter box.

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Step 2

PVC pipe cutters cut cleanly, but if you use a saw or there are any burrs, use a deburring tool to smooth the inside and outside of the cut end. Dry-fit the pipes and make alignment marks.

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Step 3

Using a small can with a small applicator brush, apply purple primer to the inside of the fitting and the pipe end. Place the pieces on a surface where they will not get dirty.

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Step 4

One pipe and fitting at a time, apply cement to the inside of the fitting and to the pipe end.

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Apply cement to the inside of one fitting

Step 5

Quickly insert the pipe into the joint and twist. Where there are alignment marks, make sure they meet. Hold for a few seconds and then wipe the joint with a damp rag.

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Breaking into Plastic Pipe with a Compression Tee: Step 1

Plastic compression tees are ideal for breaking into an existing line where it is difficult to glue a standard tee. Note the distance that the pipe should be inserted into each end of the compression tee -- usually 1/4 inch. Mark the length of the tee and the insertion points (your cut lines).

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Breaking into Plastic Pipe with a Compression Tee: Step 2

Turn off the water and drain the system. Use a plastic-pipe saw or other fine-tooth saw to cut the pipe. Deburr the pipe. Slip the nut and rubber gasket onto each end of the pipe. Bend the pipe out slightly to slip the tee into place.

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Breaking into Plastic Pipe with a Compression Tee: Step 3

Tighten the nuts with groove-joint pliers. Do not overtighten. Add the extension to the line, following the steps above for cementing plastic pipe. Turn on the water to test the extension.

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