Connecting Rigid Plastic Pipe

USE THE RIGHT PRIMER - If you want your work to pass inspection—and not leak—use the right primer. Purple-tinted primer is required by code for drainage lines and will also work on supply lines. Clear primers are fine on supply lines but won't pass inspection when it comes to drain lines. Save yourself some grief—buy the purple primer and use it everywhere.

Rigid plastic pipe was developed to replace cast iron and galvanized steel in plumbing supply and waste systems. Plastic pipe is cost-effective and easy to install. Use rigid plastic PVC (or ABS if codes allow) for drain, waste, and vent systems. Use CPVC or PEX for hot and cold water supplies. Plastic pipe is available with inside diameters (ID) of 1 1/4, 1 1/2, 2, 3, and 4 inches.

• Use 1 1/4--, 1 1/2-, and 2-inch ID PVC for sink drains and lavatories.

• Use l 1/2- and 2-inch ID pipe for tubs and showers.

• Use 3- or 4-inch ID pipe for toilets. New 1.6-gallon flush toilets work best with a 3-inch fitting.

• Drain lines and vent stacks can use 2-, 3-, or 4-inch ID pipe.

ASSEMBLE QUICKLY. Plastic pipe is joined with fast-acting solvent cements. Once you glue a fitting in place, it can’t be removed—you have to cut it apart and start over. You can’t twist fittings apart, and fine-tuning is impossible. Cut sections to length and test-fit the entire run before cementing the lines in place.

DRY-FIT ALL THE CONNECTIONS BEFORE THE FINAL ASSEMBLY. Dry-fit the connections before applying primer and cement—once you've cemented the pipe, it can't be changed. Check the fall with a level. There should be a 1/4 inch fall, or slope, for each lineal foot of run.


1 Use the correct pipe cleaners, primers and cements for the pipe you're installing. CPVC, PVC, and ABS are not interchangeable without transition fittings or special glue.

2 Cure time depends on the cement used, the size and tolerance of the pipe and fitting, and the air temperature. You will weaken the bond by trying to speed or retard the cure.

3 Keep lids on cements and primers when not in use.

4 Stir or shake cement before using.

5 The size of the adhesive and primer applicator, called a “dauber," depends on the size of its container. You’ll want a 1A-inch dauber on small-diameter pipes; a 1 1/2-inch dauber for pipes up to 3 inches; and a natural-bristle brush, swab, or roller half the pipe diameter for pipes 4 inches or more. Try to buy a can that has a dauber that matches the job at hand.

6 Do not mix primer with cement. Do not use thickened or lumpy cement. Cement should have the consistency of syrup or honey.

7 Do not handle joints until they are fully cured.

8 All colored cements and primers will leave a permanent and recognizable stain.

Connecting PVC

MATERIALS: PVC pipe and fittings, cleaner, primer cement

TOOLS: Tubing cutter, hacksaw or miter saw and box, deburring tool, knife, emery cloth, rags

LOOKS CAN BE DECEIVING - Each type of plastic pipe is composed of different materials and requires its own blend of cleaners and cements to make a proper bond. If you have to join PVC to ABS, you'll need a special glue transition fitting to make the connection. Ask at the store, and check local codes.

A tight fit - For a PVC joint to be effective the pipe must seat itself fully into the fitting. Without the adhesive as a lubricant, it’s often hard to see if the pipe is seated properly.

1 A STRAIGHT, SQUARE CUT IS NECESSARY FOR A GOOD CONNECTION. PVC tubing cutters are made for both small- and large-diameter pipes. If you don't have a cutter, you can cut the pipe with a miter saw, hacksaw, or power miter saw. Take your time and make sure you get a clean, square cut. Deburr the inside and outside edges of the pipe, and test-fit before final assembly. Clean the pipe with the manufacturer's recommended cleaner, and use the correct primer and adhesive to ensure a solid joint.

2 DEBURR THE CUT. After each cut, deburr the pipe with a deburring tool, knife, or emery cloth to remove rough edges that could interfere with the flow of water or the fit of the joint. Sand the section of pipe that will be housed by the fitting too. If you don't, the pipe won’t travel as far into the fitting as it will once you apply glue. The run will be slightly short as a result.

3 APPLY PRIMER TO THE CONNECTIONS. The primer softens the ends, preparing them for application of the cement. An inspector will often look for the permanent purple stain at the joint to make sure primer was used to help make the connection.

4 C0AT THE PIPE AND FITTING WITH CEMENT. While the primer is still damp, quickly apply a thin, even coat of cement to the surfaces. Too much cement can weaken the pipe and destroy the fitting.

5 WORK QUICKLY TO CONNECT THE PIECES. Insert the pipe into the fitting with a quick push and a quarter-turn to seat. Hold the connection for 30 seconds to prevent the heat produced by the cement from pushing the connection apart. The cement melts the surfaces and forms a secure bond. With a rag, wipe away excess cement, which can weaken the joint.

Connecting CPVC

MATERIALS: CPVC pipe and fittings, primer, dauber cement

TOOLS: Tubing cutter, hacksaw or miter saw and box, deburring tool, knife, emery cloth, rags

DANGEROUS FUMES - Fumes from primers and cements can lead to loss of consciousness. Work in a ventilated area. The fumes are also highly inflammable and explosive. DO NOT smoke or use torches or electric tools that spark [such as power drills) near areas where there may be fumes.

CPVC is used for hot and cold water supply. It is less expensive than copper but just as durable, and it withstands high temperatures and pressure in the supply system. It cuts easily with a tubing cutter or hacksaw, connections are easy, and assembly is quick. One-step cements are available for CPVC and eliminate the need to use purple primer, but one-step cements may not meet local code in many areas. Check local codes carefully to determine if primer is required. In some localities, you will fail inspection if you don’t use it. Purple primer leaves a permanent and recognizable stain on the pipe, so inspectors will know whether you’ve used it. It’s a lot easier to do the job up to code the first time to avoid the hassle of redoing it when the inspector fails your installation.

JOINING CPVC TO COPPER - You may run into a situation where copper pipe is in the walls and you don't want to remove it but you want to run CPVC for the hot and cold water supply for your new sink. No problem! A special transition fitting available at your home center or hardware store can join CPVC to brass or copper.

Deburring (removing debris left from cutting the pipe) is essential. Chips and chunks, both inside and outside, affect the final bond.

1 DEBURR THE PIPE - Removing burrs ensures even coverage with the primer and cement. Once you've deburred, sand lightly with emery cloth, so that the pipe will seat in the bottom of the fitting.

2 COAT THE SURFACES WITH PRIMER IF REQUIRED. Apply an even coat of primer to the pipe and the fitting. Primer softens the pipe to help seat it and reacts with the cement to make a permanent bond. Using a purple primer is essential in areas where priming is required by code. The resulting stain tells the inspector the joint has been properly treated prior to connection.

3 APPLY CEMENT AND ASSEMBLE THE PARTS QUICKLY BUT CAREFULLY. Use a dauber to apply an even coat of cement to the pipe and fitting and insert the pipe all the way into the fitting until it stops. Twist a quarter of a turn to spread the cement evenly. Hold the pipe together for 30 seconds to prevent the heat generated by the cement from pushing the connection apart. With a clean rag, wipe off excess cement between the fitting and pipe.

Connecting ABS

MATERIALS: ABS pipe and fittings, cleaner, primer cement, dauber

TOOLS: Tubing cutter, hacksaw or miter saw and box, deburring tool, rags

The first rigid plastic pipe approved for use in drain, waste, and vent systems was ABS. It is inexpensive, easy to cut, lightweight, and very rigid. However, it becomes brittle over time and therefore is susceptible to cracking and breaking. Before purchasing ABS pipe, check your local plumbing codes. Some communities forbid the use of ABS.

1 CUT AND DEBURR THE PIPE. Removing burrs ensures even coverage with the primer and cement. Sanding can change the diameter and cause a poor fit. Test-fit the pipe to the fitting; it should seat snugly in the fitting.

2 APPLY CEMENT AND ASSEMBLE THE PARTS QUICKLY BUT CAREFULLY. Hold the connection for 30 seconds. Don't puddle the cement on— too much cement can weaken the pipe wall. Push the connections together with a twisting motion until properly seated. The solvent produces heat that may cause the connection to push apart. Wipe away excess cement with a rag to prevent weakening of the ABS pipe walls.

PEX (FLEXIBLE PLASTIC PIPE) (cross-linked polyethylene) is a flexible plastic pipe used for hot and cold supply lines. While it is gaining wider national acceptance, PEX is primarily used in the southern United States and in parts of southern California. In these areas it can also be used to run the main supply line from an outside water meter into a slab home. Resistance to deterioration, heat, and the high pressure required for supply, plus ease of assembly, make PEX an ideal choice for do-it-yourselfers where it’s use is approved. (Check local codes.)

The system uses two types of fittings:

• Plastic compression-type fittings, which are tightened by hand and then given one full turn with pliers until snug. No tape or pipe compound is required.

• Brass ribbed fittings, which are permanently sealed to the pipe with a crimping tool and crimp ring (usually a professional installation).

The pipe, available in rolls of 50 to 100 feet, is cut with a utility knife or a tubing cutter. It is flexible enough to turn corners that would require new connections and fittings with other types of plumbing. (Follow the manufacturer's instructions for maximum bends.) Both the compression and crimped fittings are required by code to be accessible for inspection and repair and cannot be sealed in walls or ceilings. In order to make the fittings accessible, they are often grouped in manifolds behind conveniently located access

A FITTING STORY - I was really busy at work so my cousin and his buddy (who said he was a plumber) offered to help me out by installing a new drain line. They got it in no problem, but they used a straight vent tee, instead of a sanitary tee, which is required by the plumbing code. I know they just wanted to help but the inspector failed the job and we had to start over. Plumbing codes can be tricky so don't be afraid to ask questions.

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