How to Choose Plastic Pipe
- 1). Learn the difference between the plastic pipe materials that are available. Pipe made from polyvinyl chloride (PVC) is one of the most popular, but chlorinated polyvinyl chloride (CPVC) is also widely used. A wide variety of specialty plastics are also available, and are primarily used for transporting chemicals and other corrosive materials. These include polyethylene (PE) and polybutylene (PB), among others.
- 2). Consider the application. PVC is used in non-pressure applications such as drain, waste and vent piping, while CPVC is primarily used for transporting water. PB and PE piping can be used for drain and waste applications, but are also used for gaseous and corrosive materials. Because of the potential for harmful interactions, PB and PE pipes should not be used to carry fuel products like kerosene or heating oil.
- 3). Determine which pipe is best suited in terms of temperature. CPVC pipe is appropriate for carrying materials at temperatures below 180 degrees Fahrenheit. PVC pipe can be used for materials ranging from 120 to 150 degrees, while specialty plastics like PE and PB can carry materials ranging from 200 to 210 degrees Fahrenheit.
- 4). Decide what schedule of pipe to use. The schedule of a pipe represents the thickness of the pipe's walls, and generally ranges from schedule 40 to schedule 120. The lower the schedule, the thinner the walls will be. Thinner-walled pipes are more lightweight, but may not be able to carry materials under high pressure. Thicker walls may handle higher levels of pressure, but are often heavier.
- 5). Choose the correct size pipe. Plastic pipe sizes are assigned using nominal pipe size (NPS). The NPS of a pipe corresponds to the inner diameter, while the outer diameter can be much larger depending on the thickness of the pipe's walls. For example, a 1/2-inch NPS pipe has an inner diameter of 1/2 inch, but an outer diameter of approximately 0.840 inches. The exact difference between the inner and outer diameters will vary according to the schedule of the pipe.
- 6). Select a pipe with enough strength to withstand damage. The impact strength represents the pipe's ability to resist cracks or damage when an item is dropped onto the pipe. PVC and CPVC have an impact strength of 1.0 and 1.6, respectively. PE and PB piping, however, have a rating higher than 10.0, making them much more likely to resist damage.
- 7). Evaluate chemical resistance. When corrosive materials are being transported, PB or PE piping tends to be the best material for minimizing corrosion, especially under high temperatures or pressure levels. For chemicals that are linked to a low risk of corrosion, both PVC and CPVC offer a moderate level of chemical resistance.
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