What Is PVC 40/160?

About PVC

• PVC is short for polyvinyl chloride, which is a molded form of plastic based on a thermoplastic polymer of vinyl chloride. Because PVC pipe is based on vinyl, which contains chlorine and byproducts of natural gas, it is not safe to use with drinking water or hot water. However, PVC pipe still has many uses. PVC pipe can be used in drainage systems, sprinkler systems and plumbing fixtures that do not require potable or hot water.

What the 40 Means

• All PVC pipes contain a stamp on the side that show the specifications of that pipe. In the case of PVC pipe that is stamped "40/160," the first number refers to the "schedule" of pipe. The schedule is a standard reference table that shows the specific tolerances of each type of pipe, including the thickness of the pipe wall and how much pressure it can contain. Schedule 40 pipe, one of the most common types of PVC available, is available in sizes from 1/8 inch to 12 inches, and wall thicknesses from .068 inches to .406 inches. Schedule 40 pipe can withstand pressure ranging from 130 psi to more than 800 psi, depending on the diameter of the pipe.

What the 160 Means

• The second number in a PVC rating stamp refers to the amount of pressure that the pipe can withstand. In the case of 40/160 pipe, the pipe can withstand pressures up to 160 psi. Knowing the pressure limitations of your pipe is important if the line is to be charged with a pressurized liquid, such as an irrigation system. If your home water pressure exceeds the rating of the pipe, the pipe may burst and cause significant damage in the process.

Potential Dangers of PVC

• While PVC pipe is inexpensive and simple to work with, it is not a totally safe material due to its construction. PVC production creates dioxin, a chemical that has a long life in the environment can potentially cause harm to humans and other animals. When PVC is burned, dioxin may be released into the air and contribute to acid rain. Because these and other chemicals are present in PVC, water that comes into contact with the plastic should never be used as drinking water.