Which type of pipe is most commonly used for venting?

PVC pipe is most commonly used for venting due to its lightweight, ease of installation, and resistance to corrosion. These attributes make it an ideal choice for venting systems, which often require a material that can withstand the varying conditions within a plumbing system.

Vent pipes are essential for allowing gases to escape from the plumbing system and preventing pressure buildup. PVC fulfills this requirement effectively because it can handle the exhaust gases without degrading or corroding over time. Additionally, PVC pipes can be easily cut and joined with solvent cement, streamlining the installation process.

Other materials such as cast iron are heavier and more prone to corrosion, which makes them less favorable for venting applications. Steel pipe might be used in specific applications but is generally avoided in residential plumbing due to its susceptibility to rust. CPVC, while also used in plumbing, is better suited for hot water applications rather than for venting purposes. Thus, the unique characteristics of PVC make it the standard material for venting in most plumbing systems.