Pipe

The pipe itself comes in the same nominal pipe sizes as metal piping and is manufactured in several thicknesses that are designed for various applications. CPVC water pipes for example are manufactured to both Schedule 80 and Schedule 40 specifications. The wall of Schedule 80 pipe is thicker than Schedule 40 and will withstand higher internal pressure. The outside diameter however of both pipes is identical. The inner diameter of Schedule 80 pipe is smaller to accommodate the increased wall thickness.

PVC is often used for applications such as drain piping and irrigation where contamination of the water supply is not an issue. Drain pipe is usually white and is thinner than pipe used for water supply applications since it is not exposed to a pressurized liquid. It is more rigid than water piping as well. Drain pipe used in septic tank leach fields are perforated, allowing the water to soak evenly into the soil along its length. Flexible PVC pipe is often used in applications in which vibration or obstructions are an issue. Flexible pipe is used in many underground gas line installations and is purchased in rolls instead of individual pipes which allow the piping to be installed with few, if any joint connections, minimizing possible leaks.