How to Read a PVC Pipe Size Chart Accurately

Nominal Size: The nominal size is usually the first column in a PVC pipe size chart. It's a standard way of referring to the pipe size, but it's not the actual diameter. For example, a 1 - inch nominal PVC pipe doesn't have an exact diameter of 1 inch. Nominal sizes are used to simplify the identification and selection of pipes and fittings. They are based on traditional sizing systems and are widely used in the industry. In plumbing and construction, you'll often encounter nominal sizes ranging from 1/8 - inch to 24 - inches or more.

Actual Dimensions: The chart will also provide the actual outer diameter (OD) and inner diameter (ID) of the pipe. The OD is the measurement of the outside of the pipe and is crucial for fitting pipes together. The ID affects the flow capacity of the pipe. The wall thickness can be calculated by subtracting the ID from the OD and dividing by 2. For example, if a pipe has an OD of 1.315 inches and an ID of 1.049 inches, the wall thickness is (1.315 - 1.049)/2 = 0.133 inches.

Schedule/Class Designation: The schedule or class of a PVC pipe indicates its wall thickness and pressure - handling capacity. Common schedules include Schedule 40 and Schedule 80. Schedule 40 pipes have a standard wall thickness and are suitable for most general - purpose applications such as residential plumbing and light - duty drainage. Schedule 80 pipes have a thicker wall and can withstand higher pressures. The schedule number may be listed in a separate column in the chart or as part of the pipe's description. Make sure to match the correct schedule with your application's requirements.

Differences in Dimensions by Schedule: The actual dimensions of a pipe can vary depending on the schedule. For example, a 1 - inch nominal Schedule 40 pipe will have different outer and inner diameters compared to a 1 - inch nominal Schedule 80 pipe. The chart will clearly show these differences. The thicker - walled Schedule 80 pipe will have a smaller ID for the same nominal size because more material is used for the wall, which is important to note when considering flow rate and compatibility with fittings.

Standard Lengths: PVC pipes are usually available in standard lengths. The length information may be included in the chart or in the product specifications. Common lengths are 10 - feet and 20 - feet. The length you choose can affect the installation process and cost. Longer pipes can reduce the number of joints needed in a project, which can mean less potential for leaks and a quicker installation. However, longer pipes can be more difficult to handle and transport, especially in tight spaces.

Length Tolerances: Some charts may also provide information about length tolerances. These tolerances ensure that the pipes are consistent in size and can be properly joined together. For example, a small variation in the length of a pipe may not be a significant issue for most applications, but in a precise installation where multiple pipes need to be aligned, it's important to be aware of these tolerances.

Pressure Ratings: The chart may include the pressure - rating information of the pipe. This indicates the maximum internal pressure that the pipe can withstand without failure. The pressure rating is related to the pipe's schedule, diameter, and material properties. Understanding the pressure rating is crucial, especially in applications such as water supply systems where the pipes need to handle a certain amount of pressure.

Temperature Ratings: Some PVC pipe size charts also provide temperature - rating information. This is important because PVC pipes have specific temperature limitations. As the temperature rises, the physical properties of PVC change. Knowing the temperature rating helps you determine if the pipe is suitable for applications where it may be exposed to heat, such as in hot - water plumbing systems.