Pipe Schedule Chart

When working with pipe, it is common to describe them by their “schedule.” Someone unfamiliar with pipe schedules may not understand how to determine the measurements. A pipe schedule is a non-dimensional number that relates to the thickness of the wall and affects the inside diameter. It is used to help classify pipes for high or low pressure and temperature applications. To help, this blog features a pipe schedule chart and explains how you can use it to determine the measurements and schedule of a pipe that you’re working with.

What is a Pipe Schedule?

A pipe schedule refers to a standardized system used to describe the wall thickness of a pipe. It is not an exact measurement but rather a guide that correlates to the nominal wall thickness based on the pipe’s outside diameter (OD) and nominal pipe size (NPS). As the schedule number increases, the pipe’s wall thickness also becomes greater, which directly affects its strength, weight, and ability to withstand internal pressure.

Schedule 40 and Schedule 80 are the most common pipe schedules. Schedule 40 pipes have thinner walls compared to Schedule 80 pipes, making them lighter and suitable for general applications. In contrast, Schedule 80 pipes have thicker walls, offering enhanced durability and pressure resistance for more demanding environments.

Pipe Schedule Chart Components

A pipe schedule chart is a tool for understanding the dimensions and specifications of a pipe. It provides detailed information that helps users select the right pipe for their needs based on wall thickness, size, and weight.

These are the key components typically included in a pipe schedule chart:

Schedule Number (SCH)

The schedule number is a standardized designation that represents the wall thickness of a pipe. As the schedule number increases, so does the thickness of the pipe wall. This relationship is critical for determining a pipe’s pressure rating and structural strength.

Nominal Pipe Size (NPS)

Nominal Pipe Size (NPS) refers to the approximate inside diameter of a pipe for pipes with smaller diameters and the approximate outside diameter for larger pipes. It is a standardized size designation used with the schedule number to define a pipe’s dimensions.

Outside Diameter (OD)

The outside diameter is the measurement of the external width of the pipe. This value remains constant for a given Nominal Pipe Size but is needed when determining compatibility with fittings and connections.

Weight per Unit Length

Most pipe schedule charts also include the weight of the pipe per unit length (e.g., pounds per foot or kilograms per meter). This helps users estimate material handling requirements and cost calculations.

How to Use a Pipe Schedule Chart?

The conversion chart below is a great way to see the relationship between pipe size, schedules and wall thicknesses. The pipe schedule chart helps users match their measurements to standardized pipe specifications, making it easier to determine compatibility and performance requirements.

If you’re looking to determine what schedule a pipe is or what the nominal pipe size is, we suggest:

1. Measure the outside diameter and the wall thickness of the pipe
2. Refer to the pipe schedule chart and find the outside diameter
3. Find the wall thickness in the corresponding column
4. This will reveal the nominal pipe size and the schedule

For example, if you measure a pipe that has an outside diameter of 3.500 and a wall thickness of 0.300, using the pipe schedule chart, you can determine that the pipe is a 3″ schedule 80 pipe.

Pipe Schedule Chart

Download a Printable Version

Why Using a Pipe Schedule Chart Matters?

Using a pipe schedule chart ensures you select the correct pipe based on its nominal size, wall thickness, and schedule. This is essential for matching the pipe’s specifications to the requirements of your project, such as pressure resistance, flow capacity, or structural integrity.

A pipe schedule chart allows users to select pipes that meet the required pressure ratings and mechanical strength, reducing the risk of failure in critical systems. Pipes that do not meet the specifications can fail under pressure or stress, leading to costly damage or safety hazards. By choosing a pipe with the appropriate wall thickness and schedule, you ensure long-term durability.

Ready to find the right pipes for your project? Find a wide selection of pipes in various schedules, sizes, and materials at Metal Supermarkets.