Pipe Schedule Charts
If you’re struggling to understand pipe schedule charts, you’re not alone. Understanding pipe schedule charts may be confusing, but they are essential for ordering the correct size and dimension of pipe you need for your project.
Some pipe and tube distributors require NPS (nominal pipe size) and schedule numbers to place orders, while others may accept OD (outside diameter), ID (inside diameter), and wall thickness measurements. However, it’s important to understand all these measurement varieties to ensure you can correctly order and receive the pipe product you need.
Here’s a quick breakdown of pipe schedule chart terminology so you can place your order like a pro.
Pipe Sizes & Schedule Chart Terminology to Know
Pipe sizes and schedule charts include specific pipe terms and corresponding measurement information to streamline the ordering process. Pipe terminology represented in size and schedule charts include:
- NPS (Nominal Pipe Size): NPS is used for pipe measurements only and not tube
- ID (Inside Diameter): Measures the inside length of pipe between the walls
- OD (Outside Diameter): Measures the full length of the pipe to the outside of the wall
- NOTE: For NPS 14” and above, the OD is the same as NPS
- NOTE: For NPS ⅛” – 12”, the OD is larger than NPS
- Wall Thickness: The measurement of how thick a pipe wall is
- Schedule: Indicates a specific wall thickness for a given NPS
The OD measurement of pipe is not impacted by the schedule number; however, the ID measurement of pipe is. A bigger schedule number indicates a thicker pipe wall, making it stronger in terms of weight and pressure resistance, and a smaller schedule number indicates a thinner pipe wall.
How to Measure Pipe?
For starters, NPS and Schedule are both representative measurements. The NPS is a standard used, not an exact measurement. Likewise, Schedule is not an exact measurement and is a representative of a measurement that relates to wall thickness. For example, Schedule 40 has a different thickness for each NPS number.
Within a pipe size and schedule chart, there are also abbreviations to note including:
- E.H. (Extra Hard): “E.H.” relates to the wall thickness of a pipe, indicating a heavy duty, more durable pipe wall
- S: An “s” designation refers to the schedule for stainless steel material
Here’s where it gets tricky. “40s” and “Standard” (Std) are interchangeable terms, as well as “80s” and “E.H.” In fact, there are cases where “5” and “5s,” “10” and “10s,” “40” and “40s,” and “80” and “80s” are the same, but not always. As the NPS increases, these measurements become different.
If you’re more confused now than when you first started reading, I have good news! At Boyer Steel, our team is made up of industry experts who will partner with you to understand and confirm the size of pipe you need for your project. When placing your order with Boyer Steel, our team accepts orders with either NPS and Schedule numbers or the specific OD, ID, and wall thickness numbers. And, if you don’t have all of the information or don’t know what some terms mean, we can determine what you need to ensure you get the pipe that’s right for your application.
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