Carbon Steel Pipe Schedule Chart

1. What Is a Carbon Steel Pipe Schedule?

A carbon steel pipe schedule is a standardized wall-thickness designation used with a specific Nominal Pipe Size (NPS). Under ASME B36.10, the outside diameter (OD) is standardized for each NPS, while the schedule identifies the corresponding nominal wall thickness.

NPS → OD → Schedule → Wall Thickness (WT)

2. Carbon Steel Pipe Schedule Chart

The chart below lists nominal wall thicknesses (WT) and outside diameters (OD) for standard Schedule designations under ASME B36.10.

Download: Carbon Steel Pipe Schedule Chart PDF

3. Carbon Steel Pipe Schedule and Wall Thickness

The wall thickness associated with a Schedule varies by NPS. Therefore, a Schedule number alone is not enough to determine the nominal wall thickness of a carbon steel pipe.

For example, an NPS 2 pipe has an OD of 60.3 mm, but its nominal wall thickness changes with the Schedule:

To identify the nominal wall thickness of a carbon steel pipe, specify both the NPS and Schedule. The complete schedule chart above provides the corresponding dimensions for each available NPS and Schedule combination.

The schedule chart above provides nominal wall thickness by NPS and Schedule. For pipe weight by NPS, OD, Schedule, wall thickness, kg/m, and lb/ft, see our Carbon Steel Seamless Pipe Weight Chart.

4. Carbon Steel Pipe Size: NPS, DN and OD

These NPS, DN, and OD values form the basic dimensional reference for standard carbon steel pipe sizes.

NPS (Nominal Pipe Size): An inch-based nominal size designation (e.g., NPS 2).

DN (Nominal Diameter): The metric nominal size designation corresponding to the NPS (e.g., DN 50).

OD (Outside Diameter): The standardized outside diameter, which remains fixed across applicable Schedule designations for a specific NPS (e.g., 60.3 mm for NPS 2 / DN 50).

Engineering Principle: For a given NPS, the Outside Diameter (OD) remains fixed across applicable Schedule designations. The Schedule identifies the corresponding nominal wall thickness, which determines the resulting Inside Diameter (ID).

5. STD, XS and XXS Wall Thickness Designations

STD (Standard Weight), XS (Extra Strong), and XXS (Double Extra Strong) are traditional wall thickness designations still encountered in carbon steel pipe specifications and dimensional references.

For NPS 1/8 through 10, STD and SCH 40 have the same nominal wall thickness, while XS and SCH 80 have the same nominal wall thickness. XXS does not correspond directly to a Schedule designation.

For NPS 12 and larger, STD and XS wall thicknesses do not necessarily match SCH 40 and SCH 80. The applicable NPS, designation, and nominal wall thickness should therefore be checked against the dimensional standard or project specification.

6. Does Pipe Schedule Determine Pressure Rating?

No. A pipe Schedule specifies the standardized nominal wall thickness for a given Nominal Pipe Size (NPS); it does not by itself determine the pipe's pressure-retaining capacity.

For a given NPS, a higher Schedule generally indicates a thicker nominal wall. The allowable pressure also depends on the material grade, design temperature, allowable stress, corrosion allowance, and applicable design code.

For detailed pressure calculations and pressure-temperature ratings, see Carbon Steel Pipes: Pressure-Temperature Ratings.

7. FAQs

Q1. What Is a CS Pipe Schedule Chart?

A CS pipe schedule chart lists the nominal wall thickness and OD for each Schedule and Nominal Pipe Size (NPS).

Q2. What Is a Carbon Steel Pipe Thickness Chart?

A carbon steel pipe thickness chart shows the nominal wall thickness for different NPS and Schedule combinations.

Q3. How Are Carbon Steel Pipe Schedule and Thickness Related?

For a given NPS, the Schedule identifies a standardized nominal wall thickness. A higher Schedule generally corresponds to a thicker nominal wall, but the actual thickness value must be checked for the specific NPS.

Q4. What Are the Standard Carbon Steel Pipe Sizes?

Standard carbon steel pipe sizes are identified by NPS, with corresponding DN and OD values. The Schedule specifies the nominal wall thickness for each NPS.

Q5. Is the Carbon Steel Pipe Schedule Chart Available in mm?

Yes. The chart provides OD and nominal wall thickness in millimeters, with NPS and inch-based dimensions shown for reference.

Related Resources

ANSI/ASME B36.10 Pipe Dimensions

SCH 40 vs SCH 80 Pipe

Schedule 40 Seamless Pipe Dimensions, Wall Thickness and Pressure Rating

Carbon Steel Seamless Pipe Weight Chart

Carbon Steel Pipes: Pressure-Temperature Ratings