Sdr Standard Dimension Ratio
Reference data and engineering information about sdr standard dimension ratio for standard organizations applications.
Overview
Engineering reference data for Sdr Standard Dimension Ratio in standard organizations.
Key Formulas
ISO Standard
Quality management systems.
ASTM Standard
Standard test methods for tension testing.
ANSI Standard
Pipe flanges and flanged fittings.
Variables
| Symbol | Description | Unit |
|---|---|---|
| International Organization for Standardization | — | |
| American Society for Testing and Materials | — | |
| American National Standards Institute | — |
Understanding SDR and Pressure Rating
The Standard Dimension Ratio directly indicates the pipe's wall thickness relative to its diameter:
| SDR Classification | Wall Thickness | Pressure Rating |
|---|---|---|
| High SDR (e.g., 64) | Thin wall | Lower pressure rating |
| Low SDR (e.g., 11) | Thick wall | Higher pressure rating |
This inverse relationship means SDR serves as a quick indicator of pressure capability without needing to know the exact dimensions.
Example: SDR Calculation
For a 10-inch ASTM D2241 PVC Pipe with:
- Outside diameter:
- Wall thickness:
An SDR of 64 means the outside diameter is 64 times the wall thickness.
Pipe Series (S)
The Pipe Series is a dimensionless number derived from SDR, used in some piping standards:
Where:
- = pipe series (dimensionless)
- = Standard Dimension Ratio
For the example above:
Relationship Summary
Both SDR and Pipe Series express the same geometric relationship—Pipe Series is simply re-centered relative to the wall thickness rather than the full diameter.