The Standard Dimensional Ratio (SDR) is used to describe the relationship between pipe diameter and wall thickness, and therefore, the pressure rating of the pipe.
SDR is defined as the ratio of the nominal outside diameter to the nominal wall thickness. SDR = dn/en Where dn is the nominal outside diameter of the pipe and en is the nominal (minimum) wall thickness of the pipe. Therefore a higher SDR indicates a thinner-walled pipe at any given diameter.
The ratio between the pipe OD and wall thickness remains constant for all pipe sizes for a given pressure rating, and can be expressed by a simple equation. For example: 250 (Pipe OD) / 22.8 (Wall Thickness) = SDR 11.
SDR = | Pipe Outside Diameter (Minimum) |
Pipe Wall Thickness (Minimum) |
Part of the conventional pipeline SDR parameter table, If you want to get more parameter sheets, please contact us,E-mail: phds@phtopindustry.com