What Is SDR in Pipes and How to Choose
SDR (Standard Dimension Ratio) is the ratio of a pipe's outer diameter to its wall thickness. The lower the SDR number, the thicker the wall and the higher the allowable working pressure. SDR17 is typical for water supply, SDR11 for gas pipelines.
How Does SDR Relate to Pressure?
At the same diameter, a lower-SDR pipe has a thicker wall and withstands higher pressure. For example, PE100 SDR17 is rated for approximately 10 atm, while SDR11 handles 16 atm. SDR selection is based on the design working pressure with the required safety margin.
Which SDR to Choose for Water and Gas?
SDR17 is usually sufficient for drinking and technical water supply. Gas pipelines under СТ РК ГОСТ Р 50838-2011 / СТ РК ISO 4437-2014 require SDR11. When network pressure is elevated or water hammer is a concern, a heavier-wall class is used. Exact selection is always made project-specific.