CTS - Copper Tube Sizes - Dimensions used in Plumbing
1⁄4. 3⁄8. 1⁄2. 5⁄8. 3⁄4. Wall-thicknesses used for plumbing in the U.S. and Canada are the CTS - Copper Tube Sizes - Type K, L and M. In Europe the wall-thicknesses used are based on BS 2871 Copper Tubes Type X, Y and Z / EN 1057 Copper and copper alloys. Seamless, round copper tubes for water and gas in sanitary and heating applications.