Except as provided in Section M102.0 for estimating the demand load for single- and multi-family dwellings, the size of each water piping system shall be determined in accordance with the procedure set forth in Appendix A. After determining the permissible friction loss per 100 feet (30480 mm) of pipe in accordance with Section A104.0 and the demand flow in accordance with the Water Demand Calculator, the diameter of the building supply pipe, branches and risers shall be obtained from Chart A105.1(1) through Chart A105.1(7), whichever is applicable, in accordance with Section A105.0 and Section A106.0. Velocities shall be in accordance with Section A107.0. Appendix I, Figure 3 and Figure 4 shall be permitted when sizing PEX systems.
The minimum fixture branch size shall be 1/2 inch (15 mm) in diameter.