Description of construction: 1. Pipe installation elevation: Unless otherwise specified, the water supply pipe is calculated by the pipe center, and the drainage pipe is calculated by the pipe bottom. 2. Dimension unit: unless otherwise specified, the elevation is m, and the others are mm. 3. Where the water supply and drainage pipeline passes through the cast-in-place slab, roof, shear wall, column, etc., the casing shall be embedded. Where there is a waterproof requirement, the waterproof casing shall be welded. Casing size: water supply pipe is generally two gears larger than installation pipe, and drainage pipe is generally one gear larger than installation pipe