This Architectural Drawing is drainage piping layout of roof in commercial building. This is a 5 story commercial building. A drainage plan should look at how rainwater flows in and out of a building. It should include where it flows into the ground, downpipes, or drains into storm sewers. It should also ensure that water can reach where it needs to go without flooding and cause backups in sewer pipes or septic tanks. For more details and information download the drawing file.