Roof Drain Pipe Design

Take the roof s total square footage and divide by the total square footage handled by one drain.

Roof drain pipe design.

Enter table 1108 2 until you find a diameter pipe that will. A 5 inch diameter pipe with a 1 4 inch per foot slope will carry 4 720 sq ft. Horizontal drain 10 000 sq ft. Code tables outline pipe slopes of.

A minimum 5 inch diameter drain on a 1 4 inch per foot slope is required. 50 000 4 400 11 36. The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain. The published roof drain flow rate based on the head of water above the roof drain shall be used to size the storm drain drainage system in accordance with section 1106.

According to the chart for 1 8 slope per 12 of pipe for 5 000 square feet of roof area with a 6 per hour of rainfall the required pipe size is 8. The flow rate used for sizing the storm drainage piping shall be based on the maximum anticipated ponding on the roof. If you need help finding a drain ask our drain wizard or call to speak with our roof drain expert. 1 8 1 4 and 1 2 per foot.

The flexible design easily bends and holds its shape and can be extended from 25 in. Section 101 5 of the ipc tells us not to reduce the pipe size in the direction of flow. We also stock many of the top selling drains and parts onsite so most orders ship same day. Buried or underground roof drainage downspout defects clogging overflowing holes corrosion leaks that cause wet basements or crawl areas proper installation of buried downspout extensions proper installation of french drains seepage pits at flat sites gutter downspout defects cause wet basements crawl areas questions answers about installing maintaining repairing buried roof.

Or 12 drains required. To convert to an area for use in table 1108 2 do this. Hy tech is an authorized distributor of all roof drain manufacturers so you can find what you need when you need it. Rd rd 10 000 4 x 3 75 9 375 sq ft.

Section 1105 roof drains 1105 2 roof drain flow rate. The roof drainage outlets and rainwater downpipes are calculated based on the design principles for gravity drainage systems established in ss525 2006 code of practice for drainage of roofs. Use this downspout extension to divert water away from the foundation or connect to drainage pipe and catch basin to control drainage. Watts drainage products rd 300 r series 4 in.

Cast iron roof drain with 2 in. Pipe sizing is listed as amount of square foot roof areas served by the drains. But this isn t the whole story. The result is the number of drains needed.

Note that roof drain bodies and vertical conductors are sized utilizing a different table that a horizontally sloped storm line.