Sizing a roof water drain the first step in sizing a roof drain is to calculate the surface area of the roof that the drains will be covering as well as the average hourly rainfall rate at the building location.
Roof drain leader pipe.
The next step is to determine each roof area that will be served by a separate leader drain pipe scupper or downspout.
This flexible downspout extension easily bends and holds its shape and can be extended from 25 55 in.
A downspout waterspout downpipe drain spout roof drain pipe leader is a pipe for carrying rainwater from a rain gutter.
Featuring durable plastic construction this extension can be buried bent or connected to additional sections.
Downspouts are drainage pipes that direct rain water from the roof to the ground.
Vertical and horizontal storm drain piping shall be sized based on the flow rate through the roof drain.
Downspouts are usually vertical and usually extend down to ground level.
Table 1106 2 storm drain pipe sizing for si.
Divide roof area 1 by area per leader 4 to determine the number of drains required.
Approximate leader drain pipe size.
The flow rate in storm drain piping shall not exceed that specified in table 1106 2.
Roof drain selection.
Use this downspout extension to divert water away from the foundation or connect to drainage pipe and catch basin to control drainage.
There is generally a bend of 70 degrees at the bottom.
Reference leader size with hourly rainfall rate to determine roof area drained by each leader chart b.