To design a sloped or flat roof drainage system we need to know several things.
Roof drainage pipe design.
A siphonic roof drain has a special insert that acts as an air baffle and anti vortex vane such that only water is drawn off of the roof not air.
Does not include branches of the building drain refer to table 710 1 1.
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.
Each leader must be large enough to handle the volume of water to be drained the greater the leader capacity the fewer roof drains are needed.
This reveals that the minimum size for the leader pipe is 5.
Code tables outline pipe slopes of.
1 8 1 4 and 1 2 per foot.
Use this downspout extension to divert water away from the foundation or connect to drainage pipe and catch basin to control drainage.
1 inch 25 4 mm.
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.
To size the vertical roof drain for the same parameters 5 000 square feet of room area and 6 per hour of rain consult table 1106 2 figure 3.
The intersection of the panels creates mitered valleys that direct wa ter into the roof drain.
Section 101 5 of the ipc tells us not to reduce the pipe size in the direction of flow.
In general roof drains are spaced equally and are located in low points of the roof or in any areas where water accumulates.
Note that roof drain bodies and vertical conductors are sized utilizing a different table that a horizontally sloped storm line.
The flexible design easily bends and holds its shape and can be extended from 25 in.
The maximum rainfall rate anticipated in the area where the building is located the flow in liters per minute per square meter for some x number of minutes.
Pipe sizing is listed as amount of square foot roof areas served by the drains.
But this isn t the whole story.
Crickets are additional layers of ta.
Stacks shall be sized based on the total accumulated connected load at each story or branch interval as the total accumulated connected load decreases stacks are permitted to be reduced in size.
Stack diameters shall not be reduced to less than one half of the diameter of the largest stack size.
The result is the number of drains needed.
Different horizontal sloping will offer different drainage capacities.
Or 12 drains required.
Unlike traditional roof drainage systems a siphonic system is designed to operate with the piping completely charged with water during a rainstorm.
50 000 4 400 11 36.
