To convert to an area for a 4 inch per hour rainfall to enter table 1108 1 do this.
How to size roof storm drains.
When sizing roof drains the limiting factor for the amount of water each drain will carry away is the size of leader therefore increasing leader size decreases the number of drains required.
For horizontal pipes or leaders receiving two or more roof drains.
Enter table 1108 1 until you find a diameter pipe that will carry 2 344 sq ft.
2 500 4 x 3 75 2 344 sq ft.
2 total area of roof.
The four things you will need to know are.
And 4 area handled by each drain.
The four things you will need to know are.
A minimum 4 inch vertical drain is required.
Determine leader or pipe size.
2 3 4 5 6.
Step by step instructions step 1.
2 3 4 5 6 and 8 in.
Select a reference of a roof drain size with hourly rainfall together with the roof area square footage you have estimated and then determine from the chart below how many roof drains you require.
Calculate total roof area.
Roof drain connected to a 6 in.
For multiple walls use 50 percent of the maximum projected area of all walls.
Following this logic it is possible that for roof drains 6 in.
For drain areas between two opposite walls add no additional area.
Sizing data for conventional drainage storm drainage sizing precipitation rate inches hour based on 15 minute precipitation zurn makes it easy to size roof drains.
3 size of leader required.
1 rate of precipitation.
Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq.
2 total area of roof.
1 rate of precipitation.
3 size of leader required.
Or less in diameter the piping will be larger in diameter than the roof drain.
Calculate the total roof area by multiplying its length by width.
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If the area of each wall is not the same add 50 percent of the difference between the two areas.
Zurn makes it easy to size roof drains.
Each vertical drain must carry 2 500 sq ft of roof area at 3 75 inches per hour of rainfall.
For larger roof drains the pipe may be smaller such as a 10 in.
Ipc provides four steps to size the roof drains on a building.
Determine 100 year 1 hour rainfall rate used for location of building select number of roof drains and calculate the roof area sloped to each drain size horizontal storm drainage piping size vertical storm drainage piping.
