The number of roof drains shown should be verified with local code requirements.
Roof drains per square foot.
Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq.
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Round spee d catch basins.
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For 1 one inch hr.
Therefore the 100 000 sq.
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.
Area roof will require 100 000 3070 32 5 or 33 roof drains for ideal drainage.
Drainage pipe required minimum diameter.
Each drain can handle 4 600 sq.
They come in a variety of shapes tubes chains etc but their goal is to prevent gutters from overflowing and give water somewhere to go.
This reveals that the minimum size for the leader pipe is 5.
The drains should be equally spaced and located symmetrically about the roof.
Sizing data for conventional drainage.
50 000 4 400 11 36.
Use the following formula to determine g p m.
The roof drain calculator below is based on the maximum amount of rainfall in inches per hour of the hypothetical worst storm in the past 100 years and which has a two percent chance of occurring in any given year.
Divided by the 4 600 sq.
The result is the number of drains needed.
Take the roof s total square footage and divide by the total square footage handled by one drain.
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Equals 32 6 or 33 drains required.
0 cubic feet per second cfs peak runoff volume.
Roof area the 3 inch rainfall will produce 18 700 gallons in one hour at the rate of 312 gallons per minute.
And then determine from the chart below how many roof drains you require.
Or 0312 gallons per minute sq.
Gallons per minute r rainfall intensity inches hour a roof area square feet 0104 conversion factor g p m sq.
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.
0104 x r x a g p m.
We also stock many of the top selling drains and parts onsite so most orders ship same day.
The speed at which the rain collects at the drain.
For example a 3 inch per hour rainfall will build up to a 3 inch depth on a flat roof in one hour at the rate of 1 87 gallons per hour sq.
The next step is to consult table 1106 3 figure 2 to learn the required size of pipe.
0 gallons 0 cubic feet.
The downspout is the portion of the gutter that drains water away to a safe place on the ground.
Using a 10 000 sq.
