This reveals that the minimum size for the leader pipe is 5.
Roof drains per square foot.
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.
Measuring the square feet of the roof along with knowledge of local rainstorms is invaluable when.
The next step is to consult table 1106 3 figure 2 to learn the required size of pipe.
Hy tech is an authorized distributor of all roof drain manufacturers so you can find what you need when you need it.
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.
Divide total roof area by area found in step 3 to obtain the number of drains required example.
Take the roof s total square footage and divide by the total square footage handled by one drain.
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.
Or 0312 gallons per minute 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.
Gallons per minute r rainfall intensity inches hour a roof area square feet 0104 conversion factor g p m 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.
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.
We also stock many of the top selling drains and parts onsite so most orders ship same day.
Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq.
Equals 32 6 or 33 drains required.
The number of roof drains shown should be verified with local code requirements.
Divided by the 4 600 sq.
Area roof will require 100 000 3070 32 5 or 33 roof drains for ideal drainage.
For 1 one inch hr.
Therefore the 100 000 sq.
The drains should be equally spaced and located symmetrically about the roof.
Drainage pipe required minimum diameter.
Use the following formula to determine g p m.
Round spee d catch basins.
50 000 4 400 11 36.
And then determine from the chart below how many roof drains you require.
Sizing data for conventional drainage.
0 submit your design let nds evaluate and help you with preparation of your submittal drawings and specs.
0104 x r x a g p m.
The result is the number of drains needed.
Using a 10 000 sq.
The downspout is the portion of the gutter that drains water away to a safe place on the ground.
Each drain can handle 4 600 sq.
