The result is the number of drains needed.
Roof drains per square foot.
We also stock many of the top selling drains and parts onsite so most orders ship same day.
50 000 4 400 11 36.
0 submit your design let nds evaluate and help you with preparation of your submittal drawings and specs.
0 gallons 0 cubic feet.
For 1 one inch hr.
Roof area the 3 inch rainfall will produce 18 700 gallons in one hour at the rate of 312 gallons per minute.
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.
Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq.
Area roof will require 100 000 3070 32 5 or 33 roof drains for ideal drainage.
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.
Equals 32 6 or 33 drains required.
0 cubic feet per second cfs peak runoff volume.
Therefore the 100 000 sq.
Using a 10 000 sq.
If you need help finding a drain ask our drain wizard or call to speak with our roof drain expert.
The speed at which the rain collects at the drain.
Hy tech is an authorized distributor of all roof drain manufacturers so you can find what you need when you need it.
Each drain can handle 4 600 sq.
Round spee d catch basins.
0104 x r x a g p m.
Or 12 drains required.
The drains should be equally spaced and located symmetrically about the roof.
This reveals that the minimum size for the leader pipe is 5.
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.
Divided by the 4 600 sq.
Use the following formula to determine g p m.
Take the roof s total square footage and divide by the total square footage handled by one drain.
Divide total roof area by area found in step 3 to obtain the number of drains required example.
Sizing data for conventional drainage.
And then determine from the chart below how many roof drains you require.
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 number of roof drains shown should be verified with local code requirements.
Or 0312 gallons per minute sq.
Drainage pipe required minimum diameter.
