Roof Drains Per Square Foot

The downspout is the portion of the gutter that drains water away to a safe place on the ground.

Roof drains per square foot. Drainage pipe required minimum diameter. Use the following formula to determine g p m. 0104 x r x a g p m. Divide total roof area by area found in step 3 to obtain the number of drains required example.

The number of roof drains shown should be verified with local code requirements. Round spee d catch basins. 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. Gallons per minute r rainfall intensity inches hour a roof area square feet 0104 conversion factor g p m sq.

The speed at which the rain collects at the drain. Divided by the 4 600 sq. 0 submit your design let nds evaluate and help you with preparation of your submittal drawings and specs. 50 000 4 400 11 36.

Therefore the 100 000 sq. 0 gallons 0 cubic feet. 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. For 1 one inch hr.

The drains should be equally spaced and located symmetrically about the roof. If you need help finding a drain ask our drain wizard or call to speak with our roof drain expert. Equals 32 6 or 33 drains required. We also stock many of the top selling drains and parts onsite so most orders ship same day.

Area roof will require 100 000 3070 32 5 or 33 roof drains for ideal drainage. And then determine from the chart below how many roof drains you require. 0 cubic feet per second cfs peak runoff volume. Take the roof s total square footage and divide by the total square footage handled by one drain.

Or 12 drains required. 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. This reveals that the minimum size for the leader pipe is 5. Measuring the square feet of the roof along with knowledge of local rainstorms is invaluable when.

Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq. Each drain can handle 4 600 sq. Or 0312 gallons per minute sq. Using a 10 000 sq.

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. The result is the number of drains needed.