Roof Drains Per Square Foot

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Roof drains per square foot.

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. 0 gallons 0 cubic feet. The next step is to consult table 1106 3 figure 2 to learn the required size of pipe. Gallons per minute r rainfall intensity inches hour a roof area square feet 0104 conversion factor g p m sq.

Take the roof s total square footage and divide by the total square footage handled by one drain. And then determine from the chart below how many roof drains you require. Measuring the square feet of the roof along with knowledge of local rainstorms is invaluable when. The speed at which the rain collects at the drain.

Divided by the 4 600 sq. Or 0312 gallons per minute sq. Equals 32 6 or 33 drains required. Divide total roof area by area found in step 3 to obtain the number of drains required example.

0 submit your design let nds evaluate and help you with preparation of your submittal drawings and specs. The result is the number of drains needed. 50 000 4 400 11 36. Roof area the 3 inch rainfall will produce 18 700 gallons in one hour at the rate of 312 gallons per minute.

Therefore the 100 000 sq. The drains should be equally spaced and located symmetrically about the roof. For 1 one inch hr. Hy tech is an authorized distributor of all roof drain manufacturers so you can find what you need when you need it.

Drainage pipe required minimum diameter. Each drain can handle 4 600 sq. The number of roof drains shown should be verified with local code requirements. Use the following formula to determine g p m.

Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq. Sizing data for conventional drainage. 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. 0 cubic feet per second cfs peak runoff volume.

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 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. 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.

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. The downspout is the portion of the gutter that drains water away to a safe place on the ground. Area roof will require 100 000 3070 32 5 or 33 roof drains for ideal drainage. Or 12 drains required.