Roof Drain Sizing

1 in 25 4 mm 1 ft 305 mm 1 ft2 0 0929 m2 100 0 figure a101 1 example roof plan 4 a 101 2 solution.

Roof drain sizing.

And 4 area handled by each drain. 2 total area of roof. Take the roof s total square footage and divide by the total square footage handled by one drain. 1 rate of precipitation.

The sizing of roof drains must be large enough to quickly carry away all water entering the roof drains. Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq. For the purposes of this appendix the following metric conversions are applicable. Therefore the 100 000 sq.

Factors which affect proper roof drainage are deck slope drain size and placement of drains. 3 size of leader required. Roof drain system and size the scuppers denoting the required head of water above the scupper for the structural engineer. 50 000 4 400 11 36.

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 four things you will need to know are. The rain storm the flow of rainwater on the roof surface the ability of the roof drain to move the water from the roof to the piping the vertical piping the horizontal piping and the connection to the point of discharge. How to measure roof drain parts.

Click the table headings to sort by that column. The full flow capacity of a drain is not realized until the water reaches approximately 2 5 above the inlet in a four inch drain and 3 5 in a six inch drain. Designers specify compliance with bs en 12056 3 2000 that includes a calculation for the allowable capacity of the rainwater pipes. The result is the number of drains needed.

Roof water drain types and sizing sizing a roof water drain. Zurn makes it easy to size roof drains. Area roof will require 100 000 3070 32 5 or 33 roof drains for ideal drainage. The first step in sizing a roof drain is to calculate the surface area of the roof that the.

And then determine from the chart below how many roof drains you require. Or 12 drains required. The sizing of the roof drainage system must consider all components. The roof drain or gutter or drain piping or downspout leader size diameter other size constraints e g.

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. When sizing roof drains the limiting factor for the amount of water each drain will carry away is the size of leader therefore increasing leader size decreases the number of drains required.