Roof water drain types and sizing sizing a roof water drain.
Roof drain sizing.
3 size of leader required.
Area roof will require 100 000 3070 32 5 or 33 roof drains for ideal drainage.
Take the roof s total square footage and divide by the total square footage handled by one drain.
Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq.
The four things you will need to know are.
The result is the number of drains needed.
For example in the u k.
Product name manufacturer color bolt hole style lip to lip bolt to bolt 180 bolt to bolt bolt holes type of bolt used material.
1 rate of precipitation.
Click the table headings to sort by that column.
And then determine from the chart below how many roof drains you require.
2 total area of roof.
Conventional gutter systems such as those used on most houses are suitable for some low slope roofs.
The roof drain or gutter or drain piping or downspout leader size diameter other size constraints e g.
And 4 area handled by each drain.
The first step in sizing a roof drain is to calculate the surface area of the roof that the.
Designers specify compliance with bs en 12056 3 2000 that includes a calculation for the allowable capacity of the rainwater pipes.
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.
Or 12 drains required.
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.
For the purposes of this appendix the following metric conversions are applicable.
Therefore the 100 000 sq.
50 000 4 400 11 36.
The sizing of roof drains must be large enough to quickly carry away all water entering the roof drains.
Roof drain system and size the scuppers denoting the required head of water above the scupper for the structural engineer.
The sizing of the roof drainage system must consider all components.
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.
Zurn makes it easy to size roof drains.
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.
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.
