2 estimate the roof drain outlet size you will likely use.
How to size roof leader collection pipe size.
Calculate drains needed.
Calculate total roof area.
Each drain will carry away is the size of leader therefore increasing leader size decreases the number of drains required.
The first step in sizing a roof drain is to calculate the surface area of the roof that the drains will be covering as well as the average hourly rainfall rate at the building location.
Determine the size of leader to be used.
In sizing roof drains and storm drainage piping one half of the area of any vertical wall that diverts rainwater to the roof shall be added to the projected roof area for inclusion in calculating the required size of vertical conductors leaders and horizontal storm drainage piping.
The above sizing data is offered as a guide only.
The result is the number of drains needed.
Take the roof s total square footage and divide by the total square footage handled by one drain.
In a roof drainage system you have many components.
That is what is wrong.
The pipe sizing is only one component.
The sizing of the roof drainage system must consider all components.
4 leader size is selected.
300 x 500 150 000 sq.
For the purposes of this appendix the following metric conversions are applicable.
To the table in figure 8 to determine the sizes of the various components of the conventional roof drainage system including roof drains vertical leaders and horizontal drainage piping.
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 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.
4 roof drain 3 determine your building s location on the above map to determine the approximate rainfall as measured in inches per hour.
1 calculate the roof area to be drained.
Roof area is 200 x 500 100 000 sq.
This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table.
Using figure 8 the 312 g p m.
Step by step sizing of zurn drains step 1.
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.
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.
Sizing a roof water drain.
Roof drain system and size the scuppers denoting the required head of water above the scupper for the structural engineer.
