How To Size Roof Leader Collection Pipe Size

Step by step sizing of zurn drains step 1.

How to size roof leader collection pipe size.

What size of leader will be required to drain a roof 75 feet long by 50 feet wide. 3 size of leader required. 1 rate of precipitation. Determine 100 year 1 hour rainfall rate used for location of building.

1106 3 vertical leader sizing vertical leaders shall be sized based on the flow rate from horizontal gutters or the maximum flow rate through roof drains. Size vertical storm drainage piping. Step by step sizing of zurn drains. 1 inch 25 4 mm 1 foot 304 8 mm 1 gallon per minute 3 785 l m.

Calculate total roof area. 300 x 500 150 000 sq. 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. The next step is to determine each roof area that will be served by a separate leader drain pipe scupper or downspout.

Table 1106 2 storm drain pipe sizing for si. Select number of roof drains and calculate the roof area sloped to each drain. 75x50 solution 15 square inches and from table vi it is found that a 4 1 2 inch pipe has an area slightly greater than 15 inches. 2 total area of roof.

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. Roof area is 300 x 500 ft. And 4 area handled by each drain.