How To Size Roof Storm Drains

For larger roof drains the pipe may be smaller such as a 10 in.

How to size roof storm drains. To convert to an area for a 4 inch per hour rainfall to enter table 1108 1 do this. 2 total area of roof. Following this logic it is possible that for roof drains 6 in. Roof drain connected to an 8 in.

Zurn makes it easy to size roof drains. For example a 4 in. 2 3 4 5 6 and 8 in. Enter table 1108 1 until you find a diameter pipe that will carry 2 344 sq ft.

Determine leader or pipe size. Sizing data for conventional drainage storm drainage sizing precipitation rate inches hour based on 15 minute precipitation zurn makes it easy to size roof drains. Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq. Roof drainage 2016 05 11 plumbing advanced drainage systems sizing a gravity pipe work water surface pros for storm sewers sizing a gravity pipe work four s to sizing roof drains c1scapacities of sewer pipespipe sizing charts tables energy modelsdrain and sewer pipe size home owners workfour s to sizing roof drains c1scapacities of sewer.

Roof drain connected to a 6 in. Calculate the total roof area by multiplying its length by width. For horizontal pipes or leaders receiving two or more roof drains. 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.

If the area of each wall is not the same add 50 percent of the difference between the two areas. The four things you will need to know are. The four things you will need to know are. For drain areas between two opposite walls add no additional area.

A minimum 4 inch vertical drain is required. 1 rate of precipitation. Ipc provides four steps to size the roof drains on a building. For multiple walls use 50 percent of the maximum projected area of all walls.

Select a reference of a roof drain size with hourly rainfall together with the roof area square footage you have estimated and then determine from the chart below how many roof drains you require. Each vertical drain must carry 2 500 sq ft of roof area at 3 75 inches per hour of rainfall. 2 3 4 5 6. 2 total area of roof.

Calculate total roof area. Or less in diameter the piping will be larger in diameter than the roof drain. 2 500 4 x 3 75 2 344 sq ft. Step by step instructions step 1.

3 size of leader required. Determine 100 year 1 hour rainfall rate used for location of building select number of roof drains and calculate the roof area sloped to each drain size horizontal storm drainage piping size vertical storm drainage piping. And 4 area handled by each drain.