Ibc Roof Drain Sizing

Roof drain vertical requirement for horizontal roof areas at various rainfall rates leader size hourly rainfall in inches pipe open 1 1 1 2 2 2 1 2 3 4 5 6 7 8 size area inches sq.

Ibc roof drain sizing.

The flow rate used for sizing the storm drainage piping shall be based on the maximum anticipated ponding on the roof. The minimum size of any building drain serving a water closet shall be 3 inches. Or less in diameter the piping will be larger in diameter than the roof drain. The result is a roof collapse.

Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq. 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. The result is the number of drains needed. 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.

Design and installation of roof drainage systems shall comply with section 1503 of this code and sections 1106 and 1108 as applicable of the international plumbing code. Following this logic it is possible that for roof drains 6 in. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. The flow rate in storm drain piping shall not exceed that specified in table 1106 2.

50 000 4 400 11 36. 2 500 4 x 3 75 2 344 sq ft. The roof drain typically will not remove the water as fast as you may think. 1106 2 size of storm drain piping.

Roof drain connected to a 6 in. 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. To convert to an area for a 4 inch per hour rainfall to enter table 1108 1 do this. Each vertical drain must carry 2 500 sq ft of roof area at 3 75 inches per hour of rainfall.

The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. Or 12 drains required. P 1503 4 roof drainage. In total square footage covered per drain 23 14 2 880 1 920 1 440 1 150 960 720 575 480 410 360.

Example roof plan 4 a 101 2 solution. From figure 1108 4 the 100 year 60 minute precipitation is 3 75 inches per hour. P 1503 4 1 secondary emergency overflow drains or scuppers. Vertical and horizontal storm drain piping shall be sized based on the flow rate through the roof drain.

Take the roof s total square footage and divide by the total square footage handled by one drain.