Flat Roof Scupper Size

Select number of roof drains and calculate the roof area sloped to each drain.

Flat roof scupper size.

Scuppers are rectangular openings in parapet walls that are a minimum of 4 inches in width and height ranging from 4 to 6 inches. When scuppers are used for secondary emergency overflow roof drainage the quantity size location and inlet elevation of the scuppers shall be sized to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by section 1611 1. Size horizontal storm drainage piping. Scuppers shall not have an opening dimension of less than 4 inches.

4 roof drain 3 determine your building s location on the above map to determine the approximate rainfall as measured in inches per hour. To convert this roof area to an area for use with table a101 2 do this. 1 4 in ft slope building storm drain 2 500 4 x 7 2 9 375 sq ft 4 500 sq ft. 2 estimate the roof drain outlet size you will likely use.

This wizard makes it easy to calculate the roof design area by providing various shape calculations and the calculation for vertical walls area per international plumbing code ipc. Remember when making your selections that roof drains are available in 3 4 and 6 diameters and scupper drains are available in 2 3 and 4 diameters. The only unconditional guideline for scupper sizing provided by the code is that scupper openings shall be not less than 4 inches 102 mm in height and have a width that is equal to or greater than the circumference of a roof drain sized for the same roof area so we can at least be certain that round scuppers can t have a diameter of less than 4 inches and rectangular scuppers can t have any side be less than 4 inches. Each scupper is draining 2 500 sq ft of roof area.

The gutter and downspout size requirement depends upon the number of sections and length of the gutter sections as well as the number of downspouts. 1 calculate the roof area to be drained. Roof area is 200 x 500 100 000 sq. Determine 100 year 1 hour rainfall rate used for location of building.

Enter table a101 2 to find a length and head that will carry 4 500 sq ft or more. Size vertical storm drainage piping. Ipc provides four steps to size the roof drains on a building.