Flat Roof Scupper Size

4 roof drain 3 determine your building s location on the above map to determine the approximate rainfall as measured in inches per hour.

Flat roof scupper size.

Scuppers shall not have an opening dimension of less than 4 inches. If the scuppers are used as primary drainage then they are applied flush with the roof level. Ipc provides four steps to size the roof drains on a building. Size horizontal storm drainage piping.

Determine 100 year 1 hour rainfall rate used for location of building. Each scupper is draining 2 500 sq ft of roof area. Roof area is 200 x 500 100 000 sq. 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.

2 estimate the roof drain outlet size you will likely use. Scuppers are rectangular openings in parapet walls that are a minimum of 4 inches in width and height ranging from 4 to 6 inches. 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. 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.

1 calculate the roof area to be drained. Select number of roof drains and calculate the roof area sloped to each drain. Scuppers shall not have an opening dimension of less than 4 inches. 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.

To convert this roof area to an area for use with table a101 2 do this. 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. Enter table a101 2 to find a length and head that will carry 4 500 sq ft or more.