In short a scupper is a detail that provides drainage to a roof system by allowing the water runoff from the roof to exit the roof through a metal edge parapet wall or through the deck into a downspout or leader not run through the interior of the building.
Roof drain overflow scupper.
Scuppers will play one of two roles in a roof system.
Scuppers shall not have an opening dimension of less than 4 inches.
They will either be a part of the primary drainage system or they will be a part of the secondary overflow drainage system.
Scupper drain 11 3 4 inches wide x 11 3 4 high x 8 long deep drain opening area with 4 in.
Cast options ranging from iron to stainless steel.
Outer face and front lip 26ga galvanized steel with soldered seams.
Where you must drain through the wall with a scupper the overflow must be three times the required size of the roof drain and have a minimum height of 4 and again be installed no more than 2 above the roof low point.
Scupper building drainage zurn scupper roof drains from zurn manufactures a variety of sizes and finishes.