They will either be a part of the primary drainage system or they will be a part of the secondary overflow drainage system a primary drainage system is designed to remove water from the roof as quickly as possible.
Roof drain vs scupper.
An overflow drainage system will be designed to function independently of the primary system to drain water from the roof.
Roof drain speaking the language of a roofing contractor can be a difficult skill to master.
A drainage hole on the deck of a ship.
Roof drain speaking the language of a roofing contractor can be a difficult skill to master.
The best is to have a wide scupper 12 or wider so leaves and debris will wash through the scupper instead of clogging it.
Most professions develop a unique vernacular over time that allows members of the profession to speak about details and projects with ease.
Where roof drains are required secondary emergency overflow roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason.
A similar opening in a wall or parapet that allows water to drain from a roof.
Scuppers can let the water drop off the roof to the ground or can lead into a gutter system.
Scuppers are a very effective way to channel water off a roof.