Drainage requirements once the drainage system is determined the designer must ensure positive drainage by correctly positioning the roof drains.
Overflow roof drain requirements.
An additional roof drain should be added for each 10 000 square foot area.
Desired rate of drainage safety overflow requirements emergency secondary overflow roof drains are recommended.
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.
Wade 3042 13 in bo roof and roof and overflow drain one piece bo overflow roof drain overflow roof drain with 2 in external.
1106 6 size of roof gutters horizontal gutters shall be sized based on the flow rate from the roof surface.
Local codes vary but it is recommended to provide a 1 to 1 ratio roof load the maximum possible rainwater build up load should be determined and provided to the structural engineer for inclusion in the roof structure design.
Overflow drains shall be the same size as the roof drains with the inlet flow line two inches above the low point of the roof and shall be installed independent from the roof drains.
A good rule to follow is to provide two roof drains for a total roof area less than 10 000 square feet.
To prevent dangerous building loading or even structural collapse roof drainage systems using an internal or piped roof drain system should provide for overflow drains to handle excess water volume and weight loading should the roof drainage system become blocked or prove inadequate in unusual conditions.
1106 6 size of roof gutters horizontal gutters shall be sized based on the flow rate from the roof surface.
Roof overflow drain requirements.
This is to prevent overflow scuppers from acting as primary drains.
The flow rate in horizontal gutters shall not exceed that specified in table 1106 6.
By the 1997 edition of the upc section 1101 11 2 had been added that completely prescribed where and how secondary roof drainage was to be provided.
The bottom edges of the overflow scuppers that you see on existing buildings today will almost always be about two inches above the adjacent roof surface.
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.
Parapet wall roof drainage scupper and overflow scupper location shall comply with the requirements of section 1503 4 of the florida building code building.
