water flow thru roof overflow scupper

[osto]

-searching for method to calculate roof overflow scupper width

-flat roof design, 1/4" per foot slope, with perimeter parapets

- typical scupper lip +/- 2" above drain

- we assume 2" head above scupper lip

 

[cvg]

try the weir equation and use a conservative value for the coefficient.

http://www.engineeringtoolbox.com/weirs-flow-rate-d_592.html

 

[PEDARRIN2]

Factory Mutual 1-54 Roof Loads for New Construction has an excellent section on roof scuppers (and general roof drain design).

You have to register (free) which gives you access to all their data sheets and stuff.