EN 12056-3 : Gravity drainage systems inside buildings - Part 3 : Roof drainage, layout and calculation.

This European Standard applies to gravity-operated wastewater drainage systems within residential, commercial, institutional, and industrial buildings. Part 3 specifies a method for assessing the hydraulic capacity of non-siphonic roof drainage systems and defines the performance requirements for siphonic roof drainage systems. It also establishes requirements for the design and installation of roof drainage systems where these influence hydraulic performance and flow capacity.