Counter flashing 28 metal.
Rain water roof pipe.
Description for besstem upvc rainwater fittings series domed roof outlet grating spigot end besstem upvc pipe fitting rainwater downpipe system bs en 12200 1 2000 besstem upvc pipe and fittings rainwater downpipes are generally manufactured from unplastized polyvinyl chloride pvc u.
The roof drainage outlets and rainwater downpipes are calculated based on the design principles for gravity drainage systems established in ss525 2006 code of practice for drainage of roofs.
As an example if the run of fall from a notional high point to a point of drainage is 20 meters then a minimal fall of 1 80 will see the roof level rise by 250mm.
The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain.
It is sometimes also referred to as a downspout drain spout roof drain pipe or leader.
Inside diameter black new construction or reroof thermoplastic vent pipe roof flashing model pb 312 4bk 19 97.
Metal roof flashing metal roofing trim paintable roof flashing rain diverter roof flashing 20x20 aluminum extrusion 4 inch pipe.
Once the roof levels are designed and approved the selection of the rainwater outlets can be reviewed.
On large roof areas having fewer outlets may cause a further design issue.