Attenuating rainwater flow at source
Polypipe Terrain has developed a simple device to attenuate the flow of rainwater from roofs and podiums. Managing the run-off of rainwater is integral to successful SuDS (sustainable urban drainage systems). The Terrain flow control outlet, when used with Polypipe’s Permavoid system, removes the need for large conventional attenuation systems.
The Permavoid system enables rainwater to be stored and attenuated at roof and podium level. The flow-control outlet than releases the rainwater at a controlled rate.
The outlet fits within Polypipe Terrain’s range of large roof outlets. It can be rotated within itself to one of eight different positions to provide a different orifice cross-sectional area, depending on the required discharge rate specified from building planning applications.
The flow-control plate incorporates a 50 mm moulded socket in which a 50 mm section of pipe can be fitted, acting as a vent for downpipes and an overflow.
David Oliver, product manager, said, ‘Our complete rainwater-interception system offers not only designers and installers standard and water-discharge compliance but also allows for less compromise in the design process of the building.
‘It opens up an array of opportunities such as blue/green roofs and added commercial space.’
Flow tests have been carried out in accordance with BS EN 1253 to establish flow rates for a static head.