SEL Permavoid® and Roof Runoff
Dealing with the collection, initial treatment and control at source of rainwater runoff from roofs is an integral part of the surface water drainage design. There are two ways of collecting rainwater from roofs – either standard downpipes or siphonic collection. For a standard downpipe system, the SEL Source Control System incorporates a choice of two small diameter chambers (see Figs 2 and 3 below) with integral debris guard and sump prior to connection to SEL Permavoid® attenuation or infiltration systems, providing initial filtration and silt separation for the roof runoff.
For a siphonic drainage system, roof water is directed into the SEL Permavoid® units via pressure break silt chambers and bespoke manifold fabrications designed specifically to maintain the flow volume whilst reducing the high velocity of the siphonic collection system. The SEL Permavoid® units can be orientated in the configurations as used with the SEL Permachannel® bringing the same benefits of shallow construction, high permeability ratio (if being used for infiltration) and high void ratio (if being used for attenuation).
RWP connection to vertical soakaway
