New research goes down the drain
A unique collaboration between a Civil Engineer at the University of Sheffield and a local company has produced a drainage system which is up to 8 times more efficient than the standard system found on homes and buildings across the country.
The system is known as 'siphonic' drainage, and has been used widely across the world, including the UK, since it was first introduced in the 1960s. Many large industrial, commercial and retail buildings are fitted with siphonic drainage, which has clear advantages over traditional 'gravity' drainage systems. Kieran Williams and Professor Adrian Saul of the Department of Civil and Structural Engineering are working with local roof drainage specialists Fullflow to develop the new system.
'Gravity' drainage, involving the familiar gutter and downpipe arrangement, is relatively inefficient at draining water. Gravity causes the water to 'spin' as it drains from the gutter into the downpipe which means that the water 'hugs' the sides of the pipe. The result is that up to two thirds of the downpipe is made up of air, which makes the system relatively inefficient.
In contrast, siphonic drainage expels air from the system which allows for a greater flow rate. Since the system is under negative pressure (i.e. the water pushes inwards as opposed to outwards), the team employed software designers to test the system for areas of negative pressure, to avoid the possibility of the pipe imploding, or collapsing in on itself.
The team's siphonic drainage system offers a number of key benefits, as Kieran explains: "The system uses around 80% fewer downpipes and fewer outlets, thereby saving on cost. Compared to gravity drainage, the design is flexible and aesthetically pleasing, since pipes can be fitted horizontally, and only one or two downpipes are needed per gutter, freeing internal space. Underground drainage is also reduced, further saving on cost. Perhaps most importantly, siphonic drainage systems can cope with up to 8 times the flow of standard systems, thereby offering much greater performance".
Since siphonic drainage systems only require one pipe, this can be hidden very easily and offers a number of benefits to architects. The team's system has been used on a several very large constructions, typically in excess of 10,000 square feet, including a number of English football stadiums (Stamford Bridge, Hillsborough Stadium and Old Trafford) and Madrid airport, among others.
The University of Sheffield is one of only three institutions in the world working on the development of syphonic drainage, the other two being the University of South Australia in Adelaide and Heriot-Watt University in Edinburgh. Thanks to the Engineering and Physical Research Council (EPSRC) loan pool, Kieran has secured the use of a high speed camera capable of taking up to 10,000 frames per second, to experimentally verify whether the system is behaving as the team´s calculations suggests it should.
For further information, please contact Kieran Williams at:
email : kieran.williams@sheffield.ac.uk
Suggested links
The Penine Water Group at the University of Sheffield