Taylor Wimpey’s latest large-scale residential development has benefited from a large diameter stormwater attenuation tank from Polypipe.
Boasting a mix of two, three and four-bedroom homes in the idyllic Bedfordshire countryside, the 180-property Regent’s Place development in Houghton Regis utilised Polypipe’s Ridgistorm-XL large diameter piping system for a surface water attenuation system.
The system met the requirements of the site and has been to be adopted under Section 104 Agreement by Anglian Water.
Taking into account the needs of the site and local ground conditions, Polypipe worked closely with Taylor Wimpey and Consulting Engineer JPP Consulting to design an attenuation tank utilising more than 500m of Polypipe’s 2100mm Ridgistorm-XL large diameter piping system. The attenuation tank can store more than 2,052m3 of stormwater in order to cater for to both ‘1 in 30’ year and ‘1 in 100 plus 30% climate change’ year storm events.
As well as needing to cope with such storm demands, the tank was also required to sit beneath a public open space with limited footprint and a sloping gradient. The design challenge was enthusiastically taken up by the Polypipe team, who produced a tank with staggered legs to take into account conditions at the site.
Over 500m of Ridgistorm-XL was supplied, totalling to 14 Ridgistorm-XL pipe runs in 2100mm diameters. The pipe was engineered to ring stiffness SN2 by Polypipe’s technical engineers to meet ground conditions, burial depths, native soil pressures and loading on site. The system passes the required deformation and buckling checks in accordance with BS EN 1295-1.
As well as the tank’s pipe runs, the Ridgistorm-XL system incorporated a total of 34 pre-fabricated modularised fittings. This included impressive 90° bends and ‘F’, ‘T’ and double ‘T’ fittings to keep jointing to a minimum in order to save time on site and cost. The socket and spigot nature of the systems pipes and fittings allowed for easier pipe alignment and for a quicker installation utilising the electro-fusion welding jointing method.
Along with x10 RIDGISTORMAccess Manholes in diameters 1200mm and 1800mm installed for ongoing maintenance work, the attenuation tank at Regent’s Park boasts an offset 3m diameter RIDGISTORMCheck Vortex Flow Control Chamber. This controls the discharge of water from the attenuation tank at a rate of 10l/s so as not to overwhelm the local watercourse. The chamber also features a penstock flow controller to provide additional flow control when required.
Keith Millard, Senior Engineer at Taylor Wimpey said: “Polypipe designed the required stormwater attenuation system to not only fit the available area, but it also saved us time and costs on the installation by delivering the system and fittings as one piece modular units ready to install.”
Emma Nicholls, Marketing Manager at Polypipe, said: “As the UK’s leading manufacturer of sustainable drainage and water management products, we often get requests from clients to provide a response to some interesting design and engineering challenges.
“In this instance the lack of space on site, along with the sloping ground, meant that we had to provide a solution that exactly met the needs of the client and satisfied the approving water company. I’m pleased to say that we were able to do both by producing a truly unique, engineered solution.”
