Portobello Street

The Polypipe CGU team delivered a system that demonstrates how large diameter pipes can meet strict Sewers for Adoption guidelines, all while managing the traffic load from the road infrastructure.

Situated approximately three miles from Hull city centre, the Portobello Street development will provide 142 new homes for Homegroup and Hull City Council as part of the regeneration of this area of the city.

Polypipe CGU was approached to assist with the design and manufacture of a solution that met the requirements of Yorkshire Water and Hull City Council, and Polypipe CGU advised the use of large diameter plastic piping and modular manholes. Working closely with both parties, the team presented the benefits that the Polypipe CGU Ridgistorm-XL large diameter plastic pipe system could deliver over a traditional alternative.

Polypipe CGU ensured the solution fulfilled all Sewers for Adoption criteria, as well as achieving the conveyance and attenuation needs of the site. The engineered system design gained full Section 104 approval for the adoption of surface water run-off into their watercourse, and Section 38 approval for the installation of the system on the development site.

The final design incorporated over 231metres of 1200mm diameter Ridigstorm-XL large diameter plastic pipework, and the adaptability of the thermoplastic system meant that the Polypipe CGU pre-fabrication team could manufacture the pipework in a stiffness class tailored to the specific ground conditions at the location, without sacrificing overall strength and resilience.

The Ridgistorm-XL pipes were used to form four tanks to attenuate and convey surface water run-off from the development. Each tank was linked to a flow control chamber, featuring a flow control unit and penstock, to manage the release of surface water run-off into the approved watercourse.

A pre-installed weirwall in each of the chambers also provided a stable end connection to Yorkshire Water’s existing drainage system. Polypipe CGU was able to manufacture pipes and chambers with spigot and socket jointing to further reduce installation time, which also enables easy separation in the future.

With the thermoplastic structured wall system being up to 94% lighter in weight than concrete, it is already easier to handle and quicker to install, which ensured efficient installation at Portobello Street.

The design also included 12 pre-fabricated Ridgistorm-XL Manholes featuring ready-to-install access points that could be integrated at any part of the network system. The manholes were benched and channelled in accordance with Sewers for Adoption guidelines.

Trevor Smallman, Keepmoat Regeneration’s Project Manager, said: “Polypipe CGU provided a value engineered solution using Ridgistorm-XL tanks, with pipes manufactured to the perfect stiffness classification to meet our needs, together with convenient pre-fabricated pipework and manholes.

“This solution met the requirements of Yorkshire Water and Hull County Council, while also providing a robust and efficient system that was ideally suited to the development’s challenging conditions.”