Following the successful trial of non-entry inspection chambers in adoptable sewers on a new housing development, Wavin Plastics has produced a DVD to showcase their successful project and encourage other water companies and house builders to adopt this innovative approach to drainage.

The video documents how this pioneering product has benefited a brand new community in Leeds, following a joint partnership between Wavin Plastics, Yorkshire Water and Miller Homes.

The site – Allerton Bywater Millennium Village – which is one of seven English Partnership Millennium Communities, has been designed according to Planning Policy Guidance 3 (PPG3) principles. This has meant a high housing density has been achieved, which has in turn resulted in the reduction of physical space for drainage. Due to these factors, Yorkshire Water agreed to a trial of non-entry inspection chambers for use in both demarcation and main adoptable sewers.

“Yorkshire Water took a very bold step in embracing this idea of using non-entry inspection chambers on adoptable main sewers,” commented Lynton Barstow, Wavin Plastics. “This was a major breakthrough and is a principle that to date has not been considered by any other water authority. By publicising Allerton Bywater through our DVD, we hope that more water companies will consider the use of non-entry inspection chambers on adoptable sewers in the future.”

Non-entry inspection chambers, like those used at Allerton Bywater, are a welcome alternative to traditional concrete manholes. Wavin Plastic’s product, OSMA Tegra 600, has been manufactured to provide easy installation, inspection and maintenance primarily to non-adoptable domestic and commercial drainage systems.

This innovative non-entry inspection chamber is a much safer and cost-effective alternative to traditional concrete ring manholes during installation and occupation.

Tegra 600 is constructed from strong polypropylene. It is much lighter and easier to handle on site than large concrete manholes, which need to be lifted into place by heavy machinery. The Tegra 600 chamber can be installed by hand and backfilled in a day, typically three times faster than a concrete manhole. The result of this speed of installation is means a significant cut in costs.

Trevor Birch, new development manager, Yorkshire Water, commented:
“We had actually been considering the use of smaller, non-man entry, plastic inspection chambers for some time, so it was excellent timing when we were approached to take part in this trial. The high density housing at Allerton Bywater means that space is at a premium and therefore the site provided us with a good opportunity to look at the method, and to combine the use of plastic pipes and inspection chambers.”

Carolyn Rushbrook, sales and marketing director of Miller Homes, Yorkshire region, commented:
“We are delighted to have pioneered these non-entry inspection chambers at Allerton Bywater. The ground-breaking health and safety implications for those working on site made them the perfect choice for a development as innovative as Allerton Bywater Millennium Village.”

The installation advantages and health and safety benefits associated with Wavin Plastic’s OSMA non-entry inspection chambers were particularly important to Hewlett Civil Engineering, the site’s contractors.

Jim Roberts, Hewlett site manager, commented:

“The speed that this system can be installed has given some great savings to programme time and cost. In fact 95% of the first phase of ground works at Allerton Bywater has been completed ahead of schedule. And the fact that we were handling material which was so light in weight in comparison to the conventional clay or concrete drainage systems was the biggest plus for us with regard to safety.”

The Allerton Bywater Millennium Community has rejuvenated and expanded the former mining village with new housing, commercial and community space. The site comprises 520 homes and 25,000m ²of commercial and community space.