Bennetts sets the green agenda
The Department of the Environment, Transport and the Regions is keeping close tabs on Bennetts Associates' new ultra-green Wessex Water Operations Centre in Bath as an exemplar of sustainable office development.
The practice finished the £21.5 million, 1,000m 2building as a Movement for Innovation (M4I) demonstration project in July, on time and to budget. It is crammed full of environmentally-friendly features and, claims the architect, exemplifies leading-edge green thinking. It attained the highest ever BREEAM 'Excellent' rating (79) in the commercial offices sector and 10 out of 10 in an environmental performance index.
Rab Bennetts, who chairs M4I's sustainability working group, said last week that as an extension of his role he will be monitoring how the building performs in the next 12 months and urged other architects to do the same with their projects.
'This industry suffers from a high turnover of staff so they don't know how their buildings are functioning, ' he said. 'The objective is to keep a low staff turnover and go back.We're terrible as an industry at learning from what we've done. It's fantastically important to keep in touch.'
Bennetts has formulated a series of measurable indicators for M4I - embodied energy, operational energy, transport energy, waste, water and biodiversity - which will be published later this year to help establish best practice in sustainability for the first time with targets for new buildings.Wessex Water in Bath will be the key example. The building, officially opened last week, came about after Bennetts won a competitive interview ahead of Nicholas Grimshaw and Partners and Feilden Clegg Architects.
The building is E-shaped in plan and has an annual energy consumption of 80-100kWh/m 2, far less than the current best practice of 150kWh/m 2and the 300400kWh/m 2of most headquarters offices. Built on the site of a former isolation hospital, it consists of three parallel wings of naturally-ventilated office accommodation which step down the Limpley Stoke Valley, echoing in part the orientation of the old buildings.A stepped 'street' down the building with views over the countryside contains reception space, meeting areas, library and a cafe.
To the west of the street the architects designed mechanically ventilated meeting rooms, training and community rooms and the control room. A restaurant, complete with an electronic 'swipe' payment system, spills out onto a terrace.
The clients managed to persuade the local authority that its 580 staff did not need additional car spaces in courtyards between the wings, so landscape architect Bernard Ede and Grant Associates could continue its 'unmanicured'wet and dry climate planting themed scheme there instead. It has only 270 car spaces, the company operates a bus shuttle service to the station and full cycle facilities are also on offer.
Solar heat gain is avoided by running the offices on an east-west axis, which also catches the prevailing wind, while night cooling comes from high level windows controlled by the building's management system. Lights are automatically dimmable while glare from the sun and heat gain are prevented by solar shading.Many materials are locally sourced, including railway sleepers which make up 40 per cent of the aggregate and furniture from Bath - as well as engineer Buro Happold.
Rainwater provides 95 per cent of WC flushing and £15,000 was saved by segregating construction waste - 70 per cent of waste was recycled.