The development contains ten new buildings including a sports hall, reception, kitchen, vocational training workshops and a health and education unit. Skanska was contractually obliged to deliver an Excellent rating for all buildings on site as part of the MoJ’s ongoing sustainability drive.
The living unit was awarded a BREEAM Outstanding rating, with a score of 88%. A four-floor, concrete-framed building, the unit comprises 600 prison cells, dining and association space and an office. It also contains building management spaces. The plant room is located in the roof.
A feasibility study into all low and zero carbon technologies was undertaken at an early stage to establish the most appropriate technology for the type of building and the specific site requirements and restrictions.
The study looked at the demands of the building and provided analysis into payback and CO2 savings for each of the solutions. A large proportion of building materials and insulation are A/A* rated by the Green Guide to Specification.
The building is heated by biofuel boilers using waste vegetable oil from the prison kitchens. Control and server rooms are cooled using air source heat pumps while food composting and compactor facilities exist on site.
The water supply to each cell is automatically regulated. Sub-metering, water efficient sanitary ware and automatic shut-off to unoccupied areas help to further reduce consumption. Water is heated by the biofuel boilers.
The building’s energy strategy was awarded an EPC rating of 17, with CO2 halved by the biofuel boiler and air source heat pumps.
Security and cost
The predictable but unusual issue of security had to be considered at every stage of the design. Green technologies were approached from a safety standpoint.
Ray Handy, design director at Skanska, said: “Security’s paramount. It’s always a consideration. You can’t have too much attached to the roof. Or something that can be damaged and used as a weapon.”
Luckily, some of the more expensive green technologies also represented potential security hazards. Thetford says: “Roof mounted plant such as PV panels may have been a security issue, but these also were cost prohibitive and would not have provided the same CO2 reductions as the biofuel.”
Built on the previous Woolwich Arsenal site, substantial preparation was needed before construction could begin. The brownfield site was marshland and contaminated by military use but has now been restored.
Thetford says: “The main challenges included achieving ecological enhancements on a secure site.” Despite this, the site scored highly in this category, achieving 90%.
Black Poplar saplings - Britain’s most endangered tree- have been planted on site, having first been grown from seedlings in a stabilised environment then transported to site.
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