Gateway Sixth Form College, Leicester

Leicester became Britain’s first “Environment City” in 1990. Gateway College is actively in support of the City’s environmental philosophy, and wanted its new building to respond to the City Council’s ambitions.

Energy conservation and creation was one of the top priorities for the building, and its fabric was designed to exceed current statutory requirements wherever possible.

Maximising daylight – The design maximises daylight, and lighting is supplemented using intelligent lighting controls and low energy fittings wherever possible. The light and airy central glazed atrium acts as the hub and heart of the college, and is protected by brise-soleil on the southern façade. Solar control glass is employed on the rest of the south facing glazing.
‘Visible sustainability’ – Gateway College takes on one particularly unusual and bold design statement; it is not very common for building plant to be put on display, but the college wanted to actively encourage its students to take an interest in the environment through the use of ‘visible’ sustainability. The energy centre is placed in a prominent public location at the front of the building, with large glazed panels allowing good views of the Biomass boiler, which provides low carbon heating to the building. The college have also installed a LCD display in their main entrance to display and monitor the ongoing performance of the PV panels and wind turbine, also linking this to its website.
Photovoltaic glass – In keeping with the sustainability statement, the front entrance is almost fully glazed with photovoltaic laminated double glazing. The PVs, which create a dramatic first impression of the college’s commitment to the environment, provide another bold and attractive reminder of the college’s many sustainability features and its willingness to embrace on-site energy reduction and generation. In combination with the solar control glazing, the dense arrangement of the PVs also contributes to limiting solar gain on this elevation.
Natural ventilation – The building is predominantly naturally ventilated, and windows and equipment linked to the building management system control heating and cooling. Most of the teaching pods off of the main atrium have exposed precast concrete plank ceilings. These provide thermal mass to improve thermal comfort in warmer months and to moderate temperature changes. Night-time cooling is achieved via high level windows linked to the BMS system.
Wind turbines – On-site electricity generation is also provided by the college’s wind turbine. A considerable amount of research had been conducted into providing a wind turbine that took advantage of the site’s elevation. The turbine and PV’s complement each other well, both aesthetically and in terms of energy reduction, between them generating a respectable amount of power for the college. In between term times, these installations will continue to provide energy back to the National Grid, thus building up an additional saving on energy costs for the College. Output from the wind turbine was also used during the project construction stage to provide power to the site accommodation.
Sustainable drainage – Due to the impermeable clay soils allowing little absorption and poor surrounding drainage infrastructure, a large number of attenuation tanks and swales have been installed to keep the water on site. Permeable paving beneath the car parking is lined to act as an attenuation tank.

Facts and figures

For the Part L2 building regs submission the final carbon emission calculation based on ‘as built’ i.e. real information, was 17.3 kgCO2/m2.annum. This is against a Notional Building score of 37kgCO2/m2.annum, so the building has a carbon footprint of less than half that of a new build college.
This was confirmed by the EPC score of 28 against a new build score of 46 for a similar building. This score gives the college a ‘B’ rating, as I explained on Friday, this would have been an ‘A’, the threshold being 26, if the solar thermal panels had been included despite the fact they and no additional impact on reducing he buildings carbon footprint.
Target air tightness was 7m3/h/m2 at design stage, the contractor would only guarantee 10m3/h/m2 (compliance with Part L), when the building was tested they achieved a range across the Blocks of 6.39 to 6.98m3/h/m2 with the sports hall at 2.1m3/h/m2.