Concrete's thermal efficiency and adaptability means it's not only well placed to deliver the government's school construction and refurbishment programme, it can do so sustainably, says The Concrete Centre's Andrew Minson
The Sustainable Procurement Taskforce has singled out the £40bn Building Schools for the Future programme as an opportunity for the government to push sustainability and make a difference. In its report Procuring the Future, the taskforce calls for "the Treasury and the Department for Education and Skills to work with the BSF programme to ensure that it is meeting high sustainability standards".
It is here that concrete, with its inherent thermal efficiency, fire resistance, high levels of sound insulation, minimum vibration and robust finish goes to the top of the class. Not only that, but concrete buildings tend to have lower operating costs and maintenance requirements than those built of more lightweight materials.
Concrete's thermal mass is a particular advantage as it offers schools the potential to reduce their energy consumption and bills. Concrete acts as a thermal sponge, absorbing heat during the summer day, so cooling the building; the stored heat is released at night in readiness for the next day. This moderation of peak temperatures is called fabric energy storage: compared with air-conditioning, FES can reduce CO2 emissions by up to 50%. As about 90% of the environmental impact from buildings comes from heating, cooling and lighting, and only about 10% is from the embodied energy used to produce the fabric of the building itself (taken over a 60 year life-cycle), increasing the energy efficiency of school buildings through the use of concrete will significantly decrease their environmental impact.
Sustainability is about more than simply reducing energy consumption, it also means that buildings should be constructed to be adaptable for future use. In the short term, this may simply mean rearranging furniture; in the long term it may involve moving internal walls.
Concrete flat slabs or crosswall solutions, with large openings of up to 75% of the width of the classroom, allow classrooms to be joined together. Another design solution is to allow floors to span across rooms between beams or walls on the facade and corridor lines. This provides the possibility of using load-bearing cladding panels, which comprise a load bearing inner wall, insulation and an external decorative finish. These can be factory made or site-cast horizontally and tilted or lifted into position. Speed of construction is greatly enhanced when the insulation and cladding are installed with the structure.
The government has vowed to make all of its buildings carbon neutral by 2012 and cut emissions by 30% by 2020 and Procuring the Future believes that the major schools building programme being implemented should play an important part in achieving that. There is no doubt that concrete construction can significantly contribute to the sustainability standards being called for.
The Concrete Centre is to publish its report on school construction, High Performance Schools: Using Concrete Frames and Cladding, this summer.
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