“what were your results?”
easier to test and harder to destroy later on by, for example, punching a power point through it. Furthermore, the insulation should wrap the building with
the structure inside it unbroken – even if things don’t line up properly. For example, if you are designing a detail at parapet level you try to join the lines of insulation together externally. It’s not the usual, we know, but it helps to avoid thermal and cold bridging. Our approach is to use the minimal budget for robust details. We would usually use prefabricated timber frame on our
schools, insulated after installation. However, under the EFA we work on frameworks and the contractor generally goes with steel frame and poured concrete. We have tried to push them on timber frame, because environmentally we think it’s the best way to go, but they haven’t gone with it. We can only assume it is a cost issue. Another place we had worked out a cunning timber solu-
tion was reducing noise inside the schools by creating acoustic wall panels from off-the-shelf CNC and birch-based plywood. But with these costs, we have little choice but to use ceiling tiles to absorb sound. For the MVHR we would have used before, the team goes
with Breathing Buildings, a low-energy ventilation system that is proving popular among specifiers. In summary, the EFA schools are certainly basic, and if you
are – like us – trying to push the boundaries of PH, you will find experimenting in other sectors is the way to go!”
Mark Allen, head of technical for Saint Gobain Choose technology for efficiency
“Software can be the key to not only building more efficient schools’ envelopes, but creating a better quality of life for its inhabitants. DIAL is a German company that has created a free tech-
nology that helps designers create suitable artificial versus natural lighting designs in buildings. Using the tool, a school envelope is entered tagged to a particular global location and orientation and the programme will give lux values and relative visual simulations throughout using coloured squares for comparison. The benefit of this is that you are able to accurately model
the best place to put windows to maintain the correct lux values. This helps with energy conservation while providing adequate internal comfort along with correct temperatures to propagate maximum productivity in a learning environment. Many contemporary buildings are poorly designed from a lighting point of view because we use simple 1970 metrics like day-lighting factors. This can result in as-built performance, having in glare on the south side and it being too dark on the north, simply because the metric is too simple. Better design will lead to efficiencies and savings and cor-
rect lux values by choosing the right glazing characteristics and window frames, light fittings – and paint colours!
The other benefit is that by remaining in control of glare,
you can reduce the need for blinds, which subsequently then require artificial lighting. This uses excessive energy, but also produces unwanted heat, so you can control the comfort requirements of a building and reduce potential for overheat- ing and thereby remove the desire for mechanical cooling, together with related items which cost to run, maintain etc. If we do need to design for overheating then we can use
Rigidor boards on internal partitions or concrete, and, because we have optimised the solar gains versus internal lighting quality, many of the parameters that increase the overheating scenario are removed. We can therefore also optimise the requirement of heat sink materials to allow a flexibility building solution without the requirement for large thick con- crete structures. With regard to thermal mass of the envelope, there seems to
be a misunderstanding that thicker walls absorb more heat. But in fact it is only the first 100mm of dense materials that forms the heat sink and so thin layers of product can combat overheating without the excessive use of air-conditioning. These matters are not just about sustainability – but are
about healthier schools that boost teachers’ well-being and student results.”
In light of the changing funding environment, several companies have created schools which can be ordered like an off-the-shelf product with a guaranteed price tag. Sunesis from Willmott Dixon and Scape (a public-
private partnership) delivers a whole-school envelope and interior walls for a defined cost over a fixed timescale. There are 12 different designs to choose from, divided into primary and secondary, and arranged by intake for primary schools and number of pupils for secondary. As an example, £2.8 million will buy you a two-form entry primary school including nursery school measuring 11,100 sq m built over 53-59 weeks, and 30 per cent cheaper than standard-build (although the schools are bricks and mortar). However, Yorkon and Surface-to-Air are working on a
modular product called the Configurator, which offers more flexibility based on the former (a Portakabin company’s) designs. School specifiers can choose the exact dimensions of internal areas, as well as finishes while being sure that they fit the EFA price tag. “We don’t just make grey boxes anymore,” says
Portakabin director, Kevin Jones, of his company’s schools. “They come in a multitude of sizes. We can specify air source heat pumps or mechanical cooling to fit the financial targets as well as a myriad of cladding options.”
‘Software can be the key to not only building more efficient schools’ envelopes, but creating a better quality of life for
its inhabitants’ Mark Allen, head of technical for Saint Gobain
13
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