Schools face a number of design challenges shared by few other construction projects. What other building has to accommodate specialist areas dedicated to scientific experiments, dramatic performances and diverse sports activities while also providing food, IT services, vital community services and more to thousands of people on a daily basis? David Rowsell, Area Director for Morgan Sindall Construction – Northern Home Counties, discusses further.
For today’s new schools, it’s important to add to this list that a holistic approach to sustainability needs to be embedded within each element of its construction. This is crucial, as it’s likely that green building guidance is only going to become stricter as the Government looks to achieve its goal of a net-zero carbon society by 2050.
This means that new-build school projects must carefully consider the entire lifecycle of a school, from how it’s designed and built through to how it’s operated and maintained to make sure that the overall carbon footprint is as low as possible.
Milton Keynes Council’s environmental ambitions
When it came time to design a new secondary school at Glebe Farm in Wavendon, Milton Keynes Council decided that it wanted to go above and beyond the current green requirements to create a site that would set a new benchmark for sustainable school construction. This project, which is currently on site, is therefore a good case study in how to examine specific aspects of a school’s creation to minimise its environmental impact.
Procured through the Pagabo framework, a £10bn six-year Major Works Framework, Glebe Farm School is the product of a long-standing collaborative relationship between Milton Keynes Council and Morgan Sindall Construction’s Northern Home Counties business.
As the contractor confirmed to deliver the 1659-place facility, our team advised the council on how their green targets could be met through the use of new materials and innovative building processes. The council were quick to agree to these changes during the project’s design phase, in order to drastically lower the emissions that would be generated by both the school’s construction as well as its long-term use.
Creating a cleaner building site
With construction of the school having started in February, many of the recommended green building processes are currently in action at the construction site. One of the most significant ways we’ve minimised emissions during the build is by using alternative and renewable power sources for the equipment and temporary set-up.
This was accomplished by using a solar powered generator to provide clean, off-grid energy for the site’s cabins. For those less sunny days, the generator uses the bio-fuel HVO instead of diesel to make sure that the work can keep going without any disruptions. Even when not on solar power, this is still a much more sustainable energy source for the team on site, as HVO only creates 0.195kg of CO2 instead of the 2.68kg created when burning red diesel.
The green benefit of using this system was proven over the first month of the development, as the site’s sunshine and bio-fuel powered generator delivered a 72% reduction in CO2 compared to what would have been expected from a diesel driven 40kVA generator running 24 hours a day over the same time period.
One of the most significant design changes came with the decision to remove the school from the gas grid, with all the heating to be provided instead by renewable energy via roof mounted air source heat pumps (ASHP). The emission-reducing effectiveness of this move was highlighted by the Committee on Climate Change1, which stated that carbon emissions for a home can be up to 90% lower for a house and 80% lower for a naturally ventilated office when using ASHPs instead of gas.
Unlike most developments, this decision has an interesting knock-on effect for a school, as typically every science lab will require gas-powered Bunsen burners. To solve this issue, the council decided to install electric Bunsen burners instead, so that no part of the building would require a gas connection for any reason.
This is a good example of how this project is ahead of the curve, as gas Bunsen burners are still routinely specified for new schools despite the construction industry veering away from this fossil fuel in general. The move to drop gas is especially evident in the recent Future Homes Standard and its directive to take new homes off the gas grid – a direction that’s likely to be keenly felt in public sector construction over the coming years.
Redesigning through a green lens
The green design changes didn’t stop there, as renewable power became an ever more prominent part of the project, with the number of solar panels increasing and with six electric charging points added to the car park. When it came to the components used to construct the school, the Green Guide for building materials was consulted to inform sustainable specification choices, which included choosing eco-friendly PVC-free hoarding instead of a traditional option.
The Morgan Sindall Construction team worked closely with the Milton Keynes Council to ensure that the school would continue to effectively minimise emissions during its day-to-day use. A key way this was achieved was by designing a building envelope with very low air permeability to retain heat and reduce the energy required to warm the classrooms. While regulations state that schools should meet an air leakage rate of 5m3/hm2, Glebe Farm’s new school would benefit from a much better air permeability rate of only 3m3/hm2.
Externally, the school’s grounds were made to be green in more ways than one. Not only will 840 saplings donated by the Woodland Trust be planted, but all the mulch and topsoil will be reused instead of being moved, saving the emissions that would otherwise be incurred through transportation. The levels of the school’s ground were carefully redesigned and raised to accommodate this additional material.
A new generation of sustainable schools
There’s an urgent need for new schools right now, as last year saw a drastic fall in the number of education sector construction projects being started. According to Glenigan2, this drive to create more classroom space will see a 53% increase in school projects this year compared to 2020 which, for obvious reasons, saw a fall of 33% in the number of education facilities being started.
These new facilities need to not only provide high-quality teaching spaces for more students than the country has ever taught before, but local councils need to create facilities that simultaneously align with challenging sustainability objectives.
We’re committed to helping our clients achieve those objectives. The activity that has taken place at Glebe Farm is a perfect illustration of Morgan Sindall Construction’s wider environmental strategy, Decarbonising Communities. Launched earlier this year, Decarbonising Communities will enable us to support our customers and local supply chains – in Milton Keynes and across the country – in achieving their environmental ambitions and help meet our own target of net-zero carbon by 2030.
1. Committee on Climate Change: The costs and benefits of tighter standards for new buildings
2. Glenigan: Construction Industry Forecast 2021-2022