Architects: Cottrell & Vermeulen Architecture Ltd.
Location: Westcliff-on-Sea, UK
Client: Southend-on-Sea Borough Council and the Governors of Westborough Primary School. (The project was also partially funded by the Department for Education)
Photographs: Anthony Coleman
Given the fact that UK educational buildings generate approximately 15% of the UK’s carbon emissions attributable to the public sector, schools not only have a responsibility but also a unique opportunity to set an example for communities in the campaign to reduce our carbon footprints. At Cottrell & Vermeulen Architecture we are concerned that as we embark on major building programmes to refurbish primary schools, not enough has been done to test and confirm the best methods and approaches by which to proceed. There is an urgent need to better understand how schools can be refurbished in a sustainable, affordable and low carbon manner.
Refurbishment projects are known to be more complex and costly, but a preference for new build schools on the basis that refurbishments are less able to meet carbon reduction targets neglects to take account of the ‘built in’ or embodied energy of an existing building. Recent studies have shown that new build constructions can emit over four times the amount of CO2 than comprehensive refurbishments. It follows that new build constructions meeting current standards could take up to 50 years to catch up with refurbishments in terms of repaying their carbon debt through lower operational emissions, by which time they will be needing refurbishment themselves.
The design team for this project has been led by Cottrell & Vermeulen Architecture, who have being working with the school for almost 19 years. During this time we have explored new ideas and created projects, such as the award winning Cardboard Building, that have influenced Government policy, pushed the boundaries of sustainable design and created an exemplar of collaborative working.
Westborough Primary School is designated as a sustainable school. Primary aged children are very concerned about the impact on the environment and want to be involved in the development of sustainable features within their school. The process of realising a shared vision through refurbishment can itself provide an educational opportunity toward fostering a sustainable community and this will be supported by Southend’s Sustainable Schools strategy.
The recently completed ‘Zero Carbon Refurbishment’ project has been jointly funded by Southend-on-Sea Borough Council’s Primary Capital Programme and Department for Education and builds on the school managements’ progressive sustainable approach to their school. It aims to provide a testbed for ways of refurbishing older school buildings in a sustainable manner and to provide a model for future projects throughout the country. The target is for a 90% reduction in carbon emissions for the newly refurbished areas of the school.
Our approach to this project is based on the idea of Mean: reduce all energy demands; Lean: supply demands efficiently; Green: use of renewable energy.
This project will deliver information on the effectiveness of carbon reduction strategies that can be applied to a typical existing school building. The Mean, Lean, Green strategy for the school has 3 elements, and useful information will emerge from each of these:
1) From existing measurements of the buildings we know how much carbon is emitted and which uses are responsible. The refurbishment works will result in substantial savings due to improved fabric in terms of wall and roof insulation, improved windows and increased air tightness. The developments are phased, so we will be able to gather information on the effectiveness of the first phase, and compare this to the remaining part of the school to be updated later.
2) The same applies to the proposed efficiency savings due mainly to improved lighting and lighting controls, computers and system management. The impact of these has been predicted and we will learn about and report its real performance.
3) Thirdly the proposed renewable energy systems, namely biomass heating and Photo Voltaics for electricity will deliver knowledge on the impact these are able to provide within an existing school. (Wind energy was part of the original proposal but it proved impossible to achieve planning consent for this within the residential area).
The location for the majority of the work is the school’s Edwardian red-brick main building. The school buildings have been re-ordered, generally refurbished and modernised to current academic requirements. The main school entrance has been redesigned to accommodate a new reception and waiting area with improved access. In the school playground new cabin structures have been designed for play and storage and a canopy along the back of the school provides a new circulation route and supports photo-voltaic panels. Monitors around the school display energy use and carbon emissions.
The carbon reduction works can be summarised as follows:
LEAN – Interventions to reduce energy demand:
Insulation of existing walls – Insulated Dry lining board added to improve the thermal performance of existing external walls.
Insulation of roof and introduction of inner roof lining – Insulation bonded to the existing internal surface will improve both thermal and acoustic performance of the roof.
Installation of secondary glazing – A combination of double glazing and internal secondary glazing improves thermal performance.
Improvement of building air tightness – Control airflow through existing roof vents and ensure windows and doors are properly sealed.
Insulated distribution pipework – Hot water and heating pipework has been insulated to reduce losses and improve control of heating the space.
MEAN – Interventions to Supply Demands Efficiently:
Modification of fluorescent lights to use T5 lamps – Existing fluorescent light fittings modified to accept more efficient T5 lamps. Energy consumption reduced by 45%.
Lighting control – PIR/Daylight sensors used to control classroom lighting.
Computer energy management – Improvements to energy management of existing IT infrastructure.
Optimised scheduling of heating plant operation – New boiler controllers allow optimised scheduling to reduce unnecessary running hours.
Hot water – alternative generation – Providing ‘regional’ water heaters reduces hot water carbon emissions by up to 50%.
Submetering and energy management – Submetering of energy consumption will allow a detailed image of how and where energy is consumed throughout the school.
Heat Exchange – Heat exchange systems have been installed to maximise the use of energy within the ventilation and heating system.
GREEN – Interventions to use Renewables:
Solar Photovoltaic – The solar photo voltaics have been installed on the south facing pitch of the new roof structure. Outputs from a typical, UK based, solar photo voltaic array can achieve yearly electrical yields of approximately 100 kWh/m2/Year.
Biomass Boiler – As an alternative to gas boilers, a new biomass boiler is a way of meeting the heating demands of the school. The school currently uses 150KW. By installing a biomass boiler, it is estimated that 66% of the annual heating carbon emissions will be saved.
Rainwater Harvesting – A rainwater harvesting tank has been installed for toilet flushing.
This refurbishment provides a holistic strategy that aims to reduce carbon emissions by:
- Understanding the carbon footprint of the existing condition which is used as basis for all strategic interventions to the fabric of the school
- Modifying behaviour of the school based on the finding of the carbon footprint.
- Implementing lean and mean strategies – Mean: reduce all energy demands; Lean: supply demands efficiently.
- Implementing green renewable energy to the school namely biomass heating and Photo voltaics.
- Implementing a community education programme that starts with the children at the school to raise awareness of energy issues within the community
- Implementing a phased construction program that can learn from the success of the first phase