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Ensuring efficiency and air quality in school ventilation


Good indoor air quality is an often-neglected element that is crucial to enhanced wellbeing and learning. Alan Macklin and Ana Cross at Elta Group discuss how schools must factor this in alongside energy saving agendas and introduce quality-designed mechanical ventilation


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n the wake of the pandemic there has been a shift in perception regarding ventilation, with the high levels of CO2 across school building stock posing a growing concern. It must be kept in mind, however, that the pressure of sustainability goals means energy efficiency is a simultaneous matter to contend with. Historically, schools have relied on natural


ventilation measures – simply opening windows to maintain low energy usage. Yet the problem with this approach is that it does not ensure good air quality - especially when the locality of schools is considered. Many tend to be situated in suburban or heavily urbanised areas where a high count of nitrogen dioxide is present in the air, along with harmful particulates such as car brake pad dust, fumes, sulphur dioxide and other pollutants. Such poor-quality air can have a significant impact in the school environment. It has become evident from numerous scientific studies that CO2and harmful particulates directly affect pupils’ learning and concentration levels. Furthermore, there is greater concern around its detriment to wellbeing due to the vulnerability of younger individuals.


As the school rebuilding programme comes into


effect, this is added impetus for adequate ventilation to be put in place that prioritises good air quality as much as energy savings.


Regulatory updates


The importance indoor air quality is reflected in upcoming changes to legislation. While the Building Bulletin (BB 101) still stands as a framework for effective ventilation management, updates to Part F of Building Regulations will look to implement more stringent guidance. Among the expected amendments later this


year, buildings will be required to provide sufficient ventilation to keep CO2 levels below 800ppm (parts per million). This change alone signifies the growing


22 June 2022 Above: Alan Macklin and Ana Cross at Elta Group


requirement for schools to implement ventilation strategies that effectively manage indoor air quality.


Defining ‘fresh’ air


To ensure best practice, there must be an understanding of both regulations and what constitutes good quality or ‘fresh’ air. It’s already been discussed that air brought in from outside isn’t necessarily devoid of harmful compounds, and this


isn’t the only misconception around ventilation. Namely, the role of air purifiers is another element that is often misconstrued. Such applications have experienced a rise in popularity under the assumption that they ensure fresh air through recirculation and purification. However, air purifiers cannot be seen as a comprehensive solution because air will become stale and allow for CO2 and VOC (volatile organic compound) levels to increase within surroundings. A good quality ventilation system relies not only on extracting pollutants, but also close management of CO2levels. Implementing mechanical solutions It’s with the above in mind that CO2 should be


perceived as a proxy for air quality. As building occupants exhale, the CO2 level rises and the ventilation rate must be increased in order to reduce it. Measuring CO2 as part of a ventilation system can therefore enable effective control of both air quality and energy usage. Typically, building ventilation is usually set at a


constant or pre-determined rate on the basis of maximum occupancy levels. This inevitably opens


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