interiors


Ensuring indoor air quality meets acceptable levels


Schools that fall outside the scope of the latest funded programmes may fall short of new standards for air quality in their classrooms, says NICK HUDLESTON.


T


HE PRIORITY School Building Programme (PSBP) Facilities Output Specification, launched last October


by the Education Funding Agency, proposes some significant and positive changes to school ventilation specifications, when compared to the existing BB101 standard. Alongside ventilation and carbon dioxide levels, it also provides clear guides on specific performance standards for thermal comfort while recognising that indoor air quality, ventilation strategy, temperature, humidity and energy efficiency are all intrinsically linked. However, given that the PSBP is aimed


at renewing, repairing and refurbishing some of the country’s most dilapidated schools, the question has to be asked about what happens to those schools that are not especially out of date or in poor repair? Will these schools find that their pupils suffer as ‘legacy’ classroom designs struggle to meet the new standards, particularly for CO2?


Pilot


In the last quarter of 2012, SE Controls ran a pilot test with a small number of ‘non-PSBP’ primary schools in the Midlands and Northern Home Counties to gauge the actual level of CO2 in classrooms. Its NVLogiQ room controller’s integral CO2 sensor and data-logging


function was used to monitor and record carbon dioxide levels for later analysis – while its front panel display also acted as a ‘traffic light’ system for teachers, alerting them that the levels were increasing and they should manually open windows to improve ventilation. When the initial data was analysed in


January this year, the headline results raised some significant concerns and were as follows: • For most days, the daily average occupied CO2 level exceeded the recommended 1500ppm figure in BB101 • In some cases the CO2 figure was between 2500ppm and 3700ppm on every day of the week • BB101’s maximum 5000ppm level was breached four times per week in some cases • A maximum reading of 7200ppm was recorded, resulting in the CO2 levels exceeding 5000ppm for almost three hours in one case. While this was a relatively small pilot


programme, the results appear fairly consistent and suggest that air quality in schools is probably not as good as it should be. It also raises some general questions about verifying the performance of building ventilation systems in schools.


Clearly the new PSBP output specification sets out to address the


issue of CO2 levels, but as some schools are already struggling to comply with the less stringent existing standards, it is evident that any PSBP compliant system must be designed correctly and controlled effectively. In ‘post-test’ de-briefings, teachers said


they were too busy to constantly monitor and respond to signals, so relying on manual opening proved to be unviable due to the intrinsic lack of precise control. Unless automated ventilation solutions


are adopted, such as window automation linked to dedicated monitors and controllers or a hybrid mixed mode system to provide additional backup, then it’s likely that children and teachers will continue to work in poorly ventilated and non-compliant schools with the inevitable result of reduced learning performance. By utilising devices such as NVLogiQ, which can be configured to operate either as a networked system or be dedicated to individual areas, classroom CO2 levels, temperature and energy efficiency can be managed as an integrated set of parameters to provide optimal ventilation while saving energy and money.


Nick Hudleston is natural ventilation division manager at SE Controls.


www.secontrols.com educationdab.co.uk 29


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