Ventilation in schools: What five key amendments to the BB101 regulations should education design consultants be aware of?
Effective learning can only occur when schools design and build an environment which promotes productivity. To ensure that schools in the UK have a consistent benchmark, Building Bulletin 101 ‘BB101 Guidelines for ventilation, thermal comfort and indoor air quality in schools’ was published in 2006; guidelines which education consultants still reference as guidance.
A revised version of the BB101 regulations was due to be published three years ago. The time it has taken to fine-tune the guidelines illustrates the design and complexity of challenges faced by schools when it comes to choosing an appropriate strategy to heat and ventilate their classrooms and school buildings. Today, the updated document is in its final stage, and it is a document which education consultants must be informed about.
The updated regulations have highlighted five significant changes which are likely to be of interest. These are:
1. New builds and refurbished schools are now on equal footing – the original BB101 guidance only related to newly constructed school buildings, but the latest document states that schools which are undergoing refurbishment must now also comply with the guidance. The ventilation system chosen must not only meet the regulations, but its lifecycle cost must also be considered.
2. Ventilation required during out of term time – in previous versions heating and ventilation guidelines applied only to term time. In the latest revision, regardless of occupancy, the potential for overheating must be taken into account all year round. This is seen as a way of future proofing the investing in heating and ventilation systems as school buildings become more multi-purposed; and at times when pupils are on holiday or outside of teaching hours, schools are often used for school clubs, training days and as public spaces, therefore it is crucial that the building remains effectively ventilated during these periods.
3. Shift from emphasis on air volume to air quality – the original BB101 guidelines focussed entirely on whether the air volume met the familiar criteria of 3, 5 and 8 litres per second per person in every teaching space. The revised document brings with it a focus on CO2 levels instead. Where natural ventilation systems are used, the average concentration of CO2 over an occupied day should be 1,500 parts per million (ppm), and for mechanical systems, the average concentration must be 1,000 ppm. This is higher for natural systems as it must take into account external factors such as natural wind speed and wind direction; factors which mechanical systems can overcome. It is also advised that CO2 levels should be measured using sensors positioned at seat height of the pupils, which is on average 1.1 metres for primary school pupils and 1.4 metres for secondary school pupils.
4. Floor surface temperature requirement introduced – in any school that uses underfloor heating, education consultants must ensure that the surface temperature doesn’t exceed 26 degrees, primarily to prevent discomfort for teachers who are standing for long periods of time. Consequently, additional heating solutions will need to be considered to make up for the short fall in heating output with lower underfloor temperature and maintain thermal comfort.
5. Ventilation wins against acoustics – the guidelines dictate that the teacher should be able to open windows to supplement fresh air intake. This is an important change and gives the teacher more control especially in the summer months. However, in winter or in schools in inner-cities or next to busy roads it would be folly to rely on this as the main form of ventilation. A demand-controlled mechanical ventilation system should be designed to ensure that it can provide enough ventilation to maintain the appropriate air quality, then the opening windows can be used in the right circumstances to bring in additional fresh air on a warm day.
If you would like to learn more about how these regulations will impact the design of school buildings, click here to listen to Jaga’s latest webinar on the topic.