This document sets out regulations, standards and guidance on ventilation, thermal comfort and indoor air quality for school buildings. It replaces Building Bulletin 101 (BB101), ‘Ventilation of School Buildings’, 2006.

The guidelines on ventilation include:

• standards for all spaces including halls, classrooms and specialist practical areas such as science labs and design and technology spaces. Setting maximum levels of carbon dioxide in teaching spaces and minimum ventilation rates in practical spaces and specialist accommodation, eg for pupils with special needs.

The guidelines on thermal comfort include::

• guidance on room temperatures and cold draughts in order to provide a comfortable environment suitable for teaching and learning, year round.
• guidance on designing for children with disabilities who are less able to regulate their temperature than mainstream pupils.
• detailed calculation methods for thermal comfort. Adaptive thermal comfort calculations have been introduced to prevent summertime overheating based on the latest research on how people adapt to higher temperatures. These calculations use variable maximum indoor temperatures that depend on the outside temperature. This helps to avoid the unnecessary use of air conditioning by using passive measures such as night cooling and thermal mass to cool spaces in summertime.

The guidelines on indoor air quality include:

• a summary of the health effects of indoor air pollutants based on the World Health Organisation guidelines for Indoor Air Quality and the latest advice from Public Health England. This describes pollutant sources, both internally generated such as formaldehyde given off by furniture and external pollutants including nitrogen dioxide which are a major cause of concern for respiratory health.
• guidance on how to meet the maximum exposure levels for pollutants. Ways to reduce the level of outdoor air pollutants, such as Nitrogen Dioxide and Particulates from traffic, in the supply air. This includes the location of air intakes and exhausts, the management of openable windows, and filtration of supply air.
• advice on reducing sources of indoor pollutants, eg using materials that are low emitters of pollutants and dealing with pollutants generated by 3D printers and laser cutters