Ventilation: Approved Document F, Volume 1 — Dwellings

O N L I N E V E R S I O N B Appendix B: Performance-based ventilation Introduction B1 This appendix sets out the levels of moisture and other pollutants that the provisions in this approved document are designed to control. The provisions are designed to control all of the following. a. Moisture levels, as described in paragraph B2. b. Indoor air pollutants, as described in paragraph B4. c. Bio-effluents, as described in paragraph B6. NOTE: The guidance in this approved document may not be adequate to address pollutants from flueless combustion space heaters. This approved document does not address the airborne spread of infection and does not directly address contamination from outdoor sources. NOTE: A strategy for achieving good indoor air quality includes reducing the release of water vapour and air pollutants. This approved document does not provide guidance on such strategies. Performance criteria for dwellings B2 The performance criterion for moisture is that there should be no visible mould on the inner surfaces of the external walls of a properly heated dwelling with typical moisture generation. B3 Mould can grow whether the dwelling is occupied or unoccupied, so the performance criterion for humidity (given in Table B3) should be met at all times, regardless of whether there are occupants. The other pollutants listed in Table B1 are only of concern when the dwelling is occupied. NOTE: The moisture criteria to avoid house dust mite allergens are more complex and demanding than those to avoid mould. This approved document does not give guidance on the control of house dust mite allergens. B4 The performance criteria for indoor air pollutants are given in Table B1. These are based on the World Health Organization’s Guidelines for Indoor Air Quality: Selected Pollutants (2010) and Public Health England’s Indoor Air Quality Guidelines for Selected Volatile Organic Compounds (VOCs) in the UK (2019). 39 Building Regulations 2010 Approved Document F Volume 1, 2021 edition O N L I N E V E R S I O N