Last edited 01 Jul 2015

Whole building ventilation

Approved document F, Ventilation, suggests that ‘whole building ventilation’, or ‘general ventilation is:

‘…nominally continuous ventilation of rooms or spaces at a relatively low rate to dilute and remove pollutants and water vapour not removed by the operation of extract ventilation, purge ventilation or infiltration, as well as supplying outdoor air into the building. For an individual dwelling this is referred to as ‘whole dwelling ventilation’.’


  • Extract ventilation is, ‘…. The removal of air directly from a space or spaces to the outside. Extract ventilation may be by natural means (e.g. by passive stack ventilation) or by mechanical means (e.g. by an extract fan or central system).’
  • Purge ventilation is, ‘…manually controlled ventilation of rooms or spaces at a relatively high rate to rapidly dilute pollutants and/or water vapour. Purge ventilation may be provided by natural means (e.g. an openable window) or be mechanical means (e.g. a fan).’
  • Infiltration is, ‘… the uncontrolled exchange of air between inside a buildings and outside through cracks, porosity and other unintentional openings in a building, caused by pressure difference effects of the wind and/or stack effect.

Whole building ventilation might be provided by background ventilators, as illustrated below.


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