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 Home > United Kingdom > Professionals & Trade > Architects > Building Regulations & CE Labelling > Ventilation

Ventilation

​Requirement                          Background ventilation - Habitable Rooms​ ​ ​
​ ​               Dwellings ​ ​               Buildings other than dwellings
​Country ​             New / ​Existing ​                               New ​/ Existing
​England/Wales ​Minimum equivalent area of 5000mm² in each habitable room ​ ​CIBSE Application Manual AM10 (new) - ​Up to 10m² floor area = 2500mm²/over 10m² = 250mm² per 1m² of floor area
​Scotland ​12000mm² or average of 11000mm/room with 11000mm² min for habitable rooms ​ ​Min 4000mm² + 400mm²/m² up to 10m² of floor area or 400mm²/m² above 10m² of floor area ​
​Northern Ireland ​8000mm² or average of 6000mm²/room ​

​4000mm² up to 10m² of floor area or 400mm²/m² above 10m² of floor area

​Requirement

                                     ​Pure/Rapid ventilation ​ ​ ​
​           ​Dwellings ​                                                 Buildings other than dwellings ​
​Country         ​New / ​Existing                            ​New ​/ Existing
​England/Wales ​1/20 of floor area >30 degrees / 1/20 floor area <30 degree ​
     
       ​   Various depending on type of building ​
​Scotland ​     1/30 of floor area ​                         1/30 of floor area ​
​Northern Ireland ​     1/20 of floor area ​                         1/20 of floor area ​
  

 *30 degrees is the opening angle of the sash and applies to all windows


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"The difference in free and equivalent background ventilation areas is that the equivalent area has a default value included to allow for the effectiveness of the ventilator whilst the free area is just the total area of the vent."