Ventilation: Approved Document F, Volume 1 — Dwellings

O N L I N E V E R S I O N F1(1) a. Incorporating background ventilators in the replacement windows equivalent to the following. i. Habitable rooms – minimum 8000mm2 equivalent area. ii. Kitchen – minimum 8000mm2 equivalent area. iii. Bathroom (with or without a toilet) – minimum 4000mm2 equivalent area. b. If the dwelling will have continuous mechanical extract ventilation, installing background ventilators in any replacement windows which are not in wet rooms, with a minimum equivalent area of 4000mm2 in each habitable room. c. Other ventilation provisions, if it can be demonstrated to a building control body that they comply with the requirements of paragraph 3.2. NOTE: If it is not technically feasible to adopt the minimum equivalent areas set out in paragraph 3.15, the background ventilators should have equivalent areas as close to the minimum value as is feasible. 3.16 When windows are replaced as part of the work connected with a material change of use, Section 1 of this approved document should be followed in addition to paragraphs 3.14 and 3.15. Addition of a habitable room (not including a conservatory) to an existing dwelling 3.17 The requirement for adequate ventilation can be met if background ventilators are used as follows. a. If the additional room is connected to an existing habitable room which now has no windows opening to the outside, paragraphs 1.42 to 1.44 should be followed b. If the additional room is connected to an existing habitable room that still has windows opening to the outside, the following conditions apply. i. If the existing habitable room has a total background ventilator equivalent area of less than 5000mm2, paragraphs 1.42 to 1.44 should be followed. ii. If the existing habitable room has a total background ventilator equivalent area of at least 5000mm2, both of the following should be provided. • Background ventilators of at least 12,000mm2 equivalent area between the two rooms. • Background ventilators of at least 12,000mm2 equivalent area between the additional room and the outside. 3.18 As an alternative to paragraph 3.17, to ventilate the additional habitable room, one of the following methods could be used. a. A single-room heat recovery ventilator. The supply rate to the additional room should be determined as follows. i. Establish the whole dwelling ventilation rate from Table 1.3. ii. Calculate the room supply rate required from the following equation. (whole dwelling ventilation rate × Room volume) (Total volume of all habitable rooms) 25 Building Regulations 2010 Approved Document F Volume 1, 2021 edition O N L I N E V E R S I O N