Ventilation: Approved Document F, Volume 1 — Dwellings

F1(1) O N L I N E V E R S I O N Equivalent area of ventilators 1.15 The size of background ventilators (including trickle ventilators) is given in this approved document as an equivalent area in mm2, not as a free area. BS EN 13141-1 includes a method of measuring the equivalent area of background ventilator openings. 1.16 Background ventilators should have the equivalent area marked where it will be easy to see from inside the dwelling when installed, to aid verification by building control bodies. Extract ventilation 1.17 Extract ventilation to the outside should be provided in all of the following spaces. a. Kitchens. b. Utility rooms. c. Bathrooms. d. Sanitary accommodation. 1.18 Extract ventilation can be intermittent or continuous. 1.19 Minimum extract ventilation rates in litres per second (l/s) for intermittent operation extract systems are given in Table 1.1. Minimum extract ventilation rates for continuous operation extract systems are given in Table 1.2. 1.20 Extract ventilation terminals and fans, not including cooker extract hoods, should be installed to comply with both of the following conditions. a. As high as is practicable in the room. b. A maximum of 400mm below the ceiling. 1.21 Where a cooker hood is used to extract to the outside, the height of the extract hood above the hob surface should be either as specified in the manufacturer’s instructions or, if no specification is available, between 650mm and 750mm. Table 1.1 Minimum extract ventilation rates for intermittent extract systems Room Intermittent extract rate (l/s) Kitchen (cooker hood extracting to the outside)(1) 30 Kitchen (no cooker hood or cooker hood does not extract to the outside)(2) 60 Utility room 30 Bathroom 15 Sanitary accommodation(3) 6 NOTES: 1. See Diagram 1.1. 2. See Diagram 1.2. 3. As an alternative for sanitary accommodation, the purge ventilation guidance may be used. 8 Approved Document F Volume 1, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N