Regulations: Background Ventilation in England & Wales
The provision of background ventilation via through-wall ventilators and window trickle ventilators is a cost-effective, non-mechanical means of introducing fresh outside air into habitable rooms. Easy to operate and fully controllable, natural background ventilators dilute and remove airborne pollutants (including odours) from rooms and control moisture to reduce the risk of mould growths which can be a health hazard to the occupants. For your convenience, we have outlined below extracts from the following regulations:
- The Building Regulations, Approved Document F (2021 edition in England) for works and planning applications after 15 June 2023.
- The Building Regulations, Approved Document F (2022 edition in Wales) for works and planning applications after 23 November 2023.
- For detailed guidance, refer to the full versions of the regulations linked above.
Approved Document F1: Means of Ventilation
2021 edition (England) and 2022 edition (Wales)
Natural ventilation with background ventilators and intermittent extract fans (previously System 1)
- The guidance is only for less airtight dwellings i.e. dwellings with a design air permeability higher than 5m³/(h·m2) at 50 Pa or dwellings with an as-built air permeability higher than 3m³/(h·m2) at 50 Pa.
- Install background ventilators in all rooms with external walls. The minimum total equivalent area of background ventilators required in each room is in Table 1.7.
- 1.34: Background ventilators should be at least 1700mm above floor level to reduce draughts, but still be easy for the occupant to reach. Note: Background ventilators are intended to normally be left open.
- 1.53: If the dwelling has more than one exposed façade, the area of background ventilators on each façade should be similar to allow cross-ventilation.
- 1.54: If an exposed façade is close to an area of sustained loud noise (e.g. a main road), then a noise attenuating background ventilation should be fitted. See Rytons Acoustic Background Room Ventilators.
- 1.57: The total number of ventilators installed in the dwelling’s habitable rooms and kitchens should be at least the following:
-
- Four ventilators if the dwelling has one bedroom.
- Five ventilators if the dwelling with more than one bedroom.
-
- 1.58: If the dwelling has a kitchen and living room which are not separate rooms, at least three ventilators of the same area as for other habitable rooms in Table 1.7 should be provided in the open-plan space.
Background ventilators for continuous mechanical extract ventilation (previously System 3)
Where continuous mechanical extract ventilation is used, provide a minimum equivalent area of 4000mm² for each habitable room (excluding wet rooms i.e. kitchen, utility room and bathroom). Install the same number of ventilators as there are bedrooms, plus two ventilators (i.e. a one bedroom dwelling should have three background ventilators, a two bedroom dwelling should have four background ventilators, etc.).
Rytons Background Ventilation Range
Achieve compliant background ventilation in habitable rooms with Rytons controllable through-wall background ventilators or a combination of window trickle vents and through-wall sets. We are always happy to assist you with ventilation calculations and product selection – call our technical sales office on 01536 511874 for advice.
Rytons Through-wall Background Ventilation Sets
Unsilenced Range >> Acoustic Range >>
Rytons Window Trickle Ventilators
View Range >>
ARCHIVED CONTENT
Approved Document F1: Means of Ventilation (2010 edition incorporating 2013 amendments)
Natural ventilation with background ventilators and intermittent extract fans (System 1)
General notes:
- Background ventilators should be located in all rooms with external walls. Once the total requirement has been calculated, at least 5000mm² equivalent area is required in each habitable room and 2500mm² equivalent area is required in each wet room.
- Promote cross-ventilation with background ventilation of a similar area on each façade, where possible.
- Fit noise attenuating ventilators if an exposed façade is close to an area of continuous noise (e.g. a main road) – see Rytons Acoustic Background Room Ventilators.
- Position background ventilators at least 1.7m above floor level to reduce draughts but still be accessible by the occupant. Note: Background ventilators should normally be left open.
Make a System 1 calculation
| Total Floor Area (m2): | ||
| Dwelling Type: |
Single-storey located up to and including the fourth storey above ground level Multi-storey, and single-storey located more than four storeys above ground level |
|
| No. of Bedrooms: | ||
| Design Air Permeability: |
Type A: Any design air permeability Type B: Design air permeability leakier than 5m3/h.m2 at 50 Pa |
|
| Facades: |
Single facade (one exposed facade only) Multiple facades (two or more exposed facades) |
|
| Results | ||
Background ventilators for continuous mechanical extract ventilation (System 3)
For any design air permeability, provide controllable background ventilation with a minimum equivalent area of 2500mm² in each room, except wet rooms, from which air is extracted. Where the designed air permeability is leakier than 5m³/(h·m2) at 50 Pa background ventilation is not necessary.
