Time for Compliancy over Complacency
The revised Building Regulations for England – Approved Document F (Ventilation), L (Conservation of Fuel and Power) and O (Overheating) – are now in place and are a legal requirement from today.
Revisions to the Building Regulations in England were released in December 2021. The updates ensure adequate ventilation of all types, whilst the energy efficiency of housing is improved at the same time. The ventilation document works in conjunction with documents on Energy Efficiency, and for the first time, Overheating. As the saying goes, ‘Ventilate when you Insulate’.
The Approved Document for Ventilation (‘Part’ F) includes a number of important changes and moves towards more energy efficient buildings meaning that some ventilation levels have been increased to ensure sufficient air changes in dwellings.
These revisions support the Government’s proposals for the Future Homes Standard, which provides a pathway for highly efficient buildings that are zero carbon ready, better for the environment and fit for the future. Implementation of a full technical specification is scheduled for 2025.
Revisions to Part F of the Building Regulations for Wales, will come into force in November later this year, and the domestic Building Standards Technical Handbook in Scotland have also been consulted on. A detailed review of ventilation regulations in Northern Ireland is also due to take place in 2022.
Talk to our ventilation experts who can help guide you through the changes, it’s not as complicated as you may think!
Read on for our top level overview, or download our full summary of the main points.
The ventilation systems that are typically utilised in the UK have been labelled slightly differently (see table 1), and are no longer numbered. Passive Stack Ventilation has been removed.
Table 1 – Changes in ventilation systems
| 2013 (previous figures) | Current (effective from 15 June 2022) |
| System 1 – Background ventilators and intermittent extract fans | Natural ventilation with background ventilators and intermittent extract fans |
| System 2 – Passive Stack Ventilation | Removed |
| System 3 – Continuous mechanical extract (MEV) | Continuous mechanical extract ventilation |
| System 4 – Continuous mechanical supply and extract with heat recovery (MVHR) | Mechanical ventilation with heat recovery |
As before, other system designs are allowable but need sign off and proof of compliance that they achieve the ventilation rates set in the document.
Mechanical ventilation has been affected with a large increase in per bedroom rate (see table 2). Buildings that are classed as ‘less air tight’2 will require the natural ventilation and background ventilators and intermittent fans, those buildings that are ‘highly air tight’1 will require either continuous mechanical extract ventilation or mechanical ventilation with heat recovery.
Table 2 – Changes in minimal air flow rates.
| Number of bedrooms | 1 | 2 | 3 | 4 | 5 |
| 2013 – Whole dwelling ventilation rate (a.b.) l/s | 13 | 17 | 21 | 25 | 29 |
| 2022 – Minimum ventilation rate criterion 1 – by number of bedrooms | 19 | 25 | 31 | 37 | 43 |
For background ventilation, which is the continuous change of air that should be occurring in addition to extract ventilation and rapid (e.g. opening windows) ventilation, the document shows an uplift in the amount of ventilation needing to be provided when windows are being replaced. The contractor should now be fitting background vents, usually trickle vents in the windows, whether the previous windows had them fitted or not.
In new build situations, the amount of background ventilation can now be calculated in an easier way and is based on a certain amount per room, rather than based on a total amount for the whole property, which currently means someone having to add this up and allow for certain additional criteria, such as floor area, number of bedrooms and airtightness level, before calculating whether the overall number of vents comply with the total required.
When whole house ventilation systems are being installed, there is an increase in the amount of background ventilation required when used with continuous mechanical extract system. As before though mechanical ventilation with heat recovery (MVHR) does not need background vents, as it is a balanced, controlled ventilation system.