HEATING, VENTILATION & SERVICES 65 An air of improvement
Tyson Anderson of Titon outlines the main impacts of revisions to the Building Regulations, intended to strike the balance between energy efficiency, air quality and overheating in domestic settings
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evisions to Part F of the Building Regulations in England were released in December (the documents for Scotland and Wales are still under review) and there are a number of implications for specifiers of ventilation in dwellings.
It is the intention that the updates ensure adequate ventilation of all types while simultaneously improving the energy efficiency of new housing. The the new Part F works in conjunction with Approved Documents on energy efficiency, and for the first time, overheating. As the saying goes, ‘ventilate when you insulate.’ This is all part of the Government’s proposals for the Future Homes Standard, which provides a pathway for highly efficient buildings that are “zero carbon ready,” i.e. better for the environment and fit for the future. Implementation of a full technical specification to comply with the standard is scheduled for 2025. The Approved Document for Ventilation (Part F) includes a number of changes from the previous iteration, and becomes effective in June 2022. With the move towards more energy efficient buildings, some required ventilation levels have been increased to ensure sufficient air changes in dwellings.
In all instances, the revised Document redefines what airtight and less airtight levels are, which has a bearing on the type of ventilation system that should be incorporated.
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. 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” will require the natural
ADF MARCH 2022
2013 (current)
System 1 - Background ventilators and intermittent extract fans
System 2 - Passive stack ventilation
System 3 - Continuous mechanical extract (MEV)
System 4 - Continuous mechanical supply and extract with heat recovery (MVHR)
Number of bedrooms 2013 - Whole dwelling ventilation rate (a.b.) l/s
2022 - Minimum ventilation rate criterion 1 – by number of bedrooms
ventilation and background ventilators and intermittent fans, those buildings that are ‘highly air tight’ will require either continuous mechanical extract ventilation or mechanical ventilation with heat recovery.
For background ventilation, which is the continuous change of air that should be occurring in addition to extract ventilation and rapid ventilation – e.g. opening
WWW.ARCHITECTSDATAFILE.CO.UK
2021 (effective from 15 June 2022)
Natural ventilation with background ventilators and intermittent extract fans
Removed Continuous mechanical extract ventilation Mechanical ventilation with heat recovery
1 2 3 4 5 13 17 21 25 29
19 25 31 37 43
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