A Comprehensive Guide to the New British Law on Indoor Air Quality

A Comprehensive Guide to the New British Law on Indoor Air Quality

By Ruth MacEachern

Product Manager

According to the UK government, poor air quality is the “the largest environmental risk to public health, with children, the elderly and the already vulnerable most affected”. It is therefore unsurprising that recent years have seen amendments to existing legislation, as well as the introduction of various new rules and regulations. The environmental and health effects of poor indoor air quality have been well documented, resulting in the publication of new regulations and guidelines on ventilation and indoor air quality. In this article we will summarise the applicable legislation, considering its implications for homeowners and property developers. We will also address the changes required with regard to the management of indoor air quality.

UK Building Regulations: Approved Document F

In 2021, the government published an amended version of Approved Document F; the section of the UK building regulations concerning ventilation and indoor air quality. Under the amended regulations, the use of intermittent extractor fans and natural ventilation by means of background ventilators is only recommended for less airtight dwellings. A desire to reduce running costs and protect the environment has resulted in new build dwellings becoming increasingly airtight. Consequently, the new Approved Document F requires an alternative ventilation strategy, e.g., MEV/MVHR for buildings with an as-built air permeability rating of less than 3 m³/3 h.m² @ 50Pa (those rated as “highly airtight”).

Table 1.3 of the document stipulates a considerable increase in minimum whole building ventilation/airflow rates, while background ventilation requirements (e.g., window trickle vents) are now stated per habitable room and by type of room rather than based on the total floor area of the building.

The requirement for purge ventilation remains more or less unchanged, with a purge ventilation rate of at least 4 air changes per hour directly to outside still required. This can be achieved by opening hinged or pivot windows with an opening angle of 15 to 30 degrees, having a minimum total open area of at least one tenth of the room floor area. If the opening angle is greater than 30 degrees, then the  minimum total open area can be one twentieth of the room floor area.

Further reports, guidelines and regulations

The increased focus on national health and environmental conservation has resulted in the recent publication of a number of additional reports and guidelines. Examples include…

Indoor Air Quality Guidelines for selected Volatile Organic Compounds (VOCs) in the UK: published in September 2019, the guidelines outline both short-term and long-term limit values for a selection of VOCs identified as of relevance to indoor air quality.

High VOC content products such as paints have been regulated through EU Directives.

The UK government has outlined targets to achieve net zero carbon emissions by the year 2050. Among other measures, this involves new building strategies aiming to improve the airtightness of buildings. 

The Future Homes and Building Standard; a UK government commitment outlining new standards, guidelines, and regulations, aiming to ensure that all new homes built from 2025 will produce 75-80% less carbon emissions than homes delivered under current regulations.

Implications for homeowners and house builders

The increased strategic and legislative drive to decrease emissions and improve occupant health has a variety of implications for housebuilders. Rendering buildings more airtight with a view to preventing heat loss limits the natural exchange of air, resulting in stale dwellings with high levels of allergens and pathogens. Consequently, the undeniable need for enhanced air ventilation systems has resulted in new legislation calling for changes in the way domestic air quality is managed. 

For house builders, this means that the installation of high-quality mechanical ventilation systems, such as Mechanical Ventilation with Heat Recovery (MVHR) systems, has become an essential part of any construction project. This requires a great deal of advance planning and expert consultation in order to select a system that is both adequate and efficient. 

Airflow rates must be measured, with relevant notification to be submitted to building control. Ensuring an installation that is economical, effective, and compliant may well require expert consultation. While this undoubtedly comes at a cost, any additional financial outlay will certainly prove cost-effective, as the expense of retroactively correcting unsuitable installations will far outweigh the cost of professional consultation and installation. We have a wide range of articles that may be of interest, such as our article on avoiding heat loss through the installation of suitable ventilation solutions, which can be found here.

The expense of a mechanical ventilation system may be reflected in the purchase price of new build properties, buyers can look forward to increased efficiency on account of reduced heat loss, not to mention a healthier and more comfortable living environment and the satisfaction of knowing they are contributing to the achievement of the government’s climate objectives.

From a business perspective, ensuring compliance, there are several strategies that organisations can adopt to enhance air quality in their facilities. Regular ventilation, systematic cleaning, and vigilant detection and remediation of mould are among the tactics to consider. For companies worried about the operational costs of future-ready mechanical ventilation systems, our article offers an in-depth discussion on running expenses and the most economically efficient ventilation solutions.