Opinion piece: Building Regulations Part F – redressing the balance

In December 2021, the Government published the new Approved Part F (Means of Ventilation) and Part L (Conservation of Fuel and Power) of the Building Regulations. Under the new regulations, there is a significant cut in carbon emissions of 30% in New Build homes setting a challenge for housebuilders to improve both energy efficiency and airtightness of homes while increasing ventilation to help protect the health of residents. Richard Paine, product and marketing director at Vent-Axia explains.

In October last year, COP26 clearly highlighted the vital importance of global CO2 reductions. With building and construction together responsible for 39% of all carbon emissions in the world, it is no surprise that the new Building Regulations address how to reduce emissions in order to help meet the UK’s carbon targets as we move toward the Future Homes Standard on the road to Net Zero. For housebuilders, this has meant a reduction of almost a third less carbon for new homes. However, as well as being tasked with making these carbon reductions housebuilders also need to increase ventilation since as buildings become more air tight to improve efficiency it is essential to consider indoor air quality too to protect the wellbeing of inhabitants.

The pandemic has definitely highlighted the importance of indoor air quality and ventilation in buildings due to the airborne transmission of the COVID-19 virus. The new Approved Document Part F of the Building Regulations reflects the ever-growing importance of ventilation and indoor air quality as we make our buildings increasingly airtight to reduce carbon emissions. Part F’s publication heralds a vital step to improve indoor air quality with it setting out “significant changes”, which will drive adoption of low carbon ventilation as an industry standard and improve the quality of the air we breathe in buildings.

Since Kyoto, the UK has been striving to reduce its carbon emissions. Unfortunately, indoor air quality has taken a back seat. However, over the last 5 years we have all witnessed the real consequences of sealing up homes and insulating them to make them more energy efficient. It has resulted in indoor air pollution. The most visible sign of this have been condensation and mould but this is only the tip of the iceberg since homes with indoor air pollution can contain over 900 chemical and biological contaminants in the air we breathe, including viruses. The new Part F has started to redress the balance of ventilation with energy efficiency since the pandemic has clearly shown the importance of good indoor air quality to health and wellbeing

The significant cut in carbon emissions of 30% in New Build homes sets a challenge for housebuilders to improve both energy efficiency and airtightness of homes. To align with this ventilation has increased in Part F to support the safety of residents with an overall move to more advanced ventilation solutions, such as Mechanical Ventilation with Heat Recovery (MVHR) and Continuous Mechanical Extract Ventilation instead of traditional Intermittent Extract Ventilation (now referred to as Natural Ventilation throughout the document). Natural Ventilation is now only suitable for dwellings with a design air permeability higher than 5m3/(m2·h) meaning many new build dwellings will be out of scope of this technology. With the increased airtightness of buildings, and increased minimum whole dwelling ventilation rates for continuous mechanical extract units, higher performing options are needed. Here housebuilders look to favour continuous mechanical extract units that offer a 125mm diameter spigot model since the larger surface area will allow greater airflow through the fan at a much lower noise level and specific fan power (SFP). This means fewer fans are required to achieve whole house ventilation rates.

The importance of indoor air quality has definitely come to the fore now. With it comes the desire to monitor IAQ so going forward sensors, such as CO2 sensors, and controls are becoming increasingly important to housebuilders. To make it easy for housebuilders there are MEV units now available with integral and adjustable CO2 and humidity sensors, which increase ventilation rates in proportion to relative levels of pollutants within the dwelling, helping protect the safety of residents.

With the publication of the new regulations housebuilders will be looking for ventilation that both helps them meet DER requirements while improving indoor air quality. Other trends will include opting for ventilation with a low SFP and ultra-low noise levels. While demand control will prove an attractive option to enable precise ventilation in homes.

Now the importance of good indoor air quality has started to gain momentum it is vital that it continues. As we move towards the Future Homes Standard and Net Zero, our homes will become ever more air tight to meet CO2 targets. However, it is essential that ventilation also moves forward on this journey to ensure healthy homes in the future.