ACR Journal

October 2022 | November 2022 The recently updated Building Regulations came into e ect in England on June 15. The new revision of the Regulations has highlighted the importance of indoor air quality and its impact on the health and wellbeing of building occupants. Recognising the significance of adequate building ventilation in reducing the spread of airborne infection during the current pandemic, the new approved document Part F Volume 2 for buildings other than dwellings, has included several new guidelines for the purposes of good indoor air quality including: • Air quality standard for outdoor air to minimise ingress of external pollutants into buildings. • Measures to reduce risk of transmission of airborne infection for recirculation of air in shared o ces. • Indoor air pollutant levels and exposure time. • Indoor CO 2 monitoring as an indicator of overall indoor air quality to guide building ventilation. It is further recommended that VENTILATION 28 Hong Cheng of LG explores the importance of constantly monitoring indoor CO 2 levels in real-time for improved indoor air quality in line with the new new Part F of Building Regulations in England. Monitoring ventilation with CO 2 sensors a CO 2 level of 800 ppm is acceptable in suitably ventilated building and a level of 1500 ppm is a starting point at which action needs to be taken to improve ventilation. The new revision has shown that energy e ciency and adequate ventilation should go hand in hand with design, construction and building operation. These new changes will help to reduce carbon emissions associated with commercial buildings in order for the UK to achieve its target of carbon Net Zero by 2050. It has been reported that, for healthy fresh outdoor air, the CO 2 level is typically found to be below or around 400 ppm. For occupied indoor spaces, CO 2 concentration usually varies in the range of around 400 to 1000 ppm depending on the building location and the specific air exchange rate of the building. In closely packed meeting rooms, it is not surprising to find the CO 2 level is in the region of 1500-3000 ppm. It has been known that exposure to excessive levels of indoor carbon dioxide over a prolonged period can have negative health impacts on the building occupants. Although the precise relationship between indoor CO 2 level and its e ect on human health is not fully understood yet, it is only logical and sensible to keep indoor CO 2 levels below a certain limit if possible. Potential risk to health In densely populated indoor spaces such as lecture theatres, conference rooms where many people congregate, indoor CO 2 levels generated by audiences’ breathing could be excessive and potentially become a risk factor to health without adequate ventilation. If the indoor space is unventilated or poorly ventilated, the indoor CO 2 concentration will continue to accumulate and can rise to a much higher level over time. Inversely, elevated CO 2 levels in buildings indicate poor ventilation. In the indoor environment, CO 2 levels has long been used as a surrogate indicator for the quality of indoor air where the need for ventilation is linked to the presence of people. This has now become a requirement in Part F of the Building Regulations in England. CO 2 monitoring is recommended to be used as an approach to assess whether ventilation to an occupied indoor space is adequate, and can be integrated into the building ventilation management system. Volume 8 No.6 Hong Cheng Energy Recovery Ventilation (ERV) schematic