60
INSULATION
The hot topic T
We have designed houses to reduce energy consumption by making them more airtight and better insulated for the winter, without considering the consequences for use in the summer
With the UK breaking temperature records while homes become increasingly air tight, James Healey from the Institute of Acoustics looks at hitting the tricky balance between overheating and external noise
his summer saw the hottest temperatures the UK has ever experienced; 40.3˚C was recorded in
Coningsby, Lincolnshire on 19 July. People living in houses with cross-ventilation – and in quiet, non-polluted areas – have probably learned that closing curtains and windows when the sun shone helped reduce solar gain and minimise internal temperatures, while at night, opening the windows brought the benefit of colder air. However, if you live in a flat that doesn’t enable cross-ventilation, or if you live in an area with night-time noise or poor air quality, this wasn’t an option. In fact, if you live in a modern house or flat, then it’s likely that opening a window will not have provided much benefit. This is because we have ignored the impending effects of climate change and designed houses to reduce energy consumption by making them more airtight and better insulated for the winter, without considering the consequences in the summer.
Guidance & regulations In 2019, the Government released studies into the risk of overheating in our homes. In the reports it confirms that there are currently around 2,000 heat-related deaths each year in England and Wales, and this has been expected to rise to over 7,000 deaths per year by 2050. The findings of the studies have culminated in the release of a new Building Regulation – Approved Document O – specifically addressing overheating in homes and covering applications for all new dwellings, care homes and student residential buildings submitted after 15 June 2022. The Institute of Acoustics and Association of Noise Consultants (the main industry bodies) formed a working group covering Acoustics, Ventilation and Overheating which released a national
WWW.ARCHITECTSDATAFILE.CO.UK
guidance document in 2020 on how to consider the balance between overheating and noise in new homes. This guidance document has informed Approved Document O, with the government recognising that overheating strategies must be usable.
The Building Regulation stipulates that where the prescribed noise or air quality conditions are exceeded, an alternative method other than opening windows is required. However, this approach is needed in order that any overheating strategy developed is usable – there is no point developing a strategy to avoid one risk that results in causing another. Given the need to consider environmental factors within the overheating strategy, this is likely to mean that locations within city or town centres, or next to roads, rail lines with 10 or more trains at night or airports with night flights, will require an alternative to opening a window. When implemented correctly, this regulation, along with others, should improve the living conditions in our residential buildings and lead to reduced heat-related deaths. However, Approved Document O contains a significant amount of ambiguity and is open to interpretation. In recognising the need to have a clear, precise and usable method of compliance, the Acoustics, Ventilation and Overheating working group again convened to write guidance to clarify and fill the gaps.
Impact on architecture
The regulation correctly requires designers to exhaust all passive means of removing excess heat before using air conditioning. When you couple this requirement with a need to consider closed windows in a poor air quality or a high noise environment, designs need to focus on reducing heat gains as much as possible to reduce the use of mechanical systems. This inevitably
ADF DECEMBER 2022
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68
