Modern Building Services

10 MODERN BUILDING SERVICES MAY 2023 FEATURE AIR CONDITIONING, COOLING & VENTILATION A ccording to official sources, Western Europe’s 2022 heatwave may have caused 20,000 excess deaths. In England andWales 3,271 excess deaths were recorded from the start of June to the 7th September (Office for National Statistics), this is 6.2% higher than the five-year average with COVID-19 deaths excluded. The number of deaths were higher for heat-period days than non- heat-period days. During the summer heatwaves temperatures exceeded 40˚C in London. All previous regulations on overheating have been brought together into Approved Document O, to highlight the importance in the design of limiting solar gains through windows and providing adequate opening areas to remove excess heat. Approved Document O stipulates that we cannot use blinds to reduce overheating, therefore, we must either reduce the window size or greatly enhance glazing (which is often counteractive) or, alternatively, open the windows for long periods during the day which can sometimes cause problems with the site if bad acoustics are present. Moreover, buildings must comply with CIBSE’s TM59 to reduce overheating. Matters aremade worse by the fact that we are facing a climate emergency. In 2022, our highest temperature was 40.3 degrees which exceeded our record of 38.7 degrees. As an energy engineer, I feel compromised as we have now arrived at the point where the purpose of energy efficiency is to drive down heating costs and we are looking tomechanical cooling to deal with our overheating problem, which should not be the first port of call. These temperatures we have faced are comparable to a Spanish summer. The Spanish prevent overheating by keeping doors and windows shut to keep out hot air in the middle of the day, shutting blinds and utilising mechanical cooling in the evening to lower inside temperatures. We are experiencing temperatures that you expect from Spain, and yet we are not adjusting our architecture. The Spanish approach to preventing overheating In the UK it is imperative that we design buildings in a way that is sympathetic to the higher temperatures that we get and that we’ve been experiencing in our recent summers. Spanish designers consider high temperatures in building design. Their buildings feature hard ceramic floors and hard concrete ceilings to reduce the heat. Moreover, ‘persianas’, or exterior shutters, used as an external shading solution are commonplace. This Spanish approach to keeping buildings cool would be an excellent start to dealing with our overheating problem and meeting the relevant standards. It is pertinent to start having a discussion within the built environment about exterior shading for properties and moveable shutters that you often see on Spanish apartment buildings, as these features could be the solution to the British overheating problem. Alex Hill , Managing Director at Whitecode Consulting, looks at new government regulation to reduce overheating and the best solutions to prevent overheating in hospitals, offices and schools. The power of nature can keep us cool