New research will create an 85-year weather forecast aimed at transforming the way building scientists and engineers consider how differing weather conditions affect the built environment.
More than 70,000 people died across Europe during the extreme heatwave of 2003. The cause was not just the weather, but building design not being resilient enough to cope and protect occupants from external conditions.
It is widely accepted that climate change will have a significant impact on global building design and energy use in the near and distant future. With predicted temperature changes being large enough to make some buildings become uncomfortable or even fail certain regulations, the need for a better understanding of future weather trends in relation to building design is imperative in ensuring buildings become sustainable.
In the UK, there are growing concerns about what might happen in homes if the energy grid was disrupted during a cold snap. People could be left in rapidly cooling houses and it is unknown how quickly the homes would reach a critical temperature. In Australia, the potential converse issues are similar to those that Europe experienced during the 2003 heatwaves.
Researchers from the Universities of Bath, Exeter and Newcastle in the UK have been awarded a £1 million Engineering and Physical Sciences Research Council (EPSRC) grant to build a time series of predicted hourly weather conditions from now until the end of the century. These will represent both typical weather and extreme conditions, from heatwaves to cold snaps, to help better understand the interaction of the weather with building design.
The research project is being led by professor David Coley, director of the Centre for Energy and the Design of Environments (EDEn) in the Department of Architecture & Civil Engineering at the University of Bath. According to Coley, in western civilisations the greatest contributor to weather-related deaths are short-term extreme temperature changes, including both increases and decreases.
“Temporary temperature variations account for more weather-related deaths than all other weather events combined including lighting strikes, rain, flooding, hurricanes and tornadoes,” he said.
“It is important that we recognise the role buildings play in responding to and dealing with extreme weather conditions – buildings can keep people alive during extreme weather events, but they can also kill.”
The different weather characteristics will be tested on over 1,200 different building designs in order to discover how the characteristics of external temperature, wind and sun cause issues for occupants, such as over-demand on central heating systems and air conditioning.
“By better capturing these events in design weather data, architects and engineers will be able to stress test their building designs to the likelihood of over or under-heating, stress on people’s thermoregulatory systems, thermal comfort, and energy requirements," said Dr Matt Eames from the Centre of Energy and the Environment at the University of Exeter.
“Furthermore, by including the effects of climate change building designers will be able generate adaptation strategies and cost them more effectively.”
Coley says as long as there is access to historic weather for the location and good predictions of future climate, then the principles of the research could be applied to anywhere in the world.
Although the research is focused primarily on the correlation between weather conditions and the effect on a building’s internal environment, climate change and extreme temperature variations have structural design implications too.
Differences in temperature cause structures to expand and become smaller. These movements need to be taken into account through the proper design of tolerances in the structures.
In buildings where both indoor and outdoor temperatures play a role, this may give rise to higher loads and cause potential structural safety issues if not addressed.
With outside temperatures increasing, structures have to be able to withstand larger temperature differences between inside and outside, so structural systems may need to be adapted.
The difference between predicted temperature extremes and the likely more normal conditions experienced when the building was constructed is also likely to be larger if climate change patterns continue. This means that more care will need to be taken around the potential for greater dilations to take up larger expansions.
Extended periods of extremely hot temperatures also threaten increased damage to building foundations caused by ground shrinkage.
Although buildings typically have a lifespan of 50 years or more, the majority will have been designed using climatic design values calculated from historical climate data. These have assumed that the average and extreme conditions of the past will represent conditions over the future lifespan of the structure.
An appropriate balance must be struck between safety and required strength and serviceability over the life of the structure and over initial and maintenance costs. This balance can only be achieved using realistic estimates of future climatic design loads.
If the 85-year weather forecast proves successful – and, of course, predicting the success of an educated prediction is somewhat of an unknown – the impact it may have on future design codes could be significant.