Issue 33 web - Flipbook - Page 32
by Amad Kayani
Climate change is driving unprecedented changes in our
weather, which is impacting the adaptability and resilience
of existing buildings. Increasing average annual temperatures are pushing the limits of summertime comfort and
how we feel in buildings. Whilst most of the UK building
stock has been adapted for the cold, warmer weather
brings new challenges that must be overcome to provide
healthy and comfortable spaces all year round. This article
explores how Historic England have been assessing overheating in four historic office buildings from our estate.
The factors that contribute towards heat build-up can
arise from within or outside of a building. These can be
broken down into internal heat gains generated by lighting, equipment or people and external heat gains driven
by weather conditions. With climactic trends towards
warmer summers, maintaining summertime comfort is an
increasing challenge by driving up external heat gains.
Climate change is impacting the environmental resilience
of existing buildings by challenging summertime comfort
Comfort and summertime overheating
Overheating occurs when occupants of a building experience discomfort from feeling too warm. This can lead to
health implications through heat-related illness and stress.
Whilst perception of comfort is subjective, well-established systems of measurement can be used to predict
what is comfortable for most people, depending on the
activity they are doing indoors. Measuring the internal
temperature can provide a good indication of whether the
internal environment is comfortable or not. What is
deemed to be a comfortable internal temperature will vary
depending upon the type and use of the building.
The research project outlined in this article seeks to
quantify the extent of the overheating problem and
examine mitigation strategies to make historic buildings
more resilient to the impacts of climate change. A
supplementary aim of the project was to better understand
how passive measures can be used to avoid the use of air
conditioning and the generation of carbon emissions.
Figure 1 below: Aerial view of 24 Brooklands Avenue, Cambridge.
Source: Google Maps
Identifying overheating risk
The Chartered Institute of Building Services Engineers
(CIBSE) provide a structured methodology for assessing
and reporting overheating risk in new and refurbished
non-domestic buildings. The Technical Memoranda
(TM) 52 measures overheating risk through the observed
difference between external and internal air temperature,