Green rating tools and climate resilient buildings
Understanding the role of the built environment in mitigating and adapting to climate change is
essential for achieving UK and Scottish emissions targets1, as well as for the long-term resilience and
viability of both new and existing buildings. So - how can stakeholders assess how well buildings will
perform in meeting these demands?
One way in which designers developers and regulators can check whether new developments
address both the adaptation and mitigation demands of climate change is through the use of
existing sustainability or green rating tools, such as LEED in the US, BREEAM® in the UK, Green Star in
Australia and CASBEE® in Japan.
Not surprisingly, as the requirement for a demonstrable level of best practice performance becomes
more common, such green building rating tools are becoming increasingly important for design and
construction disciplines. These tools also form an essential part of the toolkit for environmental
consultants working in the sector.
Leading tools, such as BREEAM in the UK, take a holistic view of building sustainability as reflected in
the variety of categories under which projects are assessed. The key issues relating to the resilience
and adaptability of buildings over their lifecycle can be easily identified and assessed.
The following list provides examples of issues relevant to climate resilience which are awarded
credits within the BREEAM ratings scheme2. A checklist based on these issues can thus be used to
assess the extent to which both new and existing buildings are likely offer climate resilient
performance (or not).
1. Glare control/ shading: Provision of occupant controlled shading; bioclimatic design or ‘brise
soleil’. Whilst principally aimed at reducing disabling glare, such measures also have an
influence over levels of thermal comfort during periods of extreme high temperature.
2. Reduction of CO2 Emissions: Measures introduced to improve the operational energy
efficiency of a building and reduce CO2 emissions will also have an impact on the resilience of
a building during extreme heat-waves and cold spells, as well as other forms of extreme
weather. As well as ensuring that building orientation and layout are appropriate, this
includes optimising insulation levels and thermal mass; window specification; reducing air
infiltration and thermal bridging; and designing building services so that they are more able
to cope during periods of stress.
3. Low and zero carbon technologies: As well as reducing carbon emissions and operational
costs, carefully selected technologies can also harness the additional energy that is
associated with increases in temperatures, sunlight or wind speeds.
4. Natural ventilation: As well as providing a more pleasant environment for occupants,
buildings designed to be naturally ventilated are less likely to require additional mechanical
cooling during heat-waves.
1
See for example http://www.scotland.gov.uk/Publications/2010/11/15085756/7 ,
http://www.ukgbc.org/content/key-statistics-0 and http://www.rudi.net/node/2168
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For details about BREEAM see http://www.breeam.org/
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5. Free cooling: Recognised free-cooling strategies include night-time cooling, displacement
ventilation, ground or surface water cooling and absorption cooling.
6. Water consumption: For buildings which are likely to encounter increased water stress in
the future, the specification of more efficient sanitary-ware, as well as re-using rainwater
and/or grey-water is increasingly relevant.
7. Irrigation: Irrigation strategies which minimise requirements for potable water are credited
by BREEAM and other rating systems. These include use of grey/rainwater; planting which
relies on natural precipitation and situations with no mains-supplied irrigation specified.
8. Flood risk: Credits are available where developments are situated in areas of low flood risk,
or where they are designed to be resilient to extreme flood events (i.e. ground level of
buildings must be well above the design flood level).
9. Surface water runoff: Provision of drainage measures to limit peak run-off. Sizing
calculations must allow for precipitation increase from climate change.
10. Ecology issues: Several credits are available for mitigating and enhancing ecological value.
Ecologist recommendations should give the best possible chance of long term establishment
and survival of species within the development habitat.
In addition to the above, there are several other areas in which the need for future climate change
adaptation should be taken into account:
11. Materials specification: The current ‘Green Guide to Specification’ only takes into account
climate change in terms of mitigation (i.e. the Greenhouse Warming Potential (GWP) of
materials). However, closer attention should be paid to the resilience of materials in a
changing climate. For existing buildings, more thought should be given to the protection,
adaptation or replacement of materials to cope with climatic changes.
12. Design for robustness: This is currently aimed at protecting building fabric from day-to-day
wear and tear (e.g. associated with building users, vehicle movement etc). The vulnerability
of building fabric to climate change could also be covered more clearly.
13. Hard landscaping: Although provision of surface water runoff and SUDS are covered in
detail, there is little or no attention paid to the resilience of hard landscaping materials
under the increased frequency of extreme weather events.
The flip side of this list of positive attributes is shown in the attached schematic3, which illustrates
design risks that, if left un-addressed, could lead to poor performance under climate stress.
As well as considering the impacts of climate change, adaptation assessment should also take into
account the potential for other major externalities that may affect the long-term viability and
suitability of building stock, such as the continuity and cost of energy supply.
Ben Stubbs, Senior Sustainability & Energy Consultant, Faithful+Gould
Katherine Beckmann, School of the Built Environment, Heriot-Watt University
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Developed by Faithful and Gould for work with the Crown Estates
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