Page 102 - Materials Chemistry, Second Edition

Life cycle assessment: applications in the built environment

made during modelling, and data may not always be available. To overcome this, the Dutch 89
system included a penalty model designed to encourage the industry to deliver complete and
correct data. Incomplete data led to default conditions applying, which typically led to overes-
timation of results by 20% or more. However, this approach to developing and expanding the
reference database made the LCA complex and time-consuming. It also ultimately interfered
with the transparency of the process and the results, and had the effect of raising the costs and
risks of the LCA work.
In summary, the technical system that was developed in order to overcome lack of data
ultimately led to a significant and ultimately insurmountable burden falling on the process,
given the balance of institutional and political factors operating at the time. It would be a
mistake to conclude from this example that regulation and LCA do not mix well, or that LCA
cannot be applied successfully in a mandatory compliance framework. Rather, the key lesson is
that data development needs to be in place from the outset, and the necessary processes to
update data must be designed not to inhibit regulation’s key functions, which include trans-
parency and ease-of-use.

7.3 Directions for LCA in the built environment

The built environment assists human societies to meet basic needs for shelter and security.
Increasingly, it is also being developed to provide high levels of comfort and amenity, with
considerable environmental impacts. LCA has a major role in highlighting the impacts of dif-
ferent built environments across their various life cycles. Five directions can be identified for
LCA to assist improving the sustainability of the built environment over the next decade:
1. Increasing attention on reducing greenhouse gas emissions through improving the thermal
efficiency of buildings is driving changes in building design. Some of these changes lead to
a corresponding increase in embodied energy loads. There is therefore a potential ‘optimal’
investment of embodied energy for operational energy payback in some cases. LCA has an
ongoing role in improving understanding of such issues and in providing support for design
decisions. This will become more pressing as operational energy efficiency improves, since
the proportion of total energy-related impacts attributable to embodied energy will rise.
Since many buildings and their siting are unique, there is the potential to further develop
life cycle management tools to assist in this process.
2. There is a plethora of building rating tools. Their emphases vary, and many incorporate
some ‘life cycle thinking’, although most do not incorporate LCA to any significant extent.
With improvements in LCA methods and building data over the past decade or so, and with
the increasing share of embodied energy in the total energy impact, there is a strong case for
the increased use of LCA in many building rating tools. This use may vary from embodied
energy calculators or indicators to the development of more sophisticated multi-impact
assessment-based tools to support design decisions. LCA can also assist in researching and
setting appropriate functional units for tools; for example, is ‘energy use per house’, ‘energy
use per bed space’, or ‘energy use per square metre’ an appropriate unit, and what is the
sensitivity of results to assumed maintenance regimes and design life?
3. There are environmental impacts associated with buildings that normally fall outside building
regulations. These include, for example, energy consumed by products used in but not part of
the building fabric, such as appliances. Here, LCA can provide common metrics and therefore
‘bridge’ the area between consumer labelling and buildings’ environmental performance.
4. LCA has a role in urban design, where spatial disciplines and scale-based tools are commonly
used. While LCA typically assumes a functional unit, and therefore does not readily focus

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