Environmental and health related criteria for buildings - ANEC

IBO - Environmental and Health related Criteria for Buildings
Results of the study “ABC-disposal” (MÖTZL et al, 2009) showed that the LCA-indicators are
in general not sensitive to disposal processes, except the global warming potential which
mainly reflects thermal utilization of construction materials and recycling credits – both
effects depending on the allocation rules applied. It can be said in principle, that LCA is not
the fitting methodology for measuring the environmental impacts of the building’s disposal.
One main reason for this is that landfilling of inert mineral waste – by far the biggest amount
of waste left behind from dismantled buildings – does not have any LCA-relevant impacts
(except some diesel for transportation and handling). Hence, qualitative methods can bear
many more improvement options.
The more life stages of a product are aggregated, the more uncertainty of results rises due to
uncertainty in data, methodology and scenarios. This leads us to the implication that different
life stages of building structure shall be handled separately, at least in a first step of
optimisation.
Data
Reliability of data used in LCA-methodology can be questioned, as many product systems
and supply chains are more flexible than the LCA-databases and -calculations, leading to
situations where LCA-results do not necessarily represent the actual environmental impacts
at a given time (PRAKASH, REINTJES et al, 2008, p iv).
When using generic data one has to consider that differences between products in the same
product group (e.g. for bricks from different plants) can be higher than difference between
different product groups (e.g. brick or limestone).
Methodologies for aggregated evaluation of environmental product performances
One major question concerning LCA-results is how to interpret them in a reproducible way.
The numerous indicators have to be grouped and weighted in order to calculate an
aggregated estimated impact. The limitation of aggregated indicators shall be shown briefly
on the example of the “Eco-Indicator”.
Eco-indicator links the inventory data via mid-point indicators (such as climate change, ozone
layer depletion etc.) to three defined end-point indicators (damage to human health, damage
to ecosystem quality, damage to resources). The panel approach, i.e. asking a group of LCAexperts,
was used in order to weight and rank the damage categories according to their
importance.
In spite of serious attempts for a clear reproducible methodological framework, strong
questions remain concerning the data basis, the use of Disability Adjusted Life Years as
functional unit for human health and the logical cause-chain from the inventory data to the
end-point indicators. As for instance, it is impossible to predict the exact damage caused by
climate change on human health (PRAKASH, REINTJES et al, 2008, p vi).
Improvement options in regard to the building structure
LCA allows comparisons between different products provided that the product differences
are big enough (at least 30 - 50%) compared to the precision of the LCA. Normally this will
Final Report 88 31 03 2011