Z E M C H 2 0 1 2 I n t e r n a t i o n a l C o n f e r e n c e
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Because of this wide set of parameters that must be taken into account for designing
sustainable constructions there is an evident need to identify the potential environmental
gains available with realizing a building. Due to this difficult issue, several tools for
assessing building sustainability were developed.
Building sustainability tools
There are two primary methods of evaluating and communicating environmental
attributes that relate to buildings: the first one is using
Rating Systems
(RSs)
and the
other one is using
Life Cycle Assessment (LCA)
.
RSs are tools based on a multi-criteria evaluation and a framework of environmental
indicators, both qualitative and quantitative. RSs have the triple goal of evaluating,
objectively assessing and communicating the environmental quality level achieved by a
building.
They are composed of a list of criteria, divided in environmental categories, considering
human health and environment (i.e. urban environment, land use, comfort, indoor air
quality, energy efficiency, reuse of building waste, adaptability, durability and
maintenance). These systems assign a score for each strategy adopted in the project
and their sum defines the level of sustainability, according to a rating scale.
Usually, RSs award with different weights the quality of the project, the construction site
management and the building operation and maintenance.
Due to their simplified structure, they are useful guidelines for building practitioners and
for rapidly promoting the sustainable strategies in all over the world. Nowadays many
building environmental assessment tools are available, such as LEED (US), BREEAM
(UK), DGNB (D), HQE (F), CASBEE (J), Green Star (AU), Green Globe (int.) and others.
In Italy RSs have been developed in the last years following different paths.
Some of them are more oriented to the energy performance, according to the directive
2002/91/EC and 2010/31/EC. The most famous example is
ClimateHouse
standard of
the Province of Bolzano, but used everywhere in Italy.
Others systems are based on an integrated approach, including the same aspects
contained in the international RSs cited above, such as:
o
ITACA,
based on the iiSBE SBMethod and chosen by the Italian Regions as the
main reference for building sustainability assessment;
o
LEED Italia,
which is the first adaptation of US LEED NC, promoted by GBCItalia
and recognized by USGBC;
o
ARCA
, developed last year in Trentino-Alto Adige Region for assessing the
environmental quality of wooden constructions.
Mainly developed for designing low environmental impact products, LCA started to be
used during the Sixties in the industry sector, but the application of this methodology in
the construction sector is a more recent tendency.
Differently from RSs,
LCA bases only on the use of quantitative indicators, commonly
known as synthetic indicators, that can analyze the environmental inputs and outputs
related to a product or service during the different stages of its life,
“from cradle to cradle”
or
“from cradle to grave”
(from raw material extraction, through manufacture, usage
phase, reprocessing where needed, to final disposal), evaluating the quantity of depleted
resources and the amount of emissions to environmental matrixes.
Main reference for LCA is the ISO 14040 standard, in which four distinct analytical steps
are recognized:
goal and scope definition, life-cycle inventory creation, impact
assessment and results interpretation
. ISO 14040 defines LCA as: “
A technique for
assessing the environmental aspects and potential impacts associated with a product,
by: compiling an inventory of relevant inputs and outputs of a product system; evaluating
the potential environmental impacts; and interpreting the results of the inventory analysis
