Design Strategies and LCA of Alternative Solutions …
213
Finally, all the benefits—such as direct sequestration of CO 2 and reduction of
GHGs—deriving from the use of NBS were calculated in terms of CO 2 eq. using
values from the scientific literature and databases (database Qualiviva; CNT 2010;
IPCC 2007; McPherson et al. 2006) and I-Tree Eco software (V.6).
All the adopted solutions—detailed and careful selection of construction (materials and supply model), management model, maintenance solutions and NBS—have
made it possible to contain the impact of a building over 50 years to approximately
1.6 kg CO 2 eq/m
2 per year. To compensate this value, a forestry intervention on an
area of fewer than 2 ha would be sufficient.
4 Critical Aspects and Future Developments
The experience of a real participation alongside a project team and in response to a
call from a public body was definitely positive, because it shows a virtuous case of
promotion of sustainability aspects by a public administration, which therefore urges
the project team to consider the environmental aspects and leads to the involvement
of environmental consultants in an effectively integrated way from the first phases of
the project, in order to be able to achieve the ambitious goal required. However, it is
also necessary to highlight the aspects that remain critical in this type of experience.
In particular, the fact of having chosen a single environmental indicator (the carbon
footprint), considered a priority in the international debate (Rockström et al. 2017),
risks orienting the design choices in a direction that is not entirely sustainable.
As mentioned above, in order to reduce the carbon footprint of a building, the necessary choice is to use large amounts of wood in its construction. Some researchers
show that a cross-laminated timber building gives the lowest life-cycle carbon emission while a beam-and-column building gives the highest life-cycle emission (Doodo
et al. 2014). Although it might seem counterintuitive, the increasing of quantities in
the case of wood, therefore abounding rather than optimizing, decreases the carbon
footprint, since it increases the quantity of stored CO 2 that becomes a minus in the
environmental balance. However, by using more material unnecessarily, the project
brings about a disadvantage compared to all the other environmental impact indicators (only in the case of the carbon footprint is there the possibility of having the
minus sign in phases A1–A3 raw materials supply-transport to the production plant
manufacturing).
Moreover, although different methodological choices and assumptions can lead
to opposite conclusions, there is no consensus on the assessment of biogenic carbon
in LCA. Incorrect biogenic carbon assessments could lead to inefficient or counterproductive strategies, as well as missed opportunities (Breton et al. 2018). There
is a need for a government mandate for improved data quality and for support for
the development of a transparent and simplified methodology (De Wolf et al. 2017).
Therefore, making environmental choices by considering a single indicator is likely
to indicate a constructive solution with respect to a single environmental theme,
213
Finally, all the benefits—such as direct sequestration of CO 2 and reduction of
GHGs—deriving from the use of NBS were calculated in terms of CO 2 eq. using
values from the scientific literature and databases (database Qualiviva; CNT 2010;
IPCC 2007; McPherson et al. 2006) and I-Tree Eco software (V.6).
All the adopted solutions—detailed and careful selection of construction (materials and supply model), management model, maintenance solutions and NBS—have
made it possible to contain the impact of a building over 50 years to approximately
1.6 kg CO 2 eq/m
2 per year. To compensate this value, a forestry intervention on an
area of fewer than 2 ha would be sufficient.
4 Critical Aspects and Future Developments
The experience of a real participation alongside a project team and in response to a
call from a public body was definitely positive, because it shows a virtuous case of
promotion of sustainability aspects by a public administration, which therefore urges
the project team to consider the environmental aspects and leads to the involvement
of environmental consultants in an effectively integrated way from the first phases of
the project, in order to be able to achieve the ambitious goal required. However, it is
also necessary to highlight the aspects that remain critical in this type of experience.
In particular, the fact of having chosen a single environmental indicator (the carbon
footprint), considered a priority in the international debate (Rockström et al. 2017),
risks orienting the design choices in a direction that is not entirely sustainable.
As mentioned above, in order to reduce the carbon footprint of a building, the necessary choice is to use large amounts of wood in its construction. Some researchers
show that a cross-laminated timber building gives the lowest life-cycle carbon emission while a beam-and-column building gives the highest life-cycle emission (Doodo
et al. 2014). Although it might seem counterintuitive, the increasing of quantities in
the case of wood, therefore abounding rather than optimizing, decreases the carbon
footprint, since it increases the quantity of stored CO 2 that becomes a minus in the
environmental balance. However, by using more material unnecessarily, the project
brings about a disadvantage compared to all the other environmental impact indicators (only in the case of the carbon footprint is there the possibility of having the
minus sign in phases A1–A3 raw materials supply-transport to the production plant
manufacturing).
Moreover, although different methodological choices and assumptions can lead
to opposite conclusions, there is no consensus on the assessment of biogenic carbon
in LCA. Incorrect biogenic carbon assessments could lead to inefficient or counterproductive strategies, as well as missed opportunities (Breton et al. 2018). There
is a need for a government mandate for improved data quality and for support for
the development of a transparent and simplified methodology (De Wolf et al. 2017).
Therefore, making environmental choices by considering a single indicator is likely
to indicate a constructive solution with respect to a single environmental theme,