Ecological Footprint of the Life Cycle of Buildings
5
a tool for estimating EF and CF of buildings [43]. Finally, [44], analysed the BLC
(project, materialization, use and demolition) and its study according to EF (energy,
resources, CO 2 and solid waste), applying it to an exhibition centre in Wuhan (China).
Bastianoni et al. [45] calculated the EF of two Italian buildings, taking into account
the embedded energy of the materials and the construction process (estimated as
5% of the total energy of the materials). The results are reflected in land for CO 2
absorption, forest land (for wooden materials) and the area occupied by buildings.
Despite the fact that the results of these studies often remain barely comparable
due to the myriad of assumptions and decisions that must be made in the evaluation
process (life of the building and materials, maintenance operations, energy consumption of the building, building typology, calculation formulas, etc.), the following
findings are generally identified:
• The manufacturing and construction phase of the building’s life cycle, concentrated in a short period of time (1–2 years), causes the most intense environmental
impact, mainly due to the consumption of concrete and steel for the structure,
which represents a high percentage of the emissions produced during this phase
[46, 47]. This impact is diluted, the longer the life of the building is considered,
however, decisions made during this phase greatly influence the results for the
remaining phases of the building’s life cycle.
• The use and maintenance phase is generally responsible for 80–90% of the CO 2
emissions generated during the building’s life cycle [48], almost 60% of which
is caused by energy demand for heating and air conditioning [49]. Its duration,
more than 50 years, makes the reduction of emissions in the operational phase the
main objective to be pursued.
The reduction of energy consumption during the use and maintenance phase
should be achieved through decisions made during the design phase, which generally
involve the use of materials with higher built-in energy. This means that, in nearly
zero energy buildings, emissions during the construction phase represent a higher
percentage of the total emissions during the whole BLC [50]. Therefore, once the
operational energy has been reduced, the attention of researchers should focus on the
development of new insulation materials that require less energy to manufacture [51].
Although the stages of land use transformation and recovery or demolition produce a
smaller environmental impact in comparison, it is interesting to note their influence
on the biocapacity of the plot, as well as their relationship with other stages of the
BCL.
With these findings in hand, one cannot ignore the importance of anticipating
the impacts that will occur as a result of the design of the building. The knowledge
generated by the significant number of studies on environmental impact is subsequently reflected in calculation tools, generally oriented towards the environmental
certification of buildings as a means of communicating their results to society. The
development of models to measure the sustainability of buildings has been encouraged in recent years to promote policies that require minimum sustainable behaviour
for buildings.
5
a tool for estimating EF and CF of buildings [43]. Finally, [44], analysed the BLC
(project, materialization, use and demolition) and its study according to EF (energy,
resources, CO 2 and solid waste), applying it to an exhibition centre in Wuhan (China).
Bastianoni et al. [45] calculated the EF of two Italian buildings, taking into account
the embedded energy of the materials and the construction process (estimated as
5% of the total energy of the materials). The results are reflected in land for CO 2
absorption, forest land (for wooden materials) and the area occupied by buildings.
Despite the fact that the results of these studies often remain barely comparable
due to the myriad of assumptions and decisions that must be made in the evaluation
process (life of the building and materials, maintenance operations, energy consumption of the building, building typology, calculation formulas, etc.), the following
findings are generally identified:
• The manufacturing and construction phase of the building’s life cycle, concentrated in a short period of time (1–2 years), causes the most intense environmental
impact, mainly due to the consumption of concrete and steel for the structure,
which represents a high percentage of the emissions produced during this phase
[46, 47]. This impact is diluted, the longer the life of the building is considered,
however, decisions made during this phase greatly influence the results for the
remaining phases of the building’s life cycle.
• The use and maintenance phase is generally responsible for 80–90% of the CO 2
emissions generated during the building’s life cycle [48], almost 60% of which
is caused by energy demand for heating and air conditioning [49]. Its duration,
more than 50 years, makes the reduction of emissions in the operational phase the
main objective to be pursued.
The reduction of energy consumption during the use and maintenance phase
should be achieved through decisions made during the design phase, which generally
involve the use of materials with higher built-in energy. This means that, in nearly
zero energy buildings, emissions during the construction phase represent a higher
percentage of the total emissions during the whole BLC [50]. Therefore, once the
operational energy has been reduced, the attention of researchers should focus on the
development of new insulation materials that require less energy to manufacture [51].
Although the stages of land use transformation and recovery or demolition produce a
smaller environmental impact in comparison, it is interesting to note their influence
on the biocapacity of the plot, as well as their relationship with other stages of the
BCL.
With these findings in hand, one cannot ignore the importance of anticipating
the impacts that will occur as a result of the design of the building. The knowledge
generated by the significant number of studies on environmental impact is subsequently reflected in calculation tools, generally oriented towards the environmental
certification of buildings as a means of communicating their results to society. The
development of models to measure the sustainability of buildings has been encouraged in recent years to promote policies that require minimum sustainable behaviour
for buildings.