315
supply through district heating systems can be considered as an alternative at the
neighborhood scale (Oliver-Solà et al. 2009b ).
In the framework of decentralization, self-supply of endogenous resources such
as water or energy contributes to the environmental improvement of urban areas. In
this case, besides being independent of the central network, local and renewable
resources substitute the consumption of nonrenewable ones. For instance, rainwater
harvesting systems are increasingly implemented for nonpotable purposes and play
a key role in countries dealing with water scarcity. In addition, wastewater recycling
can also be integrated in the water metabolism of buildings.
5 Conclusions
LCA literature has dealt with the environmental impacts of multiple elements of the
urban fabric. However, studies only showed the individual performance of certain
elements. This study compiled LCA data in an attempt to quantify the environmental burdens of an entire street profi le as a whole, thereby combining the impacts of
the elements that constitute the urban fabric: the paved skins and the subterranean
networks. The best and worst practices were identifi ed.
The best practices in the design of streets accounted for a carbon footprint of
1.1 t of CO 2 eq. This design consisted of concrete sidewalks, asphalt pavements,
HDPE gas pipes, PVC water pipes, and concrete sewer pipe with CP1 trench. When
considering this confi guration in urban planning, the global warming potential of
streets can be reduced by 23 %. The most impacting scenario included the following
practices: granite in sidewalks, LDPE in water supply pipes and HDPE in the sewer
system with PP2 trenches. Pavements and sidewalks are the most contributing
elements to the overall environmental burdens of streets, mainly because their exposition intensifi es their maintenance.
Proper urban fabric design must consider three key aspects: the material selection,
lifespan and, in the case of subterranean networks, the installation procedures. First,
promoting cleaner production in the construction materials sector (e.g., granite
production, Mendoza et al. 2014b ) is essential to reduce the environmental burdens
of constructive assets and achieve major environmental improvements at city level.
Second, lifespan must be included in the design parameters of long-term urban
planning. Third, the installation of subterranean networks has a relevant contribution to the total impacts and must be adapted to the technical and environmental
requirements of the construction site.
Studies that quantify the environmental burdens of urban elements provide basic
information for the decision-making process when environment is considered in
urban planning. Thus, the application of life cycle thinking implies the inclusion of
environmental criteria during the conception of cities. Towards a sustainable design
of cities, urban planning studies might also integrate the social and economic dimensions in the decision-making process. From a life cycle perspective, Social Life
Cycle Assessment (S-LCA) (UNEP/SETAC 2009 ) and Life Cycle Costing (LCC)
(ISO 2008 ) methods may provide a standard quantitative way to assess urban elements.
22 Life Cycle Management Applied to Urban Fabric Planning
supply through district heating systems can be considered as an alternative at the
neighborhood scale (Oliver-Solà et al. 2009b ).
In the framework of decentralization, self-supply of endogenous resources such
as water or energy contributes to the environmental improvement of urban areas. In
this case, besides being independent of the central network, local and renewable
resources substitute the consumption of nonrenewable ones. For instance, rainwater
harvesting systems are increasingly implemented for nonpotable purposes and play
a key role in countries dealing with water scarcity. In addition, wastewater recycling
can also be integrated in the water metabolism of buildings.
5 Conclusions
LCA literature has dealt with the environmental impacts of multiple elements of the
urban fabric. However, studies only showed the individual performance of certain
elements. This study compiled LCA data in an attempt to quantify the environmental burdens of an entire street profi le as a whole, thereby combining the impacts of
the elements that constitute the urban fabric: the paved skins and the subterranean
networks. The best and worst practices were identifi ed.
The best practices in the design of streets accounted for a carbon footprint of
1.1 t of CO 2 eq. This design consisted of concrete sidewalks, asphalt pavements,
HDPE gas pipes, PVC water pipes, and concrete sewer pipe with CP1 trench. When
considering this confi guration in urban planning, the global warming potential of
streets can be reduced by 23 %. The most impacting scenario included the following
practices: granite in sidewalks, LDPE in water supply pipes and HDPE in the sewer
system with PP2 trenches. Pavements and sidewalks are the most contributing
elements to the overall environmental burdens of streets, mainly because their exposition intensifi es their maintenance.
Proper urban fabric design must consider three key aspects: the material selection,
lifespan and, in the case of subterranean networks, the installation procedures. First,
promoting cleaner production in the construction materials sector (e.g., granite
production, Mendoza et al. 2014b ) is essential to reduce the environmental burdens
of constructive assets and achieve major environmental improvements at city level.
Second, lifespan must be included in the design parameters of long-term urban
planning. Third, the installation of subterranean networks has a relevant contribution to the total impacts and must be adapted to the technical and environmental
requirements of the construction site.
Studies that quantify the environmental burdens of urban elements provide basic
information for the decision-making process when environment is considered in
urban planning. Thus, the application of life cycle thinking implies the inclusion of
environmental criteria during the conception of cities. Towards a sustainable design
of cities, urban planning studies might also integrate the social and economic dimensions in the decision-making process. From a life cycle perspective, Social Life
Cycle Assessment (S-LCA) (UNEP/SETAC 2009 ) and Life Cycle Costing (LCC)
(ISO 2008 ) methods may provide a standard quantitative way to assess urban elements.
22 Life Cycle Management Applied to Urban Fabric Planning