Civil Engineering Reference
In-Depth Information
Table 4 Replaced component and the related life span
Systems, plant components and envelope elements
Service life (years)
Windows and frames
35
Roof and floors
35
Walls
15
Solar systems
25
DHW system
50
Thermal plant, radiant floors
40
Thermal plant, gas distribution system
35
Thermal plant, heat pump
25
Thermal plant, boiler
35
Air handling unit pipes
50
Air handling unit
25
The replacement of the components with shorter life span than the building
service life is considered in the maintenance phase. Table
4
shows the replaced
component and the related life span. The same options of maintenance are taken
into account in the two assessed scenarios.
With regard to the end-of-life, three distinct steps are included for each building
scenario (Beccali et al.
2001
; Lo Mastro and Mistretta
2004
):
1. selective dismantling of reusable/recyclable materials and structures, such as
windows, steel, and aluminum;
2. controlled demolition of the structural system by hammers and shears;
3. operations for C&D waste treatment and recycling, reuse, or landfill.
All the energy consumption and environmental impacts due to transportation,
demolition, and recycling operations are calculated. Inventory data relevant to
recycling of aluminum, steel, glass, and copper are retrieved from the Ecoinvent
database (Frischknecht et al.
2007
). Thus, energy and environmental benefits in the
building life cycle due to the recycling of secondary raw materials are accounted for.
3.4 Life Cycle Impact Assessment
LCIA was carried out in order to assess the energy and environmental impacts of
the building in the two scenarios of analysis by means of suitable and meaningful
indicators.
The LCIA results were presented at the level of mid-point indicators. In order to
select relevant environmental indicators able to represent in a synthetic and
comprehensive way the LCI results about the material and energy resource con-
sumption and the environmental releases, the chosen impacts categories were
referred to the main environmental indices and characterization factors included in
the ''Environmental Product Declaration'' scheme. In detail, life cycle primary
