The Contribution of the Albedo in the Life Cycle Assessment (LCA) of Three Roofs

Abstract. The Life Cycle Assessment (LCA) is a useful tool capable of explaining
in eco-score the environmental impacts related to products, goods or services.
When applied to buildings, LCA estimates the final impact as the sum of the
loads of each building component. 
Typically, some important characteristics that can strongly influence the
environmental impacts, such as surface albedo, are not taken into account. 
This research enhances the current use of LCA including the effects of the roof
surface albedo. 
In order to consider the effects of the roof surface albedo, a climatologic
model has been used to convert the albedo of a white and green roof into
kilogram of equivalent CO2. These values have been used to model the LCA
software SimaPro 7.1 method Impact 2002+.
Furthermore, field data about the surface temperatures have been carried out
on the three roofs installed on the Con Edison â "Learning Center" in Long
Island City. It resulted that the key property of the white roof, its high
solar reflectance, consistently affects the surface temperature and as a
consequence the heat flow through the roof. 
My analyses shows that the high albedo of the white roof causes a decrease in
both the monthly average energy fluxes (~26%) and in the average fluxes through
the roof during the boreal summer (~60%). Likewise, the high albedo gives rise
to a reduction of the energy use peak (~30%) especially during summer. 
Most importantly, the reflectance has a noticeable positive influence in the
LCA evaluation, and in detail on the climate-change damage category (one of the
four damage categories of the LCA evaluated with the method Impact 2002+),
reducing the final environmental loads by about 10--30%. 
In conclusion, the whole white and green roof impact evaluations reveal a
significant decrease in the final total environmental burdens when compared
to those relative to the black roof.