Civil Engineering Reference
In-Depth Information
specifications of the product to be marketed, before deciding what is the 'cradle'
and what is the 'grave' for specific purposes. Such an approach would take a firm
on an incremental journey that would make its product differentiation clear and
accountable.
Figure 9.1
shows a very simplified model of the opportunities that life
cycle analysis might offer to construction.
Figure 9.1
Life cycle analysis of buildings and infrastructure
In this simplified model, the environment is the source of fossil fuel and raw material
inputs and a sink for waste outputs.
Inputs
Use
Outputs
Raw materials
Products
Construction
Fossil fuels
Waste
It is evident that, at each stage, the construction process burdens the environment
with many costs. At the beginning of the life cycle, a large amount of natural input
is needed for the construction phase and, as is well documented, across Europe the
construction industry consumes more raw materials than any other industrial sector.
During the operational stage, buildings are also responsible for a very significant
amount (40-50 per cent) of greenhouse gas emissions, as buildings rely heavily on
carbon-based fossil fuel energy for heating, lighting and ventilation. And finally, at all
stages up to and including demolition, there is a large amount of associated waste. In
fact, it is estimated that the construction industry accounts for 50 per cent of the total
waste stream in Europe.
The life cycle analysis of a building is complicated further by fact that there may
be several occupiers with different regimes of repair, maintenance and improvements
throughout its life span. At all times, however, there is a flow of resources from the
natural environment to the constructed product and vice versa, with varying impacts
on the environment at different phases. Consequently, no matter how exemplary the
initial environmental specification at the construction stage, the overall impact of a
building will be dominated by the way in which it is used.
For our purposes, it is important to remember that we are not dealing here with
environmental science. This text seeks to introduce economic concepts and:
•
compare ideas of mainstream economists with their environmental counterparts
•
understand the interrelationships between the economy and the environment.
These concerns form an important focus of the chapters comprising
Part B.
