Environmental lifecycle of Buildings
Figure 1: Environmental Lifecycle
of a Building.
This section has been included to
inform of both Life Cycle Assessment and Lifecycle Analysis and their potential
use in helping construction professionals make environmentally friendly
decisions.
Life-Cycle Assessment
Life cycle assessment recognises that all stages from raw
material extraction to waste management have environmental and economic
impacts. It is a tool which assesses the environmental aspects and potential
impacts associated with a product or service.
LCA can be applied to the Environmental Life Cycle of
Buildings shown above in Figure 1. Life cycle
assessment normally involves three stages:
1. An
inventory of materials and energy used and environmental releases from all
stages in the life of a product or process.
2. Impact
assessment examining potential and actual environmental and health effects
related to the use of resources (materials and energy) and environmental
releases.
3. An
improvement assessment, identifying the changes needed to bring about
environmental improvements in the product or process.
Life
Cycle Analysis
The life cycle of a
product includes raw materials acquisition, manufacturing, distribution and
transport, use, reuse and maintenance, recycling and waste management assessing
the environmental impacts from inputs and outputs related to each.
Matters to consider
when conducting a life-cycle analysis of a material include:
- What is the embodied energy of the building material
over its entire life?
- Are renewable or sustainable energy sources used in the
manufacture of the material?
- Are there less energy consuming, longer-lived
alternatives for the same application?
- Are local
sources of the material available?
- Can the material be recycled or reused at the end of its
useful life in a structure?
- How easy or difficult is the material to recycle?
- Do different construction systems offer better
opportunities for resource recovery at the end of building life?
- How much maintenance does the material require over its
life in a structure?
- How energy intensive is the maintenance regime?
- Are waste by products produced during maintenance?
- Does the material require special coatings or treatments
that could present health or
safety hazards?
- If the material off-gasses during and after
installation, how is indoor air quality affected?
- Are hazardous solid, aqueous, or gaseous wastes produced
during the manufacturing process?
- How do the amounts of waste resulting from manufacture,
fabrication, and installation compare with those from alternative
materials?
There is however a
drawback with LCA and it is the method is limited to a direct comparison of two
or more products as its code of practice is very flexible to the users and
there is no available database to carry out benchmarking of LCA results.
Consequently it may not be the most accurate decision making tool and simple
indicators should be made available to the construction industry.
Project Direction
To apply these techniques to evaluate CO2
emissions over the lifecycle of our case study with information being limited,
ambiguous and complex would constitute covering too vast a subject area
which would be a project within in its own right, we decided this was not the
focus of our project.