5.7 Example: Comparing Insulation Foaming Agents
91
In doing so, it is also valuable to consider and comment on the influence that the
chosen allocation and impact assessment methods may have had on the results, as
well as on the set system boundaries. In the context of integrated product or process
development, it is especially useful to identify which process steps within the entire
process tree are the dominant contributors to the total impacts. Knowing this can
provide clues for how to improve the design and reduce the impact as much and as
efficiently as possible.
This phase is also a good time to systematically check the data, assumptions,
and calculations used within the LCA for errors, proper structure, and good
documentation. Look to ensure that the units used are consistent and mass and
energy balances within the considered system are correct. It is also important to
complete a sensitivity analysis to identify the most influential model variables and
assumptions within the LCA and their impact on the results. Various methods and
approaches exist to analyze sensitivity, each with different levels of complexity
and detail of insight provided in their results. An introduction to and discussion
of some of the most commonly used methods within LCA are available in Jolliet
et al. (2015).
5.7
Example: Comparing Insulation Foaming Agents
With the four phases of LCA introduced, this section provides a practical example
of completing a simple LCA to compare a pair of alternative foaming agents for
use in extruded polystyrene (XPS) insulation in buildings. Each of the four phases
within LCA is described, and base data are provided for the necessary calculations.
5.7.1 Goal and Scope Definition (Phase 1)
The goal of the LCA in this example is to identify the best foaming agent for use
in XPS to insulate a building. In particular, this will be a comparison of existing
foaming agent alternatives (and not a prospective LCA considering future technologies). The target audience of the LCA results is XPS insulation manufacturers to
help them select among alternative foaming agents during production. Figure 5.16
shows the entire system for the foaming agents including production, use, and
recycling/disposal. The specific scope considered within this LCA is highlighted
in the figure and only includes resource use and emissions from the (i) production
and (ii) use of the foaming agent. The system elements of polystyrene production,
foaming of the polystyrene, and recycling/disposal are considered to be the same
regardless of the foaming agent used, and they are therefore not included in this
LCA.
The functional unit of the LCA is defined to be XPS insulation sufficient for
the foundation of a building with a base of 100 m 2 and an expected lifetime of 50
years. Several of the previously introduced methods and characterization factors will
be applied, and life cycle inventory and impact data sets hosted by the Ecoinvent
91
In doing so, it is also valuable to consider and comment on the influence that the
chosen allocation and impact assessment methods may have had on the results, as
well as on the set system boundaries. In the context of integrated product or process
development, it is especially useful to identify which process steps within the entire
process tree are the dominant contributors to the total impacts. Knowing this can
provide clues for how to improve the design and reduce the impact as much and as
efficiently as possible.
This phase is also a good time to systematically check the data, assumptions,
and calculations used within the LCA for errors, proper structure, and good
documentation. Look to ensure that the units used are consistent and mass and
energy balances within the considered system are correct. It is also important to
complete a sensitivity analysis to identify the most influential model variables and
assumptions within the LCA and their impact on the results. Various methods and
approaches exist to analyze sensitivity, each with different levels of complexity
and detail of insight provided in their results. An introduction to and discussion
of some of the most commonly used methods within LCA are available in Jolliet
et al. (2015).
5.7
Example: Comparing Insulation Foaming Agents
With the four phases of LCA introduced, this section provides a practical example
of completing a simple LCA to compare a pair of alternative foaming agents for
use in extruded polystyrene (XPS) insulation in buildings. Each of the four phases
within LCA is described, and base data are provided for the necessary calculations.
5.7.1 Goal and Scope Definition (Phase 1)
The goal of the LCA in this example is to identify the best foaming agent for use
in XPS to insulate a building. In particular, this will be a comparison of existing
foaming agent alternatives (and not a prospective LCA considering future technologies). The target audience of the LCA results is XPS insulation manufacturers to
help them select among alternative foaming agents during production. Figure 5.16
shows the entire system for the foaming agents including production, use, and
recycling/disposal. The specific scope considered within this LCA is highlighted
in the figure and only includes resource use and emissions from the (i) production
and (ii) use of the foaming agent. The system elements of polystyrene production,
foaming of the polystyrene, and recycling/disposal are considered to be the same
regardless of the foaming agent used, and they are therefore not included in this
LCA.
The functional unit of the LCA is defined to be XPS insulation sufficient for
the foundation of a building with a base of 100 m 2 and an expected lifetime of 50
years. Several of the previously introduced methods and characterization factors will
be applied, and life cycle inventory and impact data sets hosted by the Ecoinvent