EPS used as thermal insulation for buildings will save 400 times as much energy as that required to manufacture the base product.
- 72 000 litres of oil – energy costs saved over the 50 year life of the building
- 180 litres of oil – energy cost to manufacture EPS
- Based on study in Germany of a 102m2 family residence where walls and roof space are insulated with 100mm thick EPS.
EPS contains no CFC’s or HCFC’s. Insignificant amounts of carbon monoxide and styrene monomer are given off when EPS is burnt. Pentane is non-toxic and constitutes no threat to the ozone layer.
Life Cycle Assessment (LCA) – cradle to grave
The LCA presents a complete picture of EPS which supports its inherent benefits regarding the environmental impact for sustainable building and development.
*lhv = lower heating value
The figures above show the weighed averages of the characterisation and normalisation scores for the life cycle of 1kg of EPS, for densities varying between 15-20kg/m3
The study was carried in 1998 by PRC-Bouwcentrum, Netherlands in accordance IS 14040.
An LCA is a tool for assessing and evaluating the environmental impact of a product or service during its entire life cycle (from ‘cradle to grave’ by:
- Compiling an inventory of relevant inputs and outputs from and to the environment of a system.
- Evaluating the potential environmental impacts associated with those inputs and outputs.
- Interpreting and valuating the results of the inventory and impact phases in relation to the objectives of the study (ISO 1997)
- An integral approach is characteristic of the LCA-method. All impacts on the environment are taken into account. The LCA is widely accepted as a method for generating objective and verifiable environmental information.
ISO 14040 Environmental management – Life Cycle Assessment – Principles and Framework
The international Organisation for Standardisation (ISO) provides guidelines for conducting an LCA within the series IS 14040 and 14044. The main phases of an LCA are:
- Goal & Scope definition, the product or service to be assessed is defined, a functional basis for comparison is chosen and the required level of detail is defined.
- Inventory analysis of extractions and emissions. An inventory list of all the inputs and outputs of a product or service.
- Impact assessment the effects of the resource use and emissions generated are grouped and quantified into a limited number of impact categories which may then be weighted for importance.
- Interpretation, the results are reported in the most informative way possible and the need and opportunities to reduce the impact of the product(s) or service(s) on the environment are systematically evaluated.
Life Cycle Impact Assessment (LCIA)
The inventory list is the result of all input and output environmental flows of a product system. However, a long list of substances is difficult to interpret, that’s why a further step is needed known as life cycle impact assessment (LCIA). An LCIA consists of 4 steps:
- Classification: All substances are sorted into classes according to the effect they have on the environment.
- Characterisation: All the substances are multiplied by a factor which reflects their relative contribution to the environmental impact. Note: Characterisation scores are calculated per effect by multiplying emission with corresponding characterisation factors. most of the factors used have been developed by CML.
- Normalisation: The quantified impact is compared with a certain reference value, for example the average environmental impact of a European citizen in one year. Note: Normalisation scores are done by multiplying characterization scores with normalisation factors. Normalisation factors are determined by the effect scores of economic activities in a certain area during a certain amount of time. Although normalisation does not reveal anything about the weight or seriousness of environmental effects, it is likely that effects with a relatively high normalisation score also are effects that are among the relevant effects for that specific situation.
- Weighting: different value choices are given to impact categories to generate a single score.
For each substance, a schematic cause response pathway needs to be developed that describes the environmental mechanism of the substance emitted. Along this environmental mechanism an impact category indicator result can be chosen either at the midpoint or endpoint level.
- Midpoint impact category, or problem-oriented approach, translates impacts into environmental themes such as climate change, acidification, human toxicity, etc.
- Endpoint impact category, also known as the damage-oriented approach, translates environmental impacts into issues of concern such as human health, natural environment, and natural resources.
Endpoint results have a higher level of uncertainty compared with midpoint results but are easier to understand the decision makers.
Interpretation according to ISO 14044 describes a number of checks you need to make to ensure the conclusions are adequately supported by the data and procedures used in the study. The following checks are recommended:
- Sensitivity analysis
- Contribution analysis