Page 211 - Materials Chemistry, Second Edition

4.3 Structure of Impact Assessment according to ISO 14040 and 14044 195

category in the examined product system is orders of magnitude lower than that of
other impact categories.
With normalisation groups of related impact categories can also be analysed,
for example indicator values for GWP, CED, fossil resource consumption and
acidification which often, but not always, correlate by consumption of fossil fuels.

Example 2
Impact category ‘climate change’, with reference to an annually released mass of
CO -equivalents per inhabitant in Germany: resident equivalents (REQs)
2
A better illustration of normalised category indicator results can be obtained by a
‘per capita of population or a comparable measure’. This possibility is quoted in
ISO 14044.
In this case, the category indicator results caused by an inhabitant in Germany
or another geographical region are used as reference data. These reference values
are called resident equivalents (REQs).
Normalisation of the category indicator result of CO -equivalents:
2
• The category indicator value for the annual release of CO -equivalents 2003 in
2
Germany amounted to 1 017 916 500 t, and the number of inhabitants of Germany
of the year amounted to 82 532 000. 37)
• The annual release of the CO -equivalents is divided by the number of inhabitants
2
of the year. The result is the resident equivalent (REQ), with unit kilogram per
inhabitant. This REQ is the reference value. In the example this results in an
4
annual 1.23 × 10 kg of CO equivalents caused per inhabitant in Germany.
2
• The normalisation is performed by dividing the category indicator result of
the product system by the resident equivalent. The normalised value means:
Per fU of the examined product system, as many CO -equivalents are released
2
as are caused by an average of 4.05 × 10 −2 inhabitants in 1 a, or differently
expressed, 500 kg fU −1 correspond to 4.05 × 10 −2 REQs. The descriptiveness in
this form, however, is not substantially larger than for normalisation by the
specific contribution as in the Example 1.

Category indicator results (CO -equivalent) Reference value Normalised value
2
Emissions caused Annual Number of Emissions per REQ
by the product emission in inhabitants in inhabitant: 1 IAV
system per fU Germany Germany

500 kg 1.02E+12 kg 8.25E+07 1.23E+04 kg/ 4.05E−02
Inhabitants inhabitant Inhabitants

37) IFEU (2006).