Normalisation is generally used to produce a single numerical score by weighting each of the impact categories and summing them up into a single score. Environmental impact scores in life cycle assessment are shown their physical units presenting the potential to cause environmental impact and the results of different impact categories cannot be compared with each other or combined as such. One way to normalise is to divide your scores by a reference situation’s scores. This reference situation could be one building product’s share of all emission and resource use in the building over the service life of 50 years.
Normalisation converts complicated units into fractions of building product’s scores per impact category.
According to the EN ISO 14044 standard, normalization is the calculation of the magnitude of the category indicator results relative to some reference information. The aim of the normalization is to understand better the relative magnitude for each indicator result of the product under study.
One Click LCA is using this method only for BRE Eco Points, which uses certain rules for normalization provided by BRE.