Meaning and importance
To quantify the environmental impact of a material or building over its entire life cycle, you can do a life cycle analysis (LCA). Using this methodology you can objectively compare and optimise solutions, and communicate about them openly. The LCA methodology is included in standards (ISO 14040 and ISO 14044) so that calculations are carried out in a uniform way. Specifically for construction, the European standard EN 15978: 2011 specifies the calculation rules to be followed.
In order to determine the environmental impact, different environmental aspects are taken into account: global warming, acidification, water scarcity, soil intake, particulate matter, ionising radiation, etc. The different environmental aspects can be viewed separately, but are often combined in 1 aggregated score for simplicity. The information required to perform the calculations is collected in databases and is based on generic (an average brick) or product-specific data (brand A and type x brick) based on EPD (environmental product declarations). The European standard EN 15804+A2: 2019 determines how information about construction products must be recorded in an EPD.
Finally, we also have to use realistic scenarios: what distance is the product transported and how much waste is produced during the production process? At the end of life, is the product mainly incinerated or sent to landfill, or can a part be recycled? How often is a part replaced? All these elements are very context specific and are therefore better captured at the country level. For Belgium, scenarios have been captured in the technical document BE-PCR (NBN/DTD B 08-001:2017).
To support the Belgian construction sector in LCA calculations with data and scenarios that are tailored to Belgium, the TOTEM tool was developed. The tool is free to use so anyone can determine and compare the environmental impact of anything from individual materials to entire buildings. It is important to note that, although the tool is very accessible, it still requires some expertise to make comparisons in the right way and to interpret the results correctly. Following a training course (via the TOTEM website) is therefore recommended.