|Aspect||G-19 Allocation examples for wooden products|
||Increasing numbers of building products are being made of secondary raw materials (SRM), or of generated waste that can be recycled throughout their life cycle. On the one hand, recycling eliminates the need to use virgin raw materials. On the other hand, the new commercial interest in waste can be seen as a shift in their status from waste to co-product [Chen 2009].SRM are generally purchased between industrial sectors. There is then an allocation issue to share the burdens of the primary production process.The question to answer is: which allocation procedure should be chosen to allocate the impacts between the industry generating the waste or co-product and the industry that reuses it (e.g. in the case of wooden products)?|
related study objective
|☒ stand-alone LCA||☒ comparative assertion|
related study phase
|goal and scope definition||inventory analysis (LCI)||impact assessment (LCIA)||interpretation||reporting|
|new buildings||existing buildings||construction products||screening LCA||simplified LCA||complete LCA|
|Provisions||The allocation rules should comply with EN 15804 and EN 15978. In addition, the rules of national EPD programmes should be followed (if available).|
Generally speaking, the allocation rules may be defined in each national context, together with the relevant sectors that use and produce the waste or co-product).
For example, a manufacturer of building products sending .g. wooden wastes to a recycling process needs to share burdens with the next user of the waste. The allocation depends on the end-of-waste status – that is, whether those wood wastes are treated as waste (treatment allocated to the product, and reported in Module C), or whether they are treated as a new product (when the end-of-waste status is reached, the wood wastes are transformed into a product, and the processing is allocated to the next user).
One option is to look at the market value of the waste, as proposed in the ILCD Handbook (see reference above). For example, wooden waste may be reused to produce particle board. This may have an economic value that is very different from that of the main product. (“A difference of more than 25% is regarded as high,” as stated in EN 15804.) In this case, the allocation rule should be based on an economic basis. The output is a co-product, and is not waste any more (the end-of-waste status has been reached).
In addition, in EN 15804 and EN 15978, the product can be considered as a co-product or as a waste depending on the life cycle stage considered. In the above example, an economic allocation may be applied for the wooden wastes during the production stage (Module A), whereas they will be considered as waste at the end of life (Module C).
However, comparison of the impacts of both the manufacturing plant and the building end-of-life activities shows that an economic allocation for wooden wastes in Module C would be very close to a ‘no allocation’ procedure – i.e. a waste status. Indeed, the impact of the EoL process can be assumed to be negligible when compared with the production process for energy-related impacts for example.
A third guidance point concerns the use of background data. Depending on the type of background data, they may not comply with the allocation rules. As the practitioner does not have an influence on the background data, the best recommendation is to be transparent, e.g. in the LCA methodological report.
Further information and references on this issue: