G-20 (Buildings) / G-17 (Products) Allocation case: reuse, recycling and recovery

Aspect G-20 (Buildings) / G-17 (Products) Allocation case: reuse, recycling and recovery
When the lifespan of a product ends, it can be reused, recycled, or used for recovery in another product system. These recovery operations entail a benefit for the system that yielded them. How to allocate these benefits to the system under study, or to other product systems that will recover these materials, is still an open topic within the LCA community.What allocation method should be used for the reuse, recycling and recovery of construction waste?

related study objective

stand-alone LCA comparative assertion

related study phase

goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for

new buildings existing buildings building products screening LCA simplified LCA complete LCA
Provisions According to EN 15804, components for reuse and materials for recycling and energy recovery are considered as potential resources for future use. The reuse, recycling and recovery operations result in benefits, but also entail environmental loads. In the case of EPDs (products), the net environmental impacts (positive or negative) should be quantified separately in a so-called ‘Module D’. Calculation of Module D impacts should be based on average existing technology, current practice, and the net impacts of the recovery processes in comparison with the impacts of producing the substituted good (energy or primary raw material). EN 15804 provides guidelines for allocation with regard to reuse, recycling and recovery.EN 15978 refers to EN 15804 to deal with scenarios for reuse, recovery and recycling potentials outside the system boundary of the building under assessment, in order to describe the processes that lead to future substitution of resources.
Rules from:
EN 15804
6.4.3 Allocation of input flows and output emissions General Co-product allocation Allocation procedure of reuse, recycling and recovery
7.8 Modelling the system
Provisions: 7.9.2 Avoiding allocation by subdivision or virtual subdivision
Provisions: 7.9.3 Solving multifunctionality by allocation
“VI) SHALL – Attributional modelling of reuse, recycling, recovery
VI.a) Follow general rules for multifunctionality, observing specific aspects
VI.a.i) Dealing with waste and end-of-life products of negative market value that generate secondary goods
VI.a.ii) True joint process to be identified
VI.b) Provisions:
VI.b.i) Negative market value
VI.b.i) Market value equal or above zero”

14 ANNEX C: Modelling reuse, recycling, and energy recovery

Allocation can have significant effects on the results of an LCA study. Therefore the allocation method should be documented as transparently as possible, with reference, if possible, to the European standards or the ILCD Handbook. The aspect ‘Allocation example for wooden products’ provides further guidance. A recent article presenting the concept of Module D was presented at the 20120 Symposium on LCA and Construction. For deeper insight into this subject, the interested practitioner may refer to this article: [Leroy 2012].

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