I was US rep to ISO committee for “ISO 20887 design for disassembly and adaptability standard”. Also author of “Design for disassembly: aguide to closed-loop building”, done for King County. There is alot of guidance in both documents. There have in fact been many PhDs etc. on DfD including using LCA for the measurement. As far as metrics yes that is the most difficult part. Embodied carbon is clearly a baseline metric and Module D has been used in relation to DfD. The steel industry has refined the concepts of Module D to a fine art and it is good example of how to play this out in other materials or more generally. Their application of Module D concepts also points out the critical need for the “infrastructure” of design for future reuse. From this perspective, the first and easiest metric for DfD is to actually use reclaimed materials as long as this “new” use has not compromised the material for future reuses. Design to reuse, meaning use of reclaimed, is creating the future infrastructure to reclaim anything “designed for future reuse”, and then one can consider the embodied savings now. Unfortunately this brings up the allocation problem which is way too much to discuss in a post.
One general strategy is also making comparisons between standard practice and alternatives which in itself does not predict the future of course - however could be compared to the concept of energy modeling which is also only ever an “estimate” and seems to be accepted as a valid approach. So basically if you can “model” the adaptability/disassembly to be more efficient than current practice and also that the choice of materials are safely reuseable/recyclable. Information is paramount, so while qualitative, things like a “disassembly plan” and also “Materials Passports” increase ease or likelihood of future disassembly and reuse. While variations in how much disassembly might be needed at the component level, another basic rule to me is the degree of “contamination” and toxicity of the material.
Is this reflected in embodied carbon ? not really, so one would need more than simply CO2-e for this.
Any material which currently is not viable for reuse or recycling is a contaminant rendering DfD null. Lastly, one thing I have learned is that it is not an all or nothing proposition and variable per building type, so for each project, at least for the moment, can follow basic principles and metrics, with the application specific to that project and generate a “degree” of DfD that is the best fit.
Brad Guy