Hiroki Hatayama

Using decomposition analysis to forecast metal usage in the building stock

As large amounts of materials are used and have accumulated in buildings and civil engineering projects, it is necessary to understand material flow in terms of construction sectors for resource management. The consumption, discard and in-use stock of four metals (steel, aluminium, copper and zinc) in Japans building stock are forecast through to 2050. To clarify the factors that affect metal stocks and flows in construction, the metal consumption was decomposed into annual new floor area constructed and metal intensity (i.e. the amount of metal used per unit floor area). The decomposition was meaningful for understanding characteristic patterns of factors of different metals and for envisaging future scenarios based on past trends. It was estimated that the annual new floor area constructed will remain at current levels, whereas metal intensity will have a significant impact on stocks and flows. The methodology developed in this study can be used to evaluate the impact of technology changes that would take place in building and civil engineering projects.

Strategy Planning Before Urban Mining: Exploring the Targets

This study is a challenge to construct the long-term strategy for recycling. To identify the adequate targets for recycling, we proposed the concept that integrates the criticality assessment and material flow analysis. Prior to the evaluation based on the concept, we developed the framework of the existing criticality assessment for Japan. Furthermore, the information on domestic metal demand and discard were reviewed to evaluate the potential of recycling. By integrating these knowledge, the result of the pilot evaluation was presented with a future perspective of the study.