Blockchain for Supply Chain Ledgers: Tracking Toxicity Information of Construction Materials

Reducing toxicity in construction materials is paramount to improving the sustainability of the construction industry. This necessitates better knowledge of the content of these materials or products. However, there is no central register nor mandated ledger of component materials. Furthermore, from a global supply chain management perspective, it is very difficult to have access to full value chain information even from the manufacturer of the final product. This chapter explores ways to establish a supply chain ledger to track components of construction materials by using blockchain technology; to provide reliable and fully disclosed information on their chemical content and providence. It focuses on the example of PVC, but its findings are relevant to the manufacture of any other products from different component parts or materials. The findings depend on what are the most desirable features in supply chain networks. But, in general, the most suitable solution appears to be a permissioned blockchain using a proof of authority consensus mechanism. Such a system can be a closed, private network, with a set of verified and trustworthy stakeholders as participants that provide public verification via a device such as a QR code. Such a system is fast and can accommodate a large number of transactions per second, so can thus scale up in the future even if a network starts small. Given the concern with tracing materials for the purposes of sustainability, the chapter also highlights the issue of energy consumption, which is necessary for maintaining the blockchain itself, and suggests that this should be a relevant feature in the design of any supply chain system. The framework of analysis emphasises the complexities in choosing the various technical and non-technical aspects of any such supply chain systems. Nevertheless, it is achievable with existing, bespoke blockchain-based solutions, as is illustrated with the PVC supply chain network.