Make or break the loop: a cross-practitioners review of glass circularity

Abstract

End-of-life insulating glass units (IGUs) continue to follow a linear, wasteful path from renovation and demolition sites into landfills or low-value recycling. To get one step closer to the question of how to close the glass loop, this exploratory research outlines a cross-practitioners review of glass circularity in conventional Flemish and Brussels practices. A series of semi-structured interviews with network actors and an extensive literature study is conducted to identify existing and missing circular practices and to pinpoint the key barriers and opportunities. In general, the circular strategies repurpose and open-loop recycling of end-of-life IGUs are successfully applied in Flemish and Brussels construction practices. Repair, reuse, and closed-loop recycling remain unexplored. The main barriers are the lack of collaboration, logistic and labour costs to collect end-of-life IGUs, its complex disassembly, the lack of legal incentives and the conservativeness of the construction sector. Case studies, the high recycling potential and the scale of projects are found to be the main opportunities for glass circularity. The cross-practitioners’ insights in this paper contribute to close the glass loop and to further development and up-scaling of circular strategies.

Case Study on the Re-use Potential of Insulated Glass Units

“…Despite this, it is rarely stated that breaking glass to recycle as cullet renders all of the embodied carbon except the just stated benefits useless. Taking into account that currently pre-consumer glass cullets and rarely post-consumer cullets contribute to the production of glass for the building sector due to furnace compatibility and contaminations, it is questionable if investing energy to produce cullets that need to be reheated in contrast to invest energy to use whole glass panes is the most sustainable way (Rota et al 2023;Geboes et al 2022).…”

Exploring the reuse of façade components in Belgium: emerging and shifting roles to deal with uncertainties

“…In this paper we use the term ROs to refer to the following range of R-strategies: repair, reuse, refurbish, remanufacture and repurpose. [11] focused on challenges to the reuse of existing insulated glazing, and Makkink [12] described the challenges specific to reuse in Brussels. In this literature, 6 common themes emerge of recurring challenges to reuse: behavioural, financial, legal, organizational, technical and uncertainties.…”

“…manufacturer and façade consultant). Participants were mainly acting as an architect (22), private client (11) and engineer / advisor (8), but also the roles of material processor (6), contractor (5), public client (3), public administration (1) and academic researcher (1) were represented.…”

In situ detection of product age and argon concentration as measure of the re-use potential of insulating glass units in buildings

“…Flat glass is largely used for land fill (Glass for Europe 2013; Yu et al 2020). In Europe a small volume of glass from construction and demolition waste is being recycled, but mainly involves downcycling like using glass fragments for insulation material and packaging glass (European Commission 2017, Wittekoek 2020, Geboes et al 2022. Once flat glass has been downcycled it can never be recycled back into flat glass (Geboes et al 2022).…”

“…In Europe a small volume of glass from construction and demolition waste is being recycled, but mainly involves downcycling like using glass fragments for insulation material and packaging glass (European Commission 2017, Wittekoek 2020, Geboes et al 2022. Once flat glass has been downcycled it can never be recycled back into flat glass (Geboes et al 2022). This underlines the interest to maximize the circular level of IGU use, instead of maintaining the common paths of waste use.…”