Environmental impacts of substituting tempered glass with polycarbonate in construction - An attributional and consequential life cycle perspective

Attributional and consequential life cycle assessments were conducted for tempered glass and its possible replacement materials, polycarbonate. A cradle-to-cradle approach was adopted for evaluating the global warming potential, human toxicity potential, freshwater aquatic ecotoxicity potential, marine ecotoxicity potential, eutrophication potential, acidification potential and terrestrial ecotoxicity potential of both materials. The attributional approach found that replacing tempered glass with polycarbonate will result in net decrease in acidification, human toxicity, terrestrial ecotoxicity and freshwater aquatic ecotoxicity, but net increase in eutrophication; the results for global warming potential and marine ecotoxicity are inconclusive. When polycarbonate replaces tempered glass and short term consequences were considered, only the results for human toxicity and freshwater aquatic ecotoxicity are the same as those from the attributional approach. Over longer term, when the import of both materials respond correspondingly to the change in demand in Singapore - that is, for every 1 kg of change in demand, there is a corresponding change in import of 1 kg - it was found that replacing tempered glass by polycarbonate will increase global warming potential and eutrophication, while decreasing human toxicity, freshwater aquatic ecotoxicity, and marine ecotoxicity. This combined attributional and consequential studies illustrate the strengths of both approaches, as well as highlight the importance to consider longer term effects in policies aimed at replacing one material with another, to improve environmental sustainability.