CONSEQUENTIAL LIFE CYCLE ASSESSMENT OF STRUCTURAL STEEL AS BUILDING MATERIAL IN SINGAPORE

Abstract

Presently, Attributional Life Cycle Assessment (ALCA) approach is used to compare the environmental impacts of steel and concrete construction at the micro level. However, Consequential Life Cycle Assessment (CLCA) approach provides a macro and more realistic assessment of the entire environmental situation. This paper seeks to evaluate the environmental impacts due to the consequences of decisions made. These decisions are represented by two scenarios which simulate a decrease and an increase in steel consumption in the building construction industry respectively and how replacing steel with concrete will have an effect on the four environmental impact indictors – climate change, human toxicity, resource depletion and cumulative energy demand (CED). ALCA is conducted for steel and concrete to determine their environmental impacts while Material Flow Analysis (MFA) is conducted to determine the apparent consumption of steel and concrete in the industry. The data collected are then used to calculate the net environmental impacts of the two scenarios. The study has shown that a decrease in steel consumption has resulted in a decrease in the four environmental impact indicators. Conversely, an increase in steel consumption has led to an increase in these indicators. The findings have thus shown that concrete is a more environmentally friendly building material than structural steel when three life cycle stages – raw materials extraction, manufacturing and transportation, are considered for the study. Applications of the study will be made in four aspects – product and development, strategic planning, public policy making and marketing strategy, which serve as recommendations to policy makers and industry stakeholders in assessing the environmental impacts due to structural steel and concrete when making decisions.