Models and method for estimation and comparison of direct emissions in building construction in Australia and a case study

• A method for comprehensive analysis of direct emissions is presented.
• A framework is developed for identifying direct emissions reduction options.
• Emission analysis at activity and equipment levels is essential for finding direct emission reduction options.
• Estimation of emission rates is essential for effective comparison of emissions from equipment.

Building construction incurs direct emissions from equipment operation and transportation. These emissions at a collective level seem to be high, which alerts contractors who are keen to explore reduction possibilities for emissions. Understanding emission contributions at the activity and equipment level are important to achieve this target. However, none of the past studies have conducted an in-depth analysis to identify direct emissions reduction prospects at the construction stage. This study aims to develop models and method to enable the estimation and analysis of emissions at project, activity and equipment levels in a building construction. A framework is then established to provide a systematic procedure to aid the decision making for reducing direct emissions at the construction stage. A case study of foundation construction in a commercial building is presented to validate and demonstrate the functions of the framework developed. The results show a GHG emission distribution of 77.13%, 13.53% and 9.34% for materials, equipment usage and transportation respectively at the project level. CO and NOx were the governing non-GHG emissions recorded. In-depth equipment level analysis concludes the importance of considering emission rates to compare and identify critical equipment for emission reduction. Activity level analysis ushers the identification of activities with significant emissions from transportation and equipment.