As Singapore organizations intensify scope 3 emissions accounting, particularly from purchased goods and services, there is urgent need for standardized, locally relevant emission factors. The Singapore Emission Factors Registry (SEFR) was established to provide credible emission factors that support transparent and comparable scope 3 carbon accounting. This study presents a methodological framework for developing market-average emission factors based on life cycle assessment (LCA) principles, integrating guidance from the Partnership for Carbon Transparency (PACT) methodology and ISO 14067 standards, with system boundaries informed by the Product Category Rules (PCR) for Professional Cleaning Services for Buildings. While PACT methodology facilitates company-level emissions data exchange, this study adapts its principles for market-level analysis through ground-up life cycle assessment. Using security services as a case study, the framework follows the four LCA stages defined in ISO 14067 – (1) Goal and Scope Definition, (2) Life Cycle Inventory Analysis, (3) Life Cycle Impact Assessment, and (4) Interpretation. The objective was to generate representative emission factors for outsourced services, covering life cycle stages from service initiation to completion. Primary activity data were collected from local security service providers, including energy use, fuel consumption, material inputs, and waste. The 100-year Global Warming Potential (GWP100) metrics were applied to quantify greenhouse gas emissions. Finally, key emission hotspots and data gaps were identified, ensuring transparency and relevance for SEFR integration. This approach demonstrates a scalable model for emission factor development across Singapore’s service sector.
Xuan et al. (2026) studied this question.