Alexandre Belkowski’s Post

Why do two teams have a 34% difference in carbon assessment despite using the same BIM model? The answer is: the compounding effect. A 2024 Proof of Concept (PoC) initiative led by Autodesk and the WBCSD – World Business Council for Sustainable Development with a cohort of global firms (including AECOM, Arcadis, Arup, Foster + Partners, Ramboll, and Skidmore, Owings & Merrill (SOM)) highlighted a lack of industry alignment in carbon assessment methodologies. The study found a 34% variation in embodied carbon results among firms that assessed the same structural scope within a single BIM model. The variation was not attributed to the BIM model itself (it was the same), but rather to inconsistencies in how the data was used. Slight differences in methodology and assumptions compounded to create significant discrepancies in the final results: - Data extraction: Minor variations in export methodology, such as rounding decimal places, led to minor discrepancies. - Units and formats: Different regional standards for units, like using periods versus commas for decimals, can cause misinterpretation of values and errors in material quantities. - Spatial metrics: Assessors calculated the reference area (e.g., Gross Internal Area) differently, affecting the reported carbon intensity. - Assumptions: Firms made different assumptions for non-modelled elements, such as steel reinforcement, metal decking, and structural connections, which can account for a significant amount of carbon. - Carbon factors: The choice of carbon databases and the need for unit conversion can also be a source of discrepancy. The study concluded that technical guidance alone cannot resolve all the variations and that additional alignment is needed among technology providers, organisations that establish reporting frameworks, and policymakers. To address this issue, the report recommends clear guidance on BIM processes and emphasises the need for transparency and clear communication across all project stakeholders. And while collaboration remains a key theme, this approach also emphasises the importance of tech providers. By offering a standardised method for conducting carbon assessments, a platform like ORIS Materials Intelligence can partially address the very inconsistencies identified in the report, ensuring reliable and comparable results across different projects, teams, and regions. Our BIM module effortlessly integrates with existing BIM workflows and delivers up-to-date, science-backed data, reducing manual, error-prone tasks that lead to significant variances.