Assessment of Embodied Carbon in the Design Stage: A Case Study of University Hostel Building in Nigeria

It is glaring that we have a climate crisis on our hands, and that 49% of global carbon emissions are attributable to the construction industry, yet more than 60% of construction professionals in Africa and the Middle East are not actively involved in embodied carbon (EC) measurement. The study aims to quantify the cradle-to-gate (A1- A3) embodied carbon of an 8,581.37 m2 reinforced concrete University hostel in Lagos, Nigeria, using life cycle assessment (LCA) and the Inventory of Carbon and Energy (ICE) database. Material quantities were extracted from the project bill of quantities (BOQ), drawings, and specifications for a single case study, while emission factors were sourced from ICE. The results were benchmarked against LETI (2020) targets, while a comparative as-design/as-built analysis determined the carbon consequence of documented cost-driven variations. The total EC of the case study building reached 3,918,852 kgCO₂e (3,919 tCO2e), with an EC intensity of 456.67 kgCO₂e/m2-15.4% below the LETI 2030 target. Reinforcement (36.8%) and concrete (28.0%) account for 64.8% of total emissions. A cost-driven substitution of steel roof trusses with timber, without environmental intent, yielded an 89% EC saving (153,492 kgCO₂e), with a total as-built carbon saving of 211,469 kgCO₂e (5.1%) relative to the as-designed drawings. The building met all three LETI 2030 targets. This study provides the first documented case study-based EC benchmarks for Nigerian university buildings. The study findings represent the first empirical demonstration of a nexus between as design and as-built embodied carbon. Key Drivers of