Environmental impact assessment of floor system spans: A life cycle approach for sustainable structures

• The life cycle environmental impacts of flat slab structures are evaluated. • A novel method for comparing different design scenarios is proposed. • The proposed method is applied at the design, structural, and material levels. • The optimal design strategy for a general hospital is determined. • The optimal scenario is 33% more efficient than the base case. This study presents a comprehensive life cycle assessment (LCA) of flat slab structural systems for a general hospital building in Al-Khobar, Saudi Arabia, to identify environmentally optimal design strategies. Four flat slab design scenarios with varying spans and material configurations are investigated in light of Saudi Vision 2030 and the growing demand for sustainable construction practices. Using Autodesk® Revit for geometric modeling and structural analyses based on the Saudi Building Code, this study quantifies the amount of concrete and steel required for each scenario. The impacts of embodied carbon (EC) and embodied energy (EE) were assessed using a cradle-to-grave LCA framework, incorporating locally adapted coefficients for environmental impact. The results demonstrate that the product stage (A1–A3) contributes the most to total environmental impact—78% of EC and 67% of EE—highlighting the critical role of early-stage design decisions. Among the scenarios analyzed, Scenario 4, which employs shorter slab spans and optimized material use, achieved a 33% reduction in both EC and EE compared to the base case. This study introduces a novel approach to structural system evaluation in hot and arid climates and contributes valuable insights into sustainable building design in rapidly urbanizing regions. The findings support structural efficiency as a key strategy for reducing the environmental footprint of concrete-based hospital buildings and offer a practical decision-making framework applicable across similar contexts.