PurposeThis paper aims to investigate the potential role of the Emergency Department (ED) layout in enhancing its functionality. It applies a performance-based building design (PBBD) approach to evaluate emergency department functionality and efficiency as the most important criterion behind the success of the hospital service.Design/methodology/approachA quantitative approach based on space syntax theory was adopted through four syntactic maps (isovist, axial, convex, and visibility graph analysis VGA), to depict three case studies in Erbil city hospitals by analyzing three different layout typologies of ED such as Podular, Ballroom and Linear through measuring wayfinding, accessibility, privacy, visibility, time spend-length of stay and corridor circulation as layout factors.FindingsThis paper provides empirical insights on how the ED layout typology factors significantly affect producing functionally efficient EDs, whereas the Ballroom ED layout typology is the most effective compared to others. Given the importance of ED in enhancing a healthy environment for patients and staff, study findings are valuable resource for health designers, who play a critical role in ensuring patients enjoy a healthy and safe environment.Originality/valueThis paper has attempted to identify the appropriate layout of ED for effective functional performance in hospitals. A syntactical analysis between three different ED layout typologies based on the layout variables has been analysed using the PBBD approach. There has been no attempt carried out so far to analyse the functional performance of the PBBD approach in different ED layouts using layout variables.