The ever-increasing number of hospital Emergency Department (ED) visits pose a challenge to the effective running of health systems in many countries globally and multiple strategies have been adopted over the years to tackle the plight. According to a systematic review of the available literature, of the numerous models of healthcare systems used to address the issue in western countries, the FSED Model has the greatest potential for reducing hospital ED overcrowding as it can reduce the additional load by diverting minor cases, freeing up space for more urgent cases. The aim of the study is to shed light on the Free Standing Emergency Department (FSED) model and compare it with the traditional Hospital Based Emergency Department (HBED) in international contexts. In this study, 23 papers have been collected in a literature review and the main features have been highlighted; 12 case studies have been analyzed from a layout point of view and data have been collected in terms of surfaces, functions, and flow patterns. The percentages of floor areas devoted to each function have been compared to define evolution strategies in the development of emergency healthcare models and analyses. The use of FSED models is an interesting way to face the overcrowding problem and a specific range for functional area layout has been identified. Further studies on its application in different contexts are encouraged.