Numerical analysis and staircase layout optimisation for a Ro-Ro passenger ship during emergency evacuation

•A passenger ship evacuation model has been established by using FDS + EVAC.•The effects of the passenger population composition in an emergency evacuation were analysed.•The effects of the ship familiarity in an emergency evacuation were analysed.•The ship's staircase layout was optimised to facilitate the evacuation process. In this research, the effects of the passenger population composition and ship familiarity in an emergency evacuation are analysed. The results identified that the effects of different population compositions on the Ro-Ro evacuation process vary significantly. It is therefore recommended that a targeted survey of the population on a specific ship should be conducted before the evacuation analysis to improve the analysis accuracy of the evacuation process. It is not always the case that a higher familiarity with the ship staircase layout necessarily results in less time to complete the evacuation, and the issue of balanced exits has to be considered due to its significant impact. The results obtained in this research can be used to aid the ship's staircase layout optimisation to facilitate the evacuation process. Given the type of Ro-Ro vessel in this analysis, it is suggested that adding a staircase towards the bow of the ship can reduce the evacuation time by 13.6%, when considering 95% of the passengers to complete an evacuation. Similarly, adding one staircase at the stern can reduce the time by approximately 10% for all passengers to complete the evacuation. It is not recommended that the size of staircases towards the middle of the ship should be adjusted.