In the event of a fire emergency in a built environment, human behaviour plays an important role, since building occupants need to make several evacuation decisions. Exit and route choices are one of them. It is fundamental to investigate which factors influence this choice. Understanding how humans weigh different factors when they make a choice is crucial to design a safe built environment for evacuations. The main objective of this work is to study the exit choice of occupants during fires and develop an exit choice model which could be implemented in future evacuation software tools. In particular, this research focuses on the influence of two different factors: the social influence and the role-rule factor.