The most important objective of a fire safety design is to ensure that humans can safely escape from a building in the case of fire. Fire regulations are adequate for normal buildings but may not take into account the special issues of large and complicated buildings, like shopping centres, assembly facilities, etc. Numerical simulation of fire and evacuation processes can be used to improve fire safety in such buildings. However, the usability of many current evacuation models is limited, because they do not take into account the individual properties and decision making processes of humans, the dynamics of large crowds and the interaction between fire and people. In this article, a recently presented evacuation programme is developed further. The code allows the modelling of ’panic’ situations and the interaction between evacuation simulation and the state-of-the-art fire simulation. The major features of the human movement algorithm are described. A reaction function model for exit route selection and some social interactions among agents are introduced into the computer programme. This computational tool for evacuation modelling is implemented as a part of the state-of-the-art fire simulation tool Fire Dynamics Simulator (FDS). Like the current version of FDS, the evacuation module, FDS+Evac, presented in this article is made publicly and freely available.