This article demonstrates changes of the selected parameters of fire development using a fire model, which is applied in the case of chosen fire example (simulated fire). There is analysed an influence of the active fire-safety devices on the fire parameter changes (in the Part No. 3 – Discussion of Results). The main purpose of this article is to present a basic importance of the active fire-safety devices for a realistic description of the course of fire using the chosen example of fire. Such description is important for performing of the fire-engineering evaluations.