Water sprays are known to be an efficient means of fire control and suppression, as demonstrated by several large-scale and reduced-scale experimental tests. The empirical approach does not provide though sufficient insight into the complex underlying physics in order to optimize the efficiency of sprinklers and water mist systems and develop generalized engineering correlations and/or general design and installation rules. In this project, the capabilities of numerical modelling will be thoroughly examined. More specifically, several important physical models (related to the motion and heat and mass transfer of water droplets) that are implemented in a Computational Fluid Dynamics code used for fire safety engineering will be examined in detail. Sub-models that are not state-of-the-art will be improved, based on advances achieved in other research communities (for example in combustion or in drying technology). The assessment of the modelling capabilities will be based on a rigorous verification and validation procedure within a step-wise approach (for example from the case of a single water droplet to a full water spray). The foreseen advances in this area will foster the use of CFD as a more reliable tool in the design of active fire suppression systems.