A Warsaw fire-safety engineering practice and one of the leading Polish houses performing CFD computer simulations. Its work runs from fire-strategy concept design through FDS fire-and-smoke modelling, evacuation simulation and wind-effect analysis on smoke ventilation to smoke-control (fire-ventilation) design, expert opinions and hot smoke tests used to justify performance-based solutions. The team authored WizFDS, an open-source graphical interface for FDS. Its analyses support professional judgement rather than replacing it.