This document summarizes a master's thesis that investigated the impact of horizontal projections like balconies on external fire spread on building facades through numerical modeling. It conducted a literature review and validated a fire dynamics simulation program (FDS) against experimental data. Comparative analyses using FDS then compared scenarios with different balcony depths or spandrel heights. The analyses found that balconies at least 60 cm deep resulted in lower risks of external fire spread above the balcony compared to scenarios with only spandrel heights, representing a reduction in risk level allowed by building codes. Balconies of 60-100 cm also reduced surface temperatures above openings by 15-50%. Therefore, a balcony at least 60 cm deep can replace a 1