## 4 Discussions  
The specific quantitative measures that most clearly demonstrate the differences in performance between the ventilation methods are maximum temperature, pressure difference, V2 airflow velocity, and toxic gas concentrations (CO and CO\({}_{2}\)). Scenario S0 shows high maximum temperatures (300 \({}^{\circ}\)C), a negative pressure differential (\(-\)32.84 Pa), and an ascensional V2 velocity (5.73 m/s), with CO exceeding 0.12% at 116 s and CO\({}_{2}\) surpassing 4% at 130 s. Scenario S1 maintains safer temperatures (80-85 \({}^{\circ}\)C), a positive pressure differential (+73 Pa), a downward V2 velocity (2.01 m/s), and maintains CO and CO\({}_{2}\) below hazardous thresholds. Scenario S2 has moderate temperatures (140 \({}^{\circ}\)C), a positive pressure differential (+56 Pa), V2 with both directions at 0.85 m/s, with CO exceeding 0.12% at 155 s and CO\({}_{2}\) surpassing 4% at 170 s. These measures indicate that mechanical ventilation through differential pressure, as demonstrated in scenario S1, provides the most effective smoke management and optimal evacuation conditions. Sensitivity analyses were performed to assess the robustness of the simulation results concerning key parameters. The use of CFD FDS combined with polynomial chaos identified crucial variables such as fuel mass flux and activation energy, which significantly influence smoke dynamics [53]. Another study highlighted the importance of turbulent model constants and combustion efficiency through a design of experiment approach, demonstrating their significant effects on simulation outputs [54]. Our study extends these findings by analyzing ventilation scenarios, revealing that airflow configuration is critical to understanding fire behavior and optimizing evacuation strategies. This comprehensive analysis underscores the need for precise parameterization to enhance the accuracy and reliability of fire safety models. The simulation results inform practical design and operational decisions for fire safety systems in high-rise buildings by demonstrating the effectiveness of mechanical pressurization. This method stabilizes thermal conditions, maintains positive pressure, and controls toxic gas levels, thereby ensuring safe evacuation routes. Key insights include the importance of unidirectional airflow to prevent smoke ingress and the role of fan placement and door timing in managing fire intensity. These findings emphasize the necessity of precise ventilation control to enhance occupant safety and effectiveness during fire emergencies. Natural and mechanical ventilation have distinct effects on the development of fires, as seen in three scenarios. Scenario S0 involves natural upward airflow, allowing smoke to infiltrate adjacent compartments through gaps. Scenario S1 employs mechanical ventilation with a downward airflow due to the fan's position at the top, effectively containing smoke to the first floor within the stairwell. Scenario S2 presents a mix of upward and downward airflows, with a reduced output from fan 1 and the activation of fan 2, resulting in smoke dispersion up to the third floor within the stairwell. In both S1 and S2, the strategic opening of windows in the fire compartment allows the effective evacuation of smoke, protecting the rest of the building. This demonstrates the positive impact of ventilation. There is only a minimal performance difference between S1 and S2, indicating that both configurations provide significant protection against smoke propagation. As part of our future work, we intend to extend the proposed method to analyze the behavior of structures exposed to fire. Recent studies [55] have demonstrated that architectural factors (ventilation, ceiling height, and room dimensions) significantly influence the temperature field in RC elements under fire exposure. Their combined use of CFD and FEA modeling to simulate fire dynamics and heat propagation highlights the complexity and variability of real fire scenarios, which differ markedly from standardized ISO fire curves.