Natural ventilation is one of the vital means for passive energy-efficient design in green buildings. As a widely used building façade, the perforated plate is mostly utilized for appearance decoration, noise absorption, and sun shading, but its impact on the natural ventilation effect has rarely been paid attention to. In this study, the influence of the perforation rate, the perforation size, and the perforation shape on the flow coefficient of the perforated plate were simulated using the commercial CFD software Fluent, and the correlation between the flow coefficient and these geometric parameters was then regressed. The results show that the flow coefficient of perforated plate increases with the increase in perforation rate, which is slightly greater than that of ordinary building openings, and the corresponding flow coefficients of different holes rank as circle > square > triangle under the same conditions. The flow coefficient increases with the increase in the perforation size, and this effect is greater when the size is small. In addition, the flow coefficient is less affected by the size of round holes compared to triangular and square holes. The regression model indicates that both the perforation rate and the perforation size have a considerable positive influence on the flow coefficient, while the square and triangle holes have a negative influence on the flow coefficient compared with the circular hole. Moreover, the geometric parameters of perforated plates that have the greatest influence on flow coefficient are perforation rate, perforation shape, and size, in descending order.

Building drainage systems are essential for protecting occupant health and indoor air quality. While recent studies have focused on high-rise drainage dynamics and riser offset mitigation, ventilation components—particularly appliance vent pipes—remain underexplored. This study employed a full-scale proportional drainage experimental tower to assess appliance vent pipes on horizontal branches as a strategy for water seal protection in dual-riser systems. Maximum drainage capacities were quantified under varying pipe positions and diameters (DN50, DN75, DN100), alongside analyses of pressure transients and water seal losses. Results indicate that appliance vent pipes increase maximum drainage capacity from 6.5 L/s (baseline cast iron dual-riser) to 7.5 L/s, a 1.0 L/s gain, though improvements are modest. Position does not affect capacity (uniformly 7.5 L/s across configurations) but profoundly influences water seal losses: P-type trap placement yields the lowest losses on most floors, combined P-type trap/floor drain placement achieves intermediate values, and floor drain placement the highest. Thus, the P-type trap is optimal. Diameter similarly has no impact on capacity but shows nuanced effects on seals; DN75 minimizes losses on most floors, outperforming DN50 and DN100, indicating that appliance vent pipe design should adopt a height-zoned approach tailored to anticipated drainage loads and pressure characteristics. Appliance vent pipes effectively dampen positive/negative pressure fluctuations, reducing seal depletion and sewer gas risks. These findings guide engineering designs for healthier indoor environments in high-rise buildings.