Impact of Centralized Mechanical Smoke Exhaust and Make-Up Air System Design on Smoke Control Performance

The increasing complexity of modern buildings has introduced significant fire safety challenges, particularly in the context of smoke exhaust systems. During a fire, the efficacy of these systems is crucial to ensuring the safety of occupants. Within this framework, the make-up air system plays a pivotal role, not only maintaining internal pressure in the fire zone but also supporting the smoke exhaust system in expelling smoke efficiently. The performance of the make-up air system thus directly influences the overall effectiveness of smoke control. This study employs fire dynamics simulation to systematically explore the optimization of fire damper placement and the impact of dual make-up air inlet configurations. The results reveal that removing fire dampers enhances air supply to the fire floor and increases inlet velocities, which in turn reduces flame core and fire temperatures, while extending the settling time of smoke layers. Additionally, it was found that air supply velocity increases with higher fire power, increased fire floor elevation, and shorter distances between the fire source and the air supply outlets. Optimal smoke suppression and temperature control were achieved when dual air supply outlets were placed on the same side. This work demonstrates the feasibility of fire damper removal, identifies the optimal configuration for dual air supply outlets, and offers theoretical and empirical support for refining fire protection standards and optimizing engineering practices in building air supply systems.