为明确防火隔离带对大空间室内烟气蔓延特性的影响，通过数值模拟软件FDS研究了补风口位置、隔离带内排烟量及挡烟垂壁深度对隔离带阻烟效果的影响，揭示隔离带工作机理，提出优化设计原则。结果表明：仅开启无火源分区的补风口时，可在防火隔离带下方形成纵向诱导风流、更好发挥其阻烟效果，且对烟气层扰动较小；增加垂壁深度可提高火源分区储烟能力，减少烟气卷吸量、延缓烟气溢出时间并控制溢出烟气量。当隔离带内不设机械排烟时，随着垂壁深度由20%空间净高增加到40%，烟气初次溢出时间增加约50%。在防火隔离带设置机械排烟，可及时排出内部积聚烟气、有效防止烟气溢出到其他无火源分区。通过对比不同防排烟及补风策略，可见对于大空间室内火灾场景，采用“挡烟垂壁深度为空间净高40% +隔离带机械排烟量参照《烟标》确定+排烟联动相邻防烟分区补风口补风”组合措施，可达到良好的防烟控烟效果，为消防救援提供更多时间。

In order to evaluate the characteristics of fire smoke dispersion in large-space buildings, FDS software was used to investigate the effects of air-inlet position, smoke-proofing depth and smoke exhausting rate to the working efficiency of fire isolation belt. The results show that, by opening the air-inlet in the non-fire zone and closing that in the fire zone, a reverse airflow can be induced below the fire isolation belt, which resists the smoke overflow and reduces the disturbances to the smoke layer. The increase of the smoke-proofing depth can increase the space for smoke storage and reduce the height of the smoke layer, thus delaying the instant of smoke overflow by decreasing the generation rate of fire smoke. In the scenario without mechanical smoke exhausting in the fire isolation belt, the instant of smoke overflow can be delayed by about 50% when the smoke-proofing depth increases from 20% to 40%. By adopting mechanical smoke exhausting in the fire isolation belt, the accumulated smoke can be timely extracted, which can effectively prevent the smoke spilling into other non-fire zone. It is concluded that, through an overall consideration to the smoke isolation efficiency, building functions and construction costs, the combination of "40% smoke-proofing depth + adopting the mechanical smoke exhausting rate with reference to the Smoke Standard + opening the air-inlet in the adjacent non-fire zone" is recommended as an advantageous design principle for fire isolation belts.