The "Breathing Steward for Crowd Surges": How Fabric Ducts Handle Fluctuating Occupancy in Public Buildings

During mall promotions, stadium dispersals, exhibition openings, or peak train arrivals at waiting halls, the toughest challenge for public buildings isn't the "average crowd"—it's crowd size doubling or tripling within half an hour. Traditional metal ducts are designed for fixed conditions; diffuser counts and positions are locked in. During peak hours, fresh air at distant zones falls short and CO₂ spikes, while during off-peak hours, excessive airflow wastes electricity. Fiber Fabric Ducts​ act more like a smart steward that "serves air based on the crowd": using surface air supply and zoned variable permeability, they distribute fresh air precisely to where people actually gather.

Ventilation codes for public buildings set minimum per-capita fresh air requirements for high-density spaces (e.g., ≥20 m³/h·person for shopping malls and waiting rooms; ≥30 m³/h·person for libraries and art galleries). However, metal systems often suffer from "terminal unevenness": outlets near the fan are too forceful and noisy, while distant zones receive insufficient fresh air. Fabric ducts function as a long, linear plenum. Air escapes through micro-perforations or slots along the entire duct length. Combined with CFD simulations, hole density is arranged according to crowd heat maps—more holes at ticket gates, escalators, and main aisles; fewer holes in storage and equipment areas—making "fresh air follow the people."

Its operational value is highly tangible:

• No stuffiness during peaks:​ In the hour before a stadium event begins, the fabric duct's low-velocity uniform airflow gently delivers fresh air to the occupied zone below 1.8 meters. CO₂ rises slowly, keeping the audience alert and odor-free.
• No waste during off-peaks:​ At 10 a.m. when a mall is sparsely populated, variable-frequency fans can reduce speed. The fabric duct maintains a draft-free, permeable airflow—unlike metal diffusers that "whistle even at low airflow."
• Easy emergency management:​ Codes for central AC systems in public buildings require zoned operation and emergency return-air shutoff. Fabric ducts are lightweight, allow sectional valve closure, and can be entirely removed for washing. During pandemics or flu seasons, zoned ventilation and cleaning are far easier than with metal systems.

Fire safety is fully addressed: B1-class flame-retardant polyester (e.g., GB 8624 B-s1,d0) can be used for exposed areas, while A2-class non-combustible fluorosilicone fabric is available for underground or high-rise locations. Fire dampers are installed across fire compartments per regulations.

As public buildings evolve from simply "holding people" to ensuring "comfort regardless of crowd fluctuations," the value of fiber fabric ducts has shifted: they are no longer just air supply pipes, but flexible infrastructure that allocates air according to the breathing rhythm of the crowd in the era of mass gatherings.