How can fire-resistant air duct improve smoke exhaust efficiency in fire scene through low wind resistance design?
Publish Time: 2025-06-16
In fire rescue, smoke exhaust efficiency directly determines the evacuation time and rescue window period. The high wind resistance problem caused by structural defects of traditional fire-resistant air duct often causes high-temperature smoke to accumulate in the duct, forming a "chimney effect" that counteracts the smoke exhaust effect. The new generation of fire-resistant air duct achieves low wind resistance design while ensuring fire resistance through material innovation and structural optimization, becoming a key breakthrough in improving smoke exhaust efficiency in fire scene.Material selection: synergistic resistance reduction of smooth inner wall and low friction coatingThe inner wall material of fire-resistant air duct is the core factor affecting wind resistance. Traditional galvanized steel plate air ducts are easy to absorb smoke and dust due to their rough surface. After long-term use, the inner wall scales and causes a surge in wind resistance. Modern fire-resistant air ducts are made of stainless steel or composite glass fiber, and their smooth surface can reduce the friction resistance between air and the pipe wall. For example, the single-sided color steel fire-resistant air duct uses a corrugated steel plate process to form a continuous streamlined curved surface on the inner wall, and the friction coefficient is further reduced with the aluminum foil veneer. In addition, some high-end products are coated with a low-friction ceramic coating on the inner wall. This coating can still maintain hydrophobic and oleophobic properties at high temperatures, avoid smoke and dust adhesion, and ensure stable wind resistance during long-term use.Structural optimization: resistance elimination by streamlined design and modular splicingThe cross-sectional shape and splicing method of the fire-resistant air duct directly affect the efficiency of airflow. Traditional rectangular air ducts are prone to eddy currents due to right-angle elbows and splicing gaps, resulting in increased local wind resistance. The new fire-resistant air duct adopts an elliptical or circular cross-sectional design to form a uniform laminar flow in the duct. For example, the middle-layer glass fiber insulation layer of the composite fire-resistant air duct not only has thermal insulation performance, but its flexible characteristics can also be pressed into a streamlined inner cavity through a mold to reduce airflow impact. In terms of splicing technology, modular design replaces traditional welding or riveting, and seamless connection is achieved through special flanges and sealing strips to avoid airflow disturbance caused by splicing misalignment. Some products even introduce a "zero gap" buckle structure to form a continuous guide surface at the pipe connection to further reduce wind resistance.Elbows and reducers: resistance taming of large radius and guide deviceElbows and reducers in the duct system are the main sources of wind resistance. Traditional right-angle elbows are prone to form eddy zones due to sudden changes in air flow direction, while the new fire-resistant air duct adopts a large radius elbow design to smoothly turn the airflow by extending the turning radius. For example, the steel-surfaced magnesium fire-resistant air duct has built-in guide blades at the elbow to divide the airflow into multiple parallel streams and reduce turbulence. For the reducer, the tapered design replaces the traditional step-type reducer, so that the change rate of the pipe cross-sectional area is controlled within a reasonable range, avoiding energy loss caused by sudden pressure changes in the airflow. In addition, some products also install honeycomb rectifiers at the diameter change point, combing the turbulent airflow into laminar flow through regularly arranged hexagonal channels, significantly reducing local resistance.System integration: Intelligent adjustment and coordinated optimization double the efficiencyThe low wind resistance design of fire-resistant air duct needs to be coordinated with the smoke exhaust system as a whole. Traditional smoke exhaust systems often lead to the phenomenon of "big horse pulling a small cart" or "small horse pulling a big cart" due to the mismatch between fan power and pipeline resistance. Modern fire-resistant air ducts realize dynamic linkage with smoke exhaust fans through built-in pressure sensors and wind speed regulating valves. When the wind resistance in the pipeline is detected to increase, the system automatically adjusts the fan frequency or opens the backup air duct to maintain a constant smoke exhaust volume. For example, in high-rise buildings, fire-resistant air ducts and staircase air supply systems form a "negative pressure-positive pressure" synergy to accelerate smoke exhaust through pressure gradients. In addition, some intelligent air ducts also integrate CFD simulation technology, which optimizes the pipeline layout through airflow simulation before installation, avoids obstacles in the building structure, and reduces unnecessary elbows and diameter changes.Long-term maintenance: efficiency guarantee of self-cleaning and corrosion-resistant designThe low wind resistance performance of fire-resistant air duct depends on long-term maintenance guarantee. The wind resistance of traditional air ducts increases year by year due to corrosion of the inner wall and accumulation of smoke and dust, while the new fire-resistant air ducts extend their service life through self-cleaning design and corrosion-resistant materials. For example, the electromagnetically driven cleaning system can be started during non-smoke exhaust hours, and the cleaning bristles are pushed by magnetic blocks to scrape off the dirt on the inner wall. For heavy oil smoke scenes such as kitchens, the inner wall of the fire-resistant air duct is coated with oleophobic coating, so that the oil smoke forms a liquid film when passing through and slides along the pipe wall to avoid deposition. In addition, the application of the outer protective steel surface or anti-corrosion aluminum foil allows the air duct to maintain structural stability in a humid environment and avoid the roughening of the inner wall caused by rust.From material innovation to intelligent integration, the low wind resistance design of fire-resistant air duct is reshaping the efficiency boundary of smoke exhaust in fire scenes. When every inch of the pipeline can transport smoke with minimal resistance, the rescue time will be extended exponentially and the risk of casualties will be greatly reduced. This transformation from passive fire protection to active efficiency optimization not only reflects technological advancement, but also demonstrates the ultimate pursuit of life safety.
