What are the specifications for the layout of duct installation in the basement?
Publish Time: 2025-04-15
The layout of duct installation in the basement must strictly follow the technical specifications, and precise control is required from pipeline path planning, space utilization optimization, coordination with other facilities to construction details.
Pipeline path planning must take into account functionality and space limitations. Ventilation ducts should be arranged along the wall or column edge above the parking space to avoid occupying the clear height of the lane. For example, the duct needs to be laid against the bottom of the beam or the bottom of the slab, and the bridge frame is installed against the bottom of the beam when it meets the beam. After passing the beam, the upper return and the top plate are reserved with a distance of 50mm to ensure that the clear height of the lane is not less than 2.4 meters. The height of the smoke exhaust duct must be controlled within 400mm, the wind speed must be controlled at about 19m/s, and the width-to-height ratio must not exceed 8:1, so as to shorten the smoke exhaust distance to 25-30 meters and reduce system resistance.
Space utilization must follow the principle of "wind above, electricity in the middle, and water below". The ventilation duct should be located on the highest floor, with the bridge frame in the middle and the water pipe at the bottom. The distance between the air duct and the water pipe should be kept at more than 300mm, and the distance between the air duct and the bridge should be kept at more than 100mm to avoid electrical failure caused by condensed water dripping. When space is limited, shared brackets or staggered layout can be considered, but the rationality of airflow organization should be verified through CFD simulation to ensure ventilation efficiency.
Coordination with other facilities should focus on fire protection and equipment room requirements. When the smoke exhaust duct passes through the fire partition, a 280℃ fire damper should be installed, and the fire resistance limit should be ensured to be not less than 1.5 hours. The air supply duct should be kept at a distance of more than 500mm from the smoke exhaust duct, or separated by a fire wall or fireproof partition. For equipment rooms such as generator rooms and boiler rooms, the ventilation duct should be directly connected to the outdoors, and an anti-backflow device should be installed to avoid exhaust gas backflow.
Construction details should focus on sealing and seismic resistance. Galvanized flanges or common plate flanges should be used for duct connections, and the thickness of the sealing gasket should be not less than 3mm. The bite seams and rivet holes should be sealed with sealant. When crossing settlement joints or deformation joints, a flexible short pipe with a length of 200-300mm needs to be installed. The spacing of the duct brackets must meet the requirements of the specifications. When installed horizontally, the spacing of the diameter or long side ≤400mm is ≤4m, and the spacing of >400mm is ≤3m to ensure the stability of the system.
The layout of the ventilation duct also needs to consider the convenience of later maintenance. The inspection port must be set in a convenient location for operation, and the size must not be less than 450×450mm. For vertical ducts, an inspection platform or hanging basket fixing point must be set on each floor. When the diameter of the duct exceeds 1.2 meters, an inspection ladder must be set inside the duct to ensure the safety of personnel.
The layout of the basement duct installation needs to be simulated in three dimensions through BIM technology to avoid pipeline collisions in advance and optimize space utilization. At the same time, it is necessary to combine the use functions of the basement (such as garages, equipment rooms, and civil air defense areas) for zoning design to ensure that the ventilation needs and safety standards of each area are met. Through refined design and construction, the environmental quality of the basement can be improved and the long-term operation and maintenance costs can be reduced.
