Tunnel construction creates a continuously changing ventilation route. As excavation advances, fresh air must travel farther through ducting while pressure loss, leakage and connection resistance increase.
The system must provide enough clean air for workers and equipment, dilute blasting fumes, control dust and remove diesel exhaust or welding fumes from the active construction zone.
The selected fan must therefore match the current stage and expected maximum ventilation distance. A fan that performs well at a short route may not maintain the same airflow after the duct is extended.
Tunnel construction fans are often selected for ducted fresh-air delivery. The fan must provide the target airflow after all pressure losses from the complete route are included.
A longer duct, smaller diameter, damaged joints, bends and poor connection quality can reduce the actual airflow reaching the heading face. The maximum planned route should be considered during preliminary selection.
For a new project, fan and duct planning should consider the maximum tunnel length, construction equipment, contaminant sources and the expected ventilation method.
For replacement, original fan data and the current ventilation problem help determine whether a direct match or corrected airflow and pressure selection is required.
Selection should use the required airflow at the maximum planned duct resistance. Tunnel length, section, duct diameter, leakage, bends, elevation, contaminant sources and equipment emissions should be included.
A longer duct creates more friction loss and usually more leakage points. If fan pressure, duct diameter or connection quality is insufficient, the airflow reaching the heading face decreases.
The maximum planned ventilation distance should be considered. The operating method may then be adjusted during shorter stages, subject to the selected fan and control arrangement.
SDF is positioned toward tunnel construction or ducted ventilation applications, while SDS is a tunnel jet-fan direction for longitudinal airflow. Final use depends on the project design and operating stage.
Send the fan and motor nameplates, airflow, pressure, speed, power, duct route, connection sizes, installation photos and the current problem such as low airflow, slow fume removal, noise or vibration.
The suitable direction depends on whether the project requires ducted construction ventilation, local underground ventilation or longitudinal jet-fan operation. Send the tunnel and operating parameters for preliminary matching.