H1: Tunnel & Underground Ventilation Fans: Design, Jet Fan Layout & SizingMeta description: Tunnel and underground ventilation needs jet fans, reversible fans, and correct airflow modeling. Learn layout principles and how Tefeng fans serve metro, road, and mining tunnels.
IntroVentilation in tunnels and underground spaces is not just about moving air—it is about controlling smoke during fire, removing diesel exhaust, and keeping workers safe in low-visibility conditions. Unlike open buildings, a tunnel is a confined duct where airflow direction, velocity, and reversibility decide whether an emergency is survivable.
Why it matters
Fire safety: smoke extraction fans must run at high temperature (often 250–400°C for 1–2 h, per fire ratings).
Diesel exhaust: long tunnels accumulate CO and NOx from vehicles/equipment—continuous dilution required.
Reversibility: emergency scenarios need bidirectional airflow, so reversible jet fans are standard.
Recommended fan types (Tefeng series)
Application | Fan type | Tefeng series |
Metro / road tunnel | Jet (thrust) fan |
|
Reversible emergency | Reversible jet fan |
|
Auxiliary mine drive | Axial local ventilation |
|
Station / concourse | Axial or mixed-flow | GXF / HL3-2A series |
Key design notes
Jet fan thrust must overcome tunnel friction + buoyancy; model with a 1D airflow simulation before specifying count.
Mount jet fans on brackets clear of the ceiling so the Coanda effect builds wall jet efficiently.
For fire-rated units, confirm temperature class and duration against local code (e.g., EN 12101-3).
FAQQ: How many jet fans does a tunnel need? A: It depends on tunnel length, cross-section, and design velocity. Engineers size thrust from a 1D network model, then divide total thrust by single-fan rated thrust. A typical metro station might use 6–12 units per bore.
Q: Can one fan handle both ventilation and smoke extraction? A: Yes—fire-rated reversible jet fans are designed for daily ventilation and emergency smoke control, provided the temperature class matches the fire scenario.
Q: What certifications matter for tunnel fans? A: Look for fire-resistance rating (e.g., EN 12101-3 / CCCF in China), IP rating for the motor, and third-party type tests on thrust and noise.
CTA: Need a tunnel ventilation layout? [Request a quote] with your tunnel cross-section and length.