Tunnel and underground ventilation is selected from airflow direction, installed thrust, smoke strategy, pressure loss and acoustic limits—not from a fan’s maximum airflow alone.
Design tunnel and enclosed parking ventilation with YONGFAN SDS unidirectional jet fans (191–3,046 N thrust, Ø630–1600mm), SDS(R) 30-second reversible jet fans, PYHL-14A ductless jet-induction exhaust (280 °C / 30 min fire duty), HL3-2A ducted mixed-flow fans, DTF in-line axial fans (115–2,266 Pa), and 1D/2D silencers.
Calculating fan count purely as (Total Thrust / Catalog Thrust) without correcting for tunnel velocity drops installed thrust by 20–40%.
Selecting reversible SDS(R) fans with symmetric blades without accounting for the 4–6% lower thrust compared to unidirectional SDS.
Adding 1D/2D silencers after fan procurement changes assembly length, weight, support structures, and tunnel clearance.
Applying ducted mixed-flow calculations to ductless car park layouts, or omitting extract shafts for PYHL induction fans.
Longitudinal jet ventilation for road and rail tunnels (191–3,046 N static thrust, 7.9–71.8 m³/s airflow, 16–45.5 m/s exit velocity, Ø630–Ø1600 mm diameter, 4–90 kW motors). Features adjustable blade angles (18°–33° in 3° increments), IP55 Class H motor construction, and bare or silenced configurations.
Fully reversible jet fan for bidirectional tunnels and emergency smoke redirection. Utilizes a symmetric blade profile capable of full forward-to-reverse switchover within 30 seconds at rated speed. Thrust is approximately 4–6% lower than the equivalent unidirectional SDS model.
Inlet and outlet sound attenuators engineered specifically for the SDS family. 1D (1× diameter length) and 2D (2× diameter length) silencers provide approximately 9–14 dB(A) sound-pressure reduction, reducing portal and tunnel noise to municipal environmental standards (52–87 dB(A) series range).
Mixed-flow jet-induction fan for underground car parks, tunnels, and large enclosed basements. Eliminates bulky distribution ductwork by inducing space air movement toward exhaust shafts. Documented smoke-extraction configuration rated for 280 °C / 30 min fire duty.
Ducted mixed-flow fan engineered for underground systems requiring moderate-to-high static pressure to overcome duct and shaft resistance. Features compact in-line casing, sizes 2.5A–4A, and high aerodynamic efficiency for car park and metro basement ducted exhaust.
In-line tube-axial fan for conventional ducted tunnel ventilation shafts, metro stations, and plant rooms (1,886–114,829 m³/h, 115–2,266 Pa, Ø350–1600 mm, 0.5–45 kW). Documented continuous duty to 100 °C, fire-rated 280 °C / 30 min build, and optional ExdbIIBT4/CT4 explosion-proof ratings.
| System Condition | First Product Family to Evaluate | Documented Boundary | First Design Input |
|---|---|---|---|
| Longitudinal airflow in one direction | SDS Jet Fan | 191–3,046 N static thrust · Ø630–1600mm | Required effective installed thrust |
| Longitudinal airflow with 30s reversal | SDS(R) Reversible Jet Fan | Reverse ≤30s; ~4–6% lower thrust vs SDS | Emergency smoke airflow direction |
| Ductless underground car park induction | PYHL-14A Induction Fan | Fire-rated version 280 °C / 30 min | Space geometry, beam heights & shafts |
| Ducted underground car park exhaust | HL3-2A Mixed-Flow | Combined family 561–105,988 m³/h, 58–3,325 Pa | Airflow (m³/h) + duct resistance (Pa) |
| In-duct tunnel / metro station exhaust | DTF Axial Fan | 1,886–114,829 m³/h, 115–2,266 Pa | Airflow (m³/h) + external static pressure |
Provide tunnel cross-section area (m²), length (m), portal elevations, and target longitudinal air velocity (m/s).
Calculate required total thrust (N) factoring tunnel velocity, wall friction, and grouping losses (C2, C3).
Select SDS unidirectional or SDS(R) reversible models, diameter (Ø630–1600 mm), and blade angle (18°–33°).
Specify 1D or 2D silencers to meet portal noise limits, and verify 280 °C / 30 min fire emergency certificates.
YONGFAN aerodynamic engineers will calculate momentum thrust transfer, model jet fan spacing, verify reversal switchover sequences, and provide thrust test reports.
SDS jet fans undergo static thrust measurement on a dedicated test rig per GB/T 13351 at standard air density ρ=1.2 kg/m³.
Precision aluminum/steel impellers are dynamically balanced to ISO 1940 G2.5 to eliminate vibration under high velocity.
Heavy-duty totally enclosed motors feature IP55 ingress protection and Class H insulation for harsh tunnel environments.
Casings undergo degreasing, phosphating, passivation, and heavy electrostatic powder coating for corrosive tunnel air.
SDS is unidirectional. SDS(R) uses a symmetric blade profile for reversible operation and reverses from forward to reverse within 30 seconds. SDS(R) thrust is ~4–6% lower than SDS.
YONGFAN documents 191 to 3,046 N static thrust across impeller sizes Ø630 to Ø1600 mm (bare fan reference values).
Because installed effective thrust drops as tunnel air velocity rises: Ne = Ns × (1 − Vt/Vj) × C2 × C3. Tunnel speed, wall friction, and grouping losses must be included.
PYHL-14A is a ceiling-suspended ductless jet-induction fan for car parks. HL3-2A is an in-line ducted mixed-flow fan designed to overcome high duct resistance.
Yes. The source documents a PYHL-14A smoke-extraction version certified for 280 °C / 30 min fire duty.
Yes. DTF fans are documented for in-duct tunnel ventilation shafts, metro stations, and basement car parks with fire-rated and explosion-proof builds available.
They describe silencer length relative to fan diameter (1× or 2× diameter). 1D/2D silencers provide approximately 9 to 14 dB(A) sound-pressure attenuation.
No. The fan impeller reverses within 30 seconds, but the massive inertia of the moving tunnel air column takes longer to decelerate and reverse.
No. If your fire/ventilation strategy uses a single fixed direction, unidirectional SDS provides ~4–6% higher thrust and lower cost.
Tunnel geometry, target air velocity, required effective thrust, traffic/emission data, fire scenarios, airflow directions, and portal noise limits.
Catalog static thrust is measured at zero tunnel velocity; aerodynamic in-situ derating based on tunnel velocity and wall clearance is mandatory.
Confirm the exact project fire-test certificate for ordered SDS configurations before scheduling code-defined high-temperature duty.
PYHL-14A ductless jet induction requires coordinated exhaust shafts and computational fluid dynamics (CFD) modeling to verify zero dead zones.
SDS(R) symmetric blades have lower aerodynamic efficiency than unidirectional SDS; do not assume identical thrust between SDS and SDS(R).
Send your tunnel geometry, target longitudinal air velocity, car park layout, and smoke control scenarios. YONGFAN aerodynamic engineers will calculate installed thrust, select jet fans, and supply certified submittals.
