Tunnel Ventilation Fans
Tunnel ventilation projects require jet fans, main axial fans, and fire-rated dampers working as a coordinated system. Sourcing each component from a different manufacturer means three vendors, 3 timelines, and 3 points of failure on your commissioning schedule.
Knape Associates supplies the full tunnel ventilation package from multiple manufacturer lines.
Jet fans from 20N car park units through 3,100N road and rail tunnel fans. Axial fans up to 120,000 CFM for ventilation shafts. Tunnel dampers rated to 400°C for 2 hours.
1 purchase order. 1 point of contact.
When one manufacturer’s lead time stretches to 14 weeks, we pull equivalent equipment from another line without rewriting your spec.
Have questions? Need a fan quote?
Tunnel Ventilation Equipment
| Equipment Type | Application | Key Specs | Compliance |
|---|---|---|---|
| Unidirectional Jet Fans | Road tunnels, longitudinal ventilation systems | Up to 3,100N thrust, 630–1,250mm diameter, discharge velocity 20–35 m/s | EN 12101-3, AMCA 250, ISO 13350 |
| Reversible Jet Fans | Bi-directional tunnels, metro and subway systems | Up to 2,710N thrust, 630–1,250mm diameter, 300°C/2h emergency rating | EN 12101-3, NFPA 130 |
| Car Park Jet Fans | Enclosed parking garages, impulse ventilation | 20–89N thrust, 315–630mm diameter, axial and centrifugal configurations | cULus 705, ASHRAE 62.1 |
| Main Axial and Centrifugal Fans | Ventilation shafts, transverse and semi-transverse systems | Up to 120,000 CFM, 630–1,600mm diameter, 400°C/2h fire rating available | ISO 5801, BS 848, NFPA 502 |
| Tunnel Fire and Smoke Dampers | Transverse smoke control, fire zone isolation | 400°C/2h, bi-directional, tested to millions of pressure reversals | UL 555, BS 476-20, NFPA 130/502 |
| Explosion-Proof Actuators | Damper and fan control in hazardous tunnel environments | ATEX and IECEx rated for classified areas | NEC Articles 500–505 |
Jet Fans for Road Tunnels, Metro, and Car Parks
Jet fans generate longitudinal thrust to move air through a tunnel without distribution ductwork. Each fan entrains surrounding air and pushes it toward exhaust points or portals, spaced in banks every 90 to 150 meters.
In a fire scenario, these impulse fans maintain critical velocity of approximately 3 m/s to prevent smoke from backlayering against the evacuation direction.
Road Tunnel Jet Fans
Our unidirectional thrust fans range up to 1,250mm diameter and deliver up to 3,100N for longitudinal highway and vehicular tunnel systems. Discharge velocities span 20 to 35 m/s at rated thrust.
Every unit is fire rated to 300°C for 2 hours per EN 12101-3, with 400°C ratings available on request. Thrust is tested and certified to AMCA 250 and ISO 13350.
Metro and Subway Tunnel Jet Fans
NFPA 130 requires emergency ventilation in transit tunnels to operate in both directions. Our reversible configurations cover 630 to 1,250mm diameter with near-equal forward and reverse thrust up to 2,710N.
These underground ventilation fans handle the pressure pulses generated by train movement and reverse airflow direction based on fire location and passenger evacuation routes.
Car Park Jet Fans
Impulse jet fans replace traditional ducted exhaust in enclosed parking garages. Axial and centrifugal configurations range from 315 to 630mm diameter, 20 to 89N thrust, meeting ASHRAE 62.1 exhaust requirements of 0.75 CFM per square foot.
Removing the ductwork frees structural depth, reduces construction costs, and simplifies routing for sprinklers and cable trays. All parking garage fans are available with variable frequency drives for demand-controlled ventilation based on CO and NO2 levels.
Tunnel Dampers and Smoke Control Integration
Tunnel dampers control which zones extract smoke and which zones stay sealed during a fire event. In transverse and semi-transverse systems, dampers near the fire open to direct smoke into extraction ducts while adjacent zones remain isolated.
The full system coordinates damper position, fan operation, and fire detection through UL 864 UUKL smoke control panels per NFPA 130 and NFPA 502 ventilation design requirements.
| Feature | Specification |
|---|---|
| Fire rating | 400°C for 2 hours per BS 476-20 |
| Leakage classification | UL 555 rated |
| Airflow direction | Bi-directional, vertical or horizontal mount |
| Pressure endurance | Tested to millions of train-induced piston effect reversals |
| Blade linkage | Parallel or opposed, normally open or normally closed |
| Mounting | Pre-drilled flanges for bolt-on or weld-to-frame installation |
Jet fans, main axial fans, and fire-rated tunnel dampers all come from the same specification package. That eliminates the coordination gap between separate fan and damper vendors on your project and keeps your procurement on a single purchase order.
Why Source Tunnel Ventilation From 30+ Manufacturer Lines
Tunnel ventilation specs are project-specific. Fan diameter, thrust, fire rating, and damper configuration all depend on your tunnel geometry, traffic conditions, and fire scenario. Our engineering team reviews your area classification drawings and ventilation requirements before quoting. You get equipment selections matched to the project, not a catalog recommendation.
75+ years of manufacturer relationships give us access to documentation your spec package requires. That includes thrust curves tested to ISO 13350, fire test certificates per EN 12101-3, acoustic data, general arrangement drawings, and CFD support data for jet fan layout validation.
We coordinate factory acceptance testing and provide commissioning support so your tunnel ventilation system meets NFPA 130 or NFPA 502 requirements at final verification.
Call our engineering team at 713-467-2777 to start your tunnel ventilation equipment review.