Road Tunnel Ventilation - Transverse Ventilation

Transversal ventilation uses separate air ducts to introduce inside the tunnel set flow rates of fresh air and extract the flue air from the tunnel. The system grants the greatest safety and efficiency to the tunnel users but is also the most expensive solution due to the high civil work costs involved (large ventilation rooms and large cross-sections to allow ducting).
The ventilation system is normally used long bi-directional tunnels with high traffic levels and high percentage of heavy goods vehicles transit.

For transversal ventilation Systemair offers a wide range of axial fans, sound attenuators and dampers:

Axial fans AXC and AXR

• Unidirectional (AXC) or truly reversible (AXR)
• Diameters from 1.400 to 1.600 mm
• Volume flows up to 150m³/s and 5.000 Pa of pressure using contra-rotating
   fans in series
• Up to 400°C for 2h operation
• Certified according to EN 12101-3


Sound attenuators

• Cylindrical silencers with or without acoustic pod directly connected to the fan
• Limited acoustic attenuation and low pressure losses
• Should the system require higher attenuations a splitter silencer can be sized,
  the splitters can be fix or moveable types on special rails in order to allow
  the possibility of easy cleaning
• Aerodynamic nose of the splitters (on request) to reduce the pressure losses even more
• Acoustic material fire resistance classified ClassA1 in accordance to ISO EN 13501-1
• Standard finish in neoprene tissue or expanded metal sheet
• Structure material can be pre-galvanized, hot dip galvanized or stainless steel



• Multi leaf dampers with parallel or opposite blades specially designed for
  underground applications
• Made of hot dip galvanized steel after manufacture or in stainless steel
  AISI 304L/316L equivalent to EN 1.4301/1.4404
• Air leakage less than 0.1 m³/sm² at 1kPa
• Blade deflection less than L/180 at 6 kPa
• Operational cycling (open-close) up to 6 million cycling
• Actuators pneumatic, electro-pneumatic, spring return, on/off, modulating
• Supply 230 or 400V, 50 or 60 Hz, 1 or 3 ph
• The entire damper including motor can operate with hot air or smoke
  up to 400°C for 2 h certified in accordance to CETU/PIARC.


Supply grilles

• Wide range of supply grilles made of aluminium or stainless steel
  AISI304/316 equivalent to EN1.4301/1.4404
• Heavy construction suitable for underground applications
• Control dampers to set up the volume flow through the grilles