The VCOM tunnel monitor measures the concentration of carbon monoxide (CO) in tunnel atmospheres and makes a visible opacity measurement to determine the visibility within the tunnel. These measurements can be used as part of an air quality management system for ventilation control and/or secondary smoke detection within a traffic tunnel or other confined space.


  • Proven infrared spectroscopy technique for measurement of carbon monoxide (CO)
  • Visibility measurement using the widely accepted light transmission opacity technique
  • User selected unit display options of Opacity (%), Extinction Coefficient (k) or Meteorological Optical Range (MOR)
  • Temperature and humidity compensated measurements to ensure stable readings across all tunnel conditions
  • IP65 / NEMA 4X rated external enclosure supplied with quick release dust protection tubes and wall brackets
  • Intelligent analyser with optional Operator Interface


  • Designed specifically for monitoring in tunnels
  • Rugged design to withstand corrosive atmosphere and regular tunnel washing
  • Simple installation and alignment
  • Low maintenance requirements
  • Suitable for right or left hanging to enable compliance with regulations governing light emissions facing on-coming traffic flow