The TunnelTech 700 Air Quality Monitor, is an essential part of any road or rail tunnel safety system. Firstly, it monitors the atmosphere within the tunnel and ensures that the tunnel
ventilation system provides sufficient clean air to protect tunnel users health and for drivers to clearly see the road ahead.

The TunnelTech 701 analyser electrochemical cell technology to determine CO, NO & NO2 concentrations and optical attenuation to monitor Visibility levels. As there are no moving parts, reliability levels are very high and maintenance requirements are low. The sight tubes have been designed to ensure that airborne dust and contaminants do not reach the optical windows and cause drift.

Key Features

  • Measure CO, NO & NO2 & Visibility in one compact sensor
  • Advanced electrochemical cell technology
  • Integrated display and keypad, no external computer required
  • Class leading NO2 Measurement
  • Minimal maintenance requirements
  • Easy to calibrate

Products within the 700 series

  • TunnelTech 701 : CO · NO · NO2 · Vis
  • TunnelTech 702 : CO · NO · Vis
  • TunnelTech 703 : CO · Vis
  • TunnelTech 704 : NO · Vis
  • TunnelTech 705 : NO2 · Vis
  • TunnelTech 706 : CO · NO2 · Vis
  • TunnelTech 707 : NO · NO2 · Vis
  • TunnelTech 708 : Vis Only


SpecificationImagesDocumentationProduct Enquiry



Gas Species Single or multi-gas measurements available: CO, NO2, NO & Vis
Measuring units ppm for CO & NO, PPb for NO2, m-1 or m for visibility,
Calibration Automatic zero calibration – manual span check
Measurement Technique Electrochemical Cell, LED Transmitivity for Visibility
Measurement range (typical) CO : 0 – 300ppm , NO : 0 – 30ppm , NO2 : 0 – 5/10ppm, Vis: 0 – 0.015 m-1
Construction Corrosion resistant epoxy coated aluminum housing sealed to IP66
Serial Data Bi-directional RS485 Modbus Protocol
Display 32 Character alpha-numeric back-lit LCD
Power supply 24V DC, 30 VA from seperate power supply
Lang Filetype Document Size
English TunnelTech 700 Series Datasheet 400kb

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