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TunnelTech 801

Cross Tunnel Flow Monitor

The TunnelTech 801 monitoring system for continuous evaluation of air flow rate and flow direction in tunnels

Road Tunnel emission monitor analyser


Tunnel ventilation systems are designed to enable a sufficient through put of air to be maintained to ensure a safe operating environment for users.


These systems consume large amounts of power and need to be operated as efficiently as possible. To do this it is necessary to know the effectiveness of the system in terms of air flow and direction developed within the tunnel. Three decades of development, knowledge and practical experience have been utilised to produce the advanced TunnelTech 801 air flow sensor that combines the reliability of ultrasonic technology and delivers superb accuracy and reliability.


The TunnelTech 801 has been specifically designed for road, rail and civil tunnel and ventilation shaftapplications and represents the latest in compact ultrasonic sensor-head design. Ultrasonic time-of-flight measurement across any tunnel delivers a highly accurate airflow value and virtually eliminates traditional high-maintenance measurement techniques.

Features & Benefits

Product Specification

MeasurementsAirflow velocity, Volumetric flow, Airflow direction, Temperature
Measuring UnitsMetric or Imperial units for all parameters
Accuracy±0.1 m/sec*
Measurement TechniqueAcross the tunnel, dual sensor, ultrasonic transit time principle
Measurement Range (Typical)-40 to +40 m/sec, range is user configurable
ConstructionCorrosion resistant IP65 / NEMA 4X enclosure (Kynar® 720)
Outputs CommunicationRS485 Modbus, RJ45, 2x 4-20 mA, 2 x Form C SPDT relay,
Ambient Temperature Range-40 to +85°C
Power24 VDC Power Supply

Related Products

TunnelTech 700 - Gas Monitor
TunnelTech 601 - Luminance Monitor

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