1System Description
Figure 1: TunnelTech 602
The TunnelTech 602:
Is a illuminance photometer, designed for placement within a tunnel to monitor the illuminance level
within, allowing for the tunnel luminaires to be controlled in relation to the light level outside with
the intended purpose of allowing vehicles to enter, pass through and exit the tunnel safely without
impeding the through-flow of traffic.
A signal output from the TunnelTech 602 is fed to a suitable controller to adjust the level of light
intensity inside the road tunnel to the light intensity inside and outside.
Typically, the unit is mounted inside a tunnel and continuously measures the average luminance over
a standard range of 0 –20,000 lux. The luminance data is converted to a 4-20mA output and
transmitted to a host controller to control the luminaries in the tunnel entrance, interior and exit.
The TunnelTech 602 is designed in accordance with Commission Internationale de l´Eclairage, (C.I.E.),
publication 88, 1990 recommendations.
Tunnel lighting monitoring and control is most important at the entrance and exit portals, to ensure
the regulation of luminaire intensity to the correct levels to avoid Tunnel users to be affected by the
black hole effect, whereby they decelerate rapidly due to sudden darkness of the tunnel entrance and
become a hazard to other road users. This is accomplished in conjunction with The TunnelTech 602
Luminance monitor which measures the luminance of the tunnel portal mounted in the access zone,
outside the tunnel. this allowing a control unit or system to alter the light level in accordance with the
luminance outside. Once the user is inside the tunnel and accustomed to the light level change,
luminaires can be reduced in intensity via a “Luminance Reduction Curve” to allow energy to be saved.
