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Replacing a complete lighting package in the three kilometre Bamble and Kjørholt tunnels.

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  • Lamp efficacy

    Lamp efficacy

    Ensuring the lamp efficiently converts electricity into light (lm/W).

  • Ballast classification

    Ballast classification

    Controlling the electricity supply to the lamp (Energy Efficiency Index).

  • Luminaire distribution

    Luminaire distribution

    Controlling light emission using optics which bend and shape the light to the correct location.

  • System efficacy

    System efficacy

    Combining optical and thermal control within the luminaire (luminaire lm/W).

  • Presence/absence detection

    Presence/absence detection

    Presence: Lights automatically turn on/off with movement. Absence: Lights automatically turn off and must be manually switched on.

  • Daylight detection

    Daylight detection

    Artificial lighting which responds to the natural light conditions.

  • Constant illuminance

    Constant illuminance

    A function designed to produce correct light levels for the duration of the maintenance period.

  • Task-scene setting

    Task-scene setting

    Allowing the user to set scenes and adapt the lighting to different tasks.

  • Timed off

    Timed off

    Automatic cut-off can be installed to turn all lights off during unoccupied hours.

  • Task lighting

    Task lighting

    Lighting task areas with the correct amount of light.

  • Zoning of lighting

    Zoning of lighting

    Lighting is zoned according to area use.

  • Maintenance schedule

    Maintenance schedule

    Maintenance must be performed in response to product age, performance and environment.

  • Waste light

    Waste light

    Eliminating waste light which does not hit the intended target.

  • Reflectance


    Taking advantage of light which is reflected from the surface within the space.

  • Visible smart metering

    Visible smart metering

    Results of actions can be quickly seen as increased or decreased energy use to encourage responsible energy consumption.

The challenge

Opened in 1996, the Bamble and Kjørholt tunnels stretch for three kilometres through the mountains of Telemark in southern Norway, on the E18 highway. Recently it came to be time to replace the lighting in both tunnels, as part of a larger upgrade project. The full project also includes expansion into a 4 lane highway, meaning two extra tubes will be added as a next step.

The lighting solution

Thorn has supplied a complete lighting package for the Bamble and Kjørholt tunnels. A total of 950  GTLED PRO luminaires - specifically designed for tunnel lighting - were installed by electrical contractor Tratec, who also managed the comprehensive controls system.

GTLED PRO’s large and uniform luminous area, linear shape and precision optics ensure that disability glare and discomfort glare are kept to an absolute minimum, while providing the best possible luminance and uniformity levels. The solution provides levels in range from 400 cd/m2 in during daytime in the threshold(entrance) zone and down to 2 cd/m2 during night time. Since the tunnels are still in use for two-way traffic until the second set of tubes are completed, the tunnels have threshold zones on both sides. Some years ahead once the second set is completed and one-way traffic can commence, no change to the installation is required. The lighting setup is already prepared and approved for the higher 110 km/h speed limit, which requires a much longer threshold and transition zone. The threshold lighting on the opposite side will at that point only be used in case of traffic diversion and reverse traffic flow.

The GTLED PRO fittings are fully dimmable, so they can provide the right level of light according to both external lighting conditions and traffic volume. The GTLED PRO product family is designed to last many years in corrosive environments all the way up to category C5, as defined in ISO 9223:2012. The luminaire also features an innovative stainless steel mounting system. GTLED PRO is a product designed with true care, with traffic safety in mind every step of the way.

The result

The new tunnel lighting is highly efficient, creates safe and comfortable conditions for drivers, and will last a long time without requiring maintenance. It’s a great example of what can be achieved with Thorn’s specialist products and expertise in this area.