Success Stories
Tito Speri urban gallery, Brescia (BS)

Intelux range controllers and SDL probe in the Brescia urban tunnel


Among the cases in which the Public Administration has done its utmost to obtain the best results, resorting to the use of modern electronic technologies, the Tito Speri gallery in Brescia stands out, a place where, to make transit more pleasant, the Municipal Administration has an artist and color expert commissioned to decorate the interior walls with polychrome motifs of great visual impact.


The tunnel has a total length of 430 meters and is structured with a central carriageway, on a straight axis, and two sidewalks. The lighting is permanent throughout the day and night, but not always at the same level of illumination, and has "reinforcements" at the entrance and exit for a total of six batteries of floodlights (three for each entrance ).

The Digital Brightness Probe (SDL), consisting of the optical detector and the control module, manages the intensity of the luminous flux of all the lighting lines in the tunnel, intervening both on the permanent and on the reinforcement lighting to adjust the flow internal luminous to the external luminance. It is responsible for the lighting of the reinforcement lines that are inserted when the external luminance requires it, while maintaining the possibility of regulating the luminous flux. When the first line gets to work at 100%, or if required by the external luminance, the second circuit is inserted, and both are reduced to the level imposed by the external light. The same is repeated for the other reinforcement circuits.
The projector fixtures installed have bodies in light aluminum alloy and the relative electromagnetic power supply units are external, in special protected enclosures. They are equipped with metal halide vapor lamps (white light, 3000 K) with powers of 150, 250 and 400 W.
For street lighting, there are 61 luminaires in permanent service (150 W) and 112 -2 groups of 56 (150 W) for pavements. The most powerful projectors were used for the reinforcements, in the initial sections for a length of 105 meters on each side. Total quantity of projectors 285 for a nominal power (only the total power absorbed by the lamps) of 69,250 W.
The plant is equipped with an automatic regulation and stabilization system of the supply voltage of the Intelux range. Three three-phase regulators were installed for the control of the two pedestrian crossings and for the carriageway of motor vehicles, maintaining, for safety purposes, the luminance of the pavements higher than that of the carriageway. The lighting reinforcement system was equipped with five three-phase controllers. The first line serves the first reinforcement stage of the two inputs, while the other four intervene only when the external brightness requires it, being increasing or decreasing. The adjustment device is of the three-phase type with neutral for a voltage of 400 V, and is located in the electrical panel for powering the entire system. The remote control of the luminous fluxes produced by the discharge lamps is entrusted to an optical sensor (silicon photocell) outside the tunnel, mounted on an adjustable support for pointing the area on which to detect the brightness.


The adjustment of the various groups of floodlights for permanent and reinforcement lighting takes place by reading the quantity of external light and by programming the time. In this way, energy consumption is limited in the hours of low traffic and the brightness of the interior of the gallery is adjusted to natural light. In this case, the gradual adjustment of the luminous flux proves to be the most suitable means to achieve the three fundamental objectives:

  • safety and visual comfort throughout the day, in all possible weather conditions;
  • perfect illumination of the decorated polychrome walls;
  • reduction of consumption combined with the lengthening of the average life of the lamps.