Prapontin tunnel Intelux NG for intelligent lighting of the A32 tunnels
Intelux NG for intelligent lighting of the A32 tunnels - Prapontin tunnelIntelux NG for intelligent lighting of the A32 tunnels - Prapontin tunnelIntelux NG for intelligent lighting of the A32 tunnels - Prapontin tunnelIntelux NG for intelligent lighting of the A32 tunnels - Prapontin tunnel
The experience

Since the beginning of 2000 SITAF has been accomplishing a program of adaptation about all lighting plants of the A32 tunnels due to the increasing traffic flux and the new standard, in compliance with the road users’ safety and comfort, together with the energy saving needs, today confirmed by the European instruction N. 2005/32/CE.

Till now this program has carried out a renovation of Prapontin (2003) and Serre La Voute (2004) tunnel plants, according to the MD (Ministerial Decree) of 5 June 2001.
Besides, all new plants are in accordance with the more recent MD dated 14 September 2005, even if this decree isn’t required for all tunnels which have been redeveloped before its issue, according to the previous MD.
Hereafter we’re showing the results obtained in the lighting plant of Prapontin Tunnel of about 4,5 Km long.

The solution and the results

In addition to the mentioned standard and decrees, SITAF customer has imposed some additional design conditions such as:

  1. maximum respect of comfort, in particular by reduced dazzling index (increase of TI threshold) and values of global and longitudinal uniformity in order to guarantee the absence of light and dark zones on the roadway;
  2. maximum working guarantee of emergency circuits;
  3. reduction in installation costs minimizing feeding circuits of the reinforcement plant too;
  4. minimization of energy consumptions.


Item 1 induced the choice of a lighting symmetrical system both of reinforcement and permanent one, reducing, also all interdistances among the equipments under the design value in order to improve all uniformities. In order to comply with item 2 the permanent lighting circuit has been divided into two parts fed through UPS. As it concerns item 3 we have adopted power controllers having a wide controlling range, contributing to item 4 together with the choice of high pressure sodium-vapour lamps and the veiling luminance rating according to environmental measurements.

As regards the common road luminances in entrance section from 80 cd/m2 to 160 cd/m2 you need 4 levels if you don’t use controllers, 3 if you use standard electromechanical and electronical controllers, while innovating INTELUX NG controllers on down front need only 2 steps till to an entrance luminance of no less than 243 cd/m2.

The entrance luminance controlling is controlled by two luminancemeters placed at the stop distance in front of the barrel-vaults and connected with the power controllers.
These tools will be replaced in short time, by luminancemeters able to measure a veiling luminance, in order to improve the correlation with the road luminance in entrance and transition zones

The plant has been realized using lighting plants made by Schréder, type FV3, with 83M Asim optics, equipped with high pressure sodium-vapour lamps, super type, having changeable powers from 400 W to 150 W. The plant dimming has been realized by power controllers manufactured by Revetec and Intelux NG technology which guarantee till 25% of nominal luminous flux dimming range. Controllers are connected with external luminancemeters, which will be replaced, in a short time by SDL Revetec’s luminancemeters able to measure the veiling luminance, realizing, in a more accuracy way, the correlation between the external veiling luminances and the internal road one and optimizing the energy consumptions.