CNA Tunnel

Retrofit LED kits improve safety and reduce energy consumption by over 50% in this busy tunnel

The Contournement Nord d'Angers (CNA) tunnel is part of the A11 motorway that runs through the city of Angers. It is a two-lane twin-tube tunnel designed to facilitate traffic flow between Nantes and Paris. The lighting in the tunnel was provided by 1,068 PF5 luminaires installed in 2005 and Cofiroute, the tunnel operator, wanted to upgrade to LED technology to reduce energy costs.
 

Retrofit LED kit for luminaires in excellent condition

The PF5 was designed over 20 years ago to resist the damage caused by the intense corrosion found in road tunnels, both on the outside and inside of the housing, and to maintain a maximum IP 66 degree of tightness to guarantee the reliability of the luminaire's photometric and electrical equipment. Manufactured from fire-resistant composite materials, this was a crucial choice for the tunnel operator following the fire in the Mont Blanc tunnel.

After more than 18 years in service, the luminaire bodies were still in excellent condition. Cofiroute, which is committed to sustainable lighting solutions that preserve resources and reduce its carbon footprint, wanted to upgrade the lighting to more energy-efficient LED technology. 

Originally designed for discharge lamps, the PF5 is ideal for retrofitting with LEDs to deliver a higher light output using less energy, lower maintenance costs, reduce carbon emissions and contribute to a more circular economy. By choosing to retrofit the PF5 luminaires in the tunnel, Cofiroute is able to keep the original luminaires, junction boxes and distribution network, minimising waste and reducing its carbon footprint, while improving the quality of light and energy efficiency.
 

Optimised tunnel lighting design to ensure safety

The right lighting design is essential for a safe tunnel. We redesigned the tunnel lighting installation, calculating the number of luminaires and their orientation to create a curve as close as possible to the CETU (French Centre for Tunnel Studies) normative curve for an efficient and economical installation. Using our high performance LED optics, we were able to reduce the number of luminaires needed to light this 1.7km tunnel to 930, further reducing energy costs.

Due to the high volume of traffic passing through the tunnel, we strategically increased the number of luminaires at the tunnel entrances to avoid the "black hole effect" and to ensure an easy and comfortable transition in the critical zone.

Now equipped with the latest generation white LEDs, the PF5 luminaires deliver a crisp bright light with exceptional colour rendering to optimise the visual perception of drivers, highlighting any potential obstacles and increasing security in the tunnel.
 

Quick and easy installation for minimal disruption

To minimise disruption to traffic, the refurbishment was scheduled to take place over 8 nights in September and October 2024 so that the tunnel could be reopened in time for the early morning traffic.

Contournement Nord d'Angers
Angers
France

Customer

Cofiroute

Partner(s)

Installation: Lesens EREA

Application(s)

Open 18 years of service life in the CNA Tunnel, the PF5 luminaires were still as clean as the day they were installed

This was an extremely tight schedule for the installer, Lesens EREA, a VINCI company, who had to clean the exterior of the 1,068 PF5 luminaires, disconnect and remove the old lamps and reflectors, install the retrofit LED optics and reconnect the 930 fixtures. All the cables used to control the various lighting systems also had to be reinstalled. When the luminaires were opened, the interior was as clean as the day they were installed, a testament to the luminaire's IP 66 rating.

Thanks to excellent teamwork and the ease of installation and connection of the retrofit LED kits, the work was carried out quickly and efficiently to meet the deadline. 

Over 50% less energy and less carbon

A total of 1,068 PF5 luminaires fitted with high pressure sodium lamps ranging from 100 to 400W (with an average power of 269KW) lit the tunnel. As part of the new tunnel lighting design, 930 luminaires were retrofitted with LED optics with an average power of 130KW.

The energy efficiency of these LED retrofit kits has reduced the total power of the installation by more than 50%, significantly reducing the energy bill.
 

Supporting a circular economy

By conserving the existing luminaire bodies, which were in excellent condition, Cofiroute has minimised the resources and energy needed to relight this tunnel, contributing to a more circular economy. The remarkably clean interior, despite the challenging tunnel environment, highlights the effectiveness of the luminaire seals. The optics have been completely protected from dust and dirt and will provide consistent, reliable performance for years to come.

We are delighted to have contributed to ensuring a safe, comfortable and sustainable CNA Tunnel for another 20 years to come.