Italian relamping project lights up tunnels

Louise Smyth

Arianna was commissioned to upgrade street tunnel lighting in Italy to LED technology. Referred to as ‘relamping’, this conversion was required initially in the central parts of the tunnels and more recently, in the external sections, for the increased energy efficiency and longer lifetime provided by LED technology. 

On the ceiling of each street tunnel there are typically one or more stainless steel trunks on which the lights are mounted. The original lights were attached to the trunk with a mounting bracket made up of three parts. With each tunnel varying in size and shape, there was no standard setting for the lights and adjusting the mounting bracket during checks and maintenance was time-consuming and complicated. 

Arianna was looking for a one-size-fits-all latching system to attach the mounting bracket to the trunks and allow operators to adjust the LED lights without having to keep adjusting the parts on the mounting bracket. This would enable the safe, simple and secure maintenance and management of the lighting system. The latch had to be intuitive enough to allow quick installation of the lights without tools so that just one person could easily and safely position them, to keep maintenance and installation costs down. 

Because of the weight and height of the lights, it also needed to be robust enough to hold them in place effectively and maintain a high level of safety. Due to the challenging environment of the street tunnel, it was also important to identify a latching solution made of stainless steel which would be corrosion-resistant. 

Arianna identified that the TL–40, an over-centre latch created by Southco would meet its requirements for securing its LED mounting bracket. 

The TL–40 latch provides a mechanical advantage to applications through a lever-actuated mechanism which pulls panels together and holds them securely. Two draw latches are located on the side of the mounting bracket and installed using two rivets, enabling the safe fixing of the light to the cable trunk on the ceiling of the tunnel and the adjustment of the lights without the need to adjust the parts on the mounting bracket itself. It provides a standard solution which significantly improves the quality, usability and quick access to the system, making it easier for operators to install the light on the trunk and also to compensate for the tolerances in the existing trunks.

As it is small and compact, the latch provides greater flexibility for fixing the lights at different heights on the cable trunk. This means that Arianna can include a range of panel preparations with different mounting holes at varying heights and adjust them during the production process without having to use bespoke components every time to accommodate the different configurations of each trunk. 

The dual latch solution is effective at preventing accidental opening. It also allows operators to open the lighting bracket with one hand, making it much safer and easier to use, for example when holding a lightbulb in the other hand. Because the rivets are captive the bracket cannot come loose. 

Arianna has installed around 12,000 of the latches in the LED lighting system throughout street tunnels in Italy. The latch has enhanced and streamlined the process of upgrading the tunnels to LED lighting because it enables quick installation and operation. Working with Southco has also enabled Arianna to reduce the overall costs and time constraints of the project. Previously, Arianna had to fit mounting brackets of different sizes and design them and oversee the production process. 


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