LEDs have been used to illuminate the 108 year old Victoria Falls bridge between Zambia and Zimbabwe. Solid State Lighting International (SSLI) in partnership with Philips Lighting Solutions devised this lighting display.
A portion of the Zimbabwe bridge was previously lit with 800 W high pressure sodium lamps, but these not only have a short life span, their electricity consumption is also very high. In comparison, an LED solution consumes 60% less energy. Each light uses 290 watts of power at full output, steady state, yet they are able to throw the light over 200 metres.
Installation began in mid-2013. A lighting retrofit of this magnitude would usually take three to four months from sourcing of specialist lighting products to the final handover and switch on as most of the items need to be sourced and shipped from around the world.
With a 100,000 hour life span, the lights will illuminate the bridge for 15 years plus if burned for eight hours a day. After this, they will still produce 50% of their light output. As it is a working bridge, it is subject to strong vibrations from large trucks as well as trains. It was therefore not feasible for the floodlights to be attached to the bridge structure itself as the constant vibrations would quickly reduce the LED’s life and premature failure.
This was also not your typical architectural illumination project as it involved working in unusual, uneven terrain. The SSLI installation team creatively used security fencing on which to attach the LED floodlights, supporting accessories and cabling.
“Each weighing 34 kg, the project required 12 LED floodlights – also referred to as solid state lighting technology. The local bungee jump team helped to safely lower these heavy lights down the ravine and into position,” Ross Blakeway director of Solid State Lighting International, says.
The 12 floodlights are positioned at the feet and sides on either end of the bridge, six in Zambia and six in Zimbabwe. A controller and a wireless emitter are positioned on the Zimbabwe side and all information is communicated digitally across the gorge to a WiFi receiver that communicates with the floodlights on that side, thus eliminating the need to run expensive and heavy cabling across the bridge span. The line voltage and control data is merged so that each spotlight can be communicated with on a standard cable which also simplified installation and lowered the total system cost.
These high performance LED lights are also able to produce an extensive array of saturated colours which are significantly more cost effective than traditional light sources for installation, operation and maintenance.