Thorn Provides an Eye-catching Stream of Light Across the Firth of Forth – Lighting the New Queensferry Crossing

Queensferry CrossingThorn Lighting has supplied luminaires for the illumination of the Queensferry Crossing.

Thorn Lighting has worked with national M&E specialist SES Engineering Services (SES), on the new £1.35 billion bridge spanning the Firth of Forth which has been designed to relieve pressure on the Forth Road Bridge. Thorn’s Aquaforce, Altis, Deckedge and Orus LED luminaires are being used to great effect to illuminate the imposing structure and provide an eye-catching stream of light across the Forth.

The 2.7km long, iconic Queensferry Crossing is positioned upstream from the iconic Forth railway bridge and is the longest three-tower, cable-stayed bridge in the world and will serve around 24 million vehicles each year. There are three towers more than 200m high – the north and south towers are 202m and the central tower is 210m – and 23,000 miles of cabling, almost enough to wrap around the circumference of the earth, suspends the bridge from three towers. These cables provide extra strength and stiffness to the structure, yet the towers remain narrow and elegant.

Thorn’s lighting scheme for the Queensferry Crossing was specifically developed to enhance the aesthetics of the bridge and ensure an energy efficient lighting scheme was in place. The lighting technologies and luminaires were carefully chosen for each specific condition using lenses and focusing to reduce spill and glare.

Thorn’s 1kw and 2kw Altis metal halide floodlights were chosen to illuminate the three towers and ensure the distinctive shape of the bridge is highlighted at night. Altis is a high performance HID floodlight that incorporates an innovative, patented optic that offers a unique range of photometry that is perfect for the levels of vertical illuminance required for the towers. The excellent thermal management and high IP65 protection ensures consistency and stability of light over the lifetime of the fitting.

The bridge includes a specially designed 3m acrylic windshield across its entire length to reduce wind and to keep the bridge open in the event of strong gusts. For aesthetic reasons, it has 2,610 custom made ‘Deckedge’ LED linear fittings installed, to provide a continuous strip of light across the Forth. Within the decks 2,026 luminaires provide lighting for those servicing electrical equipment and the dehumidification plant. For this, IP65 rated Aquaforce LED luminaires have been installed underneath the bridge in maintenance areas to provide high quality, low energy lighting in the wet and dusty environment below the bridge. The 2,026 luminaires will provide lighting for those servicing electrical equipment and the dehumidification plant.

The 2.7km bridge is considered part of the adjoining motorway and, in terms of illumination, is defined as ‘rural’, so there is no need for overhead street lighting however, there is still a requirement for good quality illumination. For this, Orus LED, an innovative bollard mounted low level road lighting lantern that incorporates Flat Beam® technology has been installed. A total of 386 bollards, mounted 1m above the road surface along part of the bridge carriageways, provide illumination for drivers. The bollards will be utilising Transport Scotland’s CMS system to allow remote dimming and monitoring. The IP66 Orus fitting is UV-stabilised polycarbonate that protects against graffiti and also has an extra scratch-resistant treatment.

Thorn’s R2L2 LED road lantern was chosen for the approach roads, both north and south, due to its excellent lighting performance. The comprehensive range is available in three sizes with extensive optical, lumen and light distribution choices for all road applications up to ME1. For precise light placement with no waste light, R2L2's efficient (up to luminaire 100lm/W) R-PEC optic provides 11 types of light distribution. R2L2 maximises energy savings with a wide range of intelligent lighting control solutions also utilising Transport Scotland’s CMS system to allow remote dimming and monitoring.

The installed lighting will allow for dimming and remote control for future energy reduction. This supports the Scottish Government’s objectives to reduce carbon emissions, pollution of the night sky and to reduce impact on the rural landscape where this can be achieved safely and effectively. 1,000 sensors have been fitted to decrease and increase light output in line with operational requirements, allowing maintenance teams to pre-empt potential issues. The bridge has a design life of 120 years but could last longer, with the cable-stayed structure chosen because of its easier maintenance.

Paul Coggins, Zumtobel Group’s Senior Vice President Northern Europe commented: “We are proud to have played a part in this enormous project – it’s just a stunning bridge to look at and an amazing feat of modern engineering. The Queensferry Crossing is an awesome achievement and everyone involved should be congratulated on the successful completion of this truly iconic structure”.

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