Saving energy and maintenance costs on lighting need not be a matter of putting up with twilight-like conditions and missing bulbs. Using new types of luminaires and control systems is only part of the task since luminaires, both older and new types, still have to be installed and controlled correctly to ensure safe conditions for tunnel users.

Siteco Beleuchtundtechnik, an Osram business involved in tunnel lighting design and installation, has been involved with the first tunnel installations of LED luminaires in Germany and elsewhere in central Europe, but also supplies earlier types of luminaires as required by both the tunnel conditions and operators.

Austria sodium
On the A7 Muhlkreis motorway in the Linz/Bindermichl region of Austria, an artificial tunnel has been constructed by lowering the carriageways to minimize noise pollution on the neighbouring areas.The A7 carries high levels of traffic to and from the A1 West motorway. Siteco developed the lighting concept for the new tunnel and associated roads in what it describes as the most complex road construction project in Austria to date.

The project includes a three-lane motorway with a hard shoulder in dual tunnel tubes in two lengths of 1,062m in Bindermichl and 580m in Niedemhart, as well as modernising the feeder highways. The new lighting installation consists of 1,543 Siteco NIRO tunnel luminaires with stainless-steel (NIRO) structure and highpressure sodium elements, and 125 Siteco emergency guidance luminaires for rapid evacuation, also in stainless steel.

In the Bindermichl tunnel the luminaires are mounted in parallel trunking systems.The corrosion-resistance of the stainless steel case is enhanced with safety glass and an additional protective coating. The luminaires have an IP66 protection rating against foreign matter and impact.

The tunnel approaches are equipped with different Siteco luminaires including 126 NIRO custom luminaires within a dynamic traffic control system and recessed within lateral concrete surfaces and bordering the cycle and pedestrian route around roundabouts. The consultant for the project was Austrian Wagner & Partner Ziviltechniker.

One of Siteco’s projects driving the application of LED luminaires was the Porzberg Tunnel in Thuringia, Germany, opened in 2010. This employs 185 LED luminaires located in offset positions in the tunnel to achieve maximum homogeneity of lighting intensity.

First LEDs
Osram LED tunnel lighting has been used in Germany ever since the first installation in 2008 for the Thuringer Schmucketunnel on the A71 highway. Dellux Technologies of Canada selected Osram’s Golden Dragon LEDs for luminaires specially developed for tunnels. The LEDs are claimed to use 30 per cent less energy than the usual 70W high-intensity discharge lamps thanks to LED degradation compensation technology patented by Dellux. The working life of a minimum 130,000 hours (15 years), is said to be virtually maintenance-free.

Illumination in the tunnel can be varied as the semiconductor light sources can be dimmed and controlled according to the time of day and other ambient conditions. The required day luminance in the Thuringer Schmucketunnel is 4.65 candelas per square metre (cd/m2) but at night a value of 0.8cd/m2 is sufficient as determined by exterior available light. This requires a power consumption of 70W during the day but only 12W at night.

The intelligent lighting concept developed by Dellux and used in the Schmucketunnel employs customized electronic circuitry and software to increase the life of the system. "We have installed redundant LEDs in each luminaire to offset soiling and degradation losses." Said Wolfgang Medenwald, VP for business development in Europe for Dellux Technologies. "We also operate the LEDs at only 85 per cent of their rated current to achieve greater efficiency and durability. Our patented light degradation compensation technology allows us to maintain the required light levels for a minimum of 15 years despite the difficult conditions in the tunnel."

More recently Germany-based LI-EX used Osram LEDs in lighting for the new Stachus Passagen in Munich’s Karlsplatz to access the S-Bahn and U-Bahn station. Important aspects of the lighting design by the Schmidt-Konig planning office were lamp longevity, low service costs, space saving, high output, and meeting defined light-radiating characteristics. In such an installation with close public use, the architectural aesthetics of the installation were also important. The LI-EX profiles employed 65,000 LEDs of two different types. Facade and entrance lighting uses 15,000 cold-white Golden Dragon Plus LEDs for even illumination without scattered light or dazzle with low power consumption. The lighting provides natural colours for a higher level of safety. The 700m-long handrail of the entrance staircase (see photo, below right) uses 50,000 warm-white TOPLEDs in the LI-EX profiles that permit individual length adaptation to suite the different lengths of staircases. Some 18m of handrail illumination require only 100W of power.

LI-EX is part of the ‘LED-light for you’ network initiated by Osram to work jointly with customers on implementing lighting solutions using LEDs.

Hindhead and more
A new company, TRT Lighting, has inherited the list of highway tunnel application in the UK, Ireland and abroad, including many motorway tunnels, and the recently opened A3 Hindhead Tunnel as the longest land-based tunnel in the UK at 1.83km of twin bores. TRT is also continuing the long-standing co-operation with PDS (P. Ducker Systems) using the jointly developed Scanlight Tunnel lighting control system.

Scanlight was selected to control over 1,800 SON high-pressure sodium discharge lamps in the Hindhead Tunnel. The system works via a multi-channel controller area network (CAN bus) ‘backbone’ feeding the dual-layered Digital Addressable Lighting Interface (DALI) circuits for individual luminaire checking. The SON lamps used for boost, basic and night lighting are said to be the most efficient and most cost-effective lighting for a high-speed, long-length road tunnel. By virtue of the lighting layout and Scanlight control, either bore of the Hindhead Tunnel can be run in contraflow, allowing maintenance to be carried out in the alternate bore, whilst avoiding diversion of traffic through neighbouring communities without major roads.

Other major projects employing Thorlux lighting include the immersed-tube Limerick Tunnel for the N18 in Ireland, the Heathrow Airport Airside Tunnel, and refurbishment of the Bell Common Tunnel (M25) and Hatfield Tunnel (A1).

Shenzen Highway
US-based Cree has one of its strongest markets for its LED lighting sources in China. Last October China completed its largest highway lighting upgrade, on the Shenzhen highway, featuring more than a million Cree XMap XP-G and XP-E high efficiency white (HEW) LEDs. The project included Dameisha Tunnel within 75 miles (120km) of highway.

Kingsun Optoelectronic, a leading LED light company in China, selected the Cree LED lamp to comply with China’s highway lighting requirements for efficiency, brightness, luminance, heat dissipation and service life. The highway, including the tunnel, has three lanes and an emergency lane in each direction. Kingsun anticipates a 60 per cent reduction in energy consumption compared with the replaced, high-pressure sodium fixtures. According to the energy management contract (EMC) business model implemented by Kingsun, the energy savings to be achieved by the Shenzhen Highway Project have an estimated payback period of four years.

Lightpipe
BB Lighting Concepts of Sweden and the Netherlands has installed its low-energy LED-Lightpipe lighting product in many pedestrian and cycle access tunnels, but is now turning to its first traffic tunnel in Liege, Belgium, having won the work on the basis of low maintenance and long life. February 2011 was a busy time for BB Lighting Concepts. The work included the testing of new and existing installations in various pedestrian and cycle tunnels and underpasses in Sundsvall, Sweden, plus the Balder garage. The testing demonstrated excellent cold-weather performance (down to -20oC) of the companies LED Lightpipe product compared to fluorescent lighting fixtures, the output of which reduces in freezing temperatures. For example, a tunnel fitted with 500W fluorescent lights was replaced with Lightpipes of about 385W consumption. The light output was shown to be sufficient, allowing the light output to be dimmed using DALI controls. Energy savings of up to 84 per cent were achieved compared to original installations.

A similar renovation replacement was carried out in a car park in Harlingen in the Netherlands where the LED Lightpipe Stand-Alone was used, allowing the original wiring to be retained.

Italian LEDs
The first opportunity for AEC Illuminazione to demonstrate its competence in LEDs was presented by forward-thinking highway management operators for redevelopment.

AEC offered its TLED luminaire specifically developed for tunnel lighting interiors of which AEC has installed nearly 12,000 luminaires.

Most of these have been installed in major motorway tunnels such as the A1 between Florence and Bologna including the Le Croci di Calenzano tunnel in Tuscany, and the A12 between Tuscany and Genoa. TLEDs have also been installed in underpasses and urban tunnels.

Light perceptions
While there is widespread recognition of the importance of well designed tunnel lighting schemes in such functions as preventing glare, graduating illumination between the interior and exterior at different times of the day, and the changes brought about by emergency situations (including signage), in recent years there has been a lot of work on effects of different types of lighting on the facilities users, not least in tunnels and metro stations. The introduction of LEDs to public space lighting has tended to increase the alternatives available, not just for general decoration, but also to make the space safer and more comfortable for users, depending what they are doing e.g. driving, walking, waiting.

Examples of the imaginative use of LEDs are presented by the Malmo City Tunnel in Sweden, described on the Stylepark design web-site as making ‘a subterranean world of light through the symbiosis of light and space’. The new central railroad station, and two other stations at Triangeln and Hyllie, were designed to make it easy for travellers to find their bearings and to convey a sense of security.

The stations’ illumination employs Durlum LED products in designs developed by architects KHR Arkitekter, SWECO, and Metro Arkitekter. Within the underground section of Triangeln Station, light controls were designed to simulate natural daylight, since daylight could not be projected to that part of the station. Large LED panels illuminate the platform areas, plus indirect lighting covers the curved tunnel walls in white light. Brightness is adjusted according to the weather and time of day.

Indirect lighting is even more important at the Malmo C station where reflective ceilings made of textured aluminium are particularly important to cast indirect dazzle-free light across the tracks. At the

Hyllie station the emphasis is on natural indirect lighting using facetted mirrors to spread light with an even intensity.

Big Dig big bill
The costly consequences of incorrect lighting choice are being demonstrated by the Boston I-90/93 CA/T project, otherwise know as the ‘Big Dig’. In this case it is not even a matter of energy consumption and light output that is the main problem, but the often-overlooked consequences of corrosion. Corrosion can attack all tunnel fixtures, depending on the materials used, whether through groundwater leakage in old or inadequately waterproofed tunnels, or from chemicals within the tunnel such as salt/brine, antifreeze and chemical spillages. In the case of the Boston ‘Big Dig’ tunnels corrosion has attacked the lighting fixtures resulting in some failures and falls from the tunnel ceiling.

As the Massachusetts Department of Transport (Mass DOT) is promoting a lighting replacement programme costing around USD 54-55M, transportation secretary Richard Davey has said that the proposed LED lights with polymer fittings will not deteriorate long before their expected lifespan. The 25,000 existing fittings, fluorescent units with metal fixtures, were supposed to last 30 years following purchase ten years ago, Mass DOT officials say, but one fell to the traffic lane during February last year. Since then they have been held up with double plastics straps and inspected regularly. The proposed LED light sources themselves are expected to last 12 to 15 years compared to two years for a fluorescent fitting.

The weak point of the original luminaires, made by the now defunct US-based NuArt company, was quite detailed. A clamp needed to ensure watertightness actually cracked the protective powder coating on steel, allowing corrosion of the latter from salt spray.