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    LED lamps taking lighting to new limits – but not only option just yet

    Nathan Johnson

    With peaking electricity prices and a growing cultural shift towards sustainable building practices, building designers are increasingly specifying LEDs to illuminate their buildings because they are recognised as using less energy than all other alternatives.

    In recent years regulations have also supported LED uptake, for example the Building Code of Australia has become more stringent in limiting the amount of power that lighting can use in class 2-9 buildings on a square metre basis (Section J6.2 ‘Artificial lighting’). As energy requirements become increasingly stringent, LEDs are proving a great help in meeting them.  

    The changing geometries of architecture, thanks to advances in 3D modelling programs, has also necessitated an advance in lighting technology, and LEDs have come out in front in that race as well.

    LED lamps have become smaller, narrower and more flexible, they have improved in luminosity, efficacy and colour accuracy, and combined with their declining unit cost, have become, unsurprisingly, increasingly specified in Australia.

    However there are still a few applications where other lamp types will remain, at least at the moment, the preferred choice for building designers.  

    ^ 8 Chifley Square, Sydney by Rogers Stirk Harbour + Partners architects (above) employs integrated linear LED luminares from Lumino in the exposed soffits above the ground floor, level 18 reverse podium and the roof. Vibrant red and orange LED spotlights were also used on the building’s red sway bracing and exposed fire escape.

     

     

    < Woods Bagot architects called on a KLIK Systems LEDPOD light fitting system for the curving staircase handrails at The South Australian Health and Medical Research Institute (left). The system is an in-handrail linear LED light fitting system that is compact and easy to install. Image: Peter Barnes.


    SO WHERE NOT?

    HIGH-POWERED SPOTLIGHTS

    Although LEDs are used in high powered spotlight applications they often don’t perform as well as high wattage metal halides and their cost is considerably higher.

    Basically a LED light is made up of a number of micro-chips that contain positive and negative semiconductors which combine to produce a photon of light. Higher powered LED spotlights often use multiple LEDs which results in in a series of overlapping beams which is not ideal if you are after a nice even beam and general illumination.

    DIMMING
    Halogen lamps will continue to have a place in theatre applications where a completely dimmable light is needed because LEDs are difficult to dim smoothly down to one per cent.

    Some LEDs experience a “dropout,” where they only dim part of the way down to zero light output — say, to 60 per cent of maximum — instead of all the way from 100 per cent down to one per cent. Additionally, some LEDs won’t dim at all and others may dim in an abrupt or “staircase” fashion, instead of dimming smoothly and continuously.

    Some LED manufacturers can produce a perfect dimming but these can get very expensive and eat into the energy-cost savings they produce. 

    The travertine stone walls of 171 Collins Street Melbourne by Bates Smart architects are illuminated by a variety of light choices including metal halides from Meyer and ECRO for spotlighting and wall washing. Another key feature of 171 Collins Street’s ground floor is the glowing line at the base of the travertine stone wall. The wall is vertically illuminated by TiMi LED Strips from KKDC lighting manufacturers. Image: Peter Clarke.

    QUALITY ISSUES

    Although LEDs are more energy efficient than halogen lighting, the two are not always a comparable one-for-one replacement.

    LEDs are often sold and marketed on their wattage rather than their lumen output and although some packaging will say ‘replace your 50 Watt halogen with a 5 Watt LED’ the problem is that the LED won’t necessarily have the same light output as the halogen and therefore you may need to use more light fittings and often change the transformers.

    Performance claims about LEDs aren’t always correct either and the 50,000 - 100,000 hour average marketed life expectancy from some manufacturers is based on an algorithm rather than physical testing.

    This lack of physical testing and the reliance on an algorithm is more common among cheaper, younger and smaller manufacturers and some reputable brands have performed physical testing on their products.

    In order to address some of these quality issues associated with LEDs in the Australian marketplace, the Lighting Council Australia developed a voluntary quality certification scheme for the technology. The Solid State Lighting (SSL) Quality Scheme provides confidence to the market that a luminaire carrying the scheme's label matches the supplier's performance claims. SSL Labels include details such as light output, efficiency, power required, light colour and colour accuracy.

     

     

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