Electrical Contracting News (ECN) October 2016 - Page 52

SPECIAL FEATURE Lighting must be designed to assist occupants in whatever task they are undertaking. They only account for around half of light sales at present but that figure is growing quickly. While their energy efficiency is competitive, they don’t always outperform the most efficient conventional light sources so careful analysis is needed. Again, the context and setting of the lights in a particular environment must be considered. One distinct advantage of good quality LED luminaires is their longevity, which limits the time and expense associated with regular lamp replacement. However, LIGHTING some of the less reputable manufacturers of LED luminaires may have overstated the lifespan of their products – a problem that may not become apparent to customers for some time yet. Important considerations with regard to the specification of LED technology include luminaire design. The LED must be allied with a suitable luminaire that incorporates appropriate thermal management, properly designed optics and a high quality driver. These will help maximise the lumen output of the LED. The lifespan of an LED is also a vital consideration. The ‘practical life’ is defined as the period between the LED first being activated and the point at which its output falls below 70 per cent of its initial output. This is traditionally symbolised by the letter ‘L’ so, to give an example, a quoted specification might be: ‘L70, 50,000 hours’. However, for greater clarity, a further metric was added to the equation, with the letter ‘B’ denoting the percentage of the sample batch no longer producing 70 per cent or more of the initial output. Therefore the lifespan might be quoted as ‘L70B10 50,000 hours’, which means 90 per cent of the batch is still performing at a minimum of 70 per cent of the lumen value after 50,000 hours. By looking at the lumen performance of the LED luminaire and not just its wattage, the specifier will be able to compare the true performance of the LED luminaire against a conventional lamped luminaire. This will identify the benefits in reduced energy consumption for a real application while retaining the correct illumination level and quality. daylight coming from windows or rooflights for the purposes of consistent light quality and cost effectiveness. 6. What is the application? 8. Who makes the decision? It is vital to carefully consider the application to determine whether an LED is in fact the most appropriate solution for a particular situation. Applications where an LED does not offer the optimum solution include situations where capital cost is the key driver, the project is intended to have short operating hours or the temperature of the environment is especially hot as can be the case in certain industrial areas. In contrast, there are situations where LED lighting is the obvious solution. These could include cold applications, environments where the cost of maintenance and replacement of lamps is difficult or expensive, or where the operating hours are such that the energy savings are warranted. A good supplier will act as a partner in the decision-making process, ensuring that reliable information and guidance is available throughout and that all stakeholders, whether finance directors or facilities managers, are engaged. All of these groups will have a useful perspective on how the end result should be configured. One of the key questions to address is the likely return on investment. Any forecast of energy and maintenance savings should be balanced against the initial capital outlay, which enables a defined period of payback to be estimated, whether it is six months or three years. A good supplier will provide this detail upfront to ensure that nobody is left in the dark. 7. Which technology? In summary Other recent technologies, including control and automation systems, can play a considerable role in energy efficiency. For example, lighting can be automatically deactivated in a particular area when it is not occupied, which reduces reliance on manually switching off lights. Another increasingly common technique is daylight balancing, whereby light levels are automatically adjusted in line with natural A properly planned lighting scheme can reduce long term energy costs and even raise productivity through its efficacy, efficiency and suitability for the space in question. For this reason it is worth taking time to understand both the requirements of the building and the range of options available so that the most suitable solution can be found. In pursuit of this goal, professional advice is extremely valuable. Metway Addressable Lighting Control System The simple, flexible and cost effective solution for your lighting installation • • • • • • • DSI / DALI Fully addressable Fully configurable Programmable via Bluetooth Can be controlled by optional head end PC Can be integrated into an AV system Side latching G type connectors Visit us on Stand M7, Esher Hall, Sandown Park 3rd & 4th November 2016 Contact us for more information: sales@metway.co.uk | 01273 431600 | metway.co.uk 50-52 Lighting – Eaton.indd 52 Highly Versatile Range of Waterproof Call Points & Push Buttons Specially designed for use within harsh environments, the Waterproof range of Call Points and Push Buttons is ideal for indoor and outdoor applications such as oil rigs, ships, factories, wash down and pool side areas. For further information, contact Sales on info@sti-europe.com • 01527 520999 • www.sti-europe.com MANAGEMENT SYSTEMS Assessed to ISO 9001 LPCB ref. no. 653 EN54-11 Cert no. 653a/01 ReSet Series 01 13/09/2016 10:55