LEDs, or Light Emitting Diodes, are the greatest technical shift since the light bulb and they have revolutionised the illumination industry over the latest 10 years. This shift and its development has taken place at a more rapid and broader pace than anyone could foresee or even dream of - today we know that the light source of the future is LED. LEDs already produce more light/watt than the best fluorescent tubes and metal-halide lamps.
The advantages of LED are great and abundant, while the disadvantages are few. The argument of a 90% saving on energy and more than 50 times the lifetime speaks for itself. Today there are LEDs with a luminous efficacy and colour rendering so good it is possible and economical to replace most other types of light sources and luminaires with LEDs, from the smallest light source in a home environment to all the most common office and street lighting.
We are approaching a total changeover to LED solutions. The industry forecasts that LED luminaires will stand for more then 95% of the market in Europe by the year 2020.
Technology has enabled endless possibilities but also some difficulties because, as always with new technology, there are many pitfalls. Pleasingly, today there is a standard that defines how facts for LEDs and LED luminaires are to be reported. We always provide all luminaire data such as lifetime, lumens and power consumption for a complete luminaire in normal usage conditions, precisely as the standard prescribes. Make sure you ask others if they do the same so you don’t compare apples and pears!
The information given on the following pages is an attempt to describe how LED technology works and explain some of the technical terms used in the industry. This information is based on the knowledge and practical experiences of LEDs that Hide-a-lite has gathered over 10 years. It has been written for LEDs in general and for our product range specifically. In addition to the luminaire standard, facts have been gathered from Värt att veta om LED, LED för belysning inom- och utomhus and LJUSA mallen, published by Belysningsbranschen & Ljuskultur. We can also recommend these to gain in-depth knowledge in the subject.
All the information in this publication should be regarded as general and used as a guide. For more precise information, we refer you to the product description of each product at www.hidealite.com.
The lifetime of an LED and its luminous efficacy is mainly impacted by heat. Factors that affect heat in an LED are amperage, heat conduction and ambient temperature. Since an LED does not generate heat in the form of IR radiation and only some of the energy becomes light, the heat that is generated must be diverted to surrounding parts of the luminaire, which are then cooled down. An increase in heat impacts on LED performance both long and short term. In the short term with a change in colour and reduced luminous efficacy. In the long term with a faster gradual degradation and therefore shorter lifetime.
The affected lifetime is impacted by factors such as:
• Type of LED and quality (manufacture)
• With which amperage it is driven
• Environment and ambient temperature when product was installed
• Driver quality
• Luminaire design and choice of materials
According to international standards, the life expectancy of an LED luminaire is given with two values, the life expectancy of the LED module and the life expectancy of the driver. Both values are required to obtain a comparable conception of life expectancy.
The life expectancy of LED modules is given as the number of hours (h) when at least a given percentage of the lumen output remains (maintenance factor) in an L value (LX). LEDs for illumination purposes must have at least 70% of their lumen output remaining (L70). Higher values such as (L80) and (L90) can also be specified.
As a complement, a B-value (outage percentage) is given that specifies what part of a population is the maximum to be expected to fall below this value (By). B10 means 10% will fall below (LX) and B50 that half, 50%, will. B50 is described in the standard as Median Useful Life.
Lighting Europe recommends the B-value no longer being used for gradual degradation in order to facilitate comparison between different LED luminaires as an analysis has shown that the difference between a base value of B50 and B10 is so small and that the accuracy is still sufficiently high.
L70 50,000h means that 50% (B50) will light with at least 70% of the lumen output it had at manufacture after 50,000 hours.
L80 50,000h means that 50% (B50) will light with at least 80% of the lumen output it had at manufacture after 50,000 hours.
Since gradual degradation is negatively affected very rapidly as the heat surrounding the LED increases, measurement is complemented with ambient temperature (Ta) and should agree with that which applies at normal operating conditions. If no value is given, the data at normal room temperature of 25°C applies.
L70 50,000h Ta 25°C means at least 50% will light with at least 70% of the original lumen output at an ambient temperature of 25°C after 50,000 hours.
We always specify the luminous flux and life expectancy measured on the luminaire under actual operating conditions and current room temperature
Driver degradation is included in the standardised report of the LED luminaires’ life expectancy. The driver life expectancy is reported separately for complete LED luminaires and is given in hours with a degradation in per cent. 50,000h/10% means that a maximum 10% of drivers will stop working during the specified lifetime (0.2% per 1000h). Driver life expectancy is dependant on its design, quality of components and ambient temperature when in use.
Recommendations are based on ”Evaluating performance of LED based luminaires” published by Lightning Europe, supported by international product standards IEC 62722-2-1 – LED luminaires for general lighting and IEC 62717 – LED modules for general lighting.
Built-in current reduction driven with e.g. 10V, 12V or 24V, such as LED strips, light chains and LEDs for decorative purposes. Parallel connection is done here and dimensioning is controlled by the total power output.
Without built-in current reduction driven with e.g. 350mA and 700mA, such as LED downlights with the highest lumen output for illumination. Series connection applies here and dimensioning is controlled by the total secondary voltage/output.
Electronic DC voltage converter, e.g. 10V, 12V or 24V.
Electronic constant current converter, e.g. 350mA and 700mA. Both types of driver are today available both as non-dimmable and dimmable using most light regulation techniques.
Today, there are a number of LED products on the market with integrated drivers for direct connection to 230V, for example replacement light sources with GU10 or E27 base. These cannot always be controlled but today, there are many products on the market that can be controlled with standard dimmers.
The high energy efficiency and long useful life means the total impact on the environment is small, since energy consumption is low and fewer light sources need to be replaced and go to recycling. Neither are insects active at night disturbed by LED light.
The useful life of an LED is affected mostly by heat (ambient temperature). Make sure cooling and ventilation is as good as possible and always follow the manufacturer’s minimum recommendations. Always use drivers of good quality intended for use with LED modules.
Take care to ensure correct polarity when installing. If connected with the incorrect polarity, LEDs will not light up and may be permanently damaged, often after only a few seconds.
Our products have a narrower sorting than standard in the industry in order to guarantee as small a deviation as possible. Despite this, there is still a risk of deviations that can be seen with the naked eye. It is therefore important to test the lighting installation when there are high demands on uniformity.
Always check how the manufacturer has specified useful life, if it is related to degradation and in normal operating conditions, so that you are comparing apples with apples. There are still many suppliers who incorrectly specify LED life expectancy as 100,000 hours or more without relating to the standard’s maximum degradation requirement.
All information in this document should only be regarded as general and serving as a guideline. Precise information on each product is available on a product sheet and the installation instructions on our website, www.hidealite.se.