General FAQ

An LED light is a solid-state lamp that uses light-emitting diodes (LEDs) as the source of light. It is a small electronic device (a semiconductor diode) that emits light when electricity passes through it. It is one of the most efficient and prosperous light sources available on the world market. According to the latest research and further development advances of the LED industry, LED light technologies will be the leading lighting force in the future.

LEDs are dramatically increasing light output, efficiency, reliability and are becoming increasingly more brighter. The lumen output of LEDs has almost doubled in the last two years. At the end of 2009 the LED technology was mature enough to enter the high demanding market of outdoor illumination and to successfully compete with existing street lighting technologies.

LED technology has been used for several decades in various applications. White LED lamps have achieved market dominance in applications where high efficiency is important at low power levels. Some of these applications include flashlights, solar-powered garden or walkway lights, and bicycle lights. Monochromatic (colored) LED lamps are now commercially used for traffic signal lamps, where the ability to emit bright monochromatic light is a desired feature, and in strings of holiday lights. LEDs are widely used in automotive industry, military and yachting lighting. Its use in domestic electronic appliances and high tech devices is rising. LED lights have also become very popular in gardening and agriculture by 2010. First used by NASA to grow plants in space, LEDs came into use for home and commercial applications for indoor horticulture (aka grow lights).
The incredible rapid progress of LED technology in the last few years enabled LEDs to become appropriate for use in general and outdoor lighting applications. Latest LED technologies used in LED luminaires are not only satisfying the needs of quality outdoor and general illumination but are already exceeding all other technologies in all parameters.

Yes, LED street lights can efficiently replace and outperform HID lamps with numerous advantages (long lifetime, directional light distribution, high light unformity, no maintenance, durability, high color rendering index, etc.). All this without emissions that would be harmful to the environment.

While choosing the right LED solution, you have to be aware, that LED technology has progressed rapidly in the past few years, that not all LED luminaires are created equal and that some manufacturers are offering extremely low cost options, which are inferior and of poor quality. To be really sure that technical claims of the manufacturer are true, you have to inspect and test the product carefully. Only the technical characteristic of an LED cannot define the performance of an LED luminaire, since the system is composed from many critical components (like optics, thermal management, driver etc.) which are the key to optimized overall performance and efficiency.
You can recognize some low quality LED solutions by some common characteristics:

• unpleasant pale blue shine of light (color temperature 5.500 K and more)
• open casings and visible cooling ribs that indicate weakly solved problem of light heating (accumulating dirt on cooling ribs mean more maintenance cost, while openings in casing cause malfunction of electronics and reduced life expectancy)
• low quality components (optics, LEDs, driver, etc.) assembled together in manufacture with lack of technical expertise and quality control can cause uneven distribution of light beam, poor light and energy efficiency, glare etc., etc.

Always be sure that the manufacturer technical claims are not misleading but are verified with valid, acceptable and verifiable certificates. Also be sure that the manufacture has a stolid, reliable background/history and can fulfill its warranty claims together with full customer support.

The cost of LED street luminaire is higher than that of other technologies, but when considering all the benefits and cost savings you will acquire with the right LED solution, there is no other serious alternative. Due to high energy efficieny your electricity bills will be drastically reduced, you will have no maintenance cost, you will lower your carbon emission and most important you will enjoy these benefits for decades, while return on investment will be realized in less than 2 years in most cases. With a solid financial plan your cash outlay will be minimal and with the realized savings may not cost anything at all compared to what you are utilizing at the present time.

The biggest disadvantage of LED technology is lack of education and knowledge about the technology itself and lots of poor quality solutions available on the market. There is a lot of misleading information on the market, coming from two main sources:

• manufacturers with low quality solutions, which are misleading the consumer withfalse technical characteristics and claims
• competitors which sell inefficient lighting technologies, which will soon be banned, so they can deplete existing inventories.

There are also a number of companies who claim to be original manufacturers but instead buy inferior quality LED luminaires from countries which mass produce the product, put their own brand on products, change origin and then sell to unsuspecting customers for a higher price.

Some street lighting tests were made while using old immature LED technology before the year 2009 when LED technology was mature enough to seriously compete with other street lighting technologies. Results of these studies are not showing the real condition of LED street light technology today.

The result of all this confusion and organized chaos, is that the crrent market is experiencing unjustified doubt about the LED technology that is currently on the market. Who do you believe ? For the customer this is an extremely valid question. The weakness is not in technology but in cheap quality products and lack of knowledge.
Customers should always be careful and choose only verified high quality LED street light solutions from reputable manufacturers with solid backgrounds and proven history. While checking street lighting tests and reviews, you should always check which product was reviewed and from which year the product is available to avoid possible wrong conclusions.

EDs do not burn out like incadescent light bulbs. Instead LEDs over their lifetime  simply get progressively dimmer until they do not emit enough light to be useful. LED is considered to be no longer useful when it is emitting only 70% of the amount of light that it originally emitted. The time when 30% of lumen depreciation occurs is considered to be the “lifetime” of an LED.

High quality LED luminaires can go up to 100.000 hours under good working conditions. The officialy acknowledged standard for life time of high quality LED luminaires worldwide is 50.000 hours. They are still working after that time and can go up to 100.000 hours but with lower lumen output. 100.000 working hours means a lifetime between 11 and 34 years depending on how long a LED luminaire is working every day.

No. LEDs do not have the long warm-up times, which many people find annoying about CFLs (compact fluorescent lamps). Instead, the light from LEDs shines at full brilliance as soon as the switch is turned on. Also cold temperatures do not affect the performance of LED luminaire.

Unlike other light bulbs that use fragile filaments (especially incandescent light bulbs) LEDs are vibration and shock resistant. While vibration or shock easily breaks the fragile filament in an incandescent bulb and the glass tubing of a fluorescent lamp, LEDs tolerate vibration exceptionally well because they do not use filaments. Energized components of the LED are well separated from the outer surface with high quality insulation. The electrodes are embedded in the bulb matrix and the driver electronics are encased in its shell. A layer of interface material between the LED and the heat sink ensures that no current can leak to the heat sink. This make LED luminaire a completely solid-state technology which are virtually indestructible under normal circumstances.

Color Rendering Index or CRI is the calculated rendered color of an object. The higher the CRI (based upon a 0-100 scale), the more natural the colors appear. Natural outdoor light has a CRI of 100. White LEDs offer the industry’s highest CRI (80-90), making objects to be illuminated appear more natural and vibrant, which increases overall safety.

The forward current is proportional to the light output of an LED over a large operating range, so dimming can be achieved with reductions in the forward current. Because LEDs can be rapidly switched on and off with no harmfull effects, dimming can be accomplished using a method called pulse width modulation. By adjusting the relative duration of the pulse and the time between pulses, the apparent intensity of the LED can be dimmed. This is done with direct digital control, which enables frequency high enough that LED appears to be continuosly lighted without flickering.

It has been observed that when some fluorescent lighting systems are frequently dimmed, they might exhibit reliability and lamp life. This is not the case for LEDs. Life and light output degradation are determined largely by the junction temperature, with higher temperatures resulting in reduced life characteristics. Since dimming, either by reducing current or by pulse width modulation, results in lower overall junction temperatures, it will have no negative impact on LED life, it might even extend life.

IK – protection against mechanical impacts

The European standard EN 62262 ( the equivalent of international standard IEC 62262:2002) relates to IK ratings. This is an international numeric classification for the degrees of protection provided by enclosures for electrical equipment against external mechanical impacts. It provides a means of specifying the capacity of an enclosure to protect its contents from external impacts.

EN 62262 specifies the way enclosures should be mounted when tests are carried out, the atmospheric conditions that should prevail, the number of impacts (5) and their (even) distribution, and the size, style, material, dimensions etc. of the various types of hammer designed to produce the energy levels required.

IP – Ingress Protection Rating

The IP Code (or International Protection Rating, also interpreted as Ingress Protection Rating) consists of the letters IP followed by two digits and an optional letter. As defined in international standard IEC 60529, it classifies the degrees of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in electrical enclosures The digits (characteristic numerals) indicate conformity with the conditions summarized in the tables below. Where there is no protection rating with regard to one of the criteria, the digit is replaced with the letter X.

IP First number – Protection against solid objects

IP Second number – Protection against liquids

No, LEDs contain no harmful substances. Mercury is not used in LEDs, frelieving you from the environmental hazards which are present with disposing of burnt-out fluorescent, metal halide, and high pressure sodium light bulbs.

White LEDs do not emit infrared radiation (no beam heat) so, the beam of light produced by a white LED does not contain any heat. This makes LEDs ideal for shallow ceiling downlighting and display lighting.

White LEDs do not produce any ultraviolet (UV) light even though all other natural and artificial light sources do. This has many benefits:

• Limited Fabric Fading

  When using white LED light fixtures, there will be minimal fading and deterioration of fabrics, documents, or artwork due to exposure to the white light from LEDs.

• Better for Fruits & Vegetables

  Unlike light sources like metal halide, LEDs do not radiate high levels of UV rays. While it is common knowledge that heat can speed up food’s spoilage rate, it is lesser known that high UV levels can actually decrease the nutrient levels in food. Thus, using LEDs to light the produce in a super market, for example, may not only be energy efficient, it may also help the produce to maintain higher nutrient levels.

• Do Not Attract Bugs

  Since white LEDs do not emit ultraviolet light (the invisible portion of the spectrum just beyond visible violet) light fixtures using white LEDs do not attract bugs.

You can buy products from our distributors. To find out about your nearest distributor, please get in touch.

Both families Aerolite LSL and Aerolite ECO are 100% sealed, have the same design and material of the housing and use the same electronic as well as Samsung LED chips.

Aerolite LSL is using combination of lenses and reflector and has three different optic patterns: ME comfort, FN comfort and PX-L or PX-R comfort. Compared to Aerolite ECO, the Aerolite LSL with integrated Quadrom optics^TM and Matrix 3D light^TM has higher efficacy and lower glare ratings.

In comparison to Aerolite LSL, the Aerolite ECO is using only lenses, which gives us multiple optic patterns to satisfy even more different demands. Aerolite ECO has more than 10 optic patterns and its cover is thinner than the cover of Aerolite LSL.

DALI-2: The new DALI standard

The DALI protocol was first drafted in the late 1990s and has undergone a number of revisions as it has evolved. The result is version 2 of the DALI standard IEC 62386, which is known as DALI-2.

DALI-2 helps fill the gaps in the original standard, resulting in significant improvements in interoperability. DALI-2 adds new features, and introduces standardisation of control devices including the recent addition of input devices, while maintaining backwards compatibility.

DALI-2 and interoperability

DALI-2 certification vs. DALI version-1 registration

DALI-2 for control devices

DALI-2 includes control devices for the first time >> More on control devices

Control devices were not included in version 1 of the DALI standard, meaning it is not possible for control devices to carry the DALI version-1 logo. Only certified products can carry the DALI-2 logo.

Benefits of DALI-2 for control devices:

• Application controllers and Input devices defined
• Single-masters and multi-masters allowed
• Event priorities defined
• Separate addressing & grouping from control gear

DALI-2 for control gear and bus power supplies

Mixed systems of DALI and DALI-2

The following guidance applies to systems that may contain a mixture of DALI-2 and DALI version-1 products:

First, look for the DALI or DALI 2 trademarks on products:

• Control devices before DALI-2 are proprietary, and are not allowed to use the DALI version-1 trademarks.
• There were no tests for bus power supplies before DALI-2, so these are not allowed to use the DALI version-1 trademarks.

The table below gives some examples of different situations:

UGR (Unified Glare Rating) is way to calculate glare from luminaires, how light penetrates through windows and exiting different light sources.

The UGR classification helps to determine how a luminaire can cause discomfort on a working place. Mostly it is used for to determinate glare on working desks for workers who work behind a computer.

Glare is a more and more a problem on workplaces. Inappropriate luminaires, planning and positioning cause uncomfortable brightness, when light bounces off reflective surfaces, such as computer screens, shining and reflective objects as whiteboards, etc. This can cause discomfort for the workers on the workplace, in terms of headaches, eye trouble, which can then lead to employee illnesses and later on absences from work.

UGR is calculated by using an equation which takes into account a number of factors that may contribute to glare caused by a luminaire, such as the angle of the luminaire, the likelihood of glare and the luminance value (lumen output).

There are two ways to reduce glare on working areas:

Example office lighting:

• use luminaires with rated UGR lower than 19 (UGR<19) at the desk level;
• ensure that the lighting calculation and later on its installation is appropriate for the area they are being used. This means correct number and positon of luminaires.

Wrong positioning and choosing wrong products may cause discomfort.

There are a number of different UGR recommendations that should not be taking in consideration for different working areas:

GRAH Lighting offers free expert lighting calculations to ensure correct type and number of luminaires are being used for specific working areas. Our focus is to educate and to share the knowledge to ensure, that you choose a proper product for your working field.

In many cases, a table should be a quick help to see, what the UGR would be by installing a specific product. Unfortunately, this data is not always accrued. We by GRAH Lighting are focused to support our partners and customers with correct lighting calculations and results based on trustful Dialux and Relux software. UGR tables should be only guidelines but should be confirmed also by a lighting calculation.It is also important to know that there are differences in UGR values based on a working task area.

There are two group of standards that have to be taken in consideration when making a lighting calculation. This are EN 12464 and EN 13201. As also they are divided into different groups.

Indoor lighting:

• EN 12464-1 Light and lighting – Lighting of work places – Part 1: Indoor work places

Outdoor lighting:

• EN 12464-2 Light and lighting – Lighting of work places – Part 2: Outdoor work places
• EN 13201-1 Road lighting – Part 1: Guidelines on selection of lighting classes
• EN 13201-2 Road lighting – Part 2: Performance requirements
• EN 13201-3 Road lighting – Part 3: Calculation of performance
• EN 13201-4 Road lighting – Part 4: Methods of measuring lighting performance
• EN 13201-5 Road lighting – Part 5: Energy performance indicators

With the aging of the luminaire, the luminous flux is being reduced over its lifetime. This is a normal aging process, as no product is lasting forever. However, the required illuminance levels should not reduce at any time. Therefore, there are standards that help to us to choose the right maintenance factor for different working areas. The maintenance plan is part of the installation of the lighting systems. Most maintainers have a room cleaning schedule as also, how often the installation has to be checked, cleaned etc. Therefor a proper time has to be calculated between maintenance and operating hours. Less maintenance, means more luminaires “need to be installed” to guarantee the required illumination level in opposite, if maintenance cycles are more often/ regular, the higher can be maintenance factor calculated, but it is needed to take in consideration, that the maintenance costs will be higher.

With the aging of the luminaire and its system, the illumination level is decreasing. By calculation the maintenance factor we have to take different factors in consideration:

• Room Maintenance Factor (RMF)
• Luminaire Maintenance Factor (LMF)
• Lamp Lumen Maintenance Factor (LLMF)
• Lamp Survival Factor (LSF)

Solar luminaires are used for specific projects and several points must be taken into consideration:

• Location of installation;
• Wind activities on location;
• What is the required autonomy of the system;
• What will be the height of the pole;
• Where will the battery be installed (on the pole or in the ground);
• Luminaire consumption data;
• Regulation requirement;
• Motion sensor requirement

There are several reasons why we recommend putting the batteries and electronics into the ground. If the battery is in the ground, the temperature is constant and cooler than on the pole. Because cooler is the environment, longer is the lifetime of the battery. In case of higher consumptions needed, it is difficult or mostly impossible to install bigger or more batteries on the pole.  Also, if the battery is in the ground it is less exposed to vandalism. The negative part of ground installation is, that the cables must be longer, which causes more energy losses.

Everyone in LED lighting industry know the lifetime of LED light, but do you know how to indicate the end life and related lifetime? L and B can help you to know clearly.

L defines the percentage of lumen comparing with the initial lumens. B value means the failure data at the L data. So, LB value indicate the real lifetime at a certain hour.

Like L90 B10 at 50,000 hours means the LED lamp keeping 90% lumen from initial lumen and only 10% light failed to reach 90% lumen. You can get clearly L70 B50 means only 50% lamp survive at 70% lumen remaining at 50,000 hours. So L70 B50 light decay is faster than L90 B10.

1. Introduction

The present report highlights the main differences found between the standards:

• IESNA LM-79-08 (American norm) and
• EN 13032-4: 2015 (European norm)

on photometric and colorimetric measurements of LED luminaires and sources.

It must be said that the European standard, which was published 7 years later with respect to the corresponding American standard, has taken advantage of the experience gained in recent years and represents nowadays a significant step forward with respect to the American one.

1.1 Differences

The main differences between the two standards are reported below:

1.1.1 Photometry and colorimetry

A difference that is immediately evident is the different way in which Americans and Europeans refer to photometry and colorimetry. For Americans photometry consists of both photometry and colorimetry together (colorimetry is nothing more than an attribute of the photometry) whereas Europeans separate these 2 things cleanly, with photometry on one side and colorimetry on the other.

1.1.2 Measuring instruments

The largest and most obvious difference between the two standards is that:

• according to LM-79-08, measurements are to be made using Type C goniophotometers only, that is to say:
• Mirror goniophotometers: the standard doesn’t specify if it needs to be a luminaire rotating goniophotometer with the mirror revolving around the central axis mirror-photocell or a mirror rotating goniophotometer with the luminaire rotating around the vertical axis
• Sensor revolving goniophotometers
• EN 13032-4:2015 allows instead the use of any type of machine, including luminaire revolving goniophotometers. In this last case it is important that the operators indicate the conditions in which the measurement is to be carried out and that they verify that there are no variations (in light flux, for instance) during the same.

The diversity between the 2 standards is the result of a long series of photometric measurements carried out on several different types of machines (mirror goniophotometers, luminaire revolving goniophotometers, etc.) starting in 2009 – a related article is available on OxyTech’s website (http://www.oxytech.it/PDF/LEDin%20-%20Rilievi%20LED%20-%20Rv01%20070212%20-%20Ita.pdf):

Photometric measurement of LED luminaires (the article was published in LEDin magazine, February 2012).

1.1.3 Spectrometric/colorimetric parameters calculation

Another major difference regards the method used for the calculation of colour parameters (CCT, CRI, Delta(u’, v’) etc.) obtained from a goniophotometer measurement (a different method would be that of using a sphere, which is however not able to determine all the required parameters such as Delta (u’,v’)):

• standard LM-79-08 requires that measurements carried out on a Type C Goniophotometer in several C-Gamma points are then integrated by means of a weighted average whose weight is given by the intensities detected at each C-Gamma point of the measurement
• EN 13032-4 requires instead that the weight is estimated in radiance, that is to say, the actual energy involved on the basis of each wavelength and in each C-Gamma position. In this case, the evaluation is more precise

1.1.4 Measurement uncertainty calculation

EN 13032-4 includes the exact definition of the method to be used for the evaluation of the measurement uncertainty of the laboratory where the tests are carried out, whereas LM-79-08 simply refers to external standards (see regulatory and bibliographical references in sections 5 and 6 on page 14).

Poly(methyl methacrylate) (PMMA), also known as acrylic, acrylic glass, or plexiglass, as well as by the trade names Crylux, Plexiglas, Acrylite, Astariglas, Lucite, Perclax, and Perspex, is a transparent thermoplastic often used in sheet form as a lightweight or shatter-resistant alternative to glass. The same material can be used as a casting resin or in inks and coatings, among many other uses.

Acrylic weighs less than half that of glass.

Acrylic is many times stronger than glass and thus more resistant to strokes (10-20 times). When acrylic shatter, it is, in contrast to glass, in large pieces with relative blunt edges. At the same time contribute the low weight to make acrylic much safer.

Acrylic insulates better than glass and is used heavily in skylights and doors to coolers.

When compared to glass PMMA is 50% lighter, 90-92% clearer, more durable and more affordable. It can retain its properties over a long period of time even when exposed to UV rays and weather. In addition, PMMA is scratch resistant. Glass tends to be delicate as it scratches and breaks easily. When it does break, it shatters into many sharp shards. Not only is this inconvenient, but it also dangerous. Acrylic on the other hand is both scratch and shatter resistant. For the reasons stated above many opt for PMMA as a substitute for glass.