02 - Izvori Svjetla

2019

LUMIGEA

IZVORI SVJETLA (ENG) EDUKATIVNI MATERIJALI RANKO SKANSI

LUMIGEA LIGHT SOURCES LIGHT SOURCE TYPES The transformation of electrical energy into visible radiation (light generation) takes place in light sources. Basically, there are three different types of such energy transformation, namely light generation  by temperature increase (thermal radiator),  by gas discharge (discharge lamps) and  by electronic procedures in solid state bodies, electroluminescence (LED). Traditional light sources such as thermal radiators and discharge lamps were always provided in the form of lamps with sockets for replaceable operation. For the most part, this no longer applies to LED light sources. Especially nowadays, luminaires with permanently integrated LED light sources are used for many applications. In industrial nations, the quantity percentage of incandescent and halogen lamps was about 3/4 of all utilised lamps in the past, especially due to their wide distribution in residential lighting. Gas discharge lamps with a quantity percentage of about 1/4 were used predominantly for technical indoor and outdoor lighting in order to cover the great light requirements in this sector. Their main advantage is their luminous efficacy, which is 6 to 8 times that of general-use incandescent lamps.

Figure 2.98: Overview of the most common light sources Currently, both types are increasingly replaced by LED light sources. Regarding residential lighting, this happens mainly due to the incremental prohibition of incandescent lamps. Regarding technical lighting, the reason is also the increased energy efficiency, high light quality and long service life of LED products compared to discharge lamps. Altogether, LED lamps represent the most economic lighting solution for almost any application. In the following, different types of light sources and their typical applications will be explained. In addition to these light source types, there are specific light sources for medical, therapeutic and other purposes as well as for projector technology and photographic technology.

INCANDESCENT LAMPS Incandescent lamps (general-use lamps) were favoured in residential lighting. With 12 lm/W and an average service life of 1,000 hours, they were less appropriate for commercial and industrial installations.

LUMIGEA High-voltage halogen lamps for mains voltage operation and low-voltage halogen lamps with12 V or 24 V were traditionally used in sales spaces and representative installations. Their service life is at least double that of incandescent lamps and their luminous efficacy is 50% higher. Due to their instant luminous flux emission (no ignition time is needed as with discharge lamps), they were also applied for object surveillance, for example in combination with motion detectors. Mostly, they have been replaced by LED lamps or LED luminaires.

Figure 2.95: Luminous efficacy of several thermal radiators in comparison to heated tungsten W (benchmarks, curve shows maximum luminous efficacy of tungsten) 1. incandescent lamp 15 W, 90 lm, 6 lm/W 2. incandescent lamp 100 W, 1 360 lm, 13,6 lm/W 3. halogen lamp12 V, 20 W, 320 lm, 16 lm/W 4. halogen lamp12 V, 100 W, 2 200 lm, 22 lm/W 5. halogen projector lamp 24 V, 250 W, 10 000 lm, 40 lm/W

HIGH-PRESSURE DISCHARGE LAMPS LED luminaires and luminaires for discharge lamps – the usage however is decreasing – are predominantly used for technical lighting due to energy reasons. High-pressure discharge lamps are either high-pressure mercury vapour lamps, metal halide lamps or high-pressure sodium vapour lamps. High-pressure mercury vapour lamps have not been used indoors due to their low colour rendering quality (colour rendering index ≤ 70). Since April 2015, putting these lamps into circulation has been prohibited in Europe according to Commission Regulation (EC) no. 245/2009 [177] of 18 March 2009 (ecodesign directive – see also chapter 1.3.5.10 “Environmentally sound product design”). They have been almost completely replaced by the more efficient metal halide lamps.

LUMIGEA High-pressure sodium vapour lamps are characterised by their high luminous efficacy. Therefore, they were traditionally used for outdoor lighting and in high halls, for example in the steel industry where their suboptimal colour rendering can be tolerated. By using LED luminaires, the disadvantage of poor colour rendering can be avoided. In general, high-pressure lamps need an ignitor, which generates the high ignition voltage, in addition to the control gear unit. In some cases, it is also generated by the electronic control gear unit.

LOW-PRESSURE DISCHARGE LAMPS Fluorescent lamps are low-pressure mercury discharge lamps. They have been used for many decades due to their high luminous efficacy and service life and cover a high percentage of our light requirement (ca. 70%) in existing installations. Regarding newer-generation tri-phosphor fluorescent lamps, the drop in luminous flux is about 8% after 10,000 operating hours, and about 12% after 20,000 operating hours when using an electronic control gear unit ECG (see chapter “Discharge lamp luminaire operation”). Since the late 1990s, more efficient tri-phosphor fluorescent lamps with a diameter of 16 mm (T5 lamps) have also been used besides main-series 18 W, 36 W and 58 W fluorescent lamps with a diameter of 26 mm (T8 lamps) in many applications. Their advantages are higher luminous efficacy, a smaller drop in luminous flux during the operating period, their smaller diameter and ideal luminous flux at ambient temperatures between 35°C and 38°C as they usually occur in indoor luminaires. These lamps can only be operated with ECG. Fluorescent substances convert the UV radiation generated through low-pressure mercury vapour discharge into visible light. These substances consist of “rare-earth” group elements. The fluorescent lamps’ luminous flux is highly dependent on the ambient temperature (see figure). The maximum luminous flux of T5 lamps is achieved between 34°C to 38°C, meaning the temperature range inside luminaires. Due to international standards, however, the (lower) lamp luminous flux for 25°C is specified. Therefore, light output ratios turn out higher. Examples for differences in luminous flux are shown in table for T5 lamps with light colour 840. Compact fluorescent lamps are smaller-construction tri-phosphor fluorescent lamps. Lamps in lower wattage ranges from 5 W to e.g. 23 W with integrated electronic control gear unit and base E14 or compact fluorescent lamps with plug-in bases require a separate magnetic or electronic control gear unit which is integrated in the luminaire. Instead of tubular fluorescent lamps, more powerful compact fluorescent lamps, e.g. 18 W, 24 W, 36 W, 40 W and 55 W, are operated in compact round, square or rectangular luminaires which provide additional opportunities in terms of the lighting installation’s architectural design due to their design. Low-pressure sodium lamps lamps create a monochromatic yellow light colour at very high luminous efficacies (up to about 180 lm/W) at which colours are virtually no longer perceived. Therefore, it is not permitted to use them for indoor lighting according to EN 12464-1 [48]. They were used e.g. for illumination of locks, harbour installations, object protection and places where colour recognition is not important. Induction lamps are low-pressure mercury vapour lamps, similar to fluorescent lamps but without electrodes. The UV radiation generated through the discharge is also converted into visible radiation by fluorescent substances. Gas discharge is triggered by coupled-in high-frequency electric or magnetic fields. Due to high frequencies, special protective measures are required regarding electromagnetic compatibility (EMC) which are defined in international standards.

LUMIGEA LED (LIGHT-EMITTING DIODES)

(a) Schematic construction of an LED

(b) Materials for generating coloured LED light Figure 2.96: The LED

LUMIGEA Light generation in an LED (light-emitting diode) takes place in a very small range of the p-njunction of the crystalline, semi-conductive material where a part of the released energy is converted into light (electroluminescence) during recombination of positive and negative charge carriers. This generates monochromatic light of a specific colour (yellow, orange, red, green, blue) or wavelength. The generated light is narrow-bandwidth and material-specific (see table in figure 2.96 b). A reflector and lens with different visual properties (gathering, scattering etc.) improve light emission. White light is generated either by mixing red, yellow and blue LED (RGB) or by coating a blue LED with a fluorescent substance which partially converts the LED’s blue light into light of the green or red spectral range. RGB mixing is currently hardly used in general lighting applications. On one hand, neither colour rendering, expressed by the colour rendering index Ra, nor luminous efficacy of the white light generated by RGB mixing is satisfactory. On the other hand, its chromaticity coordinates change over time due to the different degradation of the individual colour LEDs (see chapter 1.2.10). However, RGB colour mixing has a broad use spectrum in decorative and well-being applications (see also chapter 3.3.1), signalling equipment (e.g. in motor vehicles, traffic light installations) and for guidance systems (in buildings or outdoor spaces). In contrast, the conversion of blue LED light through fluorescent coating is a procedure used wherever great amounts of high-quality white light are required. For example in for residential lighting, work place lighting and road lighting. High colour stability, good to excellent colour rendering properties as well as very high luminous efficacies are characteristics of this method. Regarding luminous efficacy, values exceeding 200 lm/W are measured in the laboratory. However, these lamp luminous flux figures cannot be used as technical data since the luminous efficacy is highly dependent on specific luminaire operating conditions. LED power supply as well as thermal management (see chapter 2.1.9.1) are important factors here which are closely related to the expected service life of the luminaire. Regarding residential lighting, so-called “retrofit” lamps with LED technology are widely used today. These are integrated systems consisting of LEDs and electronic components (see chapter 5.8.4) required for their operation (see chapter 2.1.9.4), often featuring E27 or E14 sockets for replacing the former general-use incandescent lamp. Retrofit lamps are rarely used in work place lighting. The reason is that luminaires in work places, in contrast to individual household luminaires, are generally operated in larger groups as lighting installations with long operating times. This leads to higher economic and safety-related requirements (see also chapter 5.6.1 “Luminaire labelling, type plate”) regarding:  energy efficiency of the luminaire,  service life of the lamp/luminaire  photometric characteristics of the lamp/luminaire for photometric planning,  electromagnetic compatibility  power factor (avoiding blind current), and  avoidance of flicker. Today, LED luminaires as optimised complete systems with built-in LED light sources and electronics fulfil these requirements much better. LED light sources are dimmed using different methods. A common method is pulse-width modulation (PWM) where, according to an adjustable ON/OFF ratio, direct current generated by the control gear unit is turned on and off, thereby regulating the energy input. In contrast to dimming via trailing-edge phase cutting in incandescent lamps, where the light of the slowly

LUMIGEA cooling filament is not extinguished, the LED follows the pulse-width-modulation practically without delay. For applications where stroboscopic effects would be disturbing, PWM dimming should be avoided. There are no physiological effects on persons at PWM frequencies above 400 Hz. Switching with smaller PWM frequencies should not be applied. To this end, appropriate control gear units (see chapter 2.1.9.4) are required, e.g. with DALI interface (see chapter 2.4.4.5). Further developments regarding the usage of electroluminescence concern organic LEDs, socalled OLED, where light is generated in an organic substance. While crystalline LED are very small single elements with a diameter of just a few millimetres, OLED can be used in particular to produce planar light emitters. Currently, they are used predominantly in display technology. An economic usage of OLED in general lighting is not expected to become reality for now.

Figure 2.97: White LED

CHARACTERISTICS OF LIGHT SOURCESThe most important characteristics of light

sources are      

power consumption generated luminous flux luminous efficacy light colour and colour rendering service life and shape as well as dimensions.

LUMIGEA

(a) retrofit lamp with E14 or G9 base

(b) retrofit lamp (tube) with G13 base Figure 2.106: Examples for retrofit lamps

LUMINOUS EFFICACY LUMINOUS EFFICACY OF LAMPS Light sources convert electrical power into visible radiation (light). A large portion of the electrical power consumed by a light source is converted into heat. Incandescent lamps emit only 5% of their electrical power as light; in fluorescent lamps the number ranges between 20% and 40%.

LUMIGEA Luminous efficacy is a measure for the efficiency of light generation. It is measured in lumens per watt (lm/W). Lamp luminous efficacy is the emitted amount of light in proportion to the electrical power consumption of open-distribution lamps under standardised environmental conditions. Among traditional light sources, the energy efficiency of gas discharge lamps and particularly fluorescent lamps with a diameter of 16 mm (so-called T5 lamps) is especially high. Additionally, control gear units which also consume power are required to operate LEDs and discharge lamps. The system luminous efficacy of a lamp circuit is defined as lamp luminous flux in proportion to lamp and control gear unit power consumption. Thus, system luminous efficacy is determined by the luminous efficacy of the lamp and the dissipation power of the required control gear units. This often has a great impact, particularly on the cost efficiency of a planned refurbishment project (see chapter 1.3.4 “Light and economic efficiency”). An overview of the different luminous efficacies of light sources is provided in figure 9.6 (control gear unit losses are not considered here). Regarding LED light sources, information about lamp or system luminous efficacy is only available for retrofit lamps. Only these can be operated with open distribution under defined conditions. In addition, optical losses occur in the luminaire due to reflexion and absorption of optical materials as well as thermal losses due to heating of the luminaire (see chapter 2.1.3.4 “Light output ratio”).

LUMINOUS EFFICACY OF LED LUMINAIRES LED components built into luminaires must be considered separately. Lamp luminous flux and consequently lamp luminous efficacy cannot be defined for them. Standardised operation of the components is not possible since luminaire and lamp can not be separated from each other. A luminaire’s construction characteristics in particular have a significant impact on thermal management (see chapter 2.1.9.1 “Thermal management”). The choice of control gear unit used in the luminaire and electrical operating conditions can also vary widely. Therefore, rated luminous flux ΦB, rated output PB and resulting luminous efficacy ΦB/PB are defined for such LED luminaires.

LUMIGEA

Figure 2.99: Luminous efficacy (approx. peak values without control gear units) and service life (related to the applicable definition) of different lamp types. Rated luminous flux: ΦB = initial luminaire luminous flux, undimmed Rated output: PB = power consumption to generate ΦB Luminous efficacy: ΦB/PB = (initial luminaire luminous flux, undimmed) / (power consumption to generate ΦB) Luminaire luminous efficacy refers to the luminaire luminous flux which emitted by the LED luminaire in proportion to the electrical power consumed by the luminaire. From this perspective, light output ratio is not applicable or it is represented by the value 1 in order to ensure error-free operation of software programs for light calculation (see chapter 2.1.3.4 “Light output ratio”). The maximum achievable theoretical luminous efficacy at monochromatic radiation is 683 lm/W; for white light in the visible spectral range between 380 nm and 780 nm, it is only 199 lm/W. Today, technically sophisticated LED luminaires reach a rated luminous efficacy of over 160 lm/W.

LUMIGEA LIGHT COLOUR The light colour of a light source is expressed by the closest colour temperature Tcp (température de couleur proximale). The closest colour temperature is the temperature of heated platinum where its colour is perceived to be the same as the respective light source (see figure 2.100). Low closest colour temperatures express warm, yellow-red-white appearing light colours such as e.g. candles, incandescent lamps and other thermal radiators. High temperatures express cool, rather white-blue light colours such as e.g. daylight with ca. 6,500 K (overcast sky). The European lighting standards give no recommendations on light colours of the used light source since their preferential choice amongst other things highly depends on what people from different regions in Europe perceive as natural light. Therefore, the choice of a suitable light colour strongly depends on regional adaption, especially in terms of how daylight appears in indoor spaces. In general, high colour temperatures, for example daylight white, are preferred in warm climate zones, even at low levels of illuminance. In cold climate zones, low colour temperatures and therefore warm white light colours are preferred.

Figure 2.100: Extract from the standard colour table according to CIE 1931 with Planckian curve representing the light colour of the heated platinum. The closest colour temperatures of e.g. fluorescent lamps are marked. E is the white point.

LUMIGEA

Table 2.36: Light colour and closest colour temperature according to EN 12464-[48] The choice of the light colour also depends on the application – meaning the visual task – and factors concerning aesthetics and psychology, room and furniture colours as well as the spatial effect of the environment. Based on recent findings, the daytime utilisation of a room also should not be neglected. Especially for rooms with extended operating times compared to the common rhythm of work, the circadian function of light is of utmost importance. Not only the light colour but also the detailed spectral composition of light has an impact. Regarding areas with night shift operation, the biological clock should not be excessively affected. In areas with early starts of work and minimal daylight supply, artificial lighting should actively support the circadian rhythm (see chapter 3.3.1 “Human Centric Lighting (HCL)” ff). Table 9.4 shows the international labelling of light colours independent of manufacturers. In addition, it provides the colour rendering of the light source, which will be explained in the subsequent paragraph.

COLOUR RENDERING For visual performance, comfort and well-being, it is important that the colours of the surroundings, objects and human skin are rendered naturally and realistically. This makes people appear attractive and healthy. Dependent on location and visual task, artificial light sources should ensure correct colour rendering comparable to natural daylight (see also figure and figure).

Figure 2.102: Good colour rendering

Figure 2.101: Insufficient colour rendering

Despite featuring identical light colour, light sources can have different colour rendering properties due to different spectral compositions of their radiation. In order to express colour rendering properties of a light source objectively, the general colour rendering index Rα was established. The colour rendering index is the measure of correspondence of the seen body colour and its appearance under the respective reference light source. To determine the value of Rα, colour variations from 8 standardised test colours occurring when the test colours are illuminated using the light source to be evaluated/the reference light source are identified. The smaller the variation, the better the colour rendering characteristic of the tested light source. A light source

LUMIGEA with Rα = 100 renders all colours ideally as under the reference light source. The lower the Rαvalue, the lower the quality of the colour rendering. A categorisation of market-based light sources for the colour rendering levels can be found in table 9.3. The reference light type for daylight white light sources is natural daylight with a colour temperature of 6,500 K, corresponding to an overcast sky without direct sunlight. For light sources with a colour temperature of < 5.000 K, the reference light type is the Planckian radiator. Lamps with a colour rendering index below 80 should not be used indoors where persons work or linger for extended periods of time. Exceptions are permissible for particular lighting tasks requiring high luminous efficacy and therefore lower colour rendering for economic reasons, for example high-pressure sodium vapour lamps. This applies e.g. for the lighting in high halls. However, appropriate measures should be taken in these cases in order to ensure a higher colour rendering at stationary and steadily occupied workstations and at locations where safety colours must be identified correctly. As the use of LED luminaires becomes more widespread, this issue increasingly fades into the background. High illuminance values can also be realised with these light sources, featuring good colour rendering and at economically reasonable expenses. This has been already taken into account in the current efforts of photometric standardisation. Manufacturers have committed themselves to a simple, generally comprehensive international labelling for light colour and colour rendering of lamps and LED luminaires in addition to manufacturer-specific labelling. It consists of three digits as depicted in table. Regarding LED light sources, colour rendering properties are expressed by the rated colour rendering index which refers to the colour rendering at initial commissioning.

Table 2.37: Ranges for the general colour rendering index Ra

Table 2.38: Colour labelling of lamps/luminaires with integrated light sources independent of manufacturers.

LUMIGEA LAMP SERVICE LIFE The service life of lamps depends on several factors. With incandescent lamps, e.g. for residential areas, specifying the statistic average service life is sufficient. It is 1,000 hours for incandescent lamps and 2,000 to 4,000 hours for halogen lamps. After this time, only 50% of lamps are still (statistically) functional. This service life is also called average service life. The same service life definition used for incandescent lamps is applied to compact fluorescent lamps with integrated (mostly electronic) control gear units which mainly serve as replacements for incandescent lamps.

Table 2.39: Benchmarks for the useful life of some lamp types Useful life (also referred to as economic service life) is specified for fluorescent lamps and compact fluorescent lamps with external control gear units as well as for high-pressure lamps and lowpressure sodium lamps. Useful life is the length of time it takes for system luminous flux (the product of the remaining functional portion of lamps and the remaining luminous flux after luminous flux drop) to reach 70% or 80% of the initial value (see benchmarks in table 9.5). The useful life of fluorescent lamps is based on a switching cycle of 3 hours (165 minutes ON and 15 minutes OFF). For high-pressure lamps, the switching cycle is defined as 12 hours (11 hours ON and 1 hour OFF). Another distinct characteristic is nominal service life. This is the time period with a switching frequency of 12 hours (11 hours ON, 1 hour OFF) after which 10% of lamps failed (abbreviation: 12B10). Benchmarks for this are also specified in table. Figure shows the fundamental progress of operability A (amount lamps which are still functional) and lamp luminous flux B dependent on operating duration. The product of both parameters is system luminous flux. Chapter 1.3.1.6 “Lamp maintenance factor” contains realistic diagrams for tubular fluorescent lamps and compact fluorescent lamps. For fluorescent lamps, economic service life (useful life) relates to 80% of system luminous flux (see also chapter 1.3.1.6“Lamp maintenance factor”). Useful life depends on a series of influencing factors, e.g. switching frequencies, lamp wattage, types of fluorescent substance and eventually product batch. Consequently, providing exact information on service life can be challenging. However, exact information about service life is not always necessary from a practical point of view since relamping usually does not occur at the end of the useful life but at a time determined for business reasons. Relamping occurs e.g. due to new illuminance measurements, in-company cost analysis for maintenance procedures and e.g. also depends on access to the lighting installation.

LUMIGEA These and other criteria are used in many cases to make a decision for group or individual lamp replacement. With tri-phosphor fluorescent lamps connected to magnetic control gear units, a useful life (average service life) of 10,000 hours (13,000 hours) can be reached under rated conditions, and up to 18,000 hours (20,000 hours) with hot-start ECGs. These values apply to rated conditions and a decrease of system luminous flux to 80% of the initial value. Derating and overloading can cause service life reductions.

Table 2.40: Benchmarks for the nominal useful life of some lamp types

Figure 2.103: Economic service life of fluorescent lamps

LUMIGEA SERVICE LIFE OF LED LIGHT SOURCES The luminous flux of LED light sources also decreases with increasing operating duration. This phenomenon is referred to as luminous flux degradation. However, total failures of LED light sources only occur after a very long period of time when the degradation is far advanced. Therefore, total failure plays only a minor role when considering the service life of this type of LED products. Total failure is only recognizable for individual LEDs, e.g. as a defective pixel on an LED display. Following the failure rate of incandescent lamps, the time of degradation to 50% of initial luminous flux (rated luminous flux) is a common definition for household LED retrofit lamp service life.

Figure 2.104: Examples of drops in luminous flux for different rated service life values Lx.

RATED SERVICE LIFE For LED luminaires, there is no conventional definition of service life, be it “nominal service life” or “economic service life”. Instead, it is common to relate the service life specified by the manufacturer to the respective specified level of luminous flux degradation. This procedure is suggested by the standards regarding luminaire performance (DIN EN 62722-1; Luminaire performance – Part 1: General Requirements [106], DIN EN 62722-2-1; Part 2-1: Particular requirements for LED luminaires [107] and LED modules [DIN IEC/PAS 62717; LED modules for general lighting – Performance requirements [16]). A more general definition of rated service life based on these standards leads to an expression in the form of LxBy (e.g. L80B10= 50,000 h). The index x describes the percentage of residual luminous flux of a luminaire due to degradation. The index y describes the percentage of a large number of luminaires which statistically undercut this luminous flux, meaning the portion of luminaires with increased drop in luminous flux (“gradual failure fraction”). The definition of “average rated service life” Lx is common on the market, without specification of By. In this case, it is assumed that the index y of the general definition is 50. Therefore, Lx refers to the statistic average of the residual luminous flux remaining at the end of service life for a large number of luminaires.

LUMIGEA    

Lx, the average rated service life Φ(Lx), the luminaire luminous flux at Lx, ΦB, the rated luminous flux (initial luminous flux), and x, the statistically averaged residual luminous flux of a luminaire at the end of service life Lx, in %.

The service life specification L80, 50,000 h for a given luminaire, e.g. means that a large number of these luminaires in total after 50,000 operating hours still generate at least 80% of their rated luminous flux (available initially and in total). Therefore, this is an average value. Until the rated service life is reached, the progress of the drop in luminous flux (degradation) can be regarded as linear in simplification (see figure 2.104). This means:

(see symbols above) In practice, this approximation can often be used beyond the scope of the rated service life specified by the manufacturer, for a period of up to 1.5 Lx (see also tables in chapter 1.3.1.2 “The lamp maintenance factor of an LED luminaire”). Common average rated service life specifications refer to different degrees of degradation: L90-, L85, L80-, L70- and L50. These values can be converted into each other to a certain extent. The choice of rated service life index has a significant impact on the maintenance factor to be specified in the lighting planning stage. Further information can be found in the tables in chapter 1.3.1.2 “The lamp maintenance factor of an LED luminaire”. The LED as a semiconductor in which electrical energy is converted is temperature-sensitive, similar to a power transistor inside an amplifier or a processor inside a computer. The extent of the luminous flux degradation – and therefore the rated service life – depends particularly on the operating temperature of the LED inside the luminaire. Correct service life specifications therefore require reliable thermal management of the LED luminaire (see also chapter 2.1.9.1 “Thermal management”) and usually relate to an ambient temperature (rated temperature) of 25°C, unless otherwise stated by the manufacturer. Based on the aforementioned standards, it is possible to specify an ambient temperature tq other than 25°C in the data sheet at which specified technical quality criteria are achieved (see also chapter 2.1.8.2 “Operating conditions” and chapter 2.1.7.5 “Performance labelling of LED luminaires”).

FAILURE RATE Total failures of LED lamps or luminaires are expressed by the Cz value (catastrophic failure) with the numeric value of z indicating the expected failure rate in per cent at a given time.1 Luminaire classification specification

LUMIGEA C5 = 100,000 h at tq = 35° C would therefore state e.g. that the LED luminaires in question feature a total failure rate of 5% at an ambient temperature of 35°C and after 100,000 operating hours. The value of a luminaire’s total failure rate at the end of the average rated service life Lx (B50, see above) is referred to as AFV (“abrupt failure value”). In practice, significant failure rates in LED products only occur with very advanced degradation. At average rated service life specifications x ≥ 80 the AFV is therefore negligible. When determining the maintenance factor, the total failure rate expressed by LSF (“lamp survival factor”) must be considered (see also chapter 1.3.1.2 “The lamp maintenance factor of an LED luminaire”).

Therefore, the lamp survival factor [Symbol] only matters for the determination of the maintenance factor after the end of the rated service life. In the tables in chapter 1.3.1.2 “The lamp maintenance factor of an LED luminaire”, this factor is already considered.

RATED SERVICE LIFE WITH CONSTANT LIGHT OUTPUT (CLO) With constant light output (CLO), the luminous flux of an LED product is constantly regulated to the level corresponding to the residual luminous flux which is statistically expected at the end of the rated service life. If luminous flux is used as the basis for lighting design, energy can be saved until the end of the rated service life which would otherwise only lead to unnecessary excess lighting. For a luminaire with rated service life Lx the following applies:

and

with

 Φ(t), the luminaire luminous flux at the time of t,  Lx, the average rated service life,  Φ'B, the rated luminous flux (initial luminous flux) of a luminaire with the same rated service life without CLO, and  x, the residual luminous flux percentage of Φ'B at the end of the rated service life.

LUMIGEA

Figure 2.105: Examples of drops in luminous flux and power control with constant light output (CLO) over a period of 1.5 Lx. Upon expiration of the rated service life, degradation can no longer be compensated and the luminaire luminous flux decreases at a rate corresponding to a luminaire without constant light output (see figure above). Generally, the power consumption of the luminaire in initial state Pnew required to provide constant luminous flux Φnew is specified in the data sheet of such luminaires. In addition, the required power consumption value Px at the end of the rated service life should be specified as well. The result for a given average rated service life Lx is derived as follows:

The power consumption is constant after the end of the rated service life, when the luminous flux Φnew can no longer be maintained. It has reached its maximum value:

LUMIGEA Over the course of the rated service life, the power consumption increases continuously (see figure):

The resulting time-dependent factor at which power consumption increases is defined as power lifetime factor PLF:

The tables in chapter 1.3.1.2 “The lamp maintenance factor of an LED luminaire” list the resulting PLF values. The energy requirement Wnew(t) of a newly installed luminaire up to a point within the rated service life is derived as a statistic average of:

The total failure rate index C is expressed by the letter “y” in some printed volumes. “z” is chosen as the index to provide a better distinction from the “gradual failure fraction” index By. The maintenance factor (MF) can be determined when LMF and RMF of the application are known.

LAMP REFERENCE The multitude of lamp types, their performance, light colours, base designs and other properties are impossible to manage. Company-specific references for similar and compatible lamps deviate from each other. However, practical applications demand a consistent lamp reference system which captures the most important cross-company lamp characteristics. The German electric lighting trade association Zentralverband der Elektrotechnik- und Elektronikindustrie (ZVEI) has developed a lamp reference system called LBS which predominantly lists lamps according to their luminaire-relevant properties; it was last updated in 2010. This system has been introduced widely in the German but also in the European luminaire industry since it enables short references sufficient to identify lamp types. The LBS system – or parts of it – is often used as a luminaire order code component, e.g. TC (tubeform compact) for compact fluorescent lamp luminaires. The LBS consists of three system blocks. The first system block specifies the light generation type, e.g. “H” for high pressure; the second system block indicates the medium used to generate light, e.g. “M” for mercury. This leads to a classification in 7 groups:

LUMIGEA 1. 2. 3. 4. 5. 6. 7.

General-use incandescent lamps Halogen lamps High-pressure discharge lamps HM (mercury vapour) High-pressure discharge lamps HI (metal halide) High-pressure discharge lamps HS (sodium vapour) Low-pressure discharge lamps LM (mercury vapour) Low-pressure discharge lamps LS (sodium vapour)

LED lamps as retrofits for incandescent lamps, halogen lamps or fluorescent lamps are not considered in the LBS system. The third system block fundamentally expresses the shape of the bulb, e.g. “T” (tube) for tubular lamps. Additional reference amendments are determined in the LBS catalogue (see www.zvei.org/en/press-media/publications/). Fluorescent lamps are low-pressure mercury discharge lamps with reference “LM” (low pressure, mercury), followed by the bulb shape specification. EXAMPLES:

LM T26 refers to a fluorescent luminaire with 26 mm tube diameter which is also referred to as T8 internationally. According to LBS, T5 lamps are referred to as T16. Older T12 lamps with 38 mm diameter are referred to as T38 according to LBS. For convenience, LM is mostly omitted. Other information such as lamp wattage, light colour and base reference can be added to this fundamental reference. At international level, the lamp reference system ILCOS (International Lamp Code System) was introduced, which is described in the international specification IEC 61231:2010 + A1:2013 and has e.g. been published as German standard in DIN EN 61231 [91]. In the catalogues of internationally operating lamp manufacturers, ILCOS references are contrasted with companyspecific lamp references in the form of a translation list. ILCOS captures nearly all lamp properties. This leads to reference lengths which are very difficult to handle in practice due to description clarity alone and can therefore not be used as an ordering component for the luminaire in question. Therefore, short (ILCOS L), extended short (ILCOS LE) or standard references (ILCOS D) are also possible as full lamp references. The structure of ILCOS references is defined in DIN EN 61231 [91] for the following lamp types: 1. Incandescent lamps 2. Halogen lamps 3. Fluorescent lamps 4. High-pressure sodium vapour lamps 5. Low-pressure sodium vapour lamps 6. High-pressure mercury vapour lamps 7. Metal halide lamps 8. LED modules and lamps 9. Lamps/starters for specific applications

LUMIGEA EXAMPLE 1

According to ILCOS D, a tubular fluorescent lamp T8 58 W with light colour 840 is referenced as follows: FD-58/40/1BE- G13-26/1500. In which: FD double ended fluorescent lamp 58 wattage 58 W 40 light colour 4,000 K 1B for Ra from 80 to 89 E starting behaviour: external starter, with pre-heating G13 base reference 26 tube diameter 26 mm 1500 length 1,500 mm EXAMPLE 2

According to ILCOS D, a drop-shaped E14 LED retrofit lamp with a power consumption of 6 W and light colour 840 is referenced as follows: DRP-6/30/1B-E14-45. In which: DR retrofit LED lamp with integrated control gear unit P drop-shaped (as the lamp requiring replacement) 6 wattage 6 W 30 light colour 3,000 K 1B for Ra from 80 to 89 E14 base reference 45 nominal diameter of the lamp’s construction (requiring replacement)

LUMIGEA Type (code)

Common ratings (watts)

Colour rendering

Colour temperature (K)

Life (hours)

Compact fluorescent lamps (FS)

5–55

good

2.700–5.000

5.000– 10.000

High-pressure mercury lamps (QE)

80–750

fair

3.300–3.800

20.000

High-pressure sodium lamps (S-)

50–1.000

poor to good

2.000–2.500

6.000– 24.000

Incandescent lamps (I)

5–500

good

2.700

1.000– 3.000

Induction lamps (XF)

23–85

good

3.000–4.000

10.000– 60.000

Low-pressure sodium lamps (LS)

26–180

monochromatic yellow colour

1.800

16.000

Low-voltage tungsten halogen lamps (HS)

12–100

good

3.000

2.000– 5.000

Metal halide lamps (M-)

35–2.000

good to excellent

3.000–5.000

6.000– 20.000

Tubular fluorescent lamps (FD)

4–100

fair to good

2.700–6.500

10.000– 15.000

Tungsten halogen lamps (HS)

100–2.000

good

3.000

2.000– 4.000

LED

0,1 - 500

good to excellent

2.200 – 6.500

>50.000