Light Factory - ERCO photometrics - LEDs in ERCO luminaires

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LEDs in ERCO luminaires
Light Factory

LEDs in ERCO luminaires


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ERCO usually uses the same highpower LEDs throughout the entire product range. This has the enormous advantage for the user that the light is of the same high quality and that luminaires producing the same colour of light can be combined as required.

Colour temperature 3000K (ww) and 4000K (nw)
Luminous efficacy ww: 105lm/W
(module at 700mA and Ts 25°) nw: 138lm/W
Colour tolerance 2SDCM
Colour rendering ww: CRI≥90 nw: CRI≥80
Lumen maintenance L90/B10 to 50.000 hours
Failure rate (statistical average) 0,1% to 50.000 hours
Operating current 350 – 1050mA

Luminous efficacy

With a luminous efficacy as high as 138lm/W, ERCO LEDs outperform all other light sources, making them the best in the market. The advantages are particularly obvious in comparison to conventional lamps.

LED modules

ERCO luminaire systems in the catalogue are differentiated according to the efficiency of their LED modules. The separate consideration of module luminous flux, luminaire luminous flux and connected load enables better evaluation of the photometric and energetic efficiency. In addition to the module values, the efficiency data for the complete luminaire is separately specified in the catalogue and data sheet for this purpose.

LED selection

As is the case with all semiconductor products, white LEDs exhibit a degree of production tolerance. Such tolerances exist in areas such as the colour loci, lumen maintenance, and forward bias. ERCO considers all these criteria in the selection of its LEDs providing users with the highest possible quality.

Colour deviation (chromaticity variation)

ERCO only uses highpower LEDs with an SDCM value of 2. This is the highest standard currently available in the market and makes these highpower LEDs ideal for use in places such as museums, shops, offices and openplan architecture. The SDCM (Standard Deviation of Colour Matching) value defines an LED in terms of colour consistency (chromaticity variation). It is based on a study conducted by American engineer David MacAdam and describes the degree of deviation from a defined chromaticity coordinate in the CIE diagram. According to MacAdam, the coordinates of all colours perceived as identical fall within an ellipse around the original colour locus. The system, created by adding further ellipses of increasing size, is used to classify the maximum colour deviation of light sources. Occasionally also referred to as MacAdam ellipse of a certain step size, the commonly accepted term is now SDCM. The higher the SDCM value, the greater the potential variation of light colour from the chromaticity coordinates specified in the technical data of the light source. The current standard is a value of 3 SDCM and higher.


LEDs in ERCO luminaires have a continuous spectrum, thereby ensuring good colour rendering for neutral white (nw, 4000K) and very good results for warm white (ww, 3000K). The LEDs deliver practically no UV or IR radiation and have a low damage factor making them ideal particularly for the illumination of sensitive and valuable objects.

Damage factor

The relative damage factor is used to assess suitable light sources for conservation requirements such as in museums. It specifies the ratio of the damaging radiation inten-sity and the illuminance. Warm white LED lighting is even better suited for delicate objects than low-voltage halogen lamps with or without UV filter.

Light source Relative damage factor f (mW/lm)
LED warm white, Ra 90 0.149
QT12-RE with UV filter 0.159
QT12-RE 0.169
HIT 930 0.182

Reference colours  R<sub>a</sub> (CRI)

Reference colours Ra (CRI)

Evaluation of colour rendering using Ra (CRI)

Colour rendering refers to the ability of a light source to reproduce colours faithfully in comparison with an ideal or natural light source. One method used to quantify the colour rendering quality with maximum objectivity is the colour rendering index, CRI, also sometimes referred to as R a in parts of Europe. It is calculated by comparing the colour rendering of the test source to that of a reference illuminant with correlated colour temperatures. A colour rendering index between 90 and 100 is considered very good, and a value between 80 and 90, as good. The CRI method is controversial in expert circles today and should only be used as a rough guide for a light source. For the best results, comparison of several light sources during a visual assessment may be worthwhile.

Reference colours TM-30

Reference colours TM-30

Evaluation of colour rendering according to TM-30

As an alternative to the Ra / CRI process, TM-30 defines the unitless values Rfand Rg. These reference the similarity to a test light source and reference spectrum with regard to colour fidelity (Rf) and saturation (Rg - gamut). The reference light source is a “black body” or standard CIE-D light source.Rf and Rg analyse the colour rendering of a light source based on 99 representative colour tones, pastel colours and saturated colours.
The optimum value for Rf is 100, whereby Rf and Ra are not identical.Rg specifies saturation of the colours and can exceed the value 100, but this in itself is not a quality criterion. Considered together, Rf and Rgenable a differentiated analysis of the colour rendering of a light source. The colour vector diagram shows the deviation of the test light source to the reference light source.

Overview charts in accordance with TM-30

Ratio of R<sub>f</sub>-R<sub>g</sub>

Ratio of Rf-Rg

Colour vector diagram

Colour vector diagram


Rf 90
Rg 99
Ra/CRI ≥90

Ratio of R<sub>f</sub> - R<sub>g</sub>

Ratio of Rf - Rg

Colour vector diagram

Colour vector diagram


Rf 81
Rg 96
Ra/CRI ≥80

Functional life

LEDs have a very low failure rate, meaning they produce light over an exceptionally long period of time. The failure rate of the highperformance LEDs used at ERCO is on average less than 0.1% up to 50,000 hours. In contrast to conventional lamps, which have a failure rate of 50%, the term “functional life” therefore is not very useful for planning purposes.

Lumen maintenance

Marktübliche LED

Marktübliche LED

ERCO LEDComparing the reduction in luminous flux of a standard LED with an ERCO highpower LED after 50,000 operating hours illustrates the superior efficiency of ERCO LEDs.


Comparing the reduction in luminous flux of a standard LED with an ERCO highpower LED after 50,000 operating hours illustrates the superior efficiency of ERCO LEDs.

As with other light sources, the luminous flux of LEDs decreases over time so that from a certain point the illuminance originally required is no longer achieved. The reliability and efficiency of LEDs depend largely on its operating conditions. ERCO luminaires therefore are thermally designed to remain below the critical temperature range when properly operated to ensure maximum luminous flux over a long life.
Since total failure of an LED is very rare, LEDs are more accurately defined by using the lumen maintenance factor over a specific period of time. As a blanket value it is common practice to indicate the time after which the luminous flux for a specific percentage of all LEDs has reduced to 70%, 80% or 90% of their original luminous flux.
The standard specification of LEDs currently used in the market is L70/B50 50,000h, i.e. after 50,000 hours, only 50% of the LEDs used still achieve 70% of their original luminous flux.

L and B values
The L value represents the percentage of original luminous flux that the LED continues to achieve after the specified number of operating hours. If no B value is indicated, B50 should always be assumed. By definition, the B value reveals nothing about the total failure of an LED. It indicates the percentage of LEDs that fall below the L value after the specified number of operating hours.

Operating hours
As a benchmark, the operating hours are always indicated together with the L and the B value. Based on the LM-80 method, ERCO LEDs are measured over a minimum of 8,334 hours and extrapolated to 50,000 hours using the TM-21 method. The operating hours may be extrapolated to a maximum of six times the actual time measured.

LEDs used at ERCO
ERCO uses highperformance LEDs with the specification L90/B10 50,000h, i.e. up to 50,000 hours, at least 90% of the LEDs still achieve 90% of their original luminous flux. This said, the remaining 10% of the LEDs will not have failed but continue to achieve up to 89% of their original luminous flux.

Forward voltage

Due to the manufacturing process, LEDs of the same type vary in terms of their forward voltage. This is the voltage drop across an LED, in other words, the volts it “consumes”. Together with the constant operating current, forward voltage defines the power consumption of an LED luminaire using the simple formula of voltage (volt) x current (ampere) = power (watt). Therefore, if the forward voltage of LEDs were to fluctuate, the energy requirement of the luminaires, though otherwise similar, would also vary. Consistent energy consumption across luminaires of the same design can only be guaranteed if the LEDs used in them are selected for their forward voltage. ERCO is one of the few luminaire manufacturers that specifies consistency in forward voltage as part of its selection criteria. The goal is to give the user assurance that the energy requirement specified for the luminaires used relates to actual figures.


LEDs and control gear are continually advanced. In order to identify clearly which LEDs and whichcontrol gear are used in a product, ERCO specifies a version number alongside the article number, which is found on each luminaire. This number applies only to a luminaire range and bears no reference to the LED generation, i.e. luminaires from different product ranges may use the same LED generation despite the difference in version number. The version number is important for the user to know and must be stated particularly when reordering luminaires.Within a given production year, ERCO always uses the latest generation of LEDs in all luminaires with a warm white or neutral white light colour.

Information on highpower LEDs

Due to the production process of LEDs, the specified typical LED parameters show statistical values only. There can be variations in the range typical for LEDs. The service life of an LED largely depends on the ambient temperatures. Therefore, the luminaires should not be installed near other sources of heat such as heating pipes, etc. Furthermore, these luminaires should not be operated when exposed to direct sunlight. ERCO luminaires are designed, manufactured and tested to all applicable standards and technical regulations. Laboratory testing is conducted at an ambient temperature of 25°C, as per IEC 60598.
The luminous flux values and other photometric data also relate to an ambient temperature of 25°C. At other temperatures, deviations from the values stated in the catalogue are possible.

The guarantee terms pertaining to the voluntary manufacturer’s guarantee of 5 (five) years given by ERCO GmbH on ERCO products shall apply in addition to our General Terms and Conditions. Full details of these current guarantee terms are available on request by e-mailing guarantee(at)

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