5C-i 

APPENDIX 5C. MODIFIED-SPECTRUM INCANDESCENT REFLECTOR LAMPS 

TABLE OF CONTENTS 

5C.1 INTRODUCTION .........................................................................................................5C-1

5C.2 BACKGROUND ...........................................................................................................5C-1

5C.2.1 Spectral Power Distribution and Commonly-Used Color Properties ..........5C-1

5C.2.2 Methods of Modifying Spectral Power Distributions..................................5C-4

5C.3 APPLICATION OF “MODIFIED SPECTRUM” DEFINITION TO IRL....................5C-4

5C.3.1 Color Requirements .....................................................................................5C-5

5C.3.2 Black-Body Locus Requirements ................................................................5C-5

5C.3.3 MacAdam-Step Requirements.....................................................................5C-6

5C.4 METHODOLOGY ........................................................................................................5C-7

5C.5 ANALYTICAL RESULTS .........................................................................................5C-10

5C.6 SELECTION OF FINAL SCALING FACTOR..........................................................5C-13

REFERENCES ........................................................................................................................5C-14

LIST OF FIGURES 

Figure 5C.1: Spectral Power Distribution of Two IRL Tested By DOE...................................5C-2

Figure 5C.2: The CIE 1931 Chromaticity Diagram...................................................................5C-3

Figure 5C.3: Combined Black-Body Locus and Color Requirements of the “ModifiedSpectrum” Definition...................................................................................5C-6

Figure 5C.4: Example of IRL That Meet the Definition of "Modified Spectrum;” 

Modified-Spectrum IRL Color Points Lie to the Lower Left of the Red 

Circle............................................................................................................5C-7

Figure 5C.5: Transmittance of a Specific Lamp Cover Glass Featuring Neodymium, 

Relative to the Standard-Spectrum Cover Glass Transmittance................5C-10

Figure 5C.6 Relationship Between Light Output Reduction and MacAdam-Step Shift For 

Lamps Tested by DOE...............................................................................5C-12

Figure 5C.7: Comparison of Standard-Spectrum and Modified-Spectrum IRL Efficacy 

Requirements .............................................................................................5C-13

LIST OF TABLES 

Table 5C.5.1: MacAdam-Step Shifts and Light Output Reductions for Lamps Tested by 

DOE ...........................................................................................................5C-11

EE-2006-STD-0131 COMMENT 101
5C-1 

APPENDIX 5C. MODIFIED-SPECTRUM INCANDESCENT REFLECTOR LAMPS 

5C.1 INTRODUCTION 

 A modified-spectrum incandescent lamp is an incandescent lamp with special coatings or 

other features that modify the wavelengths of light that exit the lamp, changing the perceived 

color of the lamp’s light. The definition of “modified-spectrum” in the Energy Policy and 

Conservation Act (EPCA) as amended by the Energy Independence and Security Act of 2007 

(EISA 2007) applies to general service incandescent lamps (GSIL) that are noticeably different 

in color than unmodified-spectrum (or standard-spectrum) GSIL, with specific additional color 

requirements described in this appendix. Some incandescent reflector lamps (IRL) are also sold 

with features that modify their spectra, and DOE believes that such IRL provide a unique utility 

to users. For example, a number of these lamps are advertised as being able to reproduce the 

spectrum of natural daylight. 

 The features that modify the spectra of incandescent lamps usually reduce the efficacies 

of the lamps. Thus, DOE is creating a modified-spectrum IRL product class and setting 

standards for these lamps by scaling efficacy requirements from the standard-spectrum IRL 

product classes. As discussed in chapter 3, Market and Technology Assessment, DOE used the 

EPCA definition of “modified spectrum” to determine what lamps would be included in this 

product class. DOE believes that the definition of “modified spectrum” was created for GSIL, as 

the EPCA definition requires the testing of clear lamps as a reference for spectrum comparison, 

but IRL are not clear lamps due to their reflective coating. This appendix describes how DOE 

adopted the EPCA definition of “modified spectrum” for IRL and developed the factor used to 

set the efficacy requirements for the modified-spectrum IRL product class. In particular, DOE 

tested IRL advertised as featuring spectral modification (such as lamps advertised as “daylight” 

lamps) by using similar standard-spectrum IRL as references for spectrum comparison. 

5C.2 BACKGROUND 

 Objects absorb, reflect, and radiate a form of energy known as electromagnetic radiation, 

which can be visualized as waves of energy that travel through open space. Different 

wavelengths of electromagnetic radiation have different common names; for example, radio 

waves have wavelengths ranging from millimeters to hundreds of thousands of kilometers, and 

visible light has wavelengths roughly between 380 and 750 nanometers (nm). Various 

wavelengths of visible light are perceived as various colors by humans. 

5C.2.1 Spectral Power Distribution and Commonly-Used Color Properties 

 Some portion of the electromagnetic radiation emitted by lamps exists in the spectrum of 

visible light. Most lamps emit multiple wavelengths of light simultaneously, and the radiant 

power (energy radiated per unit time) of each wavelength can be plotted as a spectral power 

EE-2006-STD-0131 COMMENT 101
distribution (SPD).1

 Example SPDs are shown in Figure 5C.1 for a specific standard-spectrum 

IRL and a specific modified-spectrum IRL tested by DOE for this rulemaking. 

350 400 450 500 550 600 650 700 750 800

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

Wavelength (nm)

Spectral Power (W/nm)

Modified spectrum

Standard spectrum

Figure 5C.1: Spectral Power Distribution of Two IRL Tested By DOE 

 The measurement of a lamp’s SPD allows the characterization of the lamp’s perceived 

light color. Three color properties in particular are commonly computed for lamps based on the 

SPD. One is the chromaticity, which refers to the color of the lamp’s light as indicated by a 

mapping onto a chromaticity diagram such as the CIE 1931 chromaticity diagrama shown in 

Figure 5C.2.

2

 Subtle differences in color can be quantified using MacAdam steps, named after 

David MacAdam, who studied color perception in the 1940s.3 A 3-step MacAdam ellipse is an 

ellipse that encircles a region of points on the chromaticity diagram that appear to be 

indistinguishable to most humans (in other words, they appear to be the same color). Points 

further than a distance of three MacAdam steps from any reference color point are generally 

perceived by most humans as being different in color than the reference point. 

 

5C-2 

a

 This particular figure is the chromaticity diagram for the CIE 1931 color space, created by the Commission 

Internationale de l’Eclairage (International Commission on Illumination, or CIE) in 1931. The colors on the outer 

curved boundary are composed of single wavelengths of electromagnetic radiation, with wavelengths indicated by 

the numbers. All colors inside the space are composed of a distribution of wavelengths of various powers. 

EE-2006-STD-0131 COMMENT 101
Figure 5C.2: The CIE 1931 Chromaticity Diagram 

 The curved line in the center of Figure 5C.2 is known as the black-body locus and 

represents the perceived light color emitted by a black body heated to the indicated temperature 

(in Kelvin). In the field of physics, a black body is a theoretical object that is considered to be 

the simplest emitter of electromagnetic radiation. It absorbs all electromagnetic radiation falling 

onto it (and thus reflects no radiation), and wavelengths of the radiation emitted by the body are 

related only to its temperature. Black bodies are so named because at room temperature they 

would emit mostly infrared radiation, which has a lower frequency and longer wavelength than 

visible light. Because they would also reflect no radiation, they would appear black. As the 

temperature of a black body increases, its emitted radiation increases in frequency while 

5C-3 

EE-2006-STD-0131 COMMENT 101
5C-4 

shortening in wavelength and begins to be perceived as visible light. Any object hot enough to 

emit visible light is said to incandesce, and the phenomenon of visible-light emission due to high 

temperature is known as incandescence. 

 A lamp’s correlated color temperature (CCT) is another commonly-computed color 

property and is based on the behavior of black bodies. The CCT of a lamp is the temperature of 

a black body that produces roughly the same spectral power distribution of light (and thus 

roughly the same perceived color). Incandescent lamps produce light when electric current is 

sent through the filament inside the lamp, causing the filament to heat up and incandesce. The 

SPD generated by incandescent lamps is similar to the SPD generated by a black body; thus, the 

temperature of the heated filament is near the CCT of the lamp. Many IRL have a CCT between 

2,700 K and 3,000 K. 

 The color rendering index (CRI) of a lamp is also commonly computed and refers to how 

closely the perceived color of an object illuminated by that lamp matches the perceived color of 

the same object illuminated by daylight or black-body radiation. The CRI ranges from 0 to 100; 

lamps with high CRIs illuminate objects such that humans perceive colors similar to what they 

would perceive if those objects were illuminated by daylight, or by a black body radiator. Most 

incandescent lamps without modified spectrums have a CRI near 100. 

5C.2.2 Methods of Modifying Spectral Power Distributions 

 The spectral power distributions that can be generated by incandescence are such that 

incandescing objects can only produce a narrow subset of all of the colors that the human eye 

can perceive. To produce colors that are distant from the black-body locus, the SPD of an 

incandescent object’s radiation must be modified in some way. Various methods are used to 

modify the SPD of incandescent reflector lamps. Some methods utilize specific chemicals, such 

as neodymium, that are introduced into the cover glass of the lamp. Other methods rely on 

layers of material that are sandwiched into the cover glass or coatings that are applied to the 

outside or inside faces of the glass. The compounds, layers, or coatings used to modify the SPD 

operate by reducing the power of specific wavelengths of light; thus, they act as selective filters. 

Because the total light output of the IRL is reduced when selective filtering is applied, IRL with 

modified spectrums are less efficacious than standard-spectrum IRL of the same filament type, 

bulb shape, rated voltage, and rated wattage. 

5C.3 APPLICATION OF “MODIFIED SPECTRUM” DEFINITION TO IRL 

 The Energy Policy and Conservation Act (EPCA), as amended by the Energy 

Independence and Security Act of 2007 (EISA 2007), defines “modified spectrum” as follows 

(42 U.S.C. 6291(30)(W)): 

“The term ‘modified spectrum’ means, with respect to an incandescent lamp, an incandescent 

lamp that— 

 (i) is not a colored incandescent lamp; and 

 (ii) when operated at the rated voltage and wattage of the incandescent lamp— 

EE-2006-STD-0131 COMMENT 101
5C-5 

 

(I) has a color point with (x,y) chromaticity coordinates on the Commission 

Internationale de l’Eclairage (C.I.E.) 1931 chromaticity diagram that lies below 

the black-body locus; and 

(II) has a color point with (x,y) chromaticity coordinates on the C.I.E. 1931 

chromaticity diagram that lies at least 4 MacAdam steps (as referenced in IESNA 

LM16) distant from the color point of a clear lamp with the same filament and 

bulb shape, operated at the same rated voltage and wattage.” 

 The following sections will address each component of the definition in turn as it relates 

to modified-spectrum IRL. 

5C.3.1 Color Requirements 

 The “modified spectrum” definition requires that the modified-spectrum lamp meet 

specific color requirements; namely, that it not be a “colored incandescent lamp.” (42 U.S.C. 

6291(30)(W)(i)) The amended EPCA defines “colored incandescent lamp” as follows (42 

U.S.C. 6291(30)(EE)): 

“The term ‘colored incandescent lamp’ means an incandescent lamp designated and marketed as 

a colored lamp that has— 

(i) a color rendering index of less than 50, as determined according to the test method 

given in C.I.E. publication 13.3–1995; or 

(ii) a correlated color temperature of less than 2,500K, or greater than 4,600K, where 

correlated temperature is computed according to the Journal of Optical Society of 

America, Vol. 58, pages 1528–1595 (1986).”b

 Most IRL with unmodified spectrums have a CRI near 100 and a CCT between 2700 K 

and 3,000 K. Colored incandescent lamps are lamps that have been modified, using coatings or 

other methods, so that they produce light that is perceived as blue, red, green, or other colors. 

These lamps are used for aesthetic or artistic effects and thus are not meant to reproduce object 

colors accurately. 

5C.3.2 Black-Body Locus Requirements 

 The “modified spectrum” definition also requires that a modified-spectrum incandescent 

lamp produce a perceived color with a “color point . . . that lies below the black-body locus” on 

the CIE 1931 chromaticity diagram when the lamp is operated at its rated voltage and wattage. 

(42 U.S.C. 6291(30)(W)(ii)(I)) The chromaticity diagram and black-body locus are shown in 

Figure 5C.3 along with red straight lines indicating color requirements. The combined color and 

black-body locus requirements of the “modified spectrum” definition exclude all lamps with 

color points outside of the dark grey area in the figure. 

b

 Note that EISA 2007 included “1986” as the year of publication of the article. However, 1986 is the incorrect year 

for the Journal of Optical Society of America reference; the correct year is 1968. 

EE-2006-STD-0131 COMMENT 101
1931 CIE Chromaticity Diagram

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

x

y

Figure 5C.3: Combined Black-Body Locus and Color Requirements of the “ModifiedSpectrum” Definition 

5C.3.3 MacAdam-Step Requirements 

Finally, the “modified-spectrum” definition requires that a modified-spectrum 

incandescent lamp have a color point that “lies at least 4 MacAdam steps . . . distant from the 

color point of a clear lamp with the same filament and bulb shape, operated at the same rated 

voltage and wattage.” (42 U.S.C. 6291(30)(W)(ii)(II)) Requiring the color point to be “at least 4 

MacAdam steps . . . distant from the color point of a clear lamp” ensures that modified-spectrum 

lamps will be noticeably different in color than similar clear lamps. Figure 5C.4Error! 

Reference source not found. shows a magnification of the CIE 1931 chromaticity diagram with 

an example of three IRL samples that meet the definition of “modified spectrum.” The color 

points of the three standard-spectrum and three modified-spectrum IRL samples in this pair are 

shown as blue dots in the figure. The modified-spectrum IRL have color points located below 

the black-body locus, shown in black. In addition, they meet the color requirements bounded by 

the red straight line at the right (the left bound is located outside of the area shown by the figure). 

Finally, their color points meet the MacAdam step requirement established by the three 

corresponding standard-spectrum lamps located in the center of the red ellipse; the red ellipse 

represents a distance of four MacAdam steps from the average color point of the standardspectrum IRL. 

5C-6 

EE-2006-STD-0131 COMMENT 101
Figure 5C.4: Example of IRL That Meet the Definition of "Modified Spectrum;” 

Modified-Spectrum IRL Color Points Lie to the Lower Left of the Red Circle 

 Applying the definition of “modified spectrum” requires comparing the color point of the 

IRL in question to the color point of a clear lamp. IRL, however, are not clear lamps because 

they have reflectors; IRL also commonly have frosted or textured faces. In order to apply the 

definition of “modified spectrum,” DOE developed a normalization method to model a clear 

lamp. This method is discussed in the section below. 

5C.4 METHODOLOGY 

 In order to explore the efficacy differences between standard-spectrum and modifiedspectrum IRL, DOE paired commercially available standard-spectrum IRL with available IRL in 

the same product line that were advertised as featuring spectral modification (for example, IRL 

advertised as “daylight” or “full-spectrum” lamps). First, DOE surveyed the market of 

commercially-available IRL. DOE then selected lamp models that could be identified as 

featuring spectral modification based on the manufacturers’ catalogs or marketing literature. 

Standard-spectrum lamp models were paired with the lamps featuring spectral modification such 

that the lamps in each pair had the same bulb shape, the same rated life, the same rated voltage 

and wattage, and the same class of filament shape. All lamps had a rated voltage of 120V. 

5C-7 

EE-2006-STD-0131 COMMENT 101
 In total, DOE tested seven pairs of parabolic aluminized reflector (PAR) lampsc

 from two 

major manufacturers. Six pairs consisted of halogen lamps, and one pair consisted of halogen 

infrared (HIR) lamps. Each pair contained three samples of an IRL model advertised as 

featuring spectral modification along with three samples of a corresponding standard-spectrum 

IRL model in the same product line. Halogen and HIR lamps were selected because the IRL 

design options that meet the proposed IRL standards in this rulemaking consist of both halogen 

and HIR technologies. Non-halogen incandescent lamps were not selected, as these non-halogen 

IRL have significantly different radiation spectra over wavelengths contributing to the 

calculation of lumens (in general their light outputs are shifted toward longer wavelengths) than 

HIR and halogen sources. Therefore, it is likely that the resulting scaling factor based on these 

lamps would be significantly different than for halogen sources. Because non-halogen IRL 

(representing the IRL lamp types exempted from standards) are not regulated in this rulemaking, 

DOE believes that it would be inappropriate to include non-halogen lamps in its scaling factor 

analysis. Therefore, DOE considered only halogen and HIR IRL for the computation of the 

modified-spectrum IRL scaling factor. DOE did, however, test one lamp pair featuring a smaller 

diameter (PAR16) than IRL covered by this rulemaking, in order to supplement its analysis of 

larger-diameter lamps. 

 DOE measured and recorded the SPDs of the standard-spectrum IRL samples in each 

pair, in accordance with the guidelines in 10 CFR Appendix R to Subpart B of Part 430 for 

incandescent lamps. Using the same guidelines, DOE also measured and recorded the SPDs of 

the samples of lamps advertised as featuring spectral modification IRL. DOE then utilized the 

SPDs to compute the MacAdam-step shift and corresponding lumen output reductions between 

the standard-spectrum and spectrally-modified lamps across the lamp samples in every lamp 

pair. 

 In order to do this, DOE first had to account for the fact that standard-spectrum IRL are 

not clear lamps due to the impact of their cover glass and their reflectors. DOE thus developed a 

methodology to isolate the effects of spectrum modification in order to determine the relative 

reduction in lumen output and the relative change in color that would be observed if a spectrallymodified IRL were compared to a clear lamp. The method also assumes that spectrum 

modification is achieved through the usage of neodymium in the cover glass of a modifiedspectrum lamp. The heart of the method is a model that simulates the spectral power distribution 

of a halogen capsule without any cover glass, termed HSPD in the equation below. This spectral 

power distribution is then used to simulate a clear lamp. The methodology utilizes the equation 

shown below in Eq. 5C.1: 

CGNW SPD

780

380

T

c

5

9

1

SPD CGN SPD M***

1e

10*c M**H *SA* 2















































































 

 







 Eq. 5C.1

 

5C-8 

c

 Other IRL bulb shapes, such as BR and R shapes, are not covered by the standards proposed in this rulemaking. 

EE-2006-STD-0131 COMMENT 101
Where: 

 Wm 2 2 

1  hc2c

k

hc

c2  mK 

 c = 2.99792458 ×108 m/s (velocity of light) 

 h = 6.626176 ×10-34 Js (Planck constant) 

 k = 1.380662 ×10-23 J/K (Boltzmann constant) 

and: 

 HSPD: the simulated spectral power distribution of a halogen or HIR capsule 

 MSPD: the measured spectral power distribution of a spectrally-modified lamp 

: wavelength of light emitted from the lamp filament (in meters) 

 T: temperature of the filament (in Kelvin) 

SA: surface area of the filament (in square meters), determined by selecting a black-body 

radiator with the same radiant power as the measured standard-spectrum IRL 

α: correction term for the filament surface area 

εW: emissivity of tungsten, which models a tungsten filament 

τN: transmittance of neodymium in a spectrally-modified cover glass 

τCG: transmittance of a clear cover glass 

β: combined effect of neodymium concentration and thickness of neodymium in a 

spectrally-modified cover glass 

Transmittance is the fraction of light (at a specific wavelength) hitting an object that 

travels through the object and can be measured on the other side. To determine the 

transmittance, DOE measured the transmittance of a standard-spectrum cover glass, τCG, between 

the wavelengths of 380 nm and 780 nm. DOE also measured τN using a spectrally-modified 

lamp cover glass. The cover glass transmittance for a specific lamp featuring spectral 

modification tested by DOE is shown relative to the corresponding standard-spectrum lamp 

transmittance in Figure 5C.5. Sharp dips in the plot clearly indicate which light wavelengths are 

absorbed by the combination of neodymium and cover glass. 

5C-9 

EE-2006-STD-0131 COMMENT 101
0.0

0.2

0.4

0.6

0.8

1.0

1.2

380 430 480 530 580 630 680

Spectral Transmittance

Wavelength (nm)

Figure 5C.5: Transmittance of a Specific Lamp Cover Glass Featuring Neodymium, 

Relative to the Standard-Spectrum Cover Glass Transmittance 

 DOE utilized an unconstrained nonlinear optimization program to compute α, β, and T 

and thus model the spectral power distribution of the capsule inside of a spectrally-modified 

lamp, HSPD. DOE then used HSPD and the transmittance of a cover glass without any spectrummodifying features in Eq. 5C.2 in order to obtain ISPD, the spectral power distribution of a clear 

lamp: 

SPD CG SPD   I*H Eq. 5C.2

The light output reduction is obtained by dividing MSPD by ISPD. In addition both ISPD and MSPD

were used to calculate color points. Then, the color separation from the ISPD color point to the 

MSPD color point was determined in terms of MacAdam steps. Results are presented below. 

5C.5 ANALYTICAL RESULTS 

 Once DOE determined MacAdam-step variations and light output reductions for every 

tested lamp pair. DOE then used a relationship between MacAdam-step shift and light output 

reduction for lamps featuring spectral modification. This information is shown in Table 5C.5.1

and Figure 5C.6 for every individual lamp combination tested (21 combinations of standard5C-10 

EE-2006-STD-0131 COMMENT 101
5C-11 

spectrum and spectrally-modified lamps, derived from the 7 lamp pairs that each contained three 

standard-spectrum and three spectrally-modified lamp samples). 

Table 5C.5.1: MacAdam-Step Shifts and Light Output Reductions for Lamps Tested by 

DOE 

Lamp ID 

StandardSpectrum SpectrallyModified alpha beta T 

MacAdamStep Shift 

Light 

Output 

Reduction 

105352 105349 1.249 1.076 2746.221 5.4 19.2% 

105353 105350 1.239 1.146 2746.022 5.7 20.1% 

105354 105351 1.290 1.116 2741.640 5.6 19.7% 

105374 105371 1.323 1.086 2715.983 5.5 19.3% 

105375 105372 1.344 1.096 2707.611 5.5 19.5% 

105376 105373 1.273 1.029 2726.019 5.2 18.6% 

106705 106702 1.275 0.981 2845.517 5.0 17.9% 

106706 106703 1.296 1.066 2838.923 5.4 19.0% 

106707 106704 1.271 1.055 2857.426 5.4 18.9% 

106751 106748 1.498 0.473 2699.566 2.4 10.0% 

106752 106749 1.488 0.374 2678.070 1.8 8.2% 

106753 106750 1.803 0.395 2653.760 1.9 8.6% 

105355 105276 1.337 0.425 2739.313 2.1 9.1% 

105356 105277 1.411 0.500 2750.256 2.5 10.5% 

105357 105278 1.305 0.430 2751.663 2.1 9.2% 

105358 105269 1.315 0.456 2818.707 2.3 9.7% 

105359 105270 1.272 0.448 2818.681 2.3 9.5% 

105360 105271 1.256 0.473 2821.212 2.4 10.0% 

105363 105287 1.208 0.547 2760.137 2.8 11.3% 

105364 105288 1.337 0.541 2784.910 2.7 11.2% 

105377 105289 1.325 0.495 2770.849 2.5 10.4% 

EE-2006-STD-0131 COMMENT 101
y = 44.091x1.2694

R2 = 0.9997

0

1

2

3

4

5

6

7

0% 5% 10% 15% 20%

MacAdam Steps

Light Output Reduction 

Figure 5C.6 Relationship Between Light Output Reduction and MacAdam-Step Shift For 

Lamps Tested by DOE 

 

5C-12 

EE-2006-STD-0131 COMMENT 101
5C.6 SELECTION OF FINAL SCALING FACTOR 

 The results of DOE’s analysis of commercially-available lamps indicated that a 4-

MacAdam-step shift between a standard-spectrum IRL and a lamp featuring spectral 

modifications corresponds with an approximate efficacy reduction of 15 percent. DOE thus 

selected 15 percent as the efficacy reduction factor required of IRL that meet the “modified 

spectrum” definition. A comparison of the efficacy requirements for standard spectrum and 

modified-spectrum IRL is shown in Figure 5C.7. The IRL standard that currently exists in 

EPCA is shown as the dotted stair-step line labeled “Baseline EPCA.” Note that the smoothed 

lines for the modified spectrum efficiency levels (ELs) 1 and 2 have been raised in some areas so 

that the EPCA standard is met. This is because DOE “may not prescribe any amended standard 

which increases the maximum allowable energy use . . . or decreases the minimum required 

energy efficiency, of a covered product.” (42 U.S.C. 6295(o)(1)) 

Baseline

EPCA

EL 1

EL 2

EL4

EL 3

EL5

9.0

11.0

13.0

15.0

17.0

19.0

21.0

23.0

30 40 50 60 70 80 90 100 110

Lamp Efficacy (lm/W)

Lamp Power (W)

Mod EL1

Mod EL2

Mod EL3

Mod EL4

Mod EL5

Standard Spectrum 

Modified Spectrum 

Figure 5C.7: Comparison of Standard-Spectrum and Modified-Spectrum IRL Efficacy 

Requirements 

5C-13 

EE-2006-STD-0131 COMMENT 101
5C-14 

 

REFERENCES 

1

 Rea, Mark S., ed. The IESNA Lighting Handbook: Reference & Application, 9th Edition. 

2000. The Illuminating Engineering Society of America: New York, New York. 

2

 International Energy Agency. Light’s Labour’s Lost: Policies for Energy-efficient Lighting. 

OECD/IEA, 2006. 

3

 D. L. MacAdam, "Visual Sensitivities to Color Differences in Daylight," J. Opt. Soc. Am. 32, 

247-273 (1942). 

EE-2006-STD-0131 COMMENT 101