CHAPTER 3. MARKET AND TECHNOLOGY ASSESSMENT 

TABLE OF CONTENTS 

3.1 INTRODUCTION ........................................................................................................... 3-1

3.1.1 Definitions............................................................................................................ 3-1

3.1.1.1 Fluorescent Lamps................................................................................... 3-1

3.1.1.2 General Service Fluorescent Lamps ........................................................ 3-2

3.1.1.3 Incandescent Reflector Lamps................................................................. 3-3

3.2 MARKET ASSESSMENT .............................................................................................. 3-4

3.2.1 Trade Association ................................................................................................ 3-4

3.2.2 Manufacturers and Market Share.........................................................................3-5

3.2.2.1 Small Businesses...................................................................................... 3-5

3.2.3 Regulatory Programs ........................................................................................... 3-6

3.2.3.1 Federal Energy Conservation Standards..................................................3-6

3.2.3.2 Canadian Energy Efficiency Standards ................................................... 3-9

3.2.4 Non-Regulatory Initiatives................................................................................. 3-11

3.2.4.1 Federal Energy Management Program .................................................. 3-11

3.2.4.2 Consortium for Energy Efficiency......................................................... 3-11

3.2.4.3 Energy Efficient Commercial Building Deduction................................ 3-12

3.2.4.4 Northeast Energy Efficiency Partnerships............................................. 3-12

3.2.5 Historical Shipments.......................................................................................... 3-12

3.3 TECHNOLOGY ASSESSMENT.................................................................................. 3-15

3.3.1 General Service Fluorescent Lamps .................................................................. 3-15

3.3.1.1 Highly Emissive Electrode Coatings ..................................................... 3-17

3.3.1.2 Higher Efficiency Lamp Fill Gas Composition..................................... 3-17

3.3.1.3 Higher Efficiency Phosphors .................................................................3-19

3.3.1.4 Glass Coatings ....................................................................................... 3-24

3.3.1.5 Higher Efficiency Lamp Diameter......................................................... 3-24

3.3.1.6 Multi-Photon Phosphors ........................................................................ 3-25

3.3.2 Incandescent Reflector Lamps........................................................................... 3-25

3.3.2.1 Higher Temperature Operation..............................................................3-26

3.3.2.2 Microcavity Filaments ........................................................................... 3-27

3.3.2.3 Novel Filament Materials ...................................................................... 3-28

3.3.2.4 Thinner Filaments .................................................................................. 3-28

3.3.2.5 Efficient Filament Coiling ..................................................................... 3-28

3.3.2.6 Crystallite Filament Coatings ................................................................ 3-28

3.3.2.7 Efficient Filament Orientation ............................................................... 3-28

3.3.2.8 Higher Efficiency Inert Fill Gas ............................................................ 3-29

3.3.2.9 Luminescent Gas.................................................................................... 3-29

3.3.2.10 Tungsten-Halogen Lamps ................................................................. 3-29

3.3.2.11 Higher Pressure Tungsten-Halogen Lamps....................................... 3-29

3.3.2.12 Non-Tungsten-Halogen Regenerative Cycles...................................3-30

3.3.2.13 Infrared Glass Coatings.....................................................................3-30

3.3.2.14 Infrared Phosphor Glass Coating ......................................................3-30

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3.3.2.15 Integrally Ballasted Low-Voltage Lamps ......................................... 3-30

3.3.2.16 Higher Efficiency Reflector Coatings...............................................3-31

3.3.2.17 Trihedral Corner Reflectors .............................................................. 3-31

3.3.2.18 Efficient Filament Placement............................................................ 3-31

3.4 PRODUCT CLASSES................................................................................................... 3-31

3.4.1 General Service Fluorescent Lamps .................................................................. 3-32

3.4.1.1 Physical Constraints of Fluorescent Lamps........................................... 3-33

3.4.1.2 Lumen Package...................................................................................... 3-33

3.4.1.3 Correlated Color Temperature ............................................................... 3-34

3.4.1.4 Ballast Interoperability...........................................................................3-34

3.4.1.5 Lamp Wattage........................................................................................ 3-34

3.4.1.6 Lamp Diameter ...................................................................................... 3-35

3.4.1.7 Color Rendering Index...........................................................................3-35

3.4.1.8 Product Classes and Standard Form for GSFL...................................... 3-36

3.4.2 Incandescent Reflector Lamps........................................................................... 3-36

3.4.2.1 Wattage .................................................................................................. 3-36

3.4.2.2 Modified Spectrum ................................................................................3-37

3.4.2.3 Lamp Diameter ...................................................................................... 3-38

3.4.2.4 Rated Voltage......................................................................................... 3-38

3.4.2.5 Spot Versus Flood Incandescent Reflector Lamps ................................ 3-39

3.4.2.6 Product Classes and Standard Form for IRL ......................................... 3-39

REFERENCES ..........................................................................................................................3-40

LIST OF TABLES 

Table 3.1 Federal Regulations for General Service Fluorescent Lamps ....................................3-7

Table 3.2 EPCA Standards for Fluorescent Lamp Ballasts........................................................ 3-7

Table 3.3 EPACT 2005 Standards for Fluorescent Lamp Ballasts............................................. 3-8

Table 3.4 Federal Regulations for Incandescent Reflector Lamps.............................................. 3-8

Table 3.5 Canadian Energy Efficiency Regulations for Incandescent Reflector Lamps..........3-10

Table 3.6 Federal Energy Management Program Efficiency Recommendation ......................3-11

Table 3.7 NEMA Shipments of Four-Foot Medium Bipin General Service Fluorescent Lamps.. 3-

13

Table 3.8 NEMA Shipments of Eight-Foot Single Pin Slimline General Service Fluorescent 

Lamps......................................................................................................................................... 3-14

Table 3.9 NEMA Shipments of Two-Foot U-Shaped General Service Fluorescent Lamps.....3-14

Table 3.10 NEMA Shipments of Eight-Foot Recessed Double Contact High Output General 

Service Fluorescent Lamps........................................................................................................ 3-14

Table 3.11 NEMA Shipments of Incandescent Reflector Lamps.............................................. 3-15

Table 3.12 EPCA Product Classes for General Service Fluorescent Lamps............................3-32

Table 3.13 DOE NOPR Product Classes for GSFL.................................................................. 3-36

Table 3.14 EPCA Product Classes for Incandescent Reflector Lamps ....................................3-36

Table 3.15 DOE NOPR Product Classes for IRL...................................................................... 3-39

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LIST OF FIGURES 

Figure 3.3.1 Lamp Length Effects on Efficacy......................................................................... 3-16

Figure 3.3.2 Lamp Fill Gas Effect on UV Output for T12 Lamps ........................................... 3-18

Figure 3.3.3 Lamp Fill Gas Effect on Thermionic Emission for T12 Lamps...........................3-19

Figure 3.3.4 Human Eye Photopic Spectral Luminous Efficiency Function, V(λ)..................3-20

Figure 3.3.5 Sample Power Spectrum Distribution .................................................................. 3-21

Figure 3.3.6 Average Efficacies of Lamps with a CCT of 6,500K versus 4,100K ..................3-22

Figure 3.3.7 Lamp Efficacies for Halo- and Rare-Earth Phosphors......................................... 3-23

Figure 3.3.8 Light Output versus Phosphor Thickness............................................................. 3-23

Figure 3.3.9 Bulb Diameter versus Efficacy............................................................................. 3-25

Figure 3.3.10 Radiating Characteristics of Tungsten................................................................ 3-26

Figure 3.3.11 Luminous Efficacy versus Color Temperature................................................... 3-27

Figure 3.4.1 Illustration of IRL Trial Standard Level Forms ........................................................ 1
CHAPTER 3. MARKET AND TECHNOLOGY ASSESSMENT 

3.1 INTRODUCTION 

This chapter details the market and technology assessment that the U.S. Department of 

Energy (DOE) has conducted in support of the ongoing energy conservation standards and test 

procedures rulemakings for general service fluorescent lamps (GSFL) and incandescent reflector 

lamps (IRL). These rulemakings are mandated by the Energy Policy and Conservation Act 

(EPCA), as amended, and are effective for lamps manufactured during and after July, 14, 2012. 

This chapter consists of three sections: the market assessment, the technology 

assessment, and product classes. The market assessment provides an overall picture of the 

market for the products concerned, including the nature of the products, industry structure, and 

manufacturer market shares; regulatory and non-regulatory efficiency improvement programs; 

and market trends and quantities of products sold. The technology assessment identifies a list of 

technologies to consider in the screening analysis. The product classes section discusses the 

product classes DOE considered using for this rulemaking and how they were developed. 

The information DOE gathers from the market and technology assessment serves as 

resource material for use throughout the rulemaking. DOE considers both quantitative and 

qualitative information from publicly available sources and stakeholders in this assessment. 

3.1.1 Definitions 

This rulemaking covers certain types of fluorescent and incandescent reflector lamps. 

Section 321(30) of EPCA (42 U.S.C. 6291(30)) contains definitions for “fluorescent lamp,” 

“general service fluorescent lamp,” “incandescent lamps,” and “incandescent reflector lamp.” 

DOE codified in the CFR the statutory definitions and definitions of supplementary terms for 

fluorescent and incandescent lamps. 62 FR 29222 (May 29, 1997); 10 CFR section 430.2. 

Appendix 3A lists these terms and their definitions. 

As part of this energy conservation standards rulemaking, DOE is considering extending 

coverage to additional GSFL. (42 U.S.C. 6295(i)(5)) The following sections describe in more 

detail EPCA’s definitions for fluorescent and incandescent lamps, note DOE’s interpretation of 

the definitions, and note the definitions DOE is considering revising or developing. Please see 

section III of the final rule Federal Register notice associated with this rulemaking for more 

discussion on DOE’s consideration of additional fluorescent lamps, its interpretation of EPCA’s 

definitions and its consideration revise non-statutory definitions. 

3.1.1.1 Fluorescent Lamps 

Section 321(30)(A) of EPCA (42 U.S.C. 6291(30)(A)) defines a fluorescent lamp as: 

 “a low pressure mercury electric-discharge source in which a fluorescing coating 

transforms some of the ultraviolet energy generated by the mercury discharge into light, 

including only the following: 

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(i) Any straight-shaped lamp (commonly referred to as 4-foot medium bi-pin lamps) 

with medium bi-pin bases of nominal overall length of 48 inches and rated wattage of 28 

or more. 

(ii) Any U-shaped lamp (commonly referred to as 2-foot U-shaped lamps) with 

medium bi-pin bases of nominal overall length between 22 and 25 inches and rated 

wattage of 28 or more. 

(iii) Any rapid start lamp (commonly referred to as 8-foot high output lamps) with 

recessed double contact bases of nominal overall length of 96 inches and 0.800 nominal 

amperes, as defined in ANSI C78.1-1978 and related supplements. 

(iv) Any instant start lamp (commonly referred to as 8-foot slimline lamps) with 

single pin bases of nominal overall length of 96 inches and rated wattage of 52 or more, 

as defined in ANSI C78.3-1978 (R1984) and related supplement ANSI C78.3a-1985.” 

In a final rule published May 29, 1997, DOE updated section 321(30)(A)(iv) references 

of American National Standards Institute (ANSI) standards by changing “ANSI C78.3-1978” 

and “ANSI C78.3a-1985” to ANSI C78.1-1991 and C78.3-1991.a

 62 FR 29222. 

3.1.1.2 General Service Fluorescent Lamps 

Section 321(30)(B) of EPCA (42 U.S.C. 6291(30)(B)) defines general service fluorescent 

lamps as: 

“fluorescent lamps which can be used to satisfy the majority of fluorescent applications, 

but does not include any lamp designed and marketed for the following nongeneral 

lighting applications: 

(i) Fluorescent lamps designed to promote plant growth. 

(ii) Fluorescent lamps specifically designed for cold temperature installations. 

(iii) Colored fluorescent lamps. 

(iv) Impact-resistant fluorescent lamps. 

(v) Reflectorized or aperture lamps. 

(vi) Fluorescent lamps designed for use in reprographic equipment. 

 

a

 ANSI C78.3-1978 is an ANSI-published guide to standard characteristics for instant start and cold-cathode 

fluorescent lamps. C78.1-1978 is the equivalent guide for rapid start fluorescent lamps. Supplements to C78.3-

1978 and C78.1-1978 update the guides over time. In 1991, ANSI combined the original standards with their 

supplements into C78.3-1991 and C78.1-1991, respectively. In 1997, DOE incorporated definitions for fluorescent 

lamps into the Code of Federal Regulations (CFR). 62 FR 29238. DOE used the statutory definition, but replaced 

“ANSI C78.1-1978 and related supplements” with “ANSI C78.1-1991” and replaced “ANSI C78.3-1978 (R1984) 

and related supplement C78.3a-1985” with “C78.3-1991.” 

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(vii) Lamps primarily designed to produce radiation in the ultra-violet region of 

 the spectrum. 

(viii) Lamps with a color rendering index of 87 or greater.”b

 As part of this rulemaking, under the authority of 42 U.S.C. 6295(i)(5), DOE has 

considered extending coverage to additional general service fluorescent lamps. In the final rule 

Federal Register notice, DOE considers extending energy conservation standards coverage to the 

following list of “additional general service fluorescent lamps”: 

• 4-foot, medium bipin (MBP) lamps with wattages ≥ 25 and < 28; 

• 2-foot, medium bipin U-shaped lamps with wattages ≥ 25 and < 28; 

• 8-foot recessed double contact (RDC), rapid start, high output (HO) lamps not defined in 

ANSI Standard C78.1-1991; 

• 8-foot RDC, rapid start, HO lamps (other than 0.800 nominal amperes) defined in ANSI 

Standard C78.1-1991; and 

• 8-foot single pin (SP) instant start slimline lamps, with a rated wattage ≥ 52, not defined 

in ANSI Standard C78.3-1991. 

• 4-foot T5, miniature bipin (MiniBP), straight-shaped, standard output (SO) lamps with 

rated wattage ≥ 26; 

• 4-foot T5, MiniBP, straight-shaped, HO lamps with rated wattage ≥ 49; 

 DOE has also revised the existing definitions for “rated wattage” and “colored 

fluorescent lamp,” as discussed in the final rule Federal Register notice. 

3.1.1.3 Incandescent Reflector Lamps 

Section 321(30)(F) of EPCA (42 U.S.C. 6291(30)(F)) defines an incandescent reflector 

lamp as “a lamp described in subparagraph (C)(ii)” of the definition for incandescent lamp. 

Section 321(30)(C) of EPCA (42 U.S.C. 6291(30)(C)) defines “incandescent lamp” as: 

“a lamp in which light is produced by a filament heated to incandescence by an electric 

current, including only the following: 

(i) Any lamp (commonly referred to as lower wattage nonreflector general service 

lamps, including any tungsten-halogen lamp) that has a rated wattage between 30 

and 199 watts, has an E26 medium screw base, has a rated voltage or voltage 

range that lies at least partially within 115 and 130 volts, and is not a reflector 

lamp. 

 

b

 Section 316(b) of the Energy Independence and Security Act of 2007 amended section 321(30)(B)(viii) of EPCA 

(42 U.S.C 6291(30)(B)(viii)) by replacing the exclusion for lamps with a CRI of 82 or greater, with an exclusion of 

lamps with a CRI of 87 or greater. 

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(ii) Any lamp (commonly referred to as a reflector lamp) which is not colored or 

designed for rough or vibration service applications, that contains an inner 

reflective coating on the outer bulb to direct the light, an R, PAR, ER, BR, BPAR 

or similar bulb shapes with E26 medium screw bases, a rated voltage or voltage 

range that lies at least partially within 115 and 130 volts, a diameter which 

exceeds 2.25 inches, and has a rated wattage that is 40 watts or higher. 

(iii) Any general service incandescent lamp (commonly referred to as a high- or 

higher-wattage lamp) that has a rated wattage above 199 watts (above 205 watts 

for a high wattage reflector lamp).” 

As seen above in subparagraph (ii) of the definition of “incandescent lamp” contains 

several terms that limit scope of IRL. Appendix 3A contains statutory and CFR definitions for 

many of these terms. Concerning E26 medium screw bases, DOE will use the definition of 

“medium screw base” as added to EPCA in section 135(a)(3) of the Energy Policy Act of 2005 

(EPACT 2005), Public Law 109-58. (42 U.S.C. 6291(51)) This defines an Edison screw base 

with the prefix E26 as that appearing in the “American National Standard for Electric Lamp 

Bases,” ANSI/IEC C81.61–2003, published by the American National Standards Institute. This 

version of C81.61 identifies four lamp base (cap) types with a prefix of E26, which are singlecontact medium screw (E26/24), double-contact medium screw (E26d), skirted medium screw 

for parabolic aluminized reflector (PAR) lamps (E26/50x39), and extended skirted medium 

screw for reflector (R)-lamps (E26/53x39). 

3.2 MARKET ASSESSMENT 

The following market assessment: 

 identifies the manufacturer trade association and domestic manufacturers of GSFL 

and IRL; 

 discusses manufacturer market share, regulatory programs, and non-regulatory 

initiatives; 

 defines product classes; 

 provides historical shipment data, shipment projections, and equipment lifetime 

estimates; and 

 summarizes market performance data. 

3.2.1 Trade Association 

The National Electrical Manufacturers Association (NEMA) is the trade association of 

GSFL and IRL. In addition to lamps, NEMA’s Lighting Systems Division also oversees 

products such as ballasts, emergency lighting, lighting controls, luminaires, solid state lighting, 

and other emerging lighting technologies. NEMA provides an organization through which 

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manufacturers of lighting equipment can work together on projects that affect their industry and 

business. NEMA’s activities relating to energy efficiency include:1

• “Advising DOE and executive agencies on lighting research and market transformation 

needs 

• Participating in the climate change discussions with the Administration and Congress 

• Monitoring energy-efficiency rulemakings and standards affecting lighting products by 

DOE and states 

• Promoting the national voluntary luminaire rating and information program under the 

National Lighting Collaborative 

• Supporting adoption of new ASHRAE/IESNA 90.1 lighting provisions 

• Advising the DOE Federal Energy Management Program (FEMP) on energy-efficient 

lighting recommendations 

• Coordinating with the DOE and Environmental Protection Agency on Energy Star® 

Buildings and Energy Star voluntary product labeling programs. 

• Advocating market-based approaches to enhance the use and penetration of energyefficient technologies.” 

3.2.2 Manufacturers and Market Share 

The GSFL and IRL industries are characterized by both domestic and international 

manufacturers. The majority of covered GSFL and IRL are manufactured by three large 

companies. The three manufacturers that hold the majority of the domestic market share of 

GSFL and IRL are listed below. 

• GE Consumer and Industrial of General Electric, Inc. (hereafter, “GE) 

• OSRAM Sylvania of Siemens AG (hereafter “Osram”) 

• Philips Lighting of Royal Philips Electronics (hereafter “Philips”) 

 In addition to lamps listed under this rulemaking, the lighting divisions of all three 

companies manufacture other products, such as lamp ballasts, high intensity discharge lamps, 

LED lighting, and compact fluorescent lamps (CFL). 

3.2.2.1 Small Businesses 

Small businesses may be particularly affected by the promulgation of minimum energy 

conservation standards for fluorescent and incandescent lamps. The Small Business 

Administration (SBA) defines small business manufacturing enterprises for GSFL and IRL as 

having 1,000 employees or fewer.2

 SBA lists small business size standards that are matched to 

industries as they are described in the North American Industry Classification System (NAICS). 

A size standard is the largest that a for-profit concern can be and still qualify as a small business 

for Federal Government programs. These size standards are generally the average annual 

receipts or the average employment of a firm. For lamps, the size standard is matched to NAICS 

code 335110, Electric Lamp Bulb and Part Manufacturing, which has a size standard of 1,000 

employees. 

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During its market survey, DOE contacted 57 companies that potentially manufactured 

lamps covered by this rulemaking. DOE determined that only 12 companies out of the 57 listed 

were potentially small business manufacturers of covered products. DOE contacted these 

potential small business manufactures to request an interview about the possible impacts on 

small business manufacturers. Of the 12 potential small business manufacturers, DOE 

interviewed four. Based on the information gathered during this process, DOE identified only 

one company as a small business manufacturer of covered GSFLs based on SBA’s definition of 

small business manufacturer. 

During its research and interviews, DOE learned valuable information about the overall 

market for GSFL and IRL. Small businesses in the GSFL and IRL industry are typically not 

manufacturers. If a small business does have any manufacturing, it typically manufactures 

fluorescent lamps and IRL that are not covered in this rulemaking. For example, small business 

fluorescent lamp manufacturers focus on signs, small fluorescent lamps, and vitamin D lamps, 

while the small business IRL manufacturers focus on products like rough service lamps. DOE 

found that most of the small businesses that sell covered GSFL and IRL are distributors and thus 

not small business manufacturers. These companies do not own any manufacturing equipment 

for the covered GSFL and IRL. Generally, these small businesses are lighting supply companies 

that source or rebrand products from a variety of overseas and domestic manufacturers. Even if 

a small distributor does offer its own brand of covered lamps, they typically contract with 

overseas factories to provide their products and are not involved in the manufacturing process. 

DOE studied the potential impacts on small businesses in detail in the manufacturer 

impact analysis (see chapter 13 of the TSD for more details). 

3.2.3 Regulatory Programs 

DOE is aware of several Federal and international regulatory programs that affect the 

markets for GSFL and IRL. Amendments to EPCA in the Energy Policy Act of 1992 

(EPACT1992), P.L. 102-486, established energy conservation standards for GSFL and IRL. (42 

U.S.C. 6291(1) and 6295(i)(1)) In addition, subsequent amendments to EPCA in the Energy 

Independence and Security Act of 2007 (EISA 2007), P.L. 110-140, amended the existing 

standard for IRL. 

The following section summarizes U.S. and Canadian regulatory initiatives relevant to 

the lamps covered by this rulemaking. While the following discussion is not exhaustive in 

describing all regulatory action related to GSFL and IRL, it provides detail on some notable 

initiatives that characterize recent developments in the lighting market. 

3.2.3.1 Federal Energy Conservation Standards 

Table 3.1 shows the Federal standards that regulate 4-foot MBP, 2-foot U-shaped, 8-foot 

SP slimline, and 8-foot RDC HO general fluorescent lamps. The standards mandate that lamps 

manufactured on or after the specified effective dates must meet the minimum color rendering 

index (CRI) and minimum average lamp efficacy. 42 U.S.C. 6295(i)(1); 10 CFR Section 

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430.32(n)(1) 

Table 3.1 Federal Regulations for General Service Fluorescent Lamps 

Lamp Type 

Nominal Lamp 

Wattage 

W 

Minimum 

CRI 

Minimum Average 

Lamp Efficacy 

lm/W 

Effective Date 

> 35 W 69 75.0 Nov. 1, 1995 Four-Foot Medium Bipin ≤ 35 W 45 75.0 Nov. 1, 1995 

> 35 W 69 68.0 Nov. 1, 1995 Two-Foot U-Shaped ≤ 35 W 45 64.0 Nov. 1, 1995 

> 65 W 69 80.0 May 1, 1994 Eight-Foot Slimline ≤ 65 W 45 80.0 May 1, 1994 

> 100 W 69 80.0 May 1, 1994 Eight-Foot High Output ≤ 100 W 45 80.0 May 1, 1994 

Fluorescent lamp ballasts are also regulated at the Federal level. Though they are not 

covered by this rulemaking, the ballast on which fluorescent lamps operate affects the systems’ 

operating characteristics (total system power, lumen output, etc.) and therefore will affect the 

analyses DOE conducts. On September 19, 2000, DOE issued a Final Rule establishing energy 

conservation standards for ballasts that operate one F40T12 lamp, two F40T12 lamps, two 

F96T12 lamps, or two F96T12HO lamps (hereafter referred to as ‘‘the Ballast Rule’’). 65 FR 

56740 (Sept. 19, 2000); 10 CFR 430.23(m)(4). Table 3.2 shows the energy conservation 

standards for fluorescent lamp ballasts. This rule bans the fabrication of ballasts that do not meet 

these ballast efficacy factor (BEF) requirements as of April 1, 2005. The ban on U.S. sales by 

ballast manufacturers to fixture manufacturers took effect July 1, 2005. The ban on U.S. sales of 

ballasts in lighting fixtures took effect on April 1, 2006. The ban on U.S. sales of replacement 

ballasts begins on July 1, 2010. The regulations provide for some exemptions. 

Table 3.2 EPCA Standards for Fluorescent Lamp Ballasts 

Application for Operation of 

Ballast Input 

Voltage 

V

Total Nominal 

Lamp Watts 

W

Ballast Efficacy 

Factor 

120 40 1.805 One F40T12 Lamp 277 40 1.805 

120 80 1.060 Two F40T12 Lamps 277 80 1.050 

120 150 0.570 Two F96T12 Lamps 277 150 0.570 

120 220 0.390 Two F96 T12 HO Lamps 277 220 0.390 

Sections 135(a) of EPACT 2005 amended EPCA to set additional requirements for 

fluorescent lamp ballasts operating one F34T12 lamp, two F34T12 lamps, two F96T12/ES 

lamps, or two F96T12HO/ES lamps (hereafter referred to as “the EPACT 2005 Ballast 

Standard”). (42 U.S.C. 6291(29) and 6295(g)(8)(a)) Table 3.3 outlines the EPACT 2005 Ballast 

Standards that DOE codified in the U.S. Code of Federal Regulations. (See 10 CFR 

430.32(m)(5)) This standard effectively bans the fabrication of ballasts that do not meet these 

BEF requirements as of July 1, 2009. The effective ban on U.S. sales by ballast manufacturers to 

fixture manufacturers takes effect October 1, 2009. The effective ban on U.S. sales of ballasts in 

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lighting fixtures takes effect on July 1, 2010. The ban on U.S. sales of replacement ballasts 

begins on October 1, 2010. EPACT 2005 provided some exemptions. 

Table 3.3 EPACT 2005 Standards for Fluorescent Lamp Ballasts 

Application for Operation of 

Ballast Input 

Voltage 

V 

Total Nominal 

Lamp Watts 

W 

Ballast Efficacy 

Factor 

120 34 2.61 One F34T12 Lamp 277 34 2.61 

120 68 1.35 Two F34T12 Lamps 277 68 1.35 

120 120 0.77 Two F96T12/ES Lamps 277 120 0.77 

120 190 0.42 Two F96T12HO/ES Lamps 277 190 0.42 

The Ballast Rule and the EPACT 2005 Ballast Standard effectively end the sale of 

magnetic ballasts that operate one F40T12 lamp, two F40T12 lamps, one F34 T12 lamp, two 

F34T12 lamps, or two F96T12/ES lamps. Although there are still magnetic ballasts that operate 

8-foot RDC HO lamps, these ballasts are both less efficient and more expensive than their 

electronic counterparts.3 Therefore, although the most common ballast installed in 2012 for T12 

lamps are magnetic ballasts, the most common ballast sold after 2012 will likely be electronic 

T12 or electronic T8 ballasts. 

In addition to Federal energy conservation standards for fluorescent lamps, EPCA also 

set Federal energy conservation standards for IRL. (42 U.S.C. 6295(i)(1)) Table 3.4 outlines 

these standards. EPCA mandated that all lamps manufactured after November 1, 1995 meet six 

efficacy requirements. Minimum lamp efficacy varies by nominal lamp wattage. One effect of 

these standards is increased use of higher efficacy halogen lamps as a replacement for standard 

IRL. EISA 2007 amended EPCA’s definition for incandescent reflector lamp and amended the 

standard in 42 U.S.C. 6295(i)(1). Prior to EISA 2007, the statutory definition for IRL excluded 

elliptical reflector (ER) and bulged reflector (BR) shaped lamps and lamps with a diameter less 

than 2.75 inches. However, EISA 2007 amended this definition to include ER and BR shaped 

lamps and lamps with diameter greater than 2.25 inches. EISA 2007 also amended 42 U.S.C. 

6295(i)(1) to exempt the following lamps from the minimum efficacy requirements: (1) lamps 

rated at 50 watts of less that are ER30, BR30, BR40, and ER40; (2) lamps rated at 65 watts that 

are BR30, BR40, or ER40 lamps; and (3) R20 incandescent reflector lamps rated 45 watts or 

less. 

Table 3.4 Federal Regulations for Incandescent Reflector Lamps 

Nominal Lamp Wattage 

W 

Minimum Average Lamp Efficacy 

lm/W 

40-50 10.5 

51-66 11.0 

67-85 12.5 

86-115 14.0 

116-155 14.5 

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156-205 15.0 

3.2.3.2 Canadian Energy Efficiency Standards 

The Natural Resources Canada (NRCan) Office of Energy Efficiency regulates the 

energy efficiency of GSFL and IRL in Canada. In 1992, Parliament passed the Energy 

Efficiency Act (S.C. 1992, c. 36), which concerns minimum performance levels for energy-using 

products, effective February 1995. In November 1995, Canada’s Energy Efficiency Regulations

(SOR/94-651) were amended to include GSFL and some GSIL. An amendment in April 2003 

included regulation of selected ER and BR IRL. 

Canada’s approach to the regulation of GSFL closely resembles the U.S. Federal 

Efficiency Standard discussed in section 3.2.3.1. The Canadian minimum average CRI and lamp 

efficacy levels are identical to those shown in Table 3.1. Though there are minor variations in 

definition between the U.S. and Canadian standards, they effectively cover the same product. 

The Canadian test procedures refer to a document published by the Canadian Standards 

Association (CSA). CSA is an independent standards-setting agency that establishes test 

procedures and efficiency standards that are typically adopted by the Canadian government. 

Fluorescent lamp test procedure CAN/CSA-C819-95 (2001), entitled Performance of General 

Service Fluorescent Lamps, references applicable ANSI, CIE, and IES standards. 

Canada’s approach to regulating IRL differs from the U.S. approach. Similar to the 

United States, Canada covers R, PAR, and lamps with similar bulb shapes. However, Canada 

also regulates selected ER and BR lamps. The Energy Efficiency Regulations of Canada apply 

to three categories of IRL: general service incandescent reflector lamps, BR lamps, and ER 

lamps. A “general service incandescent reflector lamp” is defined as an: 

“Incandescent reflector lamp 

 “a. with an R bulb shape, a PAR bulb shape or a bulb shape similar to R or PAR that 

 is neither ER nor BR, as described in ANSI C79.1, 

b. with an R bulb shape, a PAR bulb shape or a bulb shape similar to R or PAR that 

 is neither ER nor BR, as described in ANSI C79.1, 

c. with a nominal voltage or voltage range that lies at least partially between 100 

 volts and 130 volts, 

d. with a diameter greater than 70 mm (2.75 inches), and 

e. that has a nominal power of not less than 40 W and not more than 205 W, 

 but does not include: 

f. a coloured incandescent reflector lamp, or 

g. an incandescent reflector lamp that 

i) is of the rough or vibration service type with: 

(A) a C-11 filament, as described in the IES Handbook, with five supports 

exclusive of lead wires, 

(B) a C-17 filament, as described in the IES Handbook, with eight supports 

exclusive of lead wires, or 

(C) a C-22 filament, as described in the IES Handbook, with 16 supports 

exclusive of lead wires, 

3-9
(ii) is of the neodymium oxide type and has a lens containing not less than 5% 

neodymium oxide, 

(iii) has a coating or other containment system to retain glass fragments if the 

lamp is shattered and is specifically marked and marketed as an impact-resistant 

lamp, 

(iv) is specifically marked and marketed for plant growth use and has a spectral 

power distribution that: 

(A)is different from that of the lamps described in paragraphs (a) to (e), and 

(B) contains a filter that suppresses yellow and green portions of the spectrum, 

or 

(v) is specifically marked and marketed 

(A) as an infrared heat lamp, 

(B) for heat-sensitive use, 

(C) for mine use, 

(D) for marine, aquarium, terrarium or vivarium use, or 

(E) for airfield, aircraft or automotive use.” 

BR lamps are defined as: 

“Incandescent reflector lamp as described in ANSI C79.1, but does not include any of 

 those lamps that have 

a. a diameter of 95.25 mm (BR30) and a nominal power of less than 66 W, 

b. a diameter of 92.5 mm (BR30) and a nominal power of 85 W, or 

c. a diameter of not less than 120.65 ,mm(BR38) but not more than 127 ,mm (BR40) 

and a nominal power of less than 121 W.” 

ER lamps are defined as IRL as described in ANSI C79.1. Table 3.5 shows the Canadian 

energy conservation standards for IRL. In addition to the referenced ANSI documents in the 

definitions, the Canadian test procedures reference CAN/CSA-C862-01, Performance of 

Incandescent Reflector Lamps. The standards became effective on April 1, 1996 for GSFL and 

IRL and on January 1, 2003 for additional ER and BR lamps. 

Table 3.5 Canadian Energy Efficiency Regulations for Incandescent Reflector Lamps 

Rated Wattage 

W 

Minimum Average Lamp Efficacy 

lm/W 

ER Lamps 

50 7.0 

75 6.5 

120 10.0 

R, PAR, BR Lamps, and ER Lamps Not Covered Above 

40-50 10.5 

51-59 11.0 

60-85 12.5 

86-115 14.0 

116-155 14.5 

156-205 15.0 

 In November 2006, NRCan published a bulletin proposing to amend Canada's Energy 

Efficiency Regulations. NRCan proposed testing and labeling requirements for light output, 

3-10
input wattage, and rated lifetime for GSFL, medium base, integrally ballasted CFLs, and 

reflector and non-reflector GSIL.4

 The bulletin also proposed a definition for non-reflector 

GSIL. 

3.2.4 Non-Regulatory Initiatives 

DOE reviewed several national, regional, and local voluntary programs that promote the 

use of energy-efficient lighting in the United States. FEMP’s program for energy-efficient 

lighting, the Consortium for Energy Efficiency (CEE)’s High Performance Commercial Lighting 

Initiative, the Energy Efficient Commercial Buildings Deduction, and the Northeast Energy 

Efficiency Partnership (NEEP) are a few examples. The following section summarizes some of 

these programs for the lamps covered by this rulemaking. While it is not an exhaustive list, the 

discussion provides detail on some notable initiatives that characterize recent developments in 

the lighting market. 

3.2.4.1 Federal Energy Management Program 

FEMP helps Federal buyers identify and purchase energy-efficient products including 

certain GSFL. Section 161 of EPACT 1992 encourages energy-efficient Federal procurement. 

Executive Order 12902 and FAR section 23.704 direct agencies to purchase products in the 

upper 25 percent of energy efficiency. As Table 3.6 shows, FEMP provides recommendations of 

total light output (in lumens) and the best available models at the time of publishing.5 FEMP 

offers buyers support tools such as efficiency guidelines, cost-effectiveness examples, and a cost 

calculator. FEMP also offers training, on-site audits, demonstrations, and design assistance. 

Table 3.6 Federal Energy Management Program Efficiency Recommendation 

Lamp Type Recommended Best Available 

Four-Foot T8, 32W 2,800 lumens or more 3,000 lumens 

Four-Foot T12, 34W 2,800 lumens or more 2,900 lumens 

Eight-Foot T8, 59W 5,700 lumens or more 5,950 lumens 

Eight-Foot T12, 60W 5,600 lumens or more 6,000 lumens 

T8/U, 31-32w 2,600 lumens or more 2,850 lumens 

T12/U, 34w 2,700 lumens or more 2,760 lumens 

3.2.4.2 Consortium for Energy Efficiency 

CEE has both a Residential Lighting Initiative and a High-Performance Commercial 

Lighting Initiative. The Residential Lighting Initiative primarily promotes high efficiency 

fixtures and CFLs, neither of which is covered under this rulemaking. The purpose of CEE’s 

High-Performance Commercial Lighting Initiative is to define what constitutes “high 

performance,” and the initial efforts have focused on efficient T8 lighting products. On May 1, 

2007, CEE updated its specification for high-performance T8 lamps as a T8 lamp not greater 

than 32W with a minimum initial lamp lumens of 3,100 lumens or greater.6

 On January 23, 

2007, CEE released its specification for reduced-wattage T8 lamps as a lamp of 25W or 28W 

with minimum initial lumen output greater than or equal to 2,585 lumens or 2,400 lumens, 

respectively.7 

3-11
3.2.4.3 Energy Efficient Commercial Building Deduction 

EPACT 2005 created the Energy Efficient Commercial Buildings Deduction (26 U.S.C 

179D), which establishes a tax deduction for building owners who incur expenses for energy 

efficiency upgrades. Effective for property in service from January 1, 2006 through December 

31, 2008, the deduction allows partial deductions for improvement in interior lighting. Though 

the statute does not specify required lamp types or efficacies, it does call for an overall reduction 

in lighting power density, encouraging the use of higher performance and reduced-wattage 

GSFL. The Emergency Economic Stabilization Act of 2008 (HR-1424), approved and signed on 

October 3, 2008, extends the benefits of EPACT 2005 through December 31, 2013. 

3.2.4.4 Northeast Energy Efficiency Partnerships 

Northeast Energy Efficiency Partnerships (NEEP) is a regional nonprofit organization 

that promotes energy efficiency in the Northeast. NEEP currently runs a High Efficiency 

Commercial Lighting Initiative to “achieve cost-effective energy and demand by overcoming 

market barriers to the availability and widespread market adoption of advanced T8 fluorescent 

lighting systems.”8

 NEEP coordinates with multiple local and state governments, utilities, and 

other initiatives, such as Efficiency Vermont and the Long Island Power Authority, to promote 

efficient lighting products. Efficiency Vermont offers technical assistance and financial 

incentives to encourage energy efficiency in Vermont. This organization offers rebates of $15 

for the installation of “Super T8” lamp-and-ballast systems. It also provides a custom rebate for 

reduced-wattage T8 lamps.9 The Long Island Power Authority is a non-profit municipal electric 

utility that serves the Long Island area. It provides rebates for high-performance T8 systems and 

T5 fixtures ranging from $10 to $35.10

3.2.5 Historical Shipments 

Awareness of annual product shipment trends is an important aspect of the market 

assessment and the development of the standards rulemaking. For this rulemaking, NEMA 

publicly provided historical shipments of GSFL and IRL from 2001 to 2005 and confidential 

shipments for 2006 to 2007.11 DOE used this data for three main purposes. First, the shipment 

data and market trend information contributed to the shipments analysis and base-case forecast 

for GSFL and IRL (see chapter 9). By using historical shipment data and expert opinion on 

market trends, and calibrating forecast assumptions with recent data, DOE believes that the 

shipments model and base-case forecasts are based on a sound dataset. Second, DOE used the 

data to select the representative product classes and representative units for analysis. Generally, 

DOE selected representative product classes and units for analysis to reflect the highest volume, 

most common lamp types and wattages used in the United States today (see chapter 5). Third, 

DOE used the data to develop the market share matrices for the national impact analysis (see 

chapter 10). Based on its understanding of trends in the market, DOE estimated how the market 

would respond to the various trial standard levels. 

For GSFL, the historical shipment data is broken down by lamp length (2-foot, 4-foot, and 

8-foot), diameter (T12, T8, and T5), shape (linear and U-shaped), and in some cases, lumen 

output (SO or HO). Four-foot MBP lamps constitute the vast majority of GSFL sales. These are 

followed in order of unit sales by 8-foot SP slimline lamps and 8-foot RDC HO lamps, which 

3-12
together constitute under a quarter of GSFL sales. Four-foot MBP, 8-foot SP slimline, and 8-

foot RDC HO lamps are the most common GSFL. Shipments of 2-foot U-shaped lamps account 

for less than 5 percent of GSFL unit sales historically. DOE received confidential shipments for 

4-foot T5 MiniBP SO and HO GSFL. DOE’s research also indicated that 4-foot MiniBP SO and 

HO lamps constituted at least 2 percent of all GSFL shipments in 2004, and that this market 

share was growing.12 

GSFL in the categories of 4-foot MBP, 8-foot SP slimline, and 2-foot U-shaped lamps are 

primarily used in the commercial sectors. As Table 3.7 shows, 4-foot MBP fluorescent lamp 

shipments show a clear decrease in the T12 market share and an increase in the T8 market share. 

These shipments, coupled with information obtained from NEMA and manufacturers, suggest 

that consumers are moving away from 4-foot T12 fluorescent lamps and toward 4-foot T8 

fluorescent lamps. This trend is reflected both in the popularity of T8 lamps in new construction 

and in lighting system retrofits and renovations where the ballast is replaced. The vast majority 

of 4-foot T12 ballasts are magnetic, while the vast majority of 4-foot T8 ballasts are electronic. 

This decline of 4-foot T12 shipments will most likely be compounded in 2010 when new energy 

conservation standards for fluorescent ballasts, including replacement F40T12 ballasts and new 

F34T12 ballasts, go into effect. (See 10 CFR 430.32(m)(4)(ii) and 430.32(m)(5)-(6)) For 4-foot 

F40T12 and F34T12 lamps, discussions with manufacturers suggest that they anticipate their 

customers will shift to T8 counterparts instead of T12 lamps that operate with electronic ballasts. 

Table 3.7 NEMA Shipments of Four-Foot Medium Bipin General Service Fluorescent 

Lamps 

Unit Sales by Year 

thousands

2001 2002 2003 2004 2005 

T12 Four-Foot Medium Bipin 212,564 205,998 181,931 175,850 162,664 

T8 Four-Foot Medium Bipin 164,129 163,632 172,294 195,698 215,530 

Total Four-Foot Medium Bipin 376,593 369,630 354,225 371,548 378,194 

As Table 3.8 shows, historical shipments of 8-foot GSFL reflect a decline in shipments of 

8-foot T12 lamps and an increase in shipments of 8-foot T8 lamps. However, this increased 

market share in 8-foot T8 lamps does not sufficiently compensate for the decreased shipments of 

8-foot T12 lamps. Discussions with NEMA, manufacturers, and lighting experts suggest that a 

portion of the 8-foot T12 market is being transferred to the 4-foot T8 market. However, because 

the lumen output from a conventional 8-foot lamp-and-ballast system is significantly higher than 

that of a 4-foot lamp-and-ballast system, it is likely that one 8-foot system containing two lamps 

will be replaced by two 4-foot systems, each containing two lamps. It is therefore possible that 

any standard affecting shipments of T12 8-foot SP slimline GSFL may also notably affect the 

shipments of T8 4-foot MBP GSFL. 

3-13
Table 3.8 NEMA Shipments of Eight-Foot Single Pin Slimline General Service Fluorescent 

Lamps 

Unit Sales by Year 

thousands

2001 2002 2003 2004 2005 

T12 Eight-Foot Single Pin Slimline 43,265 41,443 37,170 36,263 33,636 

T8 Eight-Foot Single Pin Slimline 4,405 5,300 5,183 5,727 5,176 

Total Eight-Foot Single Pin Slimline 47,670 46,743 42,353 41,990 38,812 

Table 3.9 shows the historical shipments of 2-foot U-shaped GSFL. While no clear trend 

can be seen in the market share progression of U-shaped T12 and T8 lamps, the market share of 

U-shaped lamps is small compared to that of 4-foot MBP and 8-foot SP slimline lamps. 

Table 3.9 NEMA Shipments of Two-Foot U-Shaped General Service Fluorescent Lamps 

Unit Sales by Year 

thousands 

2001 2002 2003 2004 2005 

T12 Two-Foot U-Shaped 9,672 9,314 9,460 7,014 8,839 

T8 Two-Foot U-Shaped 8,014 6,784 7,018 9,224 8,659 

Total Two-Foot U-Shaped 17,686 16,098 16,478 16,238 17,496 

While 4-foot MBP, 8-foot SP slimline, and 2-foot U-shaped lamps are primarily used in 

the commercial sector, 8-foot HO lamps are primarily used in the industrial sector for 

applications such as high-bay lighting. Table 3.10 shows the historical shipments of 8-foot HO 

lamps. Discussions with experts and manufacturers indicate that most of the RDC HO lamps 

currently sold are used with electronic ballasts. The market share of 8-foot RDC HO is relatively 

small compared to that of 4-foot MBP and 8-foot SP slimline lamps. As seen in NEMA’s 

shipment data, T12 8-foot RDC HO lamps have the majority of the RDC HO market. 

Discussions with lighting experts and lamp manufacturers indicate that they expect any 

migration of the 8-foot RDC HO market to go toward T5 fluorescent lamps and metal halide 

lamps. 

Table 3.10 NEMA Shipments of Eight-Foot Recessed Double Contact High Output General 

Service Fluorescent Lamps 

Unit Sales by Year 

thousands 

2001 2002 2003 2004 2005 

T12 Eight-Foot Recessed Double Contact HO 23,887 24,398 24,206 24,591 25,442 

T8 Eight-Foot Recessed Double Contact HO 691 647 467 674 420 

Total Eight-Foot Recessed Double Contact HO 24,578 25,045 24,673 25,265 25,862 

IRL are primarily used in the commercial and residential sectors. Based on interviews 

with lighting experts, DOE estimates that approximately 80 percent of halogen IRL are used in 

the commercial sector and 20 percent are used in the residential sector. DOE also estimates that 

20 percent of the incandescent (i.e., non-halogen) reflector lamps are used in the commercial 

sector, and that the balance (80 percent) is used in the residential sector. As Table 3.11 shows, 

historical shipment data indicates that the total market share of halogen IRL is growing. 

However, its slow rate of growth suggests either that the market has reached near equilibrium or 

that competing incandescent IRL are successfully gaining market share and new installation 

3-14
opportunities. The shipment data in Table 3.11 reflect this trend, indicating comparatively large 

growth among non-halogen IRL, in contrast to the relatively flat growth for halogen IRL. 

Table 3.11 NEMA Shipments of Incandescent Reflector Lamps 

Unit Sales by Year 

thousands

2001 2002 2003 2004 2005 

PAR Incandescent 8,900 6,697 5,090 5,308 15,018 

R Incandescent 89,465 96,218 103,407 111,720 124,641 

PAR 38 Halogen 40,804 45,938 45,673 49,937 46,329 

PAR 30 and PAR 20 Halogen 32,523 27,128 30,506 35,567 39,985 

Total Incandescent Reflector Lamps 171,692 175,961 184,676 202,532 225,973 

3.3 TECHNOLOGY ASSESSMENT 

The purpose of the technology assessment is to develop a preliminary list of technologies 

that could be used to improve the efficacy of GSFL and IRL. The following assessment provides 

brief descriptions of the basic construction and operation of each lamp type, followed by a 

discussion of technology options to improve the efficacy of that lamp type. 

3.3.1 General Service Fluorescent Lamps 

The fluorescent lamp is a low pressure gas discharge source. The lamp consists of a glass 

bulb or tube, filled with low pressure mercury vapor and inert gas, with electrodes sealed onto 

both ends of the tube. An arc, in the form of primarily ultraviolet (UV) radiation, is produced by 

current flowing between the two electrodes. The phosphors coating the bulb’s inner wall then 

absorb this UV radiation and emit light in the visible spectrum. The fluorescent lamp has five 

major components in its construction: bulb, electrodes, base, gas fill, and phosphors. 

Fluorescent lamp bulbs can be manufactured in a variety of shapes and sizes. The GSFL 

lamps in this rulemaking include 4-foot and 8-foot linear lamps and 2-foot U-shaped lamps. 

Changing the shape of the lamp can alter the overall efficacy as the lamp may require a different 

voltage to maintain the discharge and UV radiation. In addition, the length of a lamp also 

influences its efficacy. As Figure 3.3.1 shows, the greater the length, the higher the efficacy, 

since losses associated with the electrodes are essentially constant. Therefore, a longer arc 

length will have less electrode power loss relative to the total losses. However, because different 

lamp shapes and lengths may provide different utility to the consumer and also depend on the 

lighting fixture, DOE is not considering these properties as technology options. Rather, as 

indicated in the discussion of product classes in Section 3.4, product classes differentiate lamps 

by their shape and length. 

3-15
Figure 3.3.1 Lamp Length Effects on Efficacy 

Source: IESNA Lighting Handbook: Reference & Application13

Two electrodes are hermetically sealed to both ends of the bulb. The electrodes are 

usually constructed from coiled tungsten wires coated with a mixture of alkaline oxides. A base 

provides an electrical connection to these electrodes and also supports the lamp. Depending on 

the start method and operational properties of the lamp (e.g., dimming, wattage, etc.), lamp 

designs may use different bases such as SP, MBP, and RDC. In its analysis, DOE determined 

that base type and size has little to no effect on efficacy and therefore did not consider these as 

technology options. Once voltage is applied to the electrodes, the tungsten coil and coatings 

emit large quantities of electrons when the coating is at the proper temperature (1,000–1,300 K). 

These electrons then collide with gaseous mercury atoms, exciting electrons within those atoms. 

As the electrons decay to their stable or ground state, they emit UV radiation primarily at 254 

nanometers (nm). In addition to the mercury vapor, an inert gas or a combination of gases is 

added to the lamp primarily to moderate the collisions of mercury ions and minimize evaporation 

of the electrode coating. As discussed above, the UV radiation is then absorbed by the 

phosphors and reemitted as light. 

 A fluorescent lamp must be operated in series with a current-limiting device, which is 

usually a magnetic or electronic ballast. Each ballast has an associated BF that affects the total 

light output of the fluorescent lamp. In addition to limiting current, ballasts also supply starting 

and operating voltages required by the lamp. Some ballasts also preheat the electrodes before 

initiating the arc. Magnetic fluorescent lamp ballasts use a variety of starting methods, including 

preheat start, instant start, or rapid start.c

 Electronic ballasts can also use a variety of starting 

 

c

 In the preheat start method, usually used with bipin bases, a current passes through both electrodes in series, 

heating them. A thermal switch then opens to apply a voltage applied across the lamp and induces the arc. Instant 

starting, usually used with a single pin base and with no heating of the electrodes, involves a high voltage (400V to 

1,000V) applied across the lamp. This voltage causes the ejection of electrons from the electrodes, creating the arc 

discharge. The arc current subsequently heats the electrodes. Rapid start lamps, operating on a bipin base, can also 

be instant started and operate similarly. However, in rapid start, the electrodes are continuously actively heated 

during operation by passing a small current to each of the electrodes while maintaining a voltage difference across 

the lamp. 

3-16
methods, including instant start, rapid start, and programmed start.d

 Because different starting 

methods result in changes in lamp efficacy, the test procedure for GSFL requires that the efficacy 

of each lamp is measured using a common starting method and ballast. However, DOE 

considers different starting methods in its analysis. For example, DOE pairs base case 4-foot 

T12 MBP lamps with magnetic, rapid-start ballasts, and base case 4-foot T8 MBP lamps with 

electronic, instant-start ballasts. Magnetic and electronic ballasts are also available in a variety 

of lamp-per-ballast designs. For example, electronic ballasts are typically manufactured in 1-, 2-

, 3-, and 4-lamp versions. 

In discussing each of the following technology options, it is important to note that the 

efficacy of a lamp, in lumens per watt (lm/W), can be affected in two major ways. One method 

is by affecting the total light output at a given wattage. This generally refers to changing the 

spectral output of the lamp to result in a larger overlap with the spectral eye sensitivity.e

 The 

second method of changing lamp efficacy is requiring a different electrical wattage input to 

maintain a given lumen output. This method involves tweaking the processes that convert 

electrical energy to visible radiation. 

3.3.1.1 Highly Emissive Electrode Coatings 

Fluorescent lamp electrodes are generally tungsten filaments coated with a mixture of 

alkaline earth oxides. The purpose of the electrodes is to emit a sufficient number of electrons to 

ionize the gas and maintain the lamp discharge. Therefore, any improvement in electrode 

coating that would allow electrons to be more easily removed from the electrodes would reduce 

the lamp power and increase the overall efficacy of the lamp. This technology option essentially 

addresses the efficiency of the conversion of electrical input power to visible radiation. As 

electrons are more easily emitted from the electrodes, a lower voltage is needed to maintain the 

arc. Conventional emissive coatings include barium oxide (BaO), calcium oxide (CaO), and 

strontium oxide (SrO). In addition to raising efficacy, the electrode coatings can result in an 

increased lamp lifetime. Without sufficient electron emission from the electrode, a large voltage 

gradient is created in front of the electrode during the cathode cycle, which is emitting negatively 

charged ions and receiving positively charged ions. This high electric field accelerates these ions 

into the electrode at a high velocity, causing electrode damage. The damage shortens the 

lifetime of the lamp. Additional materials have been mixed with existing conventional oxides to 

coat fluorescent lamp electrodes. These materials include zirconium oxide (ZrO), which extends 

lamp lifetime, and silicon carbide (SiC), which more effectively removes electrons from the 

electrode. 

3.3.1.2 Higher Efficiency Lamp Fill Gas Composition 

Fluorescent lamps contain mercury vapor, which when ionized produces UV radiation. 

They also contain a rare gas or combination of gases to facilitate ignition. These “lamp fill 

gases” affect the mobility of the mercury ions and electrons in the lamp plasma based on their 

 

d

 Programmed start ballasts delay the starting voltage until the electrodes are heated to an optimum temperature. 

Then, they may reduce the voltage on the electrodes. 

e

 A “lumen” is a measurement of the radiometric energy emission from a light source weighted by the response 

function of a human eye, called the photopic spectral luminous efficiency function, V(λ). See Figure 3.3.4 for a 

graph if this function. 

3-17
molecular weight. Lower molecular weight gases generally result in higher lamp efficacy. As 

lighter gases are used, the mobility of mercury ions and electrons increases, allowing them to 

reach greater velocities. This causes a rise in electron temperature of the plasma, facilitating 

recombination and ultimately raising the UV radiation to saturation level. However, if the 

mobility of the ions and electrons exceeds a certain optimal point, they are then able to reach the 

lamp glass surface, which prevents emission and effectively reduces UV output. 

Standard lamps generally use argon gas. Energy-saver lamps may use a mixture of 

krypton and argon. In addition, neon and xenon are sometimes blended with argon. As Figure 

3.3.2 shows, given a linear power density of 25 watts/foot (W/ft), both neon and argon result in 

similar UV radiation. However, given a high linear power density of 50 W/ft, neon clearly 

allows for higher UV radiation, and therefore higher efficacy. 

Figure 3.3.2 Lamp Fill Gas Effect on UV Output for T12 Lamps 

Source: Electric Discharge Lamps 14

These gases are usually at low pressures, ranging from 100 to 400 Pascals. As the 

pressure exceeds a certain point, elastic scattering increases, decreasing the mobility of the ions 

and electrons. This decreased mobility lowers the total UV radiation of the lamp, thereby 

decreasing lamp efficacy. Because fluorescent lamp ballasts are often current-controlled 

devices, the use of higher efficiency lamp fill gases, such as krypton, results in lower power. 

These lower power lamps, often called energy-saver lamps, have some restrictions of usage, such 

as operation in less than 60 degree Celsius ambient temperature, with reduced current ballasts, 

and with rapid-start ballasts, etc. 

Lamp fill gas composition can also affect lamp lifetime due to collisions between the 

lamp fill gas and the evaporated electrode coatings. As discussed earlier, one common emissive 

coating used on electrodes is barium oxide (BaO). During lamp operation the BaO coating 

slowly evaporates from the surface of the electrode. However, some of these escaped barium 

atoms then collide with the lamp fill gas, propelling them back toward the electrode and 

redepositing them. As Figure 3.3.3 shows, the relative thermionic emission for the cathode, a 

measure of the number of electrons emitted, is much greater for a larger molecular weight gas 

such as krypton than for a lighter gas such as neon. This is because a larger mass atom can more 

effectively collide with and change the trajectory of the barium atoms, providing a lower 

3-18
diffusion rate of the barium atoms away from the electrode. This redeposition of the electrode 

coating results in a longer lamp lifetime. 

Figure 3.3.3 Lamp Fill Gas Effect on Thermionic Emission for T12 Lamps 

Source: Electric Discharge Lamps 15

3.3.1.3 Higher Efficiency Phosphors 

As described earlier, the main purpose of phosphor in a fluorescent lamp is to absorb the 

UV radiation and reemit it as visible radiation. Therefore, one method of improving lamp 

efficacy is to increase phosphor efficiency. This can be done by increasing the phosphor’s UV 

absorption or by increasing its emission of radiation in the visible spectrum. Lamp efficacy can 

also be improved by increasing the thickness of the phosphor layer, also called phosphor weight. 

Typically, there are efficiency losses in the phosphor’s conversion of UV radiation to 

visible radiation, or light. Some of these losses are related to the extent to which the phosphors 

emit light in the visible spectrum (i.e., radiation with wavelengths between 400 to 750 

nanometers (nm)) and the extent that they radiate at visually sensitive wavelengths. 

The human eye does not have the same level of sensitivity to all wavelengths of light. 

For example, the eye is highly sensitive to light emission around 550 nanometers (nm), but less 

sensitive to emission at 450nm or 650nm. The photopic luminous efficiency function, V(λ), 

represents the response function of the human eye to light. Figure 3.3.4 depicts V(λ). 

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-

0.2

0.4

0.6

0.8

1.0

1.2

400 450 500 550 600 650 700 750

Wavelength (nanometers)

Relative Sensitivity

Figure 3.3.4 Human Eye Photopic Spectral Luminous Efficiency Function, V(λ) 

Lumens, used to calculate lamp efficacy, measures the radiometric energy emission from 

a light source weighted by the response function of the human eye, V(λ). Therefore, the specific 

wavelengths that a lamp emits will affect the lamp’s calculated efficacy. In other words, because 

the human eye is less responsive to certain wavelengths of light, such as those in the blue 

spectrum, those lamps that contain these less sensitive wavelengths will have lower efficacies. 

As such, every watt of radiometric energy emitted from a fluorescent lamp is not equal under a 

lumen-per-watt metric. 

The spectral power distribution (SPD) of light emitted from a lamp characterizes the 

amount of power radiated at each wavelength in the visible spectrum. Figure 3.3.5 illustrates a 

sample SPD. It is apparent that the light source emits more radiation at certain wavelengths than 

others. 

3-20
Figure 3.3.5 Sample Power Spectrum Distribution 

Source: www.gelighting.com16

This SPD determines the color correlated temperature (CCT) and the color rendering 

index (CRI), both important properties for measuring the color quality of light. CRI, a single 

value with no units, is a measure of the color rendering properties of a light source, or the ability 

of a light source to show the “true” color of an object as compared to a reference source.f 17 The 

maximum CRI is 100. Lower CRI values indicate greater variation in an object’s apparent color 

compared to when lit by the reference source. CCT, a single value with units of degrees Kelvin 

(K), is a measure of the color appearance of light emitted from a lamp.g,h,18 Lower CCT values 

correspond to warmer light, with more red content in the spectrum, and higher CCTs correspond 

to cooler light, with more blue content. As the spectral emission from the lamp is modified to 

change the CCT, the light emitted often contains more red or blue light. 

Given the shift in the wavelengths of light emitted from lamps with different CCTs, and 

the fact that lumens account for the amount of light emitted at particular wavelengths, the 

efficacy of lamps with different CCT can vary. For lamp spectra with very high or very low 

CCTs, the spectral emission of the lamp will not be tuned to the photopic luminous efficiency 

function V(λ) for maximum luminous efficacy. Therefore, in principle, CCTs lower than about 

3,000K and higher than about 5,000K will be less efficacious than those between 3,000K and 

 

f

 According to the IESNA Lighting Handbook, the CRI of a light source is “a measure of the degree of color shift 

objects undergo when illuminated by the light source as compared with those same objects when illuminated by a 

reference source of comparable color temperature.” 

g

 According to the IESNA Lighting Handbook, the CCT of a light source is “the absolute temperature of a 

blackbody whose chromaticity most nearly resembles that of the light source.” 

h

 While CCT is a single value, light with the same CCT value may have slightly different properties. Therefore, the 

lighting industry has defined elliptical regions in chromaticity space (called 4 MacAdam color steps) for specific 

CCT values (e.g., 2,700K, 3,000K, 3,500K, 4,000K/4,100K, 5,000K, and 6,500K) in ANSI C78.376-2001. These 

regions act as a tolerance for the color properties of the lamp. 

3-21
5,000K. Figure 3.3.6 illustrates the difference in average efficacy between 32W T8 4-foot MBP 

GSFL with different CCTs (and other attributes equivalent). 

78

80

82

84

86

88

90

92

6,500K 4,100K

CCT

Efficacy (lms/W)

Figure 3.3.6 Average Efficacies of Lamps with a CCT of 6,500K versus 4,100K 

Different types of phosphor emit light with different SPDs, and the choice of phosphor or 

blend of phosphors greatly affects the color of the lamp. There are two groupings of phosphors: 

halophosphors and rare-earth phosphors (often called tri-phosphors). Initially, halophosphors, 

typically composed of group 17 elements from the periodic table of elements, were 

predominantly used in fluorescent lamps. Then, in the late 1980s, rare-earth phosphors, which 

are generally considered to have higher phosphor efficiencies, better color rendering properties, 

and improved lumen maintenance, were integrated into the lamps. Many fluorescent lamps now 

use three narrow-band, rare-earth phosphors that emit light in the short, middle, and long 

wavelength ranges of the visible spectrum. As Figure 3.3.7 shows, the introduction of these 

three-band lamps resulted in a marked increase in efficacy. However, because rare-earth 

phosphors are considerably more expensive, longer length and larger diameter lamps commonly 

coat the bulb walls with two phosphor layers: a less expensive halophosphor layer and a rareearth phosphor layer. This maintains the SPD of the rare-earth phosphor while keeping cost 

relatively low. While some phosphors may be inherently more efficient than others, the most 

efficient ones cannot always be selected. Since the choice of phosphor or blend of phosphors 

greatly affects the illumination color of the lamp, a high efficiency phosphor may not have 

acceptable color properties. 

 

3-22
Figure 3.3.7 Lamp Efficacies for Halo- and Rare-Earth Phosphors 

Source: Phosphor Handbook 19

DOE has observed that higher-efficiency phosphors on the market typically offer higher 

CRIs. While CRI is not necessarily positively correlated to efficacy, the majority of phosphors 

offered in the market currently are. Typically lamps with a CRI in the 60s use only less efficient 

halophosphors, while lamps with a CRI in the 70s (700-series phosphor) and in the 80s (800-

series phosphor) use more efficient rare-earth phosphors. 

Apart from the type of phosphor used in a lamp, the thickness of the lamp’s phosphor 

coating also affects lamp efficacy. Generally, as phosphor thickness increases, lamp light output 

increases until it slightly decreases or stays flat. Figure 3.3.8 illustrates this point, where coating 

weight is indicative of phosphor thickness. 

Figure 3.3.8 Light Output versus Phosphor Thickness 

Source: Journal of the Electrochemical Society 20

3-23
DOE analyzed the rare earth phosphor market to understand the potential impact of the 

standards on supply and demand, pricing, growth, and the impact on consumers. See appendix 

3C for details. 

3.3.1.4 Glass Coatings 

To increase the UV absorption by the phosphors, the bulb glass can be covered with an 

antireflective coating. This coating is a refractory oxide, such as aluminum oxide (Al2O3), silicon 

oxide (SiO2), and titanium oxide (TiO2). This layer is used to reflect any UV radiation that 

passes through the phosphor back onto the phosphor, allowing a greater portion of UV to be 

absorbed. As the phosphors absorb more UV radiation, they will emit more visible light, thereby 

increasing the overall efficacy of the lamp. When these coatings are used with rare-earth 

phosphors, a good CRI can be achieved while minimizing the phosphor thickness necessary to 

absorb maximum UV radiation. 

3.3.1.5 Higher Efficiency Lamp Diameter 

Similar to lamp length, lamp diameter is another design parameter of a fluorescent lamp 

that can affect efficacy. Though both length and diameter often depend on the ballast and fixture 

in which the lamp is being installed, some manufacturers are trying to allow for variance in the 

diameter for certain fixtures. As discussed in section 3.4, product classes are not segregated by 

lamp diameter. Therefore, DOE considers lamp diameter a technology option to increase 

efficacy. 

As Figure 3.3.9 shows, there exists an optimum design diameter for a specific fluorescent 

lamp type resulting from two opposing effects. First, in small diameter lamps, an increase in 

diameter decreases the number of electrons and mercury ions that recombine at the bulb wall and 

produce no light. This lessening of non-radiative recombination results in an increase of optical 

power output and subsequently a rise in lamp efficacy. However, when the lamp diameter is 

sufficiently large as to result in minimal non-radiative recombination, a second opposing effect 

begins to influence the efficacy-diameter relation. With these larger diameter lamps, a further 

enlargement in diameter causes a greater imprisonment of radiation within the lamp. As the total 

light output is reduced, the lamp efficacy declines as well. In addition to affecting lamp efficacy, 

changing the lamp diameter alters the inner surface area of the fluorescent tube. With a larger 

diameter and therefore surface area, more phosphor is needed to coat the glass, subsequently 

increasing the cost of the lamp. 

DOE only considered lamp diameter as a design option in case of the migration from T12 

to T8 lamps. DOE’s research indicated T8 lamps are common replacements for T12 lamps, and 

though the lumen packages for T8 lamps are often less than that of T12 lamps, in this situation, it 

does not seem to be significant enough to affect consumer utility. Conversely, DOE’s research 

indicated that T5 lamps have more limited utility as replacements for T8 or T12 due to their 

greater lumen packages. As such, T5 lamps are not considered a design option to improving the 

efficacy of T8 and T12 lamps. 

3-24
Figure 3.3.9 Bulb Diameter versus Efficacy Source: IESNA Lighting Handbook: Reference & Application13

3.3.1.6 Multi-Photon Phosphors 

The use of multi-photon phosphors, or quantum-splitting phosphors, can significantly 

improve lamp efficacy. Because these phosphors emit more than one visible photon for each 

incident ultraviolet photon, a lamp would be able to emit more light for the same amount of 

power. Development of this technology remains in the research phase. 

3.3.2 Incandescent Reflector Lamps 

An incandescent lamp is a light source in which an electrical current passes through a 

filament, thermally exiting electrons which then radiate energy in the form of light and heat. 

Incandescent lamps consist of a bulb, generally composed of glass such as regular lead, soda 

lime, or borosilicate heat-resisting glass. Sealed to the bulb of the covered GSIL is an E26 

medium screw base. Within the bulb, an incandescent lamp contains a filament, filament 

supports, and sometimes a lamp fill gas. Though early incandescent lamps often used carbon, 

osmium, and tantalum filaments, current lamps generally use tungsten filaments. Tungsten’s low 

vapor pressure and high melting point allows for high operating temperatures, and consequently 

high lamp efficacies. The lamp fill gas, though not included in all incandescent lamps, is used to 

extend the lifetime of the lamp. 

IRL are incandescent lamps with a reflective coating, most commonly composed of 

aluminum or silver applied directly to part of the bulb surface. By improving directional 

lighting, reflector lamps place the same illuminance on a specific area with reduced watts. The 

most common bulb shapes of reflector lamps are R, PAR, BR, and ER. R-shaped lamps are 

primarily for indoor applications, while PAR lamps are usually used outdoors. IRL can be spot 

floods or floods. Flood IRL, which provide a greater distribution of light, typically have a beam 

spread of 16 to 40 degrees. Spot IRL have a beam spread from 9 to 16 degrees. 

3-25
The following assessment is a discussion of technology options to improve the efficacy 

of IRL. In discussing methods to affect the efficacy of an incandescent lamp, it is important to 

recognize the interrelation of a lamp’s wattage, luminous output, and lifetime. Often the most 

efficacious incandescent lamps have very low lifetimes and therefore become useless to the 

consumer. An indirect method to increase overall efficacy involves increasing lifetime. With a 

longer lifetime, a more efficacious lamp can be manufactured and will still have utility to the 

consumer. 

3.3.2.1 Higher Temperature Operation 

In the operation of an incandescent lamp, a current is passed through a tungsten filament, 

which when heated, emits light. However, an incandescent light source’s spectrum does not fall 

exclusively in the visible region of the electromagnetic spectrum, shown in Figure 3.3.10. By 

operating the filament at higher temperatures, the spectral output shifts to shorter wavelengths, 

increasing its overlap with the photopic spectral eye sensitivity. This, in effect, increases the 

luminous output for a given power input and consequently increases the lamp efficacy. As 

Figure 3.3.11 shows, increasing color temperature (a direct effect of, but not equivalent to, 

raising operating temperature) causes an increase in luminous efficacy. One way to increase the 

filament temperature is by increasing the wattage of the lamp. As a higher current passes 

through and a high voltage drop occurs over the filament, the amount of energy released in the 

form of heat increases, thereby raising the temperature. However, this significantly changes the 

luminous output of the lamp and may not meet the consumer’s needs. Other technologies that 

address a lamp’s ability to operate at high temperatures are filament thickness, inclusion of inert 

gas fills, and the use of halogen fills, all discussed below. 

Figure 3.3.10 Radiating Characteristics of Tungsten 

Source: IESNA Lighting Handbook: Reference & Application 21

3-26
Figure 3.3.11 Luminous Efficacy versus Color Temperature 

Source: IESNA Lighting Handbook: Reference & Application 22

In addition to efficacy, the change in operating temperature also affects lifetime and the 

color appearance of the lamp. At the melting temperature of tungsten, 6,120°F, the maximum 

efficacy of an incandescent lamp with an uncoiled tungsten filament is 53 lm/W. However, to 

obtain long life in an incandescent lamp, the filament should be significantly below its melting 

point. As the filament burns hotter, more tungsten evaporates from the filament. When the 

filament eventually breaks, the lamp fails. This is an example of the clear tradeoff between lamp 

efficacy and lamp lifetime. Also, to maintain the cool bulb surface, high temperature 

incandescent lamps often require larger bulbs. This affects the fixtures in which they fit. 

3.3.2.2 Microcavity Filaments 

Texturing of the filament surface can increase surface area and therefore emissivity. 

Filament surface perforations also can act as waveguides for visible light. One technology 

includes the creation of microcavity holes in the filament surface. The cavities may then be 

filled with materials such as tantalum, rhenium, molybdenum, tungsten, SiC, rare-earth elements, 

glass beads, or any combination thereof. Depending on their fabrication, this technology can 

result in a variety of effects such as greater control of emissive direction, reduction of infrared 

radiation, and increased emission efficiency over a certain bandwidth of wavelengths. 

Ultimately, these effects produce a higher overall efficacy. 

Sandia National Laboratories researchers examined microcavity resonance in a tungsten 

photonic lattice. DOE has found multiple patents referencing this technology. However, 

research indicates that materials patterned at the submicron level may experience problems with 

stability.23 

3-27
3.3.2.3 Novel Filament Materials 

In choosing a filament, some advantageous properties are high melting point, low vapor 

pressure, high strength, high ductility, and good radiating characteristics. While tungsten is 

primarily used for incandescent lamps, manufacturers also incorporate other metals such as 

rhenium to improve ductility. However, these lamps are most commonly used for applications 

requiring vibration-resistant lamps. Novel filament materials such as nitrides and carbides have 

the potential to improve lamp efficacy by emitting more light in the visible spectrum at a given 

temperature than traditional tungsten filaments. However, these novel filaments can also be 

brittle, an attribute that can shorten the lamp lifetime. 

3.3.2.4 Thinner Filaments 

A thinner filament has an increased resistance and therefore an increased operating 

temperature. As previously discussed, a higher operating temperature results in a higher lamp 

efficacy. However, as an adverse effect, an incandescent lamp with a thinner filament cannot 

withstand as much tungsten evaporation before failing, resulting in a shorter lifetime. 

3.3.2.5 Efficient Filament Coiling 

Coiling of the incandescent lamp filament can increase luminous efficacy. The light 

output of an incandescent lamp is directly proportional to the light-emitting surface area of the 

light source. By coiling the filament, a longer filament can be used, increasing luminous output 

and therefore lamp efficacy. Coiling of the tungsten also affects the heat loss from the filament. 

The more the filament is coiled, the less the effective area for convective cooling, thereby 

increasing filament temperature and lamp efficacy. IRL covered in this rulemaking generally 

contain filaments of the type C (coiled) or CC (coiled coil). The highly efficacious CC type 

filament, which is more commonly used, consists of the coil wound into another helical coil. 

3.3.2.6 Crystallite Filament Coatings 

A variety of filament coatings may be used to increase the efficacy of incandescent 

lamps. Layers of micron or submicron crystallites, comprised of thorium, tantalum, and/or 

niobium, are deposited on the filament surface. The crystallites are coated with a protective layer 

of at least one oxide of thorium, hafnium, scandium, yttrium, cerium, or zirconium. This coating 

increases the emissivity of the filament in the visible part of the spectrum without increasing the 

infrared radiation. However, as the operating temperature of the filament increases, the 

emissivity improvement due to the crystallites decreases. 

3.3.2.7 Efficient Filament Orientation 

Tungsten filament in incandescent lamps can be positioned horizontally or vertically with 

respect to the base of the bulb. Because the light emitted from the filament is distributed in all 

directions, one way to improve efficacy is by designing the lamp in a way such that the most 

amount light is able to escape the bulb. By positioning the filament in a horizontal orientation, 

the base of the lamp absorbs much of the emitted light along the length of the coil. However, by 

positioning the filament in vertical alignment, only a small portion of the light is emitted towards 

3-28
the base. Consequently, more light escapes the bulb and is used for illumination. This can 

increase the efficacy of an incandescent lamp by approximately 8 percent. 

3.3.2.8 Higher Efficiency Inert Fill Gas 

IRL covered in this rulemaking typically are filled with an inert fill gas whose primary 

purpose is to reduce the evaporation of tungsten, preventing bulb blackening and increasing 

lifetime. In addition, this fill gas increases the pressure inside the bulb or halogen capsule. 

However, the fill gas also provides a means of convective heat transfer between the heated 

filament and cool bulb surface. This cooling of the filament represents a power loss and an 

efficacy reduction due to low temperature operation. Krypton’s low thermal conductivity 

decreases the convective cooling of the filament, allowing for higher temperature operation and 

therefore higher efficacy. In addition, since the krypton molecule is larger than other elements 

such as argon, krypton more effectively slows the evaporation of the filament and therefore 

extends the life of the lamp. Xenon, having even lower heat conductivity and larger mass than 

krypton, can more drastically change efficacy and life but also at a greater cost. 

DOE analyzed the potential impact of standards on xenon availability and pricing in 

appendix 3B.

3.3.2.9 Luminescent Gas 

A large portion of the incandescent spectrum is composed of wavelengths that cannot be 

detected by the human eye. By reacting with these wavelengths, luminescent gases can convert 

some portion of the “invisible” part of the incandescent spectrum into visible light. This 

conversion increases the amount of lumens emitted by the lamp and thus improves its efficacy. 

3.3.2.10

3.3.2.11

Tungsten-Halogen Lamps 

Tungsten-halogen lamps are a subgroup of incandescent lamps which use a halogen 

element such as bromine, chlorine, fluorine, or iodine to help increase lifetime of the lamp. As 

discussed earlier, technologies that increase lifetime also indirectly improve efficacy, because 

higher temperature operation becomes more feasible while maintaining product utility. In a 

tungsten-halogen lamp, a small diameter fused quartz envelope filled with a halogen molecule 

surrounds the filament. Above 500 degrees Fahrenheit, when tungsten evaporates from the 

filament, the tungsten molecules combine with the halogen into a gaseous compound. This 

compound circulates within the envelope until it contacts the filament again. The heat of the 

filament breaks the compound, freeing the halogen and re-depositing the tungsten on the 

filament. This regenerative process greatly extends the life of incandescent lamps by reducing 

the loss of tungsten material. Also, because tungsten is not being deposited on the bulb surface, 

bulb darkening over time is greatly reduced. However, to prevent this bulb darkening, the 

halogen lamp must be operated with a sufficiently high bulb wall temperature. For this reason, 

dimming circuits that employ low-voltage operation may not reap the same benefits from using 

tungsten-halogen lamps. One drawback to the halogen technology is that the halogen capsule is 

often under high pressure and therefore susceptible to exploding. For this reason, halogen IRL 

often employ a thicker protective glass. 

Higher Pressure Tungsten-Halogen Lamps 

3-29
Increasing the pressure of the halogen capsule by increasing the density of halogen 

elements can indirectly raise the efficacy of the tungsten-halogen lamp. The increased density of 

halogen elements raises the probability that an evaporated tungsten element combines with a 

halogen element in a gaseous compound. Adding more of this gaseous compound in the capsule 

effectively increases the amount of tungsten re-deposited on the tungsten filament, which can 

lengthen the lifetime of the tungsten-halogen lamp or raise its efficacy by allowing for higher 

temperature operation of the filament. 

3.3.2.12

3.3.2.13

3.3.2.14

3.3.2.15

Non-Tungsten-Halogen Regenerative Cycles 

The regenerative cycle of filament evaporation and re-deposition can be used to greatly 

increase the life of an incandescent lamp. The filament can burn at a higher temperature than 

conventional incandescent lamps while maintaining a useful service life. The tungsten-halogen 

regenerative cycle is the most common. However, other regenerative cycles are possible. 

Implementation of a non-tungsten-halogen regenerative cycle depends on incorporating a nontungsten filament. 

Infrared Glass Coatings 

Infrared coatings on incandescent lamps are used to reflect some of the radiant energy 

emitted back onto the filament. This infrared radiation then supplies heat to the filament and the 

operating temperature increases. As discussed earlier, an increase in operating temperature 

results in a higher light output and therefore an increase in efficacy. In addition, the spectrum of 

the incandescent lamp shifts toward shorter wavelengths. These infrared coatings can be in 

many forms, such as multilayer dichroic filters and crystal lattice structures whose spacing 

defines a photonic bandgap. They can be applied to the glass halogen capsule for tungstenhalogen lamps. However, they are most commonly used in the coating of the halogen capsule 

since one can achieve the greatest directed reflection back onto the filament for the lowest 

infrared coating usage. Because the halogen capsule is most traditionally in a cylindrical shape, 

when infrared coatings are applied to a halogen lamp, manufacturers use a cylindrical capsule to 

help direct the light. Appendix 5D discusses IR coatings in greater detail. 

Infrared Phosphor Glass Coating 

Salts of the rare earths and other transition group elements contain ions at energy levels 

that are particularly suited to emit visible light when in transition24. In the presence of infrared 

light, these ions will jump to higher energy levels. In some cases, when the ions fall to lower 

energy levels, light in the visible spectrum is emitted. When used as a coating on a bulb surface, 

infrared phosphors are able to harvest the emitted infrared energy and convert it to visible light, 

potentially increasing lamp efficacy. 

Integrally Ballasted Low-Voltage Lamps 

The filaments of incandescent lamps designed to operate at a low voltages are both 

shorter in length and thicker in diameter than the filaments of incandescent lamps designed to 

operate at a higher line voltage. Increasing the thickness of the filament can improve lamp 

efficacy by increasing the filament temperatures. Using an integral ballast allows an increase in 

the efficacy of a lamp because it operates at low voltages, though it is used in a socket with main 

3-30
line voltage (i.e., it converts the operating voltage of the lamp to a lower wattage from line 

voltage). The conversion of line voltage to lower lamp operating voltages has associated energy 

losses. However, modern integral ballast technologies allow efficacy gains from low-voltage 

operation to outweigh any such conversion losses. 

3.3.2.16

3.3.2.17

3.3.2.18

Higher Efficiency Reflector Coatings 

Though aluminum is most prevalent as a reflector coating in incandescent reflector 

lamps, silver coatings can also be applied. While aluminum coatings are applied internally by 

condensation of vaporized aluminum on the inner surface of the bulb, silver can be applied both 

on the interior and exterior surfaces of the bulb. When applied externally, the silver coating is 

protected by a cooper coating and aluminum finish. Silver coatings are generally preferred over 

aluminum due to their lower light loss. Gold is also extremely reflective and can be used to 

increase the amount of directed light and therefore efficacy of the lamp. An infrared coating that 

reflects the infrared radiation back toward the lamp’s filament can also be applied. This infrared 

reflector coating, in the form of multilayer dichroic filters or crystal lattice structures, ultimately 

increases lamp efficacy by limiting the amount of energy lost through infrared radiation and by 

increasing lamp operating temperature. 

Trihedral Corner Reflectors 

Due to the shape of many reflector lamps, infrared lens technologies can be incorporated 

in the cover glass to direct infrared radiation back onto the filament. Conventional infrared 

coatings on reflector lamps direct the infrared light back into the bulb, but not directly onto the 

filament. Other parts of the lamp absorb some of this heat, which is therefore a source of energy 

loss. A trihedral corner reflector is a technology that incorporates individual corner reflectors 

into the cover glass. These reflectors’ shapes provide the unique ability to reflect light directly 

back in the direction it came. Therefore any light coming from the filament and impinging on 

the cover glass will be directed straight back to the filament. These reflectors are covered with a 

dichroic coating, allowing visible light to pass through and escape while causing infrared 

radiation to reflect back on the filament. As this radiation heats the filament, the lamp requires 

less input power to operate at a higher operating temperature, and therefore operates more 

efficaciously. 

Efficient Filament Placement 

Placement of the filament is an important aspect of incandescent reflector design. The 

placement of the filament is optimal when a portion of the spectrum emitted by the filament is 

focused back onto the filament. This additional radiation supplies heat to the filament and the 

operating temperature increases. As discussed earlier, an increase in operating temperature 

results in a higher light output and therefore an increase in efficacy. 

3.4 PRODUCT CLASSES 

When evaluating and establishing energy conservation standards, DOE divides covered 

products into classes by the type of energy used, capacity, or other performance-related features 

that affect efficiency, and factors such as the utility of the product to users. (See 42 U.S.C. 

3-31
6295(q)) DOE usually establishes different energy conservation standards for different product 

classes. DOE applied the criteria of 42 U.S.C. 6295(q) to GSFL and IRL to develop product 

classes for the final rule. This section of the TSD describes the product classes DOE has 

considered for this rulemaking. 

3.4.1 General Service Fluorescent Lamps 

In setting energy conservation standards for fluorescent lamps, EPCA established product 

classes based on its definition for fluorescent lamps and on nominal lamp wattages. Table 3.12

shows the product classes set by EPCAtwo for each lamp typefor a total of eight product 

classes. (42 U.S.C. 6295(i)(1)(B)) 

Table 3.12 EPCA Product Classes for General Service Fluorescent Lamps 

Product Class Lamp Type Nominal Lamp Wattage 

#1 Four-Foot Medium Bipin > 35 W 

#2 Four-Foot Medium Bipin ≤ 35 W 

#3 Two-Foot U-Shaped > 35 W 

#4 Two-Foot U-Shaped ≤ 35 W 

#5 Eight-Foot Single Pin Slimline > 65 W 

#6 Eight-Foot Single Pin Slimline ≤ 65 W 

#7 Eight-Foot Recessed Double Contact High Output > 100 W 

#8 Eight-Foot Recessed Double Contact High Output ≤ 100 W 

The fluorescent lamp market has changed in the 17 years since amendments to EPCA 

established these eight product classes. For example, new phosphors are used more frequently in 

general illumination applications, changing average CRI values, and new lamps have entered the 

market, shifting the market share to different lamp wattages. DOE has revised the product 

classes to reflect some of these market changes, and to enable the analysis to better represent the 

current market. DOE also reviewed the existing product classes to ensure that any additional 

GSFL it regulates fit within the same regulatory framework as existing standards. In its 

assessment of GSFL product classes, DOE looked to statutory criteria (42 U.S.C. 6295(q)) and 

identified utility and physical attributes of fluorescent lamps around which to set product classes. 

In the final rule Federal Register notice, DOE sets product classes on the following utility 

and physical attributes of fluorescent lamps: physical constraints of lamps (i.e., lamp shape and 

lamp length), lumen package (i.e., regular versus HO), and correlated color temperature.i

 DOE 

chose not to set product classes based on lamp wattage, lamp diameter (i.e., T8 vs. T12), or CRI. 

In addition, DOE did not consider interoperability of lamps on the same ballast system as a 

 

i

 In the Framework Document, DOE presented its preliminary thoughts on revising the table of standards established 

by EPCA. ((42 U.S.C. 6295(i)(1)(A); see 10 CFR 430.32(n)(1)). DOE considered subdividing the product 

categories by introducing lamp tube diameter as a differentiating variable (i.e., “>T8” and “≤T8”). In presenting this 

concept, DOE used the same wattage divisions and minimum CRI requirements that EPCA uses for these lamps, 

with T8 and T12 lamps in the same product class. Having conducted additional research on the GSFL market and 

GSFL technologies, DOE does not believe separating product classes by lamp diameter is necessary. 

3-32
differentiating factor for product classes. The following subsections discuss these lamp 

attributes and how they pertain to product class divisions. 

3.4.1.1 Physical Constraints of Fluorescent Lamps 

The physical constraints of the lamp relate to its shape and length. Because consumers 

must change a lamp fixture to substitute lamps of different geometries for one another, lamp 

shape affects utility. For example, a U-shaped lamp could not substitute for a linear-shaped lamp 

in the same fixture. Similarly, given their metric lengths, T5 lamps cannot be used as direct 

replacements for T8 or T12 lamps in some applications. These lamps may require different lamp 

holders (due to differences in length and base type). Also, a 4-foot lamp may have a different 

utility than an 8-foot lamp, as these lamps generally require different fixtures. In addition, a 

lamp’s geometry also affects its efficacy. For example, efficacy tends to increase with length. 

All else being equal, 8-foot lamps generally have higher efficacy values than 4-foot lamps. Also, 

a 2-foot U-shaped lamp, while having the same overall tube length, is less efficacious than a 4-

foot linear lamp, partly because the electrical arc within the tube has to bend to conform to the 

lamp shape. Given the impact that geometry has on both utility and efficacy, DOE maintains the 

division of product classes by lamp geometry. 

3.4.1.2 Lumen Package 

Lumen package refers to the quantity of light that a lamp-and-ballast system provides to a 

consumer. To obtain a high lumen package, certain lamps are designed to operate with ballasts 

that run the lamps at high currents. For example, 8-foot RDC HO lamps and 4-foot MiniBP HO 

lamps tend to operate at higher currents than 8-foot SP slimline lamps and 4-foot MiniBP SO, 

respectively. This difference in operating design increases the quantity of light per unit lamp 

length. 

DOE observed that consumers tend to use systems with different lumen packages for 

different applications. For example, high-lumen-output systems may be installed in certain highceiling or outdoor applications, where large quantities of light are needed. Alternatively, 

standard-lumen-output systems might be installed in lower-ceiling applications such as offices or 

hospitals, where, for example, distance between the light source and the illuminated surfaces is 

not as large. Notable differences in the application of SO versus HO lamps indicate a difference 

in utility. 

In addition to producing higher light output, operating lamps at a higher current also 

decreases efficacy. For example, the efficacy of an 8-foot RDC HO lamp is as much as 10 

percent lower than that of a comparable 8-foot SP slimline lamp. Given the observed utility 

distinctions and notable efficacy differences between SO and HO lamps, DOE maintains the 

product class division for 8-foot linear lamps between slimline and HO lamps. 

In addition, a lamp’s lumen package provides a unique utility in the form of a quantity of 

light per unit lamp length. Because 4-foot T5 MiniBP lamps have similar total lumen output as 

4- foot T8 and T12 MBP lamps over a significantly smaller surface area, T5 lamps are often 

marketed as too bright for use in direct lighting fixtures. If 4-foot T5 MiniBP lamps were 

regulated in the same product class as 4-foot MBP lamps, the standard could effectively mandate 

3-33
the use of T5 lamps. To prevent eliminating lamps appropriate for direct lighting applications, 

DOE believes that 4-foot MiniBP lamps (T5 lamps) warrant a separate product class from 4-foot 

MPB lamps (primarily T8 and T12 lamps). 

3.4.1.3 Correlated Color Temperature 

As discussed in section 3.3.1.3, in general terms, the CCT is a measure of the perceived 

color of the white light emitted from the lamp. As the spectral emission from the lamp is 

modified to change the CCT, the lamp efficacy can vary. Due to their greater blue light content, 

higher CCT fluorescent lamps tend to have lower efficacies. 

For fluorescent lamps, the differences in CCT of the light emission can be so large that 

they affect the efficacy of the lamp. Given the impact on efficacy of CCT and utility, DOE is 

establishing product classes by CCT range and setting separate efficacy requirements for GSFL 

based on CCT. DOE is considering establishing two groups that divide the span of CCT that are 

considered general purpose (between 2,500K and 7,000K). This division of product classes 

occurs at 4,500K. 

3.4.1.4 Ballast Interoperability 

Not all lamps operate on the same ballast. Even if lamps have similar geometries, 

different ballasts may be required for their operation. However, DOE treats ballast 

interoperability as an economic issue (in the LCC and NIA analyses) rather than a product class 

issue. In other words, if a consumer needs to change the ballast to replace a lamp, then the 

installed cost of both the lamp and ballast are factored into the net present value equation. For 

example, DOE considered a T8 lamp a more efficacious replacement for a T12 baseline lamp. 

Considering T8 lamps as substitutes for T12 lamps is consistent with DOE’s understanding of 

the market, and with manufacturer marketing literature. It is common practice, for example, to 

replace a T12 lamp-and-ballast system with a T8 lamp-and-ballast system. In its economic 

analysis, DOE accounts for the need to install a new ballast to operate the T8 lamp by including 

the installed cost of a new lamp and ballast for the T8 replacement. Had DOE elected to 

differentiate these lamps on ballast interoperability, or indeed, lamp diameter, this direct 

comparison may not have been made. DOE believes this approach is appropriate for this 

rulemaking because there is no unique functionality or service rendered by, for example, one T8 

lamp and an equivalent T12 lamp. 

3.4.1.5 Lamp Wattage 

The current regulations group standards by wattage. However, DOE believes that 

product classes would more appropriately structure standards if they did not divide products by 

wattage. The main function of a lamp is to provide lumen output, while other attributes such as 

CCT, for example, contribute to utility. Wattage measures the power consumed by a lamp in 

providing its service. Therefore, DOE does not construe wattage as a direct measurement of 

utility. Following guidance from 6295(q), where utility is a factor for structuring product 

classes, DOE does not establish product classes on the basis of wattage. 

3-34
Furthermore, DOE believes combining wattages within one product class would allow 

standards to stay relevant with the market. Dividing product classes by wattage locks the 

standards to a static wattage structure. While this structure may reflect current product 

availability, the market may evolve over time, shifting to different wattages. This scenario is 

illustrated by comparing the current GSFL market to the existing GSFL standard structure. 

Before the EPCA standard, the 40W GSFL was the most prevalent GSFL offered. Currently, the 

common wattages for 4-foot MBP GSFL are 40W and 34W for T12 lamps and 32W for 8-foot 

T8 lamps, where the T8 lamps are energy-saving versions of the T12 lamps.j The existing 

product class divides wattage at 35W. 

3.4.1.6 Lamp Diameter 

As discussed in section 3.3.1.5, lamp diameter is a feature of a lamp which impacts lamp 

efficacy. In general, DOE considers lamp diameter as a design option, and did not consider 

using it as a basis for developing product classes.k

 Manufacturer marketing literature and 

general guidance on lighting design and installation often promote T8 lamp-and-ballast systems 

as higher efficacy, energy-saving substitutes for T12 lamp-and-ballast systems. Such substitute 

systems have the same lengths and bases, offer comparable lumen output, and can fit within the 

same fixtures. Therefore, DOE recognizes that the diameter of the lamp will affect the efficacy, 

but the utility provided to the end-user is comparable and/or equivalent. The substitution of a T8 

lamp for a T12 lamp requires the substitution of a new ballast as well. DOE accounts for new 

ballast purchases in its economic analyses of these substitutions (i.e., the LCC and NPV 

analyses) by incorporating ballast costs in the equipment costs of the substitutes. 

As stated earlier, DOE generally considers lamp diameter a design option when there is 

no associated decrease in utility. However, when associated with a decrease in utility, DOE does 

set separate product classes for different diameter lamps. One such example is for 4-foot T5 

MiniBP lamps. In this case, as discussed earlier, DOE establishes separate product classes for 4-

foot T5 MiniBP lamps on the basis on the “physical constraints” and “lumen package” classsetting criteria. 

3.4.1.7 Color Rendering Index 

In its standard for fluorescent lamps, EPCA established both an upper and a lower bound 

on the CRI of GSL.l

 EPCA defines GSFL as having a CRI less than 82, effectively exempting 

from coverage GSFL with a CRI equal to or greater than 82. (42 U.S.C. 6291(30)(B)(vii); see 10 

CFR 430.2) EPCA also established two minimum CRI requirements for each of the four groups 

of fluorescent lamps, one at 69 CRI and one at 45 CRI. Within 4-foot MBP lamps, for example, 

EPCA requires that lamps nominally rated at greater than 35W have a minimum CRI of 69 and 

lamps nominally rated at 35W or lower have a minimum CRI of 45. (42 U.S.C. 6295(i)(1)(A); 

 

j

 Additional, reduced-wattage T8 4-foot MBP lamps are available, but the 32W version is the most common. k

 In the Framework Document, DOE considered separating GSFL with diameters smaller than or equal to T8 from 

lamps with diameters greater than T8. On further consideration, DOE has determined that the lamp diameter does 

not provide significant unique utility to end-users. 

l

 EPCA also defines GSFL as having a CRI less than 82, effectively exempting from coverage GSFL with a CRI 

equal to or greater than 82. (42 U.S.C. 6291(30)(B)(vii); see 10 CFR 430.2) 

3-35
see 10 CFR 430.32(n)(1)) In removing the wattage dividers, DOE is also effectively removing 

the primary differentiating factor that was used to establish minimum CRI requirements. DOE 

considers several approaches to resolve this issue in section III.2.a of the NOPR Federal Register 

notice. 

3.4.1.8 Product Classes and Standard Form for GSFL 

For all the reasons discussed above, DOE is considering the GSFL product classes listed 

in Table 3.13. DOE is setting constant efficacy level standards by product class, consistent with 

existing standards. This standard would apply to and be constant over the full spectrum of 

wattages and diameters for lamps covered by that lamp type and CCT. Chapter 5 provides detail 

on the selection of trial standard levels. 

Table 3.13 DOE NOPR Product Classes for GSFL 

Lamp Type 

For CCT ≤ 4,500K, 

Minimum Lamp Efficacy 

lm/W

For CCT > 4,500K, 

Minimum Lamp Efficacy 

lm/W

Four-Foot Medium Bipin Product Class #1 Product Class #7 

Two-Foot U-Shaped Product Class #2 Product Class #8 

Eight-Foot Single Pin Slimline Product Class #3 Product Class #9 

Eight-Foot Recessed Double 

Contact HO Product Class #4 Product Class #10 

Four-Foot Miniature Bipin SO Product Class #5 Product Class #11 

Four-Foot Miniature Bipin HO Product Class #6 Product Class #12 

3.4.2 Incandescent Reflector Lamps 

In setting energy conservation standards for IRL, EPCA differentiated IRL by wattage 

and established six nominal wattage ranges or “bins,” shown in Table 3.14. (42 U.S.C. 

6295(i)(1)(B)) 

Table 3.14 EPCA Product Classes for Incandescent Reflector Lamps 

Product Class Nominal Lamp Wattage 

#1 40-50 

#2 51-66 

#3 67-85 

#4 86-115 

#5 116-155 

#6 156-205 

3.4.2.1 Wattage 

For the same reasons discussed for GSFL (see section 3.4.1.5), DOE is revising the 

product classes so that they are not structured according to wattage. Instead of a structure that 

3-36
uses wattage divisions, DOE is considering one that encompasses a single range of wattages. 

DOE believes that wattage is not a direct measure of utility. DOE also believes that a structure 

that encompasses all wattage could better keep pace with the market should it shift to reduced 

wattages over time. 

As wattage increases for incandescent lamps, efficacy also generally increases. To use a 

single range of wattages while taking into account variation in efficacy by wattage, DOE is 

developing a single standard per product class as an equation. This equation sets a minimum 

efficacy requirement that varies by wattage. Chapter 5 provides more detail on selection of 

efficacy levels. 

3.4.2.2 Modified Spectrum 

EISA 2007 adopted a new definition for “colored incandescent lamp”m which supersedes 

DOE’s definition previously incorporated at 10 CFR 430.2.n

 This new statutory definition 

effectively increases the scope of energy conservation standards coverage of IRL to include any 

IRL that has a lens containing five percent or more neodymium oxide or is a plant light lamp. As 

both of these types of IRL filter out portions of the emitted spectrum of the lamp, many of these 

lamps fall under the definition of “modified spectrum” which was also adopted by the new 

energy legislation. The EISA 2007 definition of “modified spectrum” reads as follows: 

“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— 

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 (x,y) chromaticity coordinates on the C.I.E. 1931 

chromaticity diagram that lies at least 4 MacAdam steps (as reference 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.” 

 

m EISA 2007’s definition of “colored incandescent lamp” reads as follows: “ 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 

that 50, as determined according to the test method given in CIE publication 13.3-1995; or (ii) a correlated color 

temperature of less than 2,500K or greater that 4,600K, where correlated temperature is computed according to the 

Journal of Optical Society of America, Vol. 58, pages 1528-1595 (1986).” 

n

 The definition of “colored incandescent lamp” adopted by the 1997 Lamps Test Procedure Final Rule 62 FR 

29221,29228 (May 29, 1997) reads as follows: “Colored incandescent lamp means an incandescent lamp designated 

and marketed as a colored lamp that has a CRI less than 50, as determined according to the method given in CIE 

Publication 13.2 (see 10 CFR 430.22); has a correlated color temperature less than 2,500K or greater than 4,600K; 

has a lens containing 5 percent or more neodymium oxide; or contains a filter to suppress yellow and green portions 

of the spectrum and is specifically designed, designated and marketed as a plant light.” 

3-37
(42 U.S.C. 6291(30)(W)) 

Modified-spectrum lamps provide unique utility to consumers because they offer a 

different light output from incandescent lamps, much like fluorescent lamps with different CCT 

values. The same technologies that modify the spectral emission of a lamp also decrease the 

lamp’s efficacy. To modify the spectrum, the coating absorbs a portion of the light emission 

from the filament. Neodymium coatings or other coatings on modified-spectrum lamps absorb 

some of the visible emission from the incandescent filament (usually red), creating a modified, 

reduced spectral emission. Since the neodymium or other coatings absorb some of the lumen 

output from the filament, these coatings decrease the efficacy of the lamp. 

DOE is concerned that, given the newly adopted definition of “colored incandescent 

lamp,” if DOE were to subject modified-spectrum IRL to the same standard as standardspectrum IRL, then these IRL with modified-spectrum glass or coatings may not be able to 

achieve the mandatory standard. Therefore, DOE is planning to establish separate product 

classes for standard-spectrum IRL (those without modification to the spectral emission) and 

modified-spectrum IRL (some portion of the spectral emission is absorbed). However, to ensure 

that a suitable standard level is set for these lamps, such that they are neither disadvantaged nor 

advantaged compared to standard-spectrum lamps, DOE is then establishing an appropriately 

scaled efficacy requirement based on DOE’s analysis of standard-spectrum IRL. This 

requirement would be adjusted to account for the portions of the spectrum that are absorbed by 

the neodymium or spectrally enhancing coating. DOE discusses how this scaling would be 

accomplished in chapter 5 (the Engineering Analysis). 

3.4.2.3 Lamp Diameter 

IRL diameter provides a distinct utility to the consumer such as the ability of reduced 

diameter lamps to be installed in smaller fixtures. In addition, efficacy declines with a smaller 

lamp diameter for a variety of reasons. A smaller diameter lamp has an inherently lower optical 

efficiency than a larger diameter lamp given a similar filament size. Furthermore, manufacturing 

PAR20 lamps such that they could be compliant with efficacy standards would be very difficult 

since technology options available to larger lamps are not necessarily applicable to PAR20 

lamps. Therefore, DOE is proposing to establish separate product classes for lamps with a 

diameter of 2.5 inches or less and lamps with a diameter greater than 2.5 inches. 

3.4.2.4 Rated Voltage 

A sizable portion of standard halogen product sales consists of lamps with a rated voltage 

of 130V. However, DOE’s research indicates that customers almost always operate these 130V 

lamps at 120V (normal line voltage), which doubles their lifetime but reduces their efficacy 

below standard levels. When operated under 120V conditions, lamps rated at 130V in 

compliance with existing IRL efficacy standards are generally less efficacious than lamps using 

equivalent technology rated at 120V. Because of this inherent difference in efficacy, it may be 

less costly to manufacture a lamp rated at 130V and tested at 130V that complies with a standard 

3-38
than a similar 120V lamp complying with the same standard. For example, if DOE were to 

adopt a minimum efficacy requirement that would effectively require HIR technology for 120V 

lamps, due to differences in the test procedures for lamps rated at 130V, a 130V lamp may only 

need to employ an improved halogen technology, which would be less costly. If DOE does not 

establish a separate standard for lamps rated at 130V, more consumers may purchase 130V 

lamps because they are less expensive. When consumers operate these lamps at 120V, in order 

to obtain sufficient light output, they may use more energy than standards-compliant 120V 

lamps. This practice would increase energy consumption and result in lamps operating with a 

lower efficacy than any cost-justified standard level. Therefore, to preserve the energy savings 

intended by these standards, DOE establishes two separate product classes: (1) lamps with a 

rated voltage less than 125V, and (2) lamps with a rated voltage greater than or equal to 125V. 

3.4.2.5 Spot Versus Flood Incandescent Reflector Lamps 

In the Framework Document, DOE considered setting product classes for IRL based on 

beam spread. In particular, DOE considered separate standards for spot and flood IRL. DOE 

reviewed technical reports on the performance of spot and flood reflector lamps. DOE 

concluded that while there might be different utility for consumers through the light distribution 

patterns of a spot reflector lamp versus a flood reflector lamp, the difference in utility does not 

affect the efficacy of the lamp. Thus, DOE will not create separate product classes for spot and 

flood reflector lamps. 

3.4.2.6 Product Classes and Standard Form for IRL 

In sum, DOE is considering all wattages of IRL to be part of the same product class, 

allowing for the standard to be a function of the lamp wattage. As DOE considers more 

efficacious replacement lamps, the rated wattages must decrease to maintain consistent levels of 

light output and save energy. In addition, DOE is considering energy conservation standards for 

full-spectrum IRL separately from modified-spectrum IRL and also makes distinctions based on 

lamp diameter and rated voltage. Table 3.15 summarizes the eight product classes DOE 

considers for the NOPR. To facilitate stakeholder comment on the IRL product classes, DOE 

has continued the product class numbering from the GSFL. 

Table 3.15 DOE NOPR Product Classes for IRL 

Diameter Voltage 

Standard-Spectrum 

Minimum Lamp Efficacy 

lm/W

Modified-Spectrum 

Minimum Lamp Efficacy 

lm/W

≥ 125V Product Class #13 Product Class #17 > 2.5 Inches 

< 125V Product Class #14 Product Class #18 

≥ 125V Product Class #15 Product Class #19 

≤ 2.5 Inches 

< 125V Product Class #16 Product Class #20 

3-39
3-40

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

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

14 Ibid. 

15 Waymouth, John F. Electric Discharge Lamps. 1971. M.I.T. Press: Cambridge, 

Massachusetts. 

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17 Illuminating Engineering Society of North America. “The IESNA Lighting Handbook: 

Reference and Applications.” Ninth Edition. 2000. p. G-7. 

18 Illuminating Engineering Society of North America. “The IESNA Lighting Handbook: 

Reference and Applications.” Ninth Edition. 2000. p. G-8. 

19 Shionoya, Shiegeo, ed. and William M. Yen, ed. Phosphor Handbook. 1998 CRC Press: 

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20 Young, R. Gaines and E. G. F. Arnott. The Effect of Phosphor Coating Weight on the Lumen 

Output of Fluorescent Lamps. Journal of the Electrochemical Society. October 1965. 112(10): 

pp. 982-984. 

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

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

22 Ibid. 

23 Ibid. 

24 Bloembergen, N., "Solid State Infrared Quantum Counters", Physical Review Letters, 2, 84-85 

(1959).