CHAPTER 5. ENGINEERING ANALYSIS 

TABLE OF CONTENTS 

5.1 INTRODUCTION ........................................................................................................... 5-1

5.2 ENGINEERING ANALYSIS FRAMEWORK............................................................... 5-1

5.3 GENERAL SERVICE FLUORESCENT LAMPS.......................................................... 5-3

5.3.1 Four-Foot MBP GSFL With CCTs ≤ 4,500K...................................................... 5-6

5.3.1.1 Baseline Models.......................................................................................5-7

5.3.1.2 Efficacy Levels ........................................................................................5-8

5.3.1.3 System Power Rating............................................................................. 5-14

5.3.1.4 Results....................................................................................................5-23

5.3.2 Eight-foot SP Slimline GSFL With CCTs ≤ 4,500K.........................................5-31

5.3.2.1 Baseline Models.....................................................................................5-31

5.3.2.2 Efficacy Levels ......................................................................................5-32

5.3.2.3 System Power Rating............................................................................. 5-35

5.3.2.4 Results....................................................................................................5-39

5.3.3 Eight-Foot RDC HO GSFL With CCTs ≤ 4,500K............................................ 5-43

5.3.3.1 Baseline Models.....................................................................................5-43

5.3.3.2 Efficacy Levels ......................................................................................5-43

5.3.3.3 System Power Rating............................................................................. 5-47

5.3.3.4 Results....................................................................................................5-49

5.3.4 Four-foot T5 MiniBP SO GSFL With CCTs ≤ 4,500K..................................... 5-53

5.3.4.1 Baseline Models.....................................................................................5-53

5.3.4.2 Efficacy Levels ......................................................................................5-53

5.3.4.3 System Power Rating............................................................................. 5-56

5.3.4.4 Results....................................................................................................5-57

5.3.5 Four-foot T5 MiniBP HO GSFL With CCTs ≤ 4,500K .................................... 5-60

5.3.5.1 Baseline Models.....................................................................................5-60

5.3.5.2 Efficacy Levels ......................................................................................5-60

5.3.5.3 System Power Rating............................................................................. 5-63

5.3.5.4 Results....................................................................................................5-63

5.4 INCANDESCENT REFLECTOR LAMPS................................................................... 5-65

5.4.1 Baseline Models for IRL With Diameters Greater Than 2.5 Inches and Operating 

Voltages Less Than 125V..............................................................................................5-66

5.4.2 Efficacy Levels ..................................................................................................5-66

5.4.3 Results................................................................................................................5-71

5.5 SCALING TO PRODUCT CLASSES NOT ANALYZED .......................................... 5-74

5.5.1 General Service Fluorescent Lamps .................................................................. 5-75

5.5.1.1 2-foot U-Shaped GSFL With CCTs ≤ 4,500K.......................................5-75

5.5.1.2 Lamps With CCTs Above 4,500K......................................................... 5-76

5.5.2 Incandescent Reflector Lamps........................................................................... 5-80

5.5.2.1 Modified-Spectrum IRL......................................................................... 5-80

5.5.2.2 IRL With Diameters Less Than or Equal To 2.5 Inches........................ 5-81

5.5.2.3 IRL With Operating Voltages Greater Than or Equal to 125 Volts ......5-82

5-i
 

5.6 SUMMARY OF ALL EFFICACY LEVELS FOR COVERED PRODUCTS .............5-83

5.6.1 Summary of All Efficacy Levels for Covered GSFL ........................................ 5-83

5.6.2 Summary of All Efficacy Levels for Covered IRL............................................5-84

REFERENCES ..........................................................................................................................5-86

LIST OF TABLES 

Table 5.3.1 DOE Final Rule Product Classes for General Service Fluorescent Lamps..............5-4

Table 5.3.2 Baseline Lamps for Commercial and Industrial 4-Foot MBP Engineering Analysis. 5-

8

Table 5.3.3 Baseline Lamps for Residential 4-Foot MBP Engineering Analysis .......................5-8

Table 5.3.4 4-Foot MBP Lamp Designs................................................................................... 5-11

Table 5.3.5 Summary of the ELs for 4-Foot MBP Fluorescent Lamps With CCTs ≤ 4,500K . 5-13

Table 5.3.6 Lamp Replacement Engineering Analysis for a Three-Lamp 40W T12, 4,100K 

System in the Commercial and Industrial Sectors..................................................................... 5-24

Table 5.3.7 Lamp and Ballast Replacement Engineering Analysis for a Three-Lamp 40W T12, 

4,100K System in the Commercial and Industrial Sectors........................................................ 5-25

Table 5.3.8 Lamp Replacement Engineering Analysis for a Two-Lamp 40W T12, 4,100K 

System in the Residential Sector................................................................................................ 5-26

Table 5.3.9 Lamp and Ballast Replacement Engineering Analysis for a Two-Lamp 40W T12, 

4,100K System in the Residential Sector................................................................................... 5-27

Table 5.3.10 Lamp and Ballast Replacement Engineering Analysis for a Three-Lamp 34W T12, 

4,100K System in the Commercial and Industrial Sectors........................................................ 5-29

Table 5.3.12 Lamp and Ballast Replacement Engineering Analysis for a Three-Lamp 32W T8, 

4,100K System in the Commercial and Industrial Sectors........................................................ 5-30

Table 5.3.13 Baseline Units of Analysis for 8-Foot SP Slimline Lamps .................................5-32

Table 5.3.14 8-Foot SP Slimline Lamp Designs........................................................................ 5-34

Table 5.3.15. Summary of the ELs for 8-Foot SP Slimline Lamps With CCTs ≤ 4,500K.......5-35

Table 5.3.17 Lamp-and-Ballast Replacement Engineering Analysis for a 75W T12, 4,100K 

System........................................................................................................................................ 5-40

Table 5.3.18 Lamp-and-Ballast Replacement Engineering Analysis for a 60W T12, 4,100K 

System........................................................................................................................................ 5-41

Table 5.3.19 Lamp Replacement Engineering Analysis for a Two-Lamp, 59W, T8, 4,100K 

System........................................................................................................................................ 5-42

Table 5.3.20 Lamp-and-Ballast Replacement Engineering Analysis for a Two-Lamp, 59W, T8, 

4,100K System........................................................................................................................... 5-42

Table 5.3.21 Baseline Units of Analysis for 8-Foot RDC High-Output Lamps.......................5-43

Table 5.3.22 8-Foot RDC HO Lamp Designs............................................................................ 5-45

Table 5.3.23 Summary of the ELs for 8-Foot RDC HO Lamps With CCTs ≤ 4,500K............5-47

Table 5.3.24 Lamp Replacement Engineering Analysis for a 110W T12, 4,100K System .....5-50

Table 5.3.25 Lamp-and-Ballast Replacement Engineering Analysis for a 110W T12, 4,100K 

System........................................................................................................................................ 5-51

Table 5.3.26 Lamp-and-Ballast Replacement Engineering Analysis for a 95W T12, 4,100K 

System........................................................................................................................................ 5-52

Table 5.3.27 Baseline Unit of Analysis for 4-Foot T5 MiniBP Standard-Output Lamps........5-53

5-ii
 

Table 5.3.28 4-Foot T5 MiniBP SO Lamp Designs.................................................................. 5-55

Table 5.3.29 Summary of the ELs for 4-Foot T5 MiniBP SO Lamps With CCTs ≤ 4,500K ..5-56

Table 5.3.30 Lamp Replacement Engineering Analysis for a Two-Lamp 28W T5, 4,100K 

System........................................................................................................................................ 5-59

Table 5.3.31 Lamp and Ballast Replacement Engineering Analysis for a Two-Lamp 28W T5, 

4,100K System........................................................................................................................... 5-59

Table 5.3.32 Baseline Unit of Analysis for 4-Foot T5 MiniBP High-Output Lamps ..............5-60

Table 5.3.33 4-Foot T5 MiniBP HO Lamp Designs.................................................................. 5-62

Table 5.3.34 Summary of the ELs for 4-Foot T5 MiniBP HO Lamps With CCTs ≤ 4,500K..5-63

Table 5.3.35 Lamp Replacement Engineering Analysis for a Two-Lamp 54W T5, 4,100K 

System........................................................................................................................................ 5-64

Table 5.3.36 Lamp and Ballast Replacement Engineering Analysis for a Two-Lamp 54W T5, 

4,100K System........................................................................................................................... 5-64

Table 5.4.1 Product Classes for Incandescent Reflector Lamps............................................... 5-65

Table 5.4.2 IRL Representative Product Class and Baseline Lamps........................................ 5-66

Table 5.4.3 Summary of the Els for Standard-Spectrum IRL With Diameters Greater Than 2.5 

Inches and Operating Voltages Less Than 125V....................................................................... 5-71

Table 5.4.4 IRL Engineering Analysis 50W PAR30................................................................ 5-72

Table 5.4.5. IRL Engineering Analysis for 75W PAR38 ......................................................... 5-73

Table 5.4.6 IRL Engineering Analysis for 90W PAR38 .......................................................... 5-74

Table 5.5.1 Efficacy Requirements for 2-Foot U-Shaped Lamps With CCTs Less Than or Equal 

To 4,500K .................................................................................................................................. 5-76

Table 5.5.2 Efficacy Requirements For 4-Foot MBP Lamps With CCTs Above 4,500K .......5-78

Table 5.5.3 Efficacy Requirements For 8-Foot SP Slimline Lamps With CCTs Above 4,500K. 5-

78

Table 5.5.4 Efficacy Requirements For 8-Foot RDC HO Lamps With CCTs Above 4,500K. 5-79

Table 5.5.5 Efficacy Requirements For 4-Foot T5 MiniBP SO Lamps With CCTs Above 

4,500K........................................................................................................................................ 5-80

Table 5.5.6 Efficacy Requirements For 4-Foot T5 MiniBP HO Lamps With CCTs Above 

4,500K........................................................................................................................................ 5-80

Table 5.5.7 Efficacy Levels For 2-Foot U-Shaped Lamps With CCTs Greater Than 4,500K. 5-80

Table 5.5.8 Summary of the ELs for Modified-Spectrum IRL With Diameters Greater Than 2.5 

Inches and Operating Voltages Less Than 125V....................................................................... 5-81

Table 5.5.9 Summary of the ELs for Standard-Spectrum IRL With Diameters Less Than or 

Equal To 2.5 Inches and Operating Voltages Less Than 125V................................................. 5-82

Table 5.5.10 Summary of the ELs for Standard Spectrum IRL With Diameters Greater Than 2.5 

Inches and Operating Voltages Greater Than or Equal to 125V ............................................... 5-83

Table 5.6.1 Summary of All Efficacy Levels for Covered GSFL ............................................ 5-84

Table 5.6.2 Summary of Coefficients for All Efficacy Levels for Covered IRL .....................5-85

LIST OF FIGURES 

Figure 5.3.1 Initial Efficacy Levels for 4-Foot MBP Fluorescent Lamps With CCTs ≤ 4,500K. 5-

10

5-iii
 

Figure 5.3.2 Three-Lamp 32W T8 120V Ballasts with THD <20 Percent, PF >0.95, and BEF 

0.98-1.05 .................................................................................................................................... 5-14

Figure 5.3.3 Three-Lamp 30W T8 120V Ballasts with THD <20 Percent, PF >0.95, and BEF 

1.07-1.12 .................................................................................................................................... 5-15

Figure 5.3.4 Three-Lamp 28W T8 120V Ballasts with THD <20 Percent, PF >0.98, and BEF 

1.16-1.20 .................................................................................................................................... 5-15

Figure 5.3.5 Three-Lamp 25W T8 120V Ballasts with THD <20 Percent, and BEF 1.31-1.34 .. 5-

16

Figure 5.3.6 Two-Lamp 32W T8 120V Ballasts with THD <20 Percent, PF >0.95, and BEF 

1.40-1.53 .................................................................................................................................... 5-17

Figure 5.3.7 Two-Lamp 30W T8 120V Ballasts with THD <20 Percent, PF >0.95, and BEF 

1.56-1.67 .................................................................................................................................... 5-17

Figure 5.3.8 Two-Lamp 28W T8 120V Ballasts with THD <20 Percent, PF >0.98, and BEF 

1.69-1.73 .................................................................................................................................... 5-18

Figure 5.3.9 Two-Lamp 25W T8 120V Ballasts with THD <20 Percent, PF >0.98, and BEF 

1.91-1.97 .................................................................................................................................... 5-18

Figure 5.3.10 Two-Lamp 40W 120V Ballasts with <20 Percent THD, PF >0.95, and BEF 1.20-

1.22 in the Commercial and Industrial Sectors.......................................................................... 5-19

Figure 5.3.11 Three-Lamp 40W 120V Ballasts Linear Fit (Based on Slope Change from TwoLamp to Three-Lamp Ballasts for 32W T8 Applied to T12 and Common T12 Electronic Ballast)

....................................................................................................................................................5-20

Figure 5.3.12 Two-Lamp 34W 120V Ballasts with <20 Percent THD, PF >0.95, and BEF 1.42-

1.44 in the Commercial and Industrial Sectors.......................................................................... 5-20

Figure 5.3.13 Three-Lamp 34W 120V Ballasts (Based on Slope Change from Two-Lamp to 

Three-Lamp Ballasts for T8 Applied to T12 and Common T12 Electronic Ballast) ................5-21

Figure 5.3.14 Two-Lamp 40W Ballasts with <40 Percent THD, PF >0.55, and BEF 1.12-1.18 in 

the Residential Sector ................................................................................................................ 5-22

Figure 5.3.15 Two-Lamp 34W Ballasts with <50 Percent THD, PF >0.53, and BEF 1.37-1.56 in 

the Residential Sector ................................................................................................................ 5-22

Figure 5.3.16 Initial Efficacy Levels for 8-Foot SP Slimline Lamps With CCTs ≤ 4,500K....5-34

Figure 5.3.17 Two-Lamp 75W T12 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.64-0.66; Linear Fit: m=100.0, b=47.0 .................................................................................... 5-36

Figure 5.3.18 Two-Lamp 60W T12 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.79-0.80; Linear Fit: m=100.0, b=22.0 .................................................................................... 5-37

Figure 5.3.19 Two-Lamp 59W T8 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.77-0.79; Linear Fit: m=123.7, b=4.0 ...................................................................................... 5-38

Figure 5.3.20 Two-Lamp 57W T8 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.80-0.81; Linear Fit: m=50.0, b=63.5 ...................................................................................... 5-38

Figure 5.3.21 Two-Lamp 55W T8 120V Ballasts with THD <10 percent, and BEF 0.86; Linear 

Fit: m=118.4, b=-2.2.................................................................................................................. 5-39

Figure 5.3.22 Initial Efficacy Levels for 8-Foot RDC HO Lamps With CCTs ≤ 4,500K........5-45

Figure 5.3.23 Two-Lamp 110W T12 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.42-0.43; Linear Fit: m=307.7, b=-65.4 ................................................................................... 5-47

Figure 5.3.24 Two-Lamp 95W T12 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.48-0.52; Linear Fit: m=433.3, b=-204.3 ................................................................................. 5-48

5-iv
 

5-v

Figure 5.3.25 Two-Lamp 86W T8 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.54-0.55; Linear Fit: m=128.6, b=46.9 .................................................................................... 5-49

Figure 5.3.26 Initial Efficacy Levels for 4-Foot T5 MiniBP SO Lamps With CCTs ≤ 4,500K, 

35° C Operation ......................................................................................................................... 5-55

Figure 5.3.27 Two-Lamp 28W T5 Ballasts with THD <10 percent, PF >0.95, and BEF 1.52-1.67

....................................................................................................................................................5-57

Figure 5.3.28 Two-Lamp 26W T5 Ballasts with THD <10 percent, PF >0.95, and BEF 1.67-1.71

....................................................................................................................................................5-57

Figure 5.3.29 Initial Efficacy Level for 4-Foot T5 MiniBP HO Fluorescent Lamps With CCTs ≤

4,500K, 35° C Operation ........................................................................................................... 5-62

Figure 5.4.1 Initial Efficacy Levels for Standard-Spectrum IRL With Diameters Greater Than 

2.5 Inches and Operating Voltages Less Than 125V................................................................. 5-69
 

CHAPTER 5. ENGINEERING ANALYSIS 

5.1 INTRODUCTION 

This chapter provides the technical support documentation for the engineering analyses 

of general service fluorescent lamps (GSFL) and incandescent reflector lamps (IRL). Generally, 

the purpose of the engineering analysis is to develop efficacy levels (ELs) that encompass the 

range of products affected by a standard, from the baseline products to the maximum 

technologically feasible products, and develop power rating estimates for the products analyzed. 

The outputs from the engineering analysis are critical inputs to subsequent cost-benefit 

calculations for individual consumers. 

The engineering analysis follows the screening analysis (chapter 4), in which the U.S. 

Department of Energy (DOE) identifies design options that are later used for the rulemaking 

analyses. Design options include discrete technologies, such as krypton fill gas, that improve 

efficacy. DOE develops product efficacy levels associated with lamp designs that incorporate a 

range of design options. 

While some engineering analyses for other rulemakings discuss manufacturer production 

costs or selling prices and relate cost or price to efficacy, this engineering analysis does not 

address manufacturer costs or mark-ups. In this rulemaking, DOE develops end-user prices for 

lamp and lamp-and-ballast designs analyzed by discounting published list prices (i.e., “blue book 

pricing”). The product price determination (chapter 7) discusses the pricing methodology and 

results. By combining the results of the engineering analysis and the product price 

determination, DOE derives the necessary inputs for use in the life-cycle cost (LCC) analysis and 

national impacts analysis (NIA). In particular, DOE develops lamp and lamp-and-ballast designs 

associated with particular ELs and end-user prices. 

This chapter starts with an outline of the engineering analysis (section 5.2), followed by 

specifics on the engineering analysis for GSFL (section 5.3) and IRL (section 5.4). Each section 

provides detailed information on the baseline lamps and representative product classes DOE 

chooses to analyze, the development of ELs, and the results of the engineering analysis. Section 

5.5 discusses how DOE extends its results from the representative product classes to those 

products it does not analyze. 

5.2 ENGINEERING ANALYSIS FRAMEWORK 

To the extent possible, DOE bases the engineering analysis on commercially-available 

lamps that incorporate the design options identified in the technology assessment and screening 

analysis (chapter 4). For GSFL and IRL, DOE also bases the majority of the engineering 

analysis on commercially available lamps. However, where needed, DOE supplements these 

lamps with additional model lamps that use commercially-available technologies. 

5-1
The engineering analysis for each of the two categories of lamps DOE analyzes in this 

rulemaking (i.e., GSFL and IRL) follows a similar approach: 

Step 1. Representative Product Classes. DOE reviews covered lamps and the associated 

product classes. When a product has multiple product classes, DOE selects certain 

classes as “representative” and concentrates its analytical effort on these. DOE 

selects representative product classes primarily because of their high market 

volumes. Section 5.5 discusses how DOE extrapolated from representative product 

classes to other product classes. 

Step 2. Baseline Lamps. DOE selects baseline lamps from the representative product 

classes. Generally, a baseline lamp is one that just meets existing mandatory energy 

conservation standards or represents the typical lamp sold. DOE selects specific 

characteristics such as certain correlated color temperatures (CCTs), operating 

lifetimes, and light outputs to characterize the most common lamps consumers 

purchase. DOE selects multiple baseline lamps in each product class to ensure 

consideration of different high-volume lamps and their associated consumer 

economics. 

Step 3. Lamp-and-Ballast Designs. DOE selects more efficacious lamps for each baseline 

lamp in the representative product classes by considering technologies not 

eliminated in the screening analysis. DOE considers these technologies either 

explicitly as design options or implicitly as design options incorporated into 

commercially-available lamps at the efficacy levels evaluated. In identifying more 

efficacious lamp-and-ballast designs, DOE recognizes that a lamp’s lumen package 

and performance characteristics are important design criteria for consumers. For 

example, if consumers do not have the option to purchase substitution lamps or 

lamp-and-ballast systems with similar lumen packages under an energy 

conservation standard, consumers would need to change the lighting design to 

maintain a similar light output. Therefore, DOE establishes lamp-and-ballast 

designs for the engineering analysis so that potential light output is equal to, greater 

than, or no more than 10 percent less than the light output of the baseline system. 

DOE also chooses substitute lamps with performance characteristics similar to 

those of the baseline lamps. 

 In identifying more efficacious substitutes, DOE uses a database of commerciallyavailable lamps. For GSFL, DOE develops the engineering analysis based on two 

substitution cases in which consumers can maintain light output while decreasing 

energy consumption. In the first case, the consumer replaces the baseline lamp with 

a more-efficacious, lower-wattage lamp that operates on the existing ballast. In the 

second case, the consumer replaces the lamp-and-ballast system with a moreefficacious same- or lower-wattage lamp and a different ballast. For example, a 

5-2
lamp-and-ballast system with a more efficacious, same-wattage lamp and lower 

ballast factora (BF) ballast will consume less energy and maintain light output. 

 For IRL, DOE uses some commercially-available lamps, but also developed 

“model” lamps. These models incorporate designs that may not be commercially 

available for certain lamp types and wattages, but use commercially-available 

technologies. 

Step 4. Efficacy Levels. After identifying the more efficacious substitutes for each baseline 

lamp or lamp-and-ballast system, DOE develops ELs based on three factors: (1) the 

design options associated with the specific lamps being studied (e.g., grades of 

phosphor for fluorescent lamps, the use of halogen capsules for IRL, etc.); (2) the 

ability of lamps across wattages to comply with the EL of a given product class;b

and (3) the maximum technologically-feasible efficacy level. 

The sections that follow discuss how DOE applies this methodology to each product class 

to create the engineering analysis. 

5.3 GENERAL SERVICE FLUORESCENT LAMPS 

As discussed in the market and technology assessment (chapter 3), DOE revised the 

Energy Policy and Conservation Act (EPCA) table of standards for fluorescent lamps to twelve 

product classes, as shown in Table 5.3.1. Of these twelve product classes, DOE chose to analyze 

the five classes that represent high shipment volumes–4-foot medium bipin (MBP), 8-foot single 

pin (SP) slimline, 8-foot recessed double contact (RDC) high output (HO), 4-foot miniature bipin 

(MiniBP) standard output (SO), and 4-foot MiniBP HO –all with a CCT less than or equal to 

4,500 Kelvin (K). The 4-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. 

Shipments of 2-foot U-shaped lamps have accounted for less than five percent of GSFL unit 

sales historically and have remained stable at that level.1

 Given the relatively small market share 

of U-shaped lamps, DOE did not explicitly analyze these lamps. While total shipments of 4-foot 

MiniBP SO and HO lamps (often referred to as T5 lamps) currently have a relatively small 

market share, shipment trends indicate that the market for these lamps is rapidly increasing. 

Therefore, DOE directly analyzed 4-foot MiniBP SO and 4-foot MiniBP HO lamps.. In addition, 

as lamps with CCTs greater than 4,500K represent small market shares of total GSFL sales, DOE 

only analyzed lamps with CCTs less than or equal to 4,500K. DOE discusses each of the five 

representative product classes separately in the sections that follow. 

 

a

 The “ballast factor” of a ballast is the ratio of the light output of a fluorescent lamp or lamps operated on a ballast 

to the light output of the lamp(s) operated on a reference ballast. Ballast factor depends on both the ballast and the 

lamp type; a single ballast can have several ballast factors depending on lamp type. The light output of a single 

fluorescent lamp is measured on a ballast with a ballast factor of 1.0. One can reduce the light output of a lamp-andballast system by operating a lamp on a ballast with a lower ballast factor. 

b

 Efficacy levels span multiple lamps of different wattages. In selecting ELs, DOE considered whether lamps of 

different wattages can meet the efficacy levels prescribed by those ELs. 

5-3
Although DOE did not create a separate engineering analysis for 2-foot U-shaped lamps 

or lamps that have a CCT greater than 4,500K, DOE established standards for these product 

classes, based on the representative product classes directly analyzed. For instance, DOE 

extended its proposal for the 4-foot MBP product class to the 2-foot U-shaped product class. 

This was possible because 2-foot U-shaped lamps generally operate in the same way and 

typically span the same wattages as 4-foot MBP lamps. For lamps with CCTs greater than 

4,500K, DOE extended proposed standards from similar lamp types with a CCT of less than or 

equal to 4,500K as they operate in a similar fashion and generally span the same wattages. 

Section 5.5 provides more information on extending standards to the product classes DOE did 

not analyze. 

Table 5.3.1 DOE Final Rule Product Classes for General Service Fluorescent Lamps 

Lamp Type 

For CCT ≤ 4,500K 

Minimum Lamp Efficacy 

lm/W* 

For CCT > 4,500K 

Minimum Lamp 

Efficacy 

lm/W 

4-foot MBP Representative product class Scaled from ≤4,500K 

2-foot U-shaped Scaled from 4-foot MBP Scaled from ≤4,500K 

8-foot SP slimline Representative product class Scaled from ≤4,500K 

8-foot RDC HO Representative product class Scaled from ≤4,500K 

4-foot T5 MiniBP SO Representative product class Scaled from ≤ 4,500K 

4-foot T5 MiniBP HO Representative product class Scaled from ≤ 4,500K 

* lm/W = lumens per watt 

In the engineering analysis for GSFL, DOE based its ELs on lamps because the energy 

conservation standards only apply to lamps. However, DOE used a systems approach in 

analyzing these representative product classes because both lamps and ballasts determine a 

system’s energy use and light output. DOE paired a lamp with a ballast to develop lamp-andballast systems. By using a systems approach, DOE was able to demonstrate the actual energy 

consumption and light output of an operating lamp. 

Using this systems approach, DOE selected a variety of energy-saving lamp-and-ballast 

systems per EL. In general, DOE chose its lamp designs (which refer to lamp substitution 

options) and lamp-and-ballast designs (which refer to lamp-and-ballast substitution options) by 

selecting commercially-available fluorescent lamps at higher efficacies than the baseline lamps. 

Higher efficacies are achieved through a variety of technologies. As discussed in the screening 

analysis (chapter 4), DOE considered commercially available GSFL that use highly-emissive 

electrode coatings, higher-efficacy lamp fill gas composition, higher-efficacy phosphors, glass 

coatings, or higher-efficacy lamp diameter to achieve higher-efficacy lamp designs. 

For the LCC, DOE analyzed lamp-and-ballast systems that both save energy and 

maintain comparable light output. In particular, DOE considered lamp-and-ballast designs that 

emit mean lumens equal to, greater than, or no more than 10 percent less than the light output of 

the baseline system. DOE maintained light output across efficacy levels to ensure that products 

supply equivalent service in the base case and standards case. 

5-4
In assessing light output, DOE made a distinction between mean and initial lumens. 

DOE used initial lumens in its test procedures to measure compliance with a standard. This is 

consistent with consensus industry standards on efficacy measurements. Therefore, DOE used 

initial lumens to calculate ELs. However, the light output of a lamp decreases over time. To 

account for this real-world depreciation in lumens, DOE used mean lumens to determine 

equivalent substitutes in the LCC and to determine the light output of GSFL in the NIA. 

For GSFL, energy savings can be achieved either through lamp replacements or lampand-ballast replacements. For lamp replacements, DOE analyzed reduced-wattage, higherefficacy lamps for use on the existing ballast. For lamp-and-ballast replacements, DOE used a 

variety of lamp-and-ballast combinations to obtain energy savings and maintain comparable 

mean lumens. These combinations included both reduced-wattage lamps and same-wattage 

lamps. For example, energy savings could be achieved using a same-wattage, higher-efficacy 

lamp with a lower BF ballast while maintaining mean lumen output. 

Some consumers may operate non-energy-saving systems. For example, a consumer who 

pairs a same-wattage, higher-efficacy lamp with an existing ballast will get more light output but 

will not save energy. DOE did not consider such non-energy-saving systems in the LCC because 

energy savings determine whether a consumer can recoup any higher first costs of replacement 

products. However, DOE did take into account the use of both energy-saving and non-energysaving systems as well as systems that may over- or under-light when aggregating market 

behavior in the NIA. This reflects the fact that DOE cannot require consumers to change their 

ballast along with their lamp. Appendix 5A shows lamp-and-ballast designs considered in the 

NIA. 

Because DOE is using a systems approach, the system power rating is an important result 

of the engineering analysis. The system power rating represents the energy consumption rate of 

both the lamp and ballast, and therefore is greater than the rated power of the lamp alone. While 

the rated lamp power affects the system power, the system power is also affected by the type of 

ballast used, the BF of that ballast, and the number of lamps operated per ballast. 

 DOE calculated the system power data using published catalog information. For each 

lamp wattage and ballast type, DOE linearly fitted the system power rating of a lamp on several 

different ballasts with varying ballast factors. DOE used this linear fit to derive the system 

power rating of the lamp on the ballasts used in the analysis. The linear fit follows the equation 

below: 

 *  bBFmSPR Eq. 5.1 

where: 

 SPR = System Power Rating

 BF = Ballast Factor 

 m = Slope of Linear Fit

 b = Y-Intercept of Linear Fit

DOE considered both magnetic and electronic ballasts. For 4-foot T8 and 4-foot T12 

systems, DOE used system power data from manufacturer literature to develop a linear fit for 

lamps on three-lamp and two-lamp, 120V, electronic instant-start ballasts with similar ballast 

5-5
efficacy factors (BEF).c

 For some 4-foot T12s, DOE also used one-lamp and two-lamp 120V, 

magnetic, rapid-start ballasts with common ballast efficacy factors. A linear fit was not 

necessary for these magnetic systems because DOE used only one type of magnetic ballast in the 

analysis. For 8-foot T8 and 8-foot T12 SP slimline and RDC HO lamps, DOE used system 

power data from manufacturer literature to develop a linear fit for lamps on two-lamp, 120V, 

electronic instant-start ballasts. DOE also used data for some 8-foot T12 SP slimline and RDC 

HO lamps on two-lamp, 120V, magnetic, instant-start ballasts. Again, a linear fit is not 

necessary for the magnetic systems because DOE used only one ballast per lamp type in the 

analysis. For T5 lamps, DOE used system power data from manufacturer literature to develop a 

linear fit for lamps on a two-lamp, 120V, electronic programmed-start ballast. 

5.3.1 Four-Foot MBP GSFL With CCTs ≤ 4,500K 

DOE selected the 4-foot MBP with CCTs less than or equal to 4,500K product class as a 

representative product class for GSFL because it has the highest volume shipments of all the 

product classes for fluorescent lamps. DOE reviewed the range of commercially available lampand-ballast combinations to pair each lamp it analyzed with a ballast. DOE found that ballasts 

for 4-foot MBP ballasts are available in a variety of lamp-per-ballast designs. For example, 

electronic ballasts are typically manufactured in one-, two-, three-, and four-lamp versions. 

According to the 2000 rule on GSFL ballasts (“2000 Ballast Rule”),2 there are on average 2.8 

lamps per 4-foot MBP system. 62 FR 56740 (September 19, 2000). To most accurately 

represent the market and simplify the analysis, DOE used a three-lamp system for 4-foot MBP 

lamps operating on electronic ballasts in the commercial sector. (This decision effectively 

spreads the cost of a new ballast over the average number of lamps per system). To make a 

comparison between electronic and magnetic 4-foot MBP systems, and because three-lamp 

magnetic ballasts typically are not sold, DOE developed a system that combines a two-lamp 

magnetic and one-lamp magnetic ballast. This allowed DOE to compare similar light output 

packages and make a level comparison on energy use.d As a review of manufacturer catalogs 

indicated that two-lamp ballasts were most prevalent in the residential sector, DOE developed a 

separate engineering analysis for 4-foot MBP lamps in the residential sector based on these twolamp systems. 

 

c

 Energy-efficient ballasts are characterized as having higher ballast efficacy factors (BEF). The BEF is directly 

related to the quotient of the BF and the power consumed by the ballast, such that a ballast maintaining BF while 

reducing power consumption will have a higher BEF and be a more energy-efficient ballast. In its analysis, DOE 

varied the ballast BF, not the BEF (given the same lamp wattage and ballast type (“electronic” or “magnetic”)), in its 

assessment of standards for fluorescent lamps. DOE will be considering new and amended BEF standards in a 

separate fluorescent lamp ballast rulemaking. 

d DOE recognizes that the combined cost of a one-lamp and two-lamp magnetic system would be higher than the 

cost of a three-lamp system if it were manufactured. However, the comparative economics between a one-lamp and 

two-lamp magnetic ballast versus a three-lamp electronic ballast is not an issue in DOE’s calculation of the LCC. 

Since ballast standards will be effective in 2010 for non-residential 4-foot ballasts, DOE assumes that all new 4-foot 

non-residential ballast sales are electronic.

5-6
5.3.1.1 Baseline Models 

The 4-foot MBP product class represents high-volume T12 and T8 4-foot MBP lamps 

operating on various ballasts. To reflect the most common lamp and wattage combinations for 

this product class in the commercial and industrial sectors, DOE selected three baseline 

lamp/wattage combinations: a 32W T8, a 34W T12, and a 40W T12 lamp. In 2005, T8 lamps 

represented 57 percent of the 4-foot MBP shipments, of which the 32W lamp was the most 

common. The 2005 shipments of 4-foot T12 lamps represented 43 percent of all 4-foot MBP 

shipments. The 34W T12 lamp comprised approximately two-thirds of these shipments and the 

40W T12 was approximately one-third. Therefore, these three baseline lamps represent the three 

highest volume lamp diameter and wattage combinations for the 4-foot MBP product class in the 

commercial and industrial sectors. DOE also found that a significant portion of T12, 4-foot 

MBP lamps operate in the residential sector. Conversations with industry experts as well as a 

published study prepared for the utility Pacific Gas & Electric (PG&E3) revealed that residential 

consumers are most likely to buy a 40W T12 lamp; 32W T8 lamps and 34W T12 lamps are less 

common. Therefore, in the residential sector, DOE only analyzed the 40W T12 lamp as a 

baseline lamp. 

For each of these baseline model lamps, DOE developed a set of typical performance 

characteristics. For the 32W 4-foot T8 MBP lamp, DOE selected a lamp using a 700 series rare 

earth phosphor. These lamps typically have a color rendering index (CRI) of 70 to 79. During 

discussions with industry experts, DOE found that this lamp represents the majority of 4-foot T8 

MBP lamps sold. Typically, a baseline product is a unit that just meets the existing energy 

conservation standard for that product (75.0 lm/W for this product class). However, there are no 

T8 lamps in this product class with an efficacy as low as 75.0 lm/W. Therefore, DOE selected a 

lamp with an efficacy of 86.2 lm/W because it is the most common T8 lamp sold. For new 

system installations, DOE selected T8 lamps operating in three-lamp fixtures. These fixtures are 

assumed to operate on a 120V instant-start electronic ballast with a 0.88 BF. Together, the lampand-ballast combination in this three-lamp system has a light emission of approximately 6,650 

mean lumens (and 7,390 initial lumens) when operating with the baseline lamp. 

For the 34W 4-foot T12 MBP lamp, DOE selected a cool white lamp with an efficacy 

that is slightly above the minimum efficacy standard (77.9 lm/W). A review of the product 

catalogs found there are no covered 34W 4-foot T12 MBP lamps that are just compliant with the 

standard (75.0 lm/W), or any with an efficacy between 75.0 and 77.9 lm/W. For the 40W 4-foot 

T12 MBP lamp in the commercial and industrial sectors, DOE selected a lamp using 700 series 

rare earth phosphor and an efficacy of 78 lm/W. DOE paired both commercial and industrial 4-

foot T12 MBP lamps with a rapid-start 120V magnetic ballast, which exhibits a 0.88 BF when 

operating the 34W lamp and a 0.95 BF when operating the 40W lamp. This combination of 

lamp and ballast represents the most common configuration for this lamp in existing and new 

installations. Together, this lamp-and-ballast combination in a three-lamp fixture creates a 

system package of over 6,070 mean lumens (and nearly 7,000 initial lumens) for the baseline 

34W lamps and approximately 8,210 mean lumens (and 9,120 initial lumens) for the baseline 

40W lamps. As mentioned earlier, DOE assumed the three-lamp fixture is wired using two 

magnetic ballasts – a one-lamp and a two-lamp ballast connected in tandem with an adjacent 

fixture. 

5-7
In the residential sector, DOE only analyzed the 40W 4-foot T12 MBP lamp as a baseline 

lamp. After reviewing available catalog information, DOE found that the most common 40W 

T12 lamp sold in the residential sector is different from the 40W T12 baseline lamp for the 

commercial and industrial sectors. DOE chose a 40W 4-foot T12 MBP baseline lamp for the 

residential sector that has a slightly lower efficacy and shorter lifetime than the typical 40W T12 

lamp sold in the commercial sector: 76.8 lm/W and 15,000 hours. A review of catalog 

information and a PG&E study revealed that the most common residential sector ballast is a lowpower factor 2-lamp magnetic rapid-start T12 system with a ballast factor of 0.68.3

 

For all baseline lamps and the more efficacious lamp designs, DOE analyzed fluorescent 

lamps with a CCT of 4,100K. DOE selected this CCT because it represents the highest volume 

CCT for this category of lamps and because it falls within the CCT span of the analyzed product 

class (2,500K to 4,500K). Additionally, the typical lifetime for the three baseline models for this 

product class in the commercial and industrial sectors is 20,000 hours (using a 3-hour on-off 

testing cycle). In the residential sector, the typical lifetime was found to be 15,000 hours (using 

a 3-hour on-off testing cycle). While there are lamps in this product class that have other 

lifetimes under the 3 hour on-off testing cycle, such as 18,000 or 24,000 hrs, these lamps do not 

represent the typical unit sold for these three lamp types. 

Table 5.3.2 Baseline Lamps for Commercial and Industrial 4-Foot MBP Engineering 

Analysis 

Nominal 

Wattage 

CCT Rated 

Efficacy* 

Initial 

Light 

Output 

Mean 

Light 

Output 

Lamp Life 

Diameter 

W 

CRI 

K lm/W lm lm hr 

T12 40 70 4,100 78.0 3,200 2,880 20,000 

T12 34 62 4,100 77.9 2,650 2,300 20,000 

T8 32 75 4,100 86.2 2,800 2,520 20,000 

* Rated efficacy is based on the rated wattage of the lamps, which for T12 lamps is 41W and 34W and for the 32W 

T8 lamp is 32.5W. 

Table 5.3.3 Baseline Lamps for Residential 4-Foot MBP Engineering Analysis 

Nominal 

Wattage 

CCT Rated 

Efficacy* 

Initial 

Light 

Output 

Mean 

Light 

Output 

Lamp Life 

Diameter 

W 

CRI 

K lm/W lm lm hr 

T12 40 70 4,100 76.8 3,150 2,860 15,000 

* Rated efficacy is based on the rated wattage of the lamps, which for T12 lamps is 41W. 

5.3.1.2 Efficacy Levels 

For the 4-foot MBP with CCTs less than or equal to 4,500K product class, DOE 

established ELs around design options that are consistent across all baseline lamps. Because 

these lamps have different efficacy values and some represent various design options, some ELs 

affect only three of the four baseline lamps. However, the full range of ELs ultimately specifies 

5-8
requirements that are above the efficacy values of all the baseline lamps sold, and therefore 

affect all four baseline lamps. 

In selecting ELs, DOE considered two different paths to energy savings. The first 

involves reduced-wattage replacement lamps that could be installed in a socket and operate on 

the existing ballast. These lower-wattage replacement lamps have a higher efficacy and 

therefore produce approximately the same light output as the baseline lamp (i.e., light output 

never drops below 10 percent of the baseline system). 

The other path to energy savings involves lamps that have the same or lower wattage in 

comparison with the baseline lamp, but operate on a new ballast with a different BF so the 

system power rating is lower. DOE selected a ballast with a particular BF in conjunction with 

the more efficacious lamp to produce approximately the same light output as the baseline lamp 

(i.e., light output never drops below 10 percent of the baseline system). 

Below is a summary of the ELs considered for 4-foot MBP lamps. The following 

discussion identifies the steps and technologies associated with each EL DOE considered. As 

discussed in the screening analysis (chapter 4), DOE used design options that achieve a higher 

efficacy with highly-emissive electrode coatings, higher-efficacy lamp fill gas composition, 

higher-efficacy phosphors, glass coatings, or higher-efficacy lamp diameter. Because highefficacy phosphors and lamp diameter are common methods to achieve higher efficacies, DOE 

identified the diameter and phosphor associated with each EL: 

EL1. This level affects the three T12 baseline lamps. Because the baseline T8 lamp is 

above this efficacy level, consumers using the T8 lamp are not affected. The 34W T12 moves 

from a cool white halophosphor to a 700 series rare earth phosphor. The 40W T12 lamp moves 

from the 700 series rare earth to either an improved 700 series rare earth phosphor or 800 series 

lamp. 

EL2. This level also only affects T12 lamps. For the 34W T12, the lamps change from 

700 series to 800 series rare earth phosphor. The 40W T12 lamp at this level uses a premium 

800 series rare earth phosphor. 

EL3. This level affects all four baseline lamps. The 32W T8 lamp that used 700 series 

rare earth phosphor in the baseline migrates to an 800 series rare earth phosphor in a 32W lamp. 

The 34W T12 lamp uses an 800 series rare earth phosphor, and may incorporate other design 

options to enhance efficacy, such as a different gas fill or increased thickness of the bulb-wall 

phosphor. At this level there are no 40W T12 lamps that are commercially available. 

EL4. This level affects all four baseline lamps. No 4,100K T12 lamps are commercially 

available that meet this efficacy requirement. Therefore, users of T12 lamps would be forced to 

replace their ballasts and operate T8 lamps instead. This level requires the use of an improved 

800 series rare earth phosphor in full-wattage (32W) T8 lamps. A 30W T8 and 25W T8 lamp 

that produces an equivalent amount of light as the baseline unit on a similar ballast meet this EL. 

EL5. This level affects all three baseline lamps. However, no T12 lamps that can meet 

this efficacy requirement are commercially available. Therefore, users of T12 lamps would be 

forced to replace their ballasts and operate T8 lamps instead. For the T8 lamps, this level 

5-9
represents “max-tech,” the highest efficacy level available today. It uses premium 800 series 

rare earth phosphor and may incorporate other efficacy improvements, such as a different gas fill 

or increased thickness of the bulb-wall phosphor. The 28W T8 lamp that produces an equivalent 

amount of light on the same ballast as the baseline unit meets this EL. 

DOE then developed five initial ELs based on catalog values of commercially-available 

fluorescent lamps that DOE selected to analyze. Figure 5.3.1 illustrates the five initial ELs on a 

plot of the efficacies of these lamps vs. their rated wattages. A line at 75 lm/W denotes the 

existing energy conservation standard (from the Energy Policy Act of 1992 (EPACT 1992)). 

Square boxes and labels identify the four baseline lamps. The plot also shows replacement 

lamps DOE considered for each lamp at higher efficacies. Some lamps are at the same wattage, 

but have a higher efficacy; others have a combination of lower wattage and higher efficacy so 

that the lamp-and-ballast system produces light output no less than 10 percent of the baseline. 

EPACT 1992

72.0

74.0

76.0

78.0

80.0

82.0

84.0

86.0

88.0

90.0

92.0

94.0

96.0

98.0

100.0

24 26 28 30 32 34 36 38 40 42

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

4-foot T8 medium bipin 4-foot T12 medium bipin

34W T12 Baseline 40W T12 Commercial Baseline

32W T8 Baseline

40W T12 Residential Baseline

Figure 5.3.1 Initial Efficacy Levels for 4-Foot MBP Fluorescent Lamps With CCTs ≤

4,500K 

Table 5.3.4 provides detailed information on the 4-foot MBP lamp designs used in the 

engineering analysis and subsequent analyses. 

5-10
Table 5.3.4 4-Foot MBP Lamp Designs 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial Light 

Output 

Mean 

Light 

Output 

Life CRI 

EL 

Lamp 

Diameter 

W W lm/W lm lm hr

Baseline/0* T12 40 41.0 76.8 3,150 2,860 15,000 70 

Baseline/0** T12 40 41.0 78.0 3,200 2,880 20,000 70 

Baseline/0** T12 34 34.0 77.9 2,650 2,300 20,000 62 

1 T12 40 41.0 80.5 3,300 3,000 20,000 80 

1 T12 34 34.0 82.4 2,800 2,460 20,000 70 

1 T12 40 41.0 82.9 3,400 3,060 24,000 80 

2 T12 34 34.0 85.3 2,900 2,610 20,000 80 

Baseline/2 T8 32 32.5 86.2 2,800 2,520 20,000 75 

2 T12 40 41.0 87.8 3,600 3,250 24,000 85 

3 T8 32 32.5 90.8 2,950 2,710 20,000 82 

3 T12 34 34.0 91.2 3,100 2,790 24,000 85 

4 T8 32 32.5 92.3 3,000 2,850 24,000 85 

4 T8 25 26.6 93.0 2,475 2,350 30,000 85 

4 T8 30 30.4 93.8 2,850 2,680 20,000 82 

5 T8 32 32.5 95.4 3,100 2,915 24,000 82 

5 T8 28 28.4 96.0 2,725 2,560 18,000 82 

*This baseline lamp is used only in the residential sector. 

**These baseline lamps are used only in the commercial and industrial sectors. 

As seen above, DOE used commercially-available lamps and their associated rated 

efficacies (rated initial lumen output divided by the ANSI rated wattage) to determine the design 

options required to meet each efficacy level. However, to establish the minimum efficacy 

requirements for each efficacy level, DOE coupled catalog data on commercially-available lamps 

with data submitted to DOE by manufacturers for the purpose of compliance with existing 

energy conservation standards for general service fluorescent lamps. By analyzing manufacturer 

compliance reports, DOE found that efficacies of lamps when reported for the purpose of 

compliance often vary from catalog-rated values. Because the test procedures for GSFL 

incorporate a tolerance factor comparing measured lamp wattage to ANSI-rated wattage, the 

measured efficacy of the lamps may be significantly different from the rated efficacy. In 

addition, using rated lamp efficacy does not account for lot-to-lot production variability which 

does affect the efficacy at which the lamps comply. As the efficacy reported for compliance is 

related to the lower limit of the 95-percent confidence interval, significant variability in 

production may result in compliance efficacies that are lower than rated efficacies. 

For these reasons, to establish GSFL minimum efficacy requirements associated with 

each efficacy level, DOE used lamp efficacy values submitted to DOE for the purpose of 

compliance with existing energy conservation standards. Specifically, DOE determined the 

compliance efficacies of commercially-available lamps used in the engineering analysis. For 

example, as seen in Figure 5.3.1, DOE established EL2 such that three specific lamps comply: 

5-11
the baseline 32W T8 lamp, the 34W T12 800 series lamp with initial lumen output of 3,100 

lumens, and the 40W T12 800 series lamps with initial lumen output of 3,250 lumens. Through 

examining compliance report data, DOE found that the 34W T12 lamp had the lowest 

compliance efficacy of the three (81 lm/W), and therefore, set EL2 at 81 lm/W. Because DOE 

did not have compliance report data on every lamp design analyzed, in such situations DOE used 

compliance report data of lamps with similar design options to determine the appropriate 

minimum efficacy requirement. Figure 5.3.2 below shows all compliance report data for 4-foot 

MBP lamps with CCTs less than or equal to 4,500K. 

70.0

75.0

80.0

85.0

90.0

95.0

100.0

24.0 26.0 28.0 30.0 32.0 34.0 36.0 38.0 40.0

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

4ft MBP <=4500 HALO

4ft MBP <=4500, 700 SERIES

4ft MBP <=4500, 800 SERIES

Figure 5.3.2 All Compliance Report Data for 4-Foot MBP Fluorescent Lamps with CCTs ≤

4,500K 

Although DOE obtained compliance reports submitted over the past 15 years, DOE only 

considered the most recent data when verifying efficacy levels. DOE believes that data 

contained in compliance reports submitted 2007 and 2008 accurately account for adjustments 

over the past 15 years to photometry facilities used for NIST and NVLAP testing that may have 

resulted in a reduction of reported lumens for some products. Figure 5.3.3 only shows 

compliance report data submitted in 2007 and 2008 for 4-foot MBP lamps with CCTs less than 

or equal to 4,500K. 

5-12
70.00

75.00

80.00

85.00

90.00

95.00

100.00

24.0 26.0 28.0 30.0 32.0 34.0 36.0 38.0 40.0

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

4ft MBP <=4500 HALO

4ft MBP <=4500, 700 SERIES

4ft MBP <=4500, 800 SERIES

Figure 5.3.3 2007 and 2008 Compliance Report Data for 4-Foot MBP Fluorescent Lamps 

with CCTs ≤ 4,500K 

Table 5.3.5 summarizes the resulting efficacy requirements at each level, after accounting for 

compliance report data, for 4-foot MBP lamps with CCTs less than or equal to 4,500K. 

Table 5.3.5 Summary of the ELs for 4-Foot MBP Fluorescent Lamps With CCTs ≤ 4,500K 

Efficacy Level Efficacy Requirement 

lm/W

EL1 78 

EL2 81 

EL3 85 

EL4 89 

EL5 93 

Section 5.3.1.4 provides additional information on the lamp-and-ballast systems DOE 

uses in the engineering analysis. 

5-13
5.3.1.3 System Power Rating 

The system power rating is an important result of the engineering analysis. DOE 

calculated the system power rating, which represents the energy consumption rate of the lamps in 

combination with a ballast, using published catalog information. For each lamp wattage and 

ballast type, DOE applied a linear fit to several points identifying the system power rating of a 

lamp on a ballast and the ballast factor of the ballast. The fit follows the form of Eq. 5.1 where 

SPR = m * BF + b. DOE used a linear form because the relationship is approximately linear 

over the range of BFs and wattages considered. 

The ballasts DOE used typically have a total harmonic distortion (THD) less than 20 

percent, power factors (PF) greater than 0.95, and typical ballast efficacy factors. Because 

ballast efficiencies naturally increase as lamp wattages decrease, there is a natural progression to 

higher typical BEFs at lower wattages. Also, because there is less manufacturer literature on 

system power ratings of ballasts with lower wattage lamps, DOE used fewer points to develop a 

linear fit for the energy-saving lamp wattages. Figure 5.3.4 to Figure 5.3.7 show the linear fit 

and ballast characteristics DOE uses to derive the system power rating for 3-lamp, 4-foot T8 

lamps on electronic ballasts. 

y = 88.5x + 8.9

60.0

65.0

70.0

75.0

80.0

85.0

90.0

95.0

100.0

105.0

110.0

0.70 0.75 0.80 0.85 0.90 0.95 1.00

Ballast Factor

System Power Rating (W)

Linear Fit: m=88.5, b=8.9

Figure 5.3.4 Three-Lamp 32W T8 120V Ballasts with THD <20 Percent, PF >0.95, and 

BEF 0.98-1.05 

5-14
y = 82.522x + 7.7509

60.0

70.0

80.0

90.0

100.0

110.0

120.0

0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40

Ballast Factor

System Power Rating (W)

Figure 5.3.5 Three-Lamp 30W T8 120V Ballasts with THD <20 Percent, PF >0.95, and 

BEF 1.07-1.12 

y = 77.701x + 6.9252

55.0

60.0

65.0

70.0

75.0

80.0

85.0

90.0

95.0

100.0

105.0

0.60 0.80 1.00 1.20 1.40

Ballast Factor

System Power Rating (W)

Linear Fit: m=82.5, b=7.8

Linear Fit: m=77.7, b=6.9

Figure 5.3.6 Three-Lamp 28W T8 120V Ballasts with THD <20 Percent, PF >0.98, and 

BEF 1.16-1.20 

5-15
40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.50 0.70 0.90 1.10 1.30

Ballast Factor

System Power Rating (W)

Linear Fit: m=70.8, b=4.2

Figure 5.3.7 Three-Lamp 25W T8 120V Ballasts with THD <20 Percent, and BEF 1.31-

1.34 

Figure 5.3.8 to Figure 5.3.11 show the linear fit and ballast characteristics DOE used to 

derive the system power rating for two-lamp, 4-foot T8 MBP lamps on electronic ballasts DOE 

used the system power rating for these ballasts to derive both the system power rating for 4-foot 

T8 systems in the residential sector, 4-foot T12 electronically ballasted systems and for 

additional systems DOE used in the national impact analysis. The ballasts DOE used typically 

have a THD less than 20 percent, PFs greater than 0.95, and typical BEFs. Because ballast 

efficiencies naturally increase as lamp wattages decrease, there is a natural progression to higher 

typical BEFs at lower wattages. Also, because there is less manufacturer literature on system 

power ratings of ballasts with lower wattage lamps, DOE used fewer points to develop a linear 

fit for the energy-saving lamp wattages. 

5-16
40.0

45.0

50.0

55.0

60.0

65.0

70.0

75.0

80.0

85.0

0.70 0.80 0.90 1.00 1.10 1.20

Ballast Factor

System Power Rating (W)

Linear Fit: m=69.1, b= -2.24

Figure 5.3.8 Two-Lamp 32W T8 120V Ballasts with THD <20 Percent, PF >0.95, and BEF 

1.40-1.53 

40.0

45.0

50.0

55.0

60.0

65.0

70.0

75.0

80.0

85.0

90.0

0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40

Ballast Factor

System Power Rating (W)

Linear Fit: m=56.8, b=4.6

Figure 5.3.9 Two-Lamp 30W T8 120V Ballasts with THD <20 Percent, PF >0.95, and BEF 

1.56-1.67 

5-17
35.0

40.0

45.0

50.0

55.0

60.0

65.0

70.0

75.0

0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40

Ballast Factor

System Power Rating (W)

Linear Fit: m=56.2, b=1.8

Figure 5.3.10 Two-Lamp 28W T8 120V Ballasts with THD <20 Percent, PF >0.98, and 

BEF 1.69-1.73 

30.0

35.0

40.0

45.0

50.0

55.0

60.0

65.0

70.0

0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30

Ballast Factor

System Power Rating (W)

Linear Fit: m=49.2, b=2.1

Figure 5.3.11 Two-Lamp 25W T8 120V Ballasts with THD <20 Percent, PF >0.98, and 

BEF 1.91-1.97 

5-18
Figure 5.3.12 to Figure 5.3.15 show the linear fit and ballast characteristics DOE used to 

derive the system power rating for three-lamp, 4-foot T12 MBP lamps on electronic ballasts. 

Because manufacturer literature for these lamps is uncommon, DOE extrapolated linear fits from 

the two-lamp, 4-foot T12 based on the relative difference between the three-lamp and two-lamp 

32W T8 slopes. To develop the y-intercept, DOE used a data point from manufacturer literature 

for three-lamp, 4-foot T12s with a common BEF. 

68.0

69.0

70.0

71.0

72.0

73.0

74.0

75.0

0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94

Ballast Factor

System Power Rating (W)

Linear Fit: m=50.5, b=28.5

Figure 5.3.12 Two-Lamp 40W 120V Ballasts with <20 Percent THD, PF >0.95, and BEF 

1.20-1.22 in the Commercial and Industrial Sectors 

5-19
90.0

95.0

100.0

105.0

110.0

115.0

120.0

0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05

Ballast Factor

System Power Rating (W)

Figure 5.3.13 Three-Lamp 40W 120V Ballasts Linear Fit (Based on Slope Change from 

Two-Lamp to Three-Lamp Ballasts for 32W T8 Applied to T12 and Common T12 

Electronic Ballast) 

54.0

56.0

58.0

60.0

62.0

64.0

66.0

68.0

0.70 0.75 0.80 0.85 0.90 0.95 1.00

Ballast Factor

System Power Rating (W)

Linear Fit: m=67.9, b=47.9

Linear Fit: m=50.0, b=17.5

Figure 5.3.14 Two-Lamp 34W 120V Ballasts with <20 Percent THD, PF >0.95, and BEF 

1.42-1.44 in the Commercial and Industrial Sectors 

5-20
70.0

75.0

80.0

85.0

90.0

95.0

100.0

105.0

110.0

0.75 0.80 0.85 0.90 0.95 1.00

ANSI Input Power (W)

Ballast Factor

Linear Fit: m=67.9, b=31.9

Figure 5.3.15 Three-Lamp 34W 120V Ballasts (Based on Slope Change from Two-Lamp to 

Three-Lamp Ballasts for T8 Applied to T12 and Common T12 Electronic Ballast) 

Figure 5.3.16 and Figure 5.3.17 show the linear fit and ballast characteristics DOE used 

to derive the system power rating for two-lamp, 4-foot T12 MBP lamps on electronic ballasts in 

the residential sector. To develop the linear fit, DOE used parameters of two 40W T12 and 

34WT12 residential electronic ballasts. 

5-21
50.0

55.0

60.0

65.0

70.0

75.0

80.0

85.0

90.0

0.6 0.7 0.7 0.8 0.8 0.9 0.9 1.0 1.0

Ballast Factor

System Power Rating (W)

Figure 5.3.16 Two-Lamp 40W Ballasts with <40 Percent THD, PF >0.55, and BEF 1.12-

1.18 in the Residential Sector 

 

30

40

50

60

70

80

0.6 0.7 0.8 0.9 1

Ballast Factor

System Power Rating (W)

Linear Fit: m=70.0, b=12.5

Linear Fit: m=140.0, b=-57.0

Figure 5.3.17 Two-Lamp 34W Ballasts with <50 Percent THD, PF >0.53, and BEF 1.37-

1.56 in the Residential Sector 

5-22
5-23

5.3.1.4 Results 

As discussed above, DOE evaluated multiple baseline lamps for each product class to 

provide a comprehensive understanding of the consumer economics. For each baseline lamp, 

DOE considered only energy-saving options that result in approximately the same light output as 

the baseline lamp system. Energy savings could either be achieved through lamp or lamp and 

ballast replacements. Appendix 5A provides information on the additional lamp-and-ballast 

designs DOE uses in the NIA. 

Table 5.3.6 presents the engineering characteristics of lamp replacement options for a 

baseline 40W 4-foot T12 MBP 4,100K lamp in the commercial and industrial sectors. Although 

a 34W T12 lamp is often considered a reduced-wattage replacement of the 40W T12 lamp, there 

are no lamp options that emit enough lumens to fall within 10 percent of the baseline system 

lumens. The highest efficacy 34W T12 lamp replacement is shown below in Table 5.3.6. The 

light output of this lamp-and-ballast design is 10.3 percent less than that of the baseline system. 

The same drop in lumen output is also exhibited by the 34W T12 lamp on an electronic ballast of 

the same BF. 

Table 5.3.7 presents the engineering characteristics of lamp and ballast replacement 

options for a 40W 4-foot T12 MBP, 4,100K lamp in the commercial and industrial sectors. Note 

that at the higher ELs, DOE considered some T8 substitutes for the 40W T12 lamp. As 

discussed earlier, DOE adjusted the BF so that the combination of lamp and ballast maintains 

light output so that potential light output is equal to, greater than, or no more than 10 percent less 

than the light output of the baseline system. All standards-case lamps for lamp and ballast 

replacements are placed on electronic T12s or ballasts since ballast standards will be effective in 

2010 for the commercial and industrial sectors. 
Table 5.3.6 Lamp Replacement Engineering Analysis for a Three-Lamp 40W T12, 4,100K System in the C

Industrial Sectors 

Nominal 

Wattage Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr 

Ballast 

Type 

Ballast 

Factor* 

W 

Baseline T12 40 41.0 78.0 3,200 2,880 20,000 Magnetic 0.95 129.0 

EL3 T12 34 34.0 91.2 3,100 2,790 24,000 Magnetic 0.88 108.0 

*Note: This difference in BFs does not represent a ballast replacement. Instead, the BF of magnetic ballasts changes when a different w

5-24
Table 5.3.7 Lamp and Ballast Replacement Engineering Analysis for a Three-Lamp 40W T12, 4,100K Sys

Commercial and Industrial Sectors 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Sys

Ini

Li

Ou

Efficacy Level 

Lamp 

Diameter 

W W Lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W lm 

Baseline T12 40 41.0 78.0 3,200 2,880 20,000 Magnetic 0.95 129.0 9,1Baseline T12 40 41.0 78.0 3,200 2,880 20,000 Electronic 0.88 107.7 8,4

EL1 T12 40 41.0 80.5 3,300 3,000 20,000 Electronic 0.88 107.7 8,7EL1 T12 40 41.0 80.5 3,300 3,000 20,000 Electronic 0.87 107.0 8,6EL1 T12 40 41.0 82.9 3,400 3,060 24,000 Electronic 0.87 107.0 8,8

Baseline/EL2 T8 32 32.5 86.2 2,800 2,520 20,000 Electronic 1.18 113.3 9,9

EL2 T12 40 41.0 87.8 3,600 3,250 24,000 Electronic 0.87 107.0 9,3EL3 T12 34 34.0 91.2 3,100 2,790 24,000 Electronic 0.88 91.7 8,1EL3 T8 32 32.5 90.8 2,950 2,710 20,000 Electronic 1.00 97.4 8,8EL4 T8 32 32.5 92.3 3,000 2,850 24,000 Electronic 0.88 86.8 7,9EL4 T8 30 30.4 93.8 2,850 2,680 20,000 Electronic 1.00 90.3 8,5EL4 T8 25 26.6 93.0 2,475 2,350 30,000 Electronic 1.18 87.7 8,7EL5 T8 32 32.5 95.4 3,100 2,915 24,000 Electronic 0.88 86.8 8,1EL5 T8 28 28.4 96.0 2,725 2,560 18,000 Electronic 1.00 84.6 8,1

Table 5.3.8 presents the engineering characteristics of lamp replacement options for a baseline 40W 4-foo

lamp in the residential sector. The highest efficacy 34W T12 lamp replacement is shown below in Table 5.3.8. Tof this lamp-and-ballast design is 5.3 percent less than that of the baseline system. 

5-25
Table 5.3.9 presents the engineering characteristics of lamp and ballast replacement options for a 40W 4-

4,100K lamp in the residential sector. Note that at the higher ELs, DOE considered some T8 substitutes for the 4discussed earlier, DOE adjusted the BF so that the combination of lamp and ballast maintains light output so that is equal to, greater than, or no more than 10 percent less than the light output of the baseline system. There is oncase lamp at EL3 that is placed on a magnetic ballast. Magnetic ballasts will continue to be sold in the residentiaregulations so consumers have the option to purchase a magnetic ballast in the standards case if it is an energy-saunderstands that certain residential ballasts cannot operate reduced-wattage (e.g., 34W T12) lamps. However, beresidential ballasts can operate reduced-wattage lamps, DOE is considering these lamp-and-ballasts systems as an consumers in the residential sector. Consumers can also purchase lower ballast factor ballasts in order to maintai

package to the baseline 40W T12 magnetic system. However, DOE did not consider other lamps on magnetic ba

34W T12 standards-case lamp at EL3 shown in the table because the systems either do not save energy or are no

lumen output of the baseline system. All other standards-case lamps for lamp and ballast replacements are place

ballasts. Table 5.3.8 Lamp Replacement Engineering Analysis for a Two-Lamp 40W T12, 4,100K System in the Re

Nominal 

Wattage Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr 

Ballast 

Type 

Ballast 

Factor* 

W 

Baseline T12 40 41 76.8 3,150 2,860 15,000 Magnetic 0.68 70.0 

EL3 T12 34 34 91.2 3,100 2,790 24,000 Magnetic 0.66 60.0 

*Note: This difference in BFs does not represent a ballast replacement. Instead, the BF of magnetic ballasts changes when a different w

5-26
Table 5.3.9 Lamp and Ballast Replacement Engineering Analysis for a Two-Lamp 40W T12, 4,100K Syst

Sector 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Sys

Ini

Li

Ou

Efficacy Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W lm 

Baseline T12 40 41.0 76.8 3,150 2,860 15,000 Magnetic 0.68 70.0 4,2

EL1 T12 40 41.0 80.5 3,300 3,000 20,000 Electronic 0.65 58.0 4,2EL1 T12 34 34.0 82.4 2,800 2,460 20,000 Electronic 0.85 62.0 4,7EL1 T12 40 41.0 82.9 3,400 3,060 24,000 Electronic 0.65 58.0 4,4EL2 T12 34 34.0 85.3 2,900 2,610 20,000 Electronic 0.75 48.0 4,3EL2 T8 32 32.5 86.2 2,800 2,520 20,000 Electronic 0.78 51.6 4,3

Baseline/EL2 T8 32 32.5 86.2 2,800 2,520 20,000 Electronic 0.88 58.6 4,9

EL2 T12 40 41.0 87.8 3,600 3,250 24,000 Electronic 0.65 58.0 4,6EL3 T12 34 34.0 91.2 3,100 2,790 24,000 Magnetic 0.66 60.0 4,0EL3 T12 34 34.0 91.2 3,100 2,790 24,000 Electronic 0.75 48.0 4,6EL3 T8 32 32.5 90.8 2,950 2,710 20,000 Electronic 0.75 49.6 4,4EL3 T8 32 32.5 90.8 2,950 2,710 20,000 Electronic 0.78 51.6 4,6

5-27
Table 5.3.9 Lamp and Ballast Replacement Engineering Analysis for a Two-Lamp 40W T12, 4,100K Syst

Sector (continued) 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Syst

Ini

Lig

Out

Efficacy Level 

Lamp 

Diameter 

W 

W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W lm 

EL4 T8 32 32.5 92.3 3,000 2,850 24,000 Electronic 0.75 49.6 4,5EL4 T8 32 32.5 92.3 3,000 2,850 24,000 Electronic 0.78 51.6 4,6EL4 T8 30 30.4 93.8 2,850 2,680 20,000 Electronic 0.75 47.2 4,2EL4 T8 30 30.4 93.8 2,850 2,680 20,000 Electronic 0.78 48.9 4,4EL4 T8 25 26.6 93.0 2,475 2,350 30,000 Electronic 0.78 40.5 3,8EL4 T8 25 26.6 93.0 2,475 2,350 30,000 Electronic 0.88 45.4 4,3EL5 T8 32 32.5 95.4 3,100 2,915 24,000 Electronic 0.71 46.8 4,4EL5 T8 32 32.5 95.4 3,100 2,915 24,000 Electronic 0.75 49.6 4,6EL5 T8 28 28.4 96.0 2,725 2,560 18,000 Electronic 0.78 45.6 4,2

Table 5.3.10 presents the engineering analysis results for the replacement lamp-and-ballast combinations 

T12 MBP baseline lamp in the commercial and industrial sectors. DOE has not identified any lower-wattage dir

designs that could operate on the same ballast and save energy. In this table, T8 lamp and ballast replacements abaseline lamp, and the BF is selected so that the new system’s light output never drops below 10 percent of the b

5-28
Table 5.3.10 Lamp and Ballast Replacement Engineering Analysis for a Three-Lamp 34W T12, 4,100K Sy

Commercial and Industrial Sectors 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W 

W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T12 34 34.0 77.9 2,650 2,300 20,000 Magnetic 0.88 108.0 Baseline T12 34 34.0 77.9 2,650 2,300 20,000 Electronic 0.88 91.7 

EL1 T12 34 34.0 82.4 2,800 2,460 20,000 Electronic 0.88 91.7 EL1 T12 34 34.0 82.4 2,800 2,460 20,000 Electronic 0.86 90.3 EL2 T12 34 34.0 85.3 2,900 2,610 20,000 Electronic 0.86 90.3 

Baseline/EL2 T8 32 32.5 86.2 2,800 2,520 20,000 Electronic 0.88 86.8 

EL3 T8 32 32.5 90.8 2,950 2,710 20,000 Electronic 0.78 77.9 EL3 T12 34 34.0 91.2 3,100 2,790 24,000 Electronic 0.86 90.3 EL4 T8 32 32.5 92.3 3,000 2,850 24,000 Electronic 0.75 75.3 EL4 T8 30 30.4 93.8 2,850 2,680 20,000 Electronic 0.78 72.2 EL4 T8 25 26.6 93.0 2,475 2,350 30,000 Electronic 0.88 66.5 EL5 T8 32 32.5 95.4 3,100 2,915 24,000 Electronic 0.71 71.7 EL5 T8 28 28.4 96.0 2,725 2,560 18,000 Electronic 0.78 67.5 

Table 5.3.11 presents the engineering analysis results for the 32W 4-foot T8 MBP baseline lamp replacem

commercial and industrial sectors. As shown below in Table 5.3.11, there are no lamp replacement options at ELlumens of reduced wattage lamp replacement options below this EL are not maintained.

Table 5.3.12 presents the engineering analysis results for the replacement lamp and ballast combinations 

MBP baseline lamp in the commercial and industrial sectors. For lamp-and-ballast replacement combinations, th

that the new system’s light output is equal to, greater than, or no more than 10 percent less than the light output o

5-29
5-30

Table 5.3.11 Lamp Replacement Engineering Analysis for a Three-Lamp 32W T8, 4,100K System in the CIndustrial Sectors 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm Lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline/ 

EL2 T8 32 32.5 86.2 2,800 2,520 20,000 Electronic 0.88 86.8 

EL4 T8 30 30.4 93.8 2,850 2,680 20,000 Electronic 0.88 80.4 EL4 T8 25 26.6 93.0 2,475 2,350 30,000 Electronic 0.88 66.5 EL5 T8 28 28.4 96.0 2,725 2,560 18,000 Electronic 0.88 75.3 

Table 5.3.12 Lamp and Ballast Replacement Engineering Analysis for a Three-Lamp 32W T8, 4,100K SysCommercial and Industrial Sectors 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline/ 

EL2 T8 32 32.5 86.2 2,800 2,520 20,000 Electronic 0.88 86.8 

EL3 T8 32 32.5 90.8 2,950 2,710 20,000 Electronic 0.78 77.9 EL4 T8 32 32.5 92.3 3,000 2,850 24,000 Electronic 0.75 75.3 EL4 T8 30 30.4 93.8 2,850 2,680 20,000 Electronic 0.78 72.2 EL4 T8 25 26.6 93.0 2,475 2,350 30,000 Electronic 0.88 66.5 EL5 T8 32 32.5 95.4 3,100 2,915 24,000 Electronic 0.75 75.3 EL5 T8 28 28.4 96.0 2,725 2,560 18,000 Electronic 0.88 75.3 
5.3.2 Eight-foot SP Slimline GSFL With CCTs ≤ 4,500K 

5.3.2.1 Baseline Models 

The 8-foot SP slimline lamps with CCTs less than or equal to 4,500K are commonly 

manufactured in both T8 and T12 diameters. As discussed in chapter 3, the T12 diameter 

represents approximately 85 percent of all 8-foot SP slimline lamp shipments. However, DOE 

projects that by 2011, T8s will account for 26 percent of all 8-foot SP slimline lamp shipments. 

Therefore, DOE selected its baseline models for this product class from both the T12 and T8 

diameter. The two most popular wattages associated with the 8-foot T12 SP slimline lamp type 

are the 60W and 75W. For the 60W lamp, the cool white halophosphor is the most popular. 

Therefore, DOE selected this as the baseline. The most common 75W T12 lamp purchased uses 

a rare earth 700 series phosphor. For T8 lamps, the most popular wattage is 59W. The most 

common lamp purchased at this wattage uses a rare earth 700 series phosphor. As with the 4-

foot MBP, DOE selects a CCT of 4,100K because it is the most common CCT for this lamp type. 

When selecting baseline lamps, DOE found small variances in the reported lumen outputs 

(and therefore efficacies). DOE selected the least efficacious baseline lamps to ensure that all 

the major manufacturers have a product available at the baseline. 

DOE’s review of product literature for 8-foot T12 SP slimline lamps indicated that a 

12,000-hour lifetime is typical, although this is shorter than the lifetime of the 4-foot MBP. T12 

lamps with a 15,000-hour lifetime for a 3-hour cycle are marketed as extended performance 

products. Therefore, DOE used a lifetime of 12,000 hours for a 3-hour cycle for the baseline unit 

of analysis for T12 lamps. 

DOE’s review of product literature for 8-foot T8 SP slimline lamps indicated that 15,000 

hours is a typical lifetime. T8 lamps with a 24,000-hour lifetime for a 3-hour cycle are marketed 

as extended performance products. Therefore, DOE used a lifetime of 15,000 hours for a 3-hour 

cycle for the baseline unit of analysis for T8 lamps. 

The most common ballast for 8-foot T12 SP slimline lamps is a two-lamp, instant-start, 

120V, magnetic ballast. This ballast typically has a 0.94 BF when a 75W 8-foot T12 SP slimline 

lamp is installed and a 0.88 BF when a 60W 8-foot T12 SP slimline lamp is installed. The most 

common ballast used for 8-foot T8 SP slimline lamps is a two-lamp, instant-start, 120V, 

electronic ballast with a 0.88 BF. The 75W T12 baseline lamp-and-ballast combination creates a 

lumen package of approximately 11,100 mean lumens (and 12,070 initial lumens). The 60W 

T12 baseline lamp-and-ballast combination creates a lumen package of approximately 8,210 

mean lumens (and 9,330 initial lumens). The 59W T8 baseline lamp-and-ballast combination 

creates a lumen package of almost 9,030 mean lumens (and more than 10,030 initial lumens). 

5-31
Table 5.3.13 Baseline Units of Analysis for 8-Foot SP Slimline Lamps 

Nominal 

Wattage CCT Rated Efficacy* 

Initial 

Light 

Output 

Mean 

Light 

Output 

Lamp Life 

Diameter 

W 

CRI 

K lm/W lm lm hr 

T12 75 70 4,100 85.6 6,420 5,906 12,000 

T12 60 62 4,100 87.6 5,300 4,664 12,000 

T8 59 70 4,100 94.8 5,700 5,130 15,000 

* Rated efficacy is based on the rated wattage of the lamps, which is 75W and 60.5W for T12 lamps and 60.1W for 

T8 lamps. 

5.3.2.2 Efficacy Levels 

As with the previous product class, DOE established ELs for design options that are 

consistent across the three baseline 8-foot SP slimline lamps. However, not every EL affects 

every baseline lamp. Because the three baseline lamps have different efficacy values, the first 

EL only affects the 75W lamp. However, for EL4 and above, the requirements affect all three 

baseline lamps. 

In selecting ELs, DOE considered two different paths to energy savings. One involves 

reduced-wattage replacement lamps, which could be installed in a socket and operate on the 

existing ballast. These lower-wattage replacement lamps have a higher efficacy and therefore 

produce about the same light output as the baseline lamp (i.e., light output never drops below 10 

percent of the baseline system). The other path to energy savings involves lamps that have the 

same or lower wattage in comparison with the baseline lamp, but operate on a new ballast with a 

different BF so the system energy is lower. DOE selected the BF with the more-efficacious lamp 

to produce approximately the same light output as the baseline lamp (i.e., light output never 

drops below 10 percent of the baseline system). 

The following discussion identifies the steps and technologies associated with each EL 

DOE considered. As discussed in the screening analysis (chapter 4), DOE used design options 

with highly emissive electrode coatings, higher efficacy lamp fill gas composition, higher 

efficacy phosphors, glass coatings, or higher efficacy lamp diameter to achieve a higher efficacy 

level. Because high-efficacy phosphors and lamp diameter are common methods to achieve 

higher efficacies, DOE identified the diameter and phosphor associated with each EL based on 

an analysis of catalog data: 

EL1. This level affects just the 75W T12 baseline lamp, moving this technology from a 

700 series rare earth phosphor to an 800 series rare earth phosphor. This level does not affect the 

60W T12 baseline lamp since it is above the baseline efficacy. 

EL2. This level represents the highest efficacy for the T12 lamp at 75W. At that 

efficacy, the lamp incorporates premium 800 series rare earth phosphor. For the 60W lamp, this 

level requires a 700 series rare earth phosphor. 

EL3. DOE selected this level because it represents the only viable 60W replacement that 

would operate on a 75W ballast with the same CCT as the baseline lamp (4,100K). No lamps at 

5-32
75W can achieve this EL. For the 60W lamp, this level requires an improved 700 series rare 

earth phosphor. 

EL4. At this level, ballast changes may be required for those users who need a lamp with 

a CCT of 4,100K, since only 4,100K T8 lamps are compliant. T8 lamps transition from a 700 

series rare earth phosphor at EL3 to an 800 series rare earth phosphor. 

EL5. At this level, ballast changes are required for T8 technology. Also, at this level 

lamps use the premium 800 series rare earth phosphor. This level represents the highest efficacy 

level available, or max-tech for 8-foot SP slimline lamps. 

Figure 5.3.18 illustrates five initial ELs based on catalog values of commerciallyavailable fluorescent lamps on a plot of selected 8-foot SP slimline lamps analyzed by DOE to 

determine efficacy level requirements. A line at 80.0 lm/W denotes the existing energy 

conservation standard (from EPACT). Square boxes and labels identify the two baseline lamps. 

The plot shows the replacement lamps DOE considered. Some are the same wattage, but have a 

higher efficacy; others have lower wattage and higher efficacy so that the lamp-and-ballast 

system maintains light output at no less than 10 percent of the baseline lamp-and-ballast system. 

EL1

EL2

EL3

EL4

EL5

EPACT 1992

75.0

77.0

79.0

81.0

83.0

85.0

87.0

89.0

91.0

93.0

95.0

97.0

99.0

101.0

103.0

105.0

52 54 56 58 60 62 64 66 68 70 72 74 76 78

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

8-foot T8 single pin slimline 8-foot T12 single pin slimline

75W T12 Baseline

60W T12 Baseline

59W T8 Baseline

5-33
Figure 5.3.18 Initial Efficacy Levels for 8-Foot SP Slimline Lamps With CCTs ≤ 4,500K 

Table 5.3.14 provides detailed information on the 8-foot SP slimline lamp designs used in 

the engineering analysis and subsequent analyses. 

Table 5.3.14 8-Foot SP Slimline Lamp Designs 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial Light 

Output 

Mean Light 

Output Life CRI 

EL 

Lamp 

Diameter 

W W lm/W lm lm hr

Baseline/0 T12 75 75.0 85.6 6,420 5,906 12,000 70 

1 T12 75 75.0 87.3 6,550 6,157 12,000 80 

Baseline/1 T12 60 60.5 87.6 5,300 4,664 12,000 62 

2 T12 75 75.0 92.0 6,900 6,370 15,000 80 

2 T12 60 60.5 92.6 5,600 5,152 12,000 70 

Baseline/3 T8 59 60.1 94.8 5,700 5,130 15,000 75 

3 T12 60 60.5 97.5 5,900 5,480 15,000 73 

4 T8 59 60.1 98.2 5,900 5,428 15,000 82 

5 T8 59 60.1 101.5 6,100 5,795 18,000 85 

5 T8 57 57.0 101.8 5,800 5,450 24,000 81 

5 T8 55 55.0 103.6 5,700 5,415 18,000 82 

As seen above, DOE used commercially-available lamps and their associated rated 

efficacies (rated initial lumen output divided by the ANSI rated wattage) to determine the design 

options required to meet each efficacy level. However, to establish the minimum efficacy 

requirements for each efficacy level, DOE coupled catalog data on commercially-available lamps 

with data submitted to DOE by manufacturers for the purpose of compliance with existing 

energy conservation standards for general service fluorescent lamps. DOE’s use of compliance 

report data is discussed in further detail in section 5.3.1.2. Figure 5.3.19 below shows all 

compliance report data for 8-foot SP slimline lamps with CCTs less than or equal to 4,500K. 

As discussed in section 5.3.1.2, DOE considered only recent compliance report data in 

establishing minimum efficacy requirements. Figure 5.3.19 depicts compliance report data from 

the years 2007 and 2008 in gray circles. For 8-foot SP slimline lamps, DOE found that not 

enough data existed from compliance reports submitted in 2007 and 2008 to establish several of 

efficacy levels with reasonable certainty. Therefore, DOE adjusted these levels to reflect the 

minimum efficacy requirements recommended by NEMA in their written comments. Table 

5.3.15 summarizes the resulting efficacy requirements for 8-foot SP slimline lamps with CCTs 

less than or equal to 4,500K, after accounting for compliance data. 

5-34
80.0

85.0

90.0

95.0

100.0

105.0

110.0

54.0 56.0 58.0 60.0 62.0 64.0 66.0 68.0 70.0 72.0 74.0 76.0

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

8ft Slimline <=4500 HALO

8ft Slimline <=4500, 700 SERIES

8ft Slimline <=4500, 800 SERIES

Figure 5.3.19 All Compliance Report Data for 8-Foot SP Slimline Lamps with CCTs ≤

4,500K 

Table 5.3.15. Summary of the ELs for 8-Foot SP Slimline Lamps With CCTs ≤ 4,500K 

Efficacy Level Efficacy Requirement 

lm/W

EL1 86 

EL2 92 

EL3 95 

EL4 97 

EL5 98 

Section 5.3.2.4 presents additional information about the lamp and ballast systems DOE 

develops in the engineering analysis. 

5.3.2.3 System Power Rating 

For each lamp wattage and ballast type, DOE linearly fit the system power rating of a 

lamp on several different ballasts with varying BFs. 

5-35
Figure 5.3.20 to Figure 5.3.21 show the linear fit and ballast characteristics DOE used to 

derive the system power rating for 2-lamp, 8-foot T12 SP slimline lamps on electronic ballasts. 

The fit follows the form of Eq. 5.1 where SPR  *  bBFm . The ballasts DOE chose for these 

calculations typically have a THD less than 20 percent, PF greater than 0.95, and typical BEF. 

Because ballast efficiencies naturally increase as lamp wattages decrease, there is a natural 

progression to higher typical BEFs at lower wattages. 

126.0

128.0

130.0

132.0

134.0

136.0

138.0

140.0

142.0

0.78 0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94

ANSI Input Power (W)

Ballast Factor

Figure 5.3.20 Two-Lamp 75W T12 120V Ballasts with THD <20 percent, PF >0.95, and 

BEF 0.64-0.66; Linear Fit: m=100.0, b=47.0 

5-36
100.0

102.0

104.0

106.0

108.0

110.0

112.0

114.0

116.0

0.78 0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94

Ballast Factor

System Power Rating (W)

Figure 5.3.21 Two-Lamp 60W T12 120V Ballasts with THD <20 percent, PF >0.95, and 

BEF 0.79-0.80; Linear Fit: m=100.0, b=22.0 

Figure 5.3.22 to Figure 5.3.24 show the linear fit and ballast characteristics DOE used to 

derive the system power rating for two-lamp, 8-foot T8 SP slimline lamps on electronic ballasts. 

The ballasts DOE used for these calculations typically have a THD less than 20 percent, PF 

greater than 0.95, and typical BEF. Because ballast efficiencies naturally increase as lamp 

wattages decrease, there is a natural progression to higher typical BEFs at lower wattages. Also, 

because there is less manufacturer literature on system power ratings of ballasts with lower 

wattage lamps, DOE used fewer points to develop a linear fit at the energy saving lamp wattages. 

5-37
100.0

110.0

120.0

130.0

140.0

150.0

160.0

0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25 1.30

Ballast Factor

System Power Rating (W)

Figure 5.3.22 Two-Lamp 59W T8 120V Ballasts with THD <20 percent, PF >0.95, and 

BEF 0.77-0.79; Linear Fit: m=123.7, b=4.0 

105.0

105.5

106.0

106.5

107.0

107.5

108.0

0.84 0.85 0.86 0.87 0.88 0.89

Ballast Factor

System Power Rating (W)

Figure 5.3.23 Two-Lamp 57W T8 120V Ballasts with THD <20 percent, PF >0.95, and BEF 

0.80-0.81; Linear Fit: m=50.0, b=63.5 

5-38
5-39

80

90

100

110

120

130

140

150

0.70 0.80 0.90 1.00 1.10 1.20

Ballast Factor

System Power Rating (W)

Figure 5.3.24 Two-Lamp 55W T8 120V Ballasts with THD <10 percent, and BEF 0.86; 

Linear Fit: m=118.4, b=-2.2 

5.3.2.4 Results 

DOE evaluated three baseline lamps for the 8-foot SP slimline product class: a 75W T12 

lamp, a 60W T12 lamp, and a 59W T8 lamp. For each baseline lamp, DOE considered both 

direct-replacement lamps that operate on the existing ballast and lamp-and-ballast replacement 

designs that result in approximately the same light output as the baseline lamp. As discussed 

earlier, DOE adjusted the BF so that the light output of the lamp-and-ballast design system never 

drops below 10 percent of the baseline system. 

Table 5.3.16 and Table 5.3.17 present the engineering characteristics of the lamp 

replacement and lamp-and-ballast replacement designs for the baseline 75W 8-foot T12 SP 

slimline, 4,100K lamp system. Although a 60W T12 lamp is often considered a reduced-wattage 

replacement of the 75W T12 lamp, there are no lamp options with a CCT of 4,100K that emit 

enough lumens to fall within 10 percent of the baseline system mean lumens. The highestefficacy 4,100K, 60W T12 lamp replacement is shown below in Table 5.3.16. The light output of 

this lamp-and-ballast design is 13 percent less than that of the baseline system. DOE also 

included lamp-and-ballast replacement options for a 75W T12, 4,100K lamp. Note that at the 

higher ELs, DOE considers some T8 substitutes for the 75W T12 lamp. 
Table 5.3.16 Lamp Replacement Engineering Analysis for a 75W T12, 4,100K System 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

System 

Light 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor* 

W lm 

Baseline T12 75 75.0 85.6 6,420 5,906 12,000 Magnetic 0.94 158.0 12,

EL3 T12 60 60.5 97.5 5,900 5,480 15,000 Magnetic 0.88 126.0 10,

*Note: This difference in BFs does not represent a ballast replacement. Rather, the BF of magnetic ballasts changes when the lower waTable 5.3.17 Lamp-and-Ballast Replacement Engineering Analysis for a 75W T12, 4,100K System 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

Syste

Pow

Rati

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T12 75 75.0 85.6 6,420 5,906 12,000 Magnetic 0.94 158Baseline T12 75 75.0 85.6 6,420 5,906 12,000 Electronic 0.88 135

EL1 T12 75 75.0 87.3 6,550 6,157 12,000 Electronic 0.85 132EL2 T12 75 75.0 92.0 6,900 6,370 15,000 Electronic 0.85 132

Baseline/EL3 T8 59 60.1 94.8 5,700 5,130 15,000 Electronic 1.18 149

EL5 T8 59 60.1 101.5 6,100 5,795 18,000 Electronic 0.88 112

5-40
Table 5.3.18 presents the engineering analysis results for the replacement lamp-and-ballast combinations 

T12 SP slimline baseline lamp. DOE did not identify any lower-wattage direct lamp replacement designs that co

same ballast as a 60W T12 and save energy. In this table, DOE considered T8 lamp-and-ballast replacements for and selected the BF so that the light output of the new system never drops below 10 percent of the baseline systeTable 5.3.18 Lamp-and-Ballast Replacement Engineering Analysis for a 60W T12, 4,100K System 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline/EL1 T12 60 60.5 87.6 5,300 4,664 12,000 Magnetic 0.88 126.0 Baseline/EL1 T12 60 60.5 87.6 5,300 4,664 12,000 Electronic 0.88 110.0 

EL2 T12 60 60.5 92.6 5,600 5,152 12,000 Electronic 0.85 107.0 EL3 T12 60 60.5 97.5 5,900 5,480 15,000 Electronic 0.85 107.0 

Baseline/EL3 T8 59 60.1 94.8 5,700 5,130 15,000 Electronic 0.88 112.8 

EL4 T8 59 60.1 98.2 5,900 5,428 15,000 Electronic 0.78 100.4 EL5 T8 57 57.0 101.8 5,800 5,450 24,000 Electronic 0.78 102.5 EL5 T8 59 60.1 101.5 6,100 5,795 18,000 Electronic 0.78 100.4 

Table 5.3.19 and Table 5.3.20 present the engineering analysis results for the lamp replacement and lamp

replacement options for the 59W 8-foot T8 SP slimline baseline lamp. In Table 5.3.19, no lamp replacement opt

shown because the system lumens of reduced-wattage lamp replacement options below this EL are more than 10 

of the baseline system. For lamp-and-ballast replacement combinations, DOE selected the BF so that the light ou

system is equal to, greater than, or no more than 10 percent less than the light output of the baseline system. 

5-41
5-42

Table 5.3.19 Lamp Replacement Engineering Analysis for a Two-Lamp, 59W, T8, 4,100K System 

Nominal 

Wattage Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Powe

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline/EL3 T8 59 60.1 94.8 5,700 5,130 15,000 Electronic 0.88 112.8 

EL5 T8 57 57.0 101.8 5,800 5,450 24,000 Electronic 0.88 107.5 EL5 T8 55 55.0 103.6 5,700 5,415 18,000 Electronic 0.88 102.0 

Table 5.3.20 Lamp-and-Ballast Replacement Engineering Analysis for a Two-Lamp, 59W, T8, 4,100K Sys

Nominal 

Wattage Rated 

Wattage* 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Powe

Ratin

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline/EL3 T8 59 60.1 94.8 5,700 5,130 15,000 Electronic 0.88 112.

EL4 T8 59 60.1 98.2 5,900 5,428 15,000 Electronic 0.85 109.EL5 T8 57 57.0 101.8 5,800 5,450 24,000 Electronic 0.85 106.EL5 T8 59 60.1 101.5 6,100 5,795 18,000 Electronic 0.78 100.EL5 T8 55 55.0 103.6 5,700 5,415 18,000 Electronic 0.88 102.
5.3.3 Eight-Foot RDC HO GSFL With CCTs ≤ 4,500K 

5.3.3.1 Baseline Models 

The 8-foot RDC HO lamps with CCTs ≤ 4,500K are manufactured in both T8 and T12 

diameters. As discussed in chapter 3, the T12 diameter represents the majority of 8-foot RDC 

HO lamp shipments today and will continue to represent the majority in 2011. Therefore, DOE 

selected its baseline models for this product class from the T12 diameter, which represents the 

most popular lamp type. 

The two most popular wattages associated with the 8-foot T12 RDC HO lamp type are 

the 95W and 110W. For the 95W lamp, the cool white halophosphor lamp is the most popular. 

Therefore, DOE selected this lamp as the baseline 95W lamp. For the 110W T12 lamp, the most 

common lamp purchased uses a rare earth 700 series phosphor. The efficacy of both baseline 

lamps is approximately 2 lm/W greater than the EPACT 1992 standard level of 80 lm/W, but no 

other lamps met the EPACT 1992 CRI requirements, which are lower than either baseline lamp. 

As with the baseline fluorescent lamps in other covered product classes, DOE selected a CCT of 

4,100K because it is the most common CCT for this lamp type. 

The typical operating lifetime for these lamps is the same as that of the 8-foot SP slimline 

T12 lamps. The lamp lifetime is typically 12,000 hours. Lamps with a 15,000-hour lifetime on a 

3-hour cycle are marketed as extended performance products. Therefore, DOE used a lifetime of 

12,000 hours for a 3-hour cycle for the baseline unit of analysis for 8-foot RDC HO lamps. 

DOE used a rapid-start, 120V, magnetic ballast for the baseline 8-foot T12 RDC systems 

as current regulations do not ban magnetic cold-temperature ballasts, which operate a large 

portion of the installed base of 8-foot T12 RDC HO lamps. The ballast has a ballast factor of 

0.95 when used with 110W lamps and a ballast factor of 0.91 when used with 95W lamps. 

Together, the 110W T12 baseline lamp-and-ballast combination creates a lumen package of 

approximately 15,480 mean lumens (and 17,200 initial lumens), while the 95W T12 baseline 

lamp-and-ballast combination creates a lumen package of approximately 12,650 mean lumens 

(and 14,560 initial lumens). 

Table 5.3.21 Baseline Units of Analysis for 8-Foot RDC High-Output Lamps 

Nominal 

Wattage CCT Rated Efficacy* 

Initial Light 

Output 

Mean Light 

Output Lamp Life 

Diameter 

W 

CRI 

K lm/W lm lm hr 

T12 110 70 4,100 80.1 9,050 8,145 12,000 

T12 95 62 4,100 82.5 8,000 6,950 12,000 

* Rated efficacy is based on the rated wattage of the lamps, which is 97W for the 95W T12 and 113W for the 110W 

T12. 

5.3.3.2 Efficacy Levels 

As with the previous product class, DOE established ELs around design options that are 

consistent across the two baseline lamps. In selecting ELs, DOE considered two different paths 

to energy savings. The first involves reduced-wattage replacement lamps that could be installed 

5-43
in a socket and operate on the existing ballast. These lower-wattage replacement lamps have a 

higher efficacy and therefore produce approximately the same light output as the baseline lamp 

(i.e., light output never drops below 10 percent of the baseline system). The other path to energy 

savings involves lamps that have the same rated wattage as the baseline lamp, but operate on a 

new ballast with a different BF, so system energy is lower. DOE selected the BF with the more 

efficacious lamp to produce approximately the same light output as the baseline lamp (i.e., light 

output never drops below 10 percent of the baseline system). 

The following discussion identifies the steps and technologies associated with each EL 

DOE considered. As discussed in the screening analysis (chapter 4), DOE used design options 

with highly-emissive electrode coatings, higher-efficacy lamp fill gas composition, higherefficacy phosphors, glass coatings, or higher-efficacy lamp diameter to achieve higher efficacy 

levels. Because high-efficacy phosphors and lamp diameter are common methods to achieve 

higher efficacies, DOE identified the diameter and phosphor associated with each EL: 

EL1. This level requires a 110W T12 lamp to use 800 series rare earth phosphor. 

EL2. This level cannot be achieved by any 110W T12 lamp. This level also requires the 

95W T12 lamp to move to a rare earth 700 series phosphor. 

EL3. This level cannot be achieved by any 110W T12 lamp. For a 95W T12 lamp, this 

level requires a shift to the 800 series rare earth phosphor. 

EL4. This level eliminates all T12 lamps; only T8 lamps comply which requires a ballast 

change. This standard level can be achieved with a 700 series rare earth phosphor in the T8 

lamp. 

EL5. This level also eliminates all T12 lamps; only T8 lamps comply, which requires a 

ballast change. This standard level represents the highest efficacy level available, or max-tech 

for 8-foot RDC HO lamps. This level can only be achieved with an 800 series rare earth 

phosphor in the T8 lamp. 

Figure 5.3.20 illustrates five initial ELs that DOE selected to analyze based on catalog 

values of commercially-available fluorescent lamps on a plot of selected fluorescent lamps. A 

line at 80.0 lm/W denotes the existing energy conservation standard (from EPACT 1992). 

Square boxes and labels identify the two baseline lamps. The plot also shows the high-efficacy 

replacement lamps DOE considered for each baseline lamp. Some are at the same wattage, but 

have a higher efficacy; others have a combination of lower wattage and higher efficacy so that 

the light output never drops below 10 percent of the baseline system. 

5-44
EL1

EL2

EL3

EL4

EPACT 1992

EL5

75.0

77.0

79.0

81.0

83.0

85.0

87.0

89.0

91.0

93.0

95.0

97.0

99.0

101.0

103.0

105.0

80 82 84 86 88 90 92 94 96 98 100 102 104 106 108 110 112 114

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

8-foot T12 recessed 

double contact HO

8-foot T8 recessed 

double contact HO

110W T12 Baseline

95W T12 Baseline

 Figure 5.3.25 Initial Efficacy Levels for 8-Foot RDC HO Lamps With CCTs ≤ 4,500K 

Table 5.3.22 provides detailed information on the 8-foot RDC HO lamp designs used in 

the engineering analysis and subsequent analyses. 

Table 5.3.22 8-Foot RDC HO Lamp Designs 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial Light 

Output 

Mean Light 

Output Life CRI 

EL 

Lamp 

Diameter 

W W lm/W lm lm hr

Baseline/0 T12 110 113 80.1 9,050 8,145 12,000 70 

Baseline/0 T12 95 97 82.5 8,000 6,950 12,000 62 

1 T12 110 113 83.2 9,400 8,648 12,000 80 

2 T12 95 97 86.1 8,350 7,515 12,000 70 

3 T12 95 97 87.6 8,500 7,650 12,000 80 

3 T12 95 97 88.9 8,625 7,750 12,000 85 

4 T8 86 86 91.9 7,900 7,100 24,000 78 

4 T8 86 86 93.0 8,000 7,200 18,000 75 

5 T8 86 86 95.3 8,200 7,800 18,000 86 

As seen above, DOE used commercially-available lamps and their associated rated 

efficacies (rated initial lumen output divided by the ANSI rated wattage) to determine the design 

5-45
options required to meet each efficacy level. However, to establish the minimum efficacy 

requirements for each efficacy level, DOE coupled catalog data on commercially-available lamps 

with data submitted to DOE by manufacturers for the purpose of compliance with existing 

energy conservation standards for general service fluorescent lamps. DOE’s use of compliance 

report data is discussed in further detail in section 5.3.1.2. 

As discussed in section 5.3.1.2, DOE considered only recent compliance report data in 

establishing minimum efficacy requirements. Figure 5.3.26 depicts compliance report data from 

the years 2007 and 2008 in gray circles. For 8-foot RDC HO lamps, DOE found that not enough 

data existed from compliance reports submitted in 2007 and 2008 to establish several of efficacy 

levels with reasonable certainty. Therefore, DOE adjusted these levels to reflect the minimum 

efficacy requirements recommended by NEMA in their written comments. Table 5.3.23 

summarizes the resulting efficacy requirements for 8-foot RDC HO lamps with CCTs less than 

or equal to 4,500K, after accounting for compliance data. 

80.0

82.0

84.0

86.0

88.0

90.0

92.0

94.0

96.0

98.0

100.0

85.0 90.0 95.0 100.0 105.0 110.0 115.0

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

8ft RDC HO <=4500 HALO

8ft RDC HO <=4500, 700 SERIES

8ft RDC HO <=4500, 800 SERIES

Figure 5.3.26 All Compliance Report Data for 8-Foot RDC HO Lamps with CCTs ≤

4,500K 

5-46
Table 5.3.23 Summary of the ELs for 8-Foot RDC HO Lamps With CCTs ≤ 4,500K 

Efficacy Level Efficacy Requirement 

lm/W

EL1 83 

EL2 86 

EL3 88 

EL4 92 

EL5 95 

Section 5.3.3.4 presents additional information on the lamp-and-ballast systems DOE 

develops in the engineering analysis. 

5.3.3.3 System Power Rating 

For each lamp wattage and ballast type, DOE linearly fit the system power rating of a 

lamp on several different BFs versus the BF of each ballast. Figure 5.3.27 to Figure 5.3.28 show 

the linear fit and ballast characteristics DOE used to derive the system power rating for twolamp, 8-foot T12 RDC HO lamps on electronic ballasts. The fit followed the form of Eq. 5.1 

where SPR = m * BF + b. The ballasts DOE chose for these calculations typically have a THD 

less than 20 percent, PF greater than 0.95, and typical BEF. Because ballast efficiencies 

naturally increase as lamp wattages decrease, there is a natural progression to higher typical 

BEFs at lower wattages. 

185.0

190.0

195.0

200.0

205.0

210.0

215.0

220.0

0.83 0.85 0.87 0.89 0.91

Ballast Factor

Sytem Power Rating (W)

Figure 5.3.27 Two-Lamp 110W T12 120V Ballasts with THD <20 percent, PF >0.95, and 

BEF 0.42-0.43; Linear Fit: m=307.7, b=-65.4 

5-47
155.0

160.0

165.0

170.0

175.0

180.0

185.0

190.0

0.84 0.85 0.86 0.87 0.88 0.89 0.90

Ballast Factor

System Power Rating (W)

Figure 5.3.28 Two-Lamp 95W T12 120V Ballasts with THD <20 percent, PF >0.95, and 

BEF 0.48-0.52; Linear Fit: m=433.3, b=-204.3 

Figure 5.3.29 shows the linear fit and ballast characteristics DOE used to derive the 

system power rating for two-lamp, 8-foot T8 RDC HO lamps on electronic ballasts. The ballasts 

DOE used for these calculations typically have a THD less than 20 percent, PF greater than 0.95, 

and typical BEF. 

5-48

145.0

147.0

149.0

151.0

153.0

155.0

157.0

159.0

161.0

163.0

165.0

0.8 0.82 0.84 0.86 0.88 0.9

Ballast Factor

System Power Rating (W)
5-49

Figure 5.3.29 Two-Lamp 86W T8 120V Ballasts with THD <20 percent, PF >0.95, and 

BEF 0.54-0.55; Linear Fit: m=128.6, b=46.9 

5.3.3.4 Results 

DOE evaluated two baseline lamps for the 8-foot RDC HO with CCTs ≤ 4,500K product 

class: a 110W T12 lamp and a 95W T12 lamp. For each baseline lamp, DOE considered only 

energy-saving options that result in approximately the same light output as the baseline lamp. 

Energy savings can either be achieved through lamp replacements or lamp-and-ballast 

replacements. Additional lamp-and-ballast designs that DOE uses in the NIA are available in 

appendix 5A. 

Table 5.3.24 and Table 5.3.25 present the engineering characteristics of lamp 

replacement and lamp-and-ballast replacement designs for a baseline 110W 8-foot T12 RDC 

HO, 4,100K lamp. There are no lamp replacement designs at EL1 because the system lumens of 

the 95W lamp replacement options below EL3 emit less than 10 percent of the baseline system. 

For lamp-and-ballast replacement options, DOE considered some T8 substitutes for the 

110W T12 lamp at higher ELs. In events of new construction and renovation, for instance, DOE 

assumed that some of these 8-foot T8 RDC HO systems will be spaced closer together so that the 

potential light output is equal to, greater than, or no more than 10 percent less than the light 

output of the baseline system. 

 

 As discussed earlier, DOE also adjusted the BF such that the system light output of the 

lamp-and-ballast design is equal to, greater than, or no more than 10 percent less than the light 

output of the baseline system.
Table 5.3.24 Lamp Replacement Engineering Analysis for a 110W T12, 4,100K System 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T12 110 113 80.1 9,050 8,145 12,000 Magnetic 0.95 237.0 

EL3 T12 95 97 87.6 8,500 7,650 12,000 Magnetic 0.91 203.0 EL3 T12 95 97 88.9 8,625 7,750 12,000 Magnetic 0.91 203.0 

5-50
Table 5.3.25 Lamp-and-Ballast Replacement Engineering Analysis for a 110W T12, 4,100K System 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T12 110 113 80.1 9,050 8,145 12,000 Magnetic 0.95 237.0 

EL1 T12 110 113 83.2 9,400 8,648 12,000 Electronic 0.88 205.4 

EL2* T12 95 97 86.1 8,350 7,515 12,000 Electronic 0.90 185.6 EL2* T12 95 97 86.1 8,350 7,515 12,000 Magnetic 0.91 203.0 

EL3 T12 95 97 87.6 8,500 7,650 12,000 Magnetic 0.91 203.0 EL3 T12 95 97 88.9 8,625 7,750 12,000 Magnetic 0.91 203.0 EL3 T12 95 97 88.9 8,625 7,750 12,000 Electronic 0.90 185.6 

EL3* T12 95 97 87.6 8,500 7,650 12,000 Electronic 0.90 185.6 EL4* T8 86 86 91.9 7,900 7,100 24,000 Electronic 0.88 160.0 EL4* T8 86 86 93.0 8,000 7,200 18,000 Electronic 0.81 151.0 

EL5 T8 86 86 95.3 8,200 7,800 18,000 Electronic 0.88 160.0 

EL5* T8 86 86 95.3 8,200 7,800 18,000 Electronic 0.81 151.0 

* These systems are used only in the new construction/renovation scenario in the LCC analysis. Under this event, slightly more (betwe

systems are installed where there would have been one baseline system to be within 10 percent mean lumens of the baseline system. Thlumen output of these systems are multiplied by a factor (between 1.12 and 1.33) in the LCC analysis. 

Table 5.3.26 presents the engineering analysis results for the replacement lamp-and-ballast combinations 

T12 RDC HO baseline lamp. DOE did not identify any lower-wattage direct lamp replacement designs that coulballast as a 95W T12 and save energy. In this table, DOE considered T8 lamp-and-ballast replacements for the b

selects the BF so that the new system has a light output of no less than 10 percent of the baseline system. 

5-51
5-52

Table 5.3.26 Lamp-and-Ballast Replacement Engineering Analysis for a 95W T12, 4,100K System 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr 

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T12 95 97 82.5 8,000 6,950 12,000 Magnetic 0.91 203.0 

EL2 T12 95 97 86.1 8,350 7,515 12,000 Electronic 0.89 181.3 EL3 T12 95 97 88.9 8,625 7,750 12,000 Electronic 0.88 177.0 EL3 T12 95 97 87.6 8,500 7,650 12,000 Electronic 0.88 177.0 EL3 T8 86 86 91.9 7,900 7,100 24,000 Electronic 0.88 160.0 EL4 T8 86 86 93.0 8,000 7,200 18,000 Electronic 0.88 160.0 EL5 T8 86 86 95.3 8,200 7,800 18,000 Electronic 0.81 151.0 
5.3.4 Four-foot T5 MiniBP SO GSFL With CCTs ≤ 4,500K 

5.3.4.1 Baseline Models 

Currently, only 4-foot T5 MiniBP SO lamps utilizing rare-earth phosphors are sold on the 

US market. DOE recognizes, however, that 4-foot T5 MiniBP SO halophosphor lamps may be 

introduced to the US market and purchased widely by consumers if efficacy standards for 4-foot 

T5 MiniBP SO lamps are not established. Because 4-foot T5 halophosphor MiniBP SO lamps 

do not exist currently, DOE developed a baseline model 4-foot T5 MiniBP SO halophosphor 

lamp by applying efficacy data from shorter length halophosphor SO T5 lamps that are currently 

available and creating a relationship between length and efficacy. The baseline 4-foot T5 

MiniBP SO lamp that DOE modeled is a 28W halophosphor lamp with an efficacy of 86 lm/W 

when operated at 35° C. The lamp has a CCT of 4,100K, a CRI of 62, and a rated lifetime of 

20,000 hours. Although this lamp is not commercially available today, it is the least efficacious 

lamp that may be commercially available when standards take effect. For further information on 

the development of the 4-foot T5 MiniBP SO halophosphor baseline, see appendix 5B of this 

TSD. 

DOE found that a range of ballast factors are available for the 4-foot T5 product classes, 

and the most common ballast is a 2-lamp ballast. Because the light output of the 4-foot T5 

MiniBP SO halophosphor baseline lamp is much lower than T5 lamps sold on the market today, 

DOE chose the highest ballast factors available. Thus, DOE paired its baseline 4-foot T5 

MiniBP SO lamp with 1.15 ballast factor and 1.00 ballast factor programmed-start electronic 

ballasts. Together, the 28W lamps and 1.00 BF ballast combination creates a lumen package of 

3,348 mean lumens (and 4,782 initial lumens), while the 28W lamps and 1.15 BF ballast 

combination creates a lumen package of 3,850 mean lumens (and 5,499 initial lumens). 

Table 5.3.27 Baseline Unit of Analysis for 4-Foot T5 MiniBP Standard-Output Lamps 

Nominal 

Wattage CCT 

Rated 

Efficacy 

(at 35° 

C)* 

Initial Light 

Output 

Mean Light 

Output Lamp Life 

Diameter 

W 

CRI 

K lm/W lm Lm hr 

T5 28 62 4,100 86.0 2,391 1,674 20,000 

* Rated efficacy is based on the rated wattage of the lamp, which is 27.8W. 

5.3.4.2 Efficacy Levels 

In selecting ELs, DOE considered two different paths to energy savings. The first 

concentrated on reduced-wattage replacement lamps that could be installed in a socket and 

operate on the existing ballast. These lower-wattage replacement lamps have a higher efficacy 

and therefore produce approximately the same light output as the baseline lamp (i.e., light output 

never drops below 10 percent of the baseline system). The other path to energy savings involved 

lamps that have the same rated wattage as the baseline lamp, but operate on a new ballast with a 

different BF, so system energy is lower. DOE selected the BF with the more efficacious lamp to 

5-53
produce approximately the same light output as the baseline lamp (i.e., light output never drops 

below 10 percent of the baseline system). 

For the 4-foot T5 MiniBP SO with CCTs ≤ 4,500K product class DOE analyzed two 

efficacy levels: the first efficacy level prevents the introduction of less efficacious halophosphor 

lamps on the market, while the second efficacy level raises the efficacy of the current highest 

volume 4-foot T5 MiniBP SO lamps on the market. 

The following discussion identifies the steps and technologies associated with each EL 

DOE considered. DOE is aware that many T5 standard-output lamps are operated at 35° C; 

because DOE is most interested in the efficacy of lamps at typical operating conditions, DOE 

developed initial efficacy levels for T5 standard-output lamps based on 35° C catalog data. As 

discussed in the screening analysis (chapter 4), DOE used design options with highly-emissive 

electrode coatings, higher-efficacy lamp fill gas composition, higher-efficacy phosphors, glass 

coatings, or higher-efficacy lamp diameter to achieve higher efficacy levels for GSFL. For 4-

foot T5 MiniBP SO, the primary design option DOE assessed was the use of higher-efficacy 

phosphors. No other diameters than T5 were available as design options for this product class. 

DOE identified the phosphor associated with each EL: 

EL1. This efficacy level is characterized by lamps that use 800-series phosphors and 

have a rated catalog efficacy (initial lamp lumens divided by ANSI rated wattage) of 104 lm/W 

at 35° C operation. They are the most common 4-foot T5 MiniBP SO lamps currently on the 

market. 

EL2. This level characterizes higher efficacy 4-foot T5 MiniBP SO lamps that use 

improved 800-series phosphors. Specifically, there is a reduced-wattage (26W) 4-foot T5 

MiniBP SO lamp (with a rated efficacy of 112 lm/W at 35° C operation) and a full-wattage 

(28W) lamp (with a rated efficacy of 110 lm/W at 35° C operation) that are more efficacious 

than the lamps that just meet efficacy level 1. 

Figure 5.3.30 illustrates two initial ELs based on catalog values of commerciallyavailable fluorescent lamps that DOE selected to analyze on a plot of selected fluorescent lamps. 

A square box and a label identifies the baseline lamp. The plot also shows the high-efficacy 

replacement lamps DOE is considering for the baseline lamp. Some are at the same wattage as 

the baseline lamp, but have a higher efficacy; one lamp has a combination of lower wattage and 

higher efficacy. 

5-54
EL1

EL2

75.0

80.0

85.0

90.0

95.0

100.0

105.0

110.0

115.0

120.0

125.0

20 22 24 26 28 30

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

28W T5 Baseline

Figure 5.3.30 Initial Efficacy Levels for 4-Foot T5 MiniBP SO Lamps With CCTs ≤

4,500K, 35° C Operation 

Table 5.3.28 provides detailed information on the 4-foot T5 MiniBP SO lamp designs 

used in the engineering analysis and subsequent analyses. 

Table 5.3.28 4-Foot T5 MiniBP SO Lamp Designs 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

(at 35° C)

Initial Light 

Output 

Mean Light 

Output Life CRI 

EL 

Lamp 

Diameter 

W W lm/W Lm lm hr

Baseline/0 T5 28 27.8 86.0 2,391 1,674 20,000 62 

1 T5 28 27.8 104.3 2,900 2,660 20,000 85 

2 T5 28 27.8 109.7 3,050 2,898 20,000 85 

2 T5 26 26.0 111.5 2,900 2,660 25,000 85 

As seen above, DOE used commercially-available lamps and their associated rated 

efficacies (rated initial lumen output divided by the ANSI rated wattage) to determine the design 

options required to meet each efficacy level. However, similar to previously discussed product 

classes, these rated efficacy values do not necessarily correspond to how these lamps may 

comply under energy conservation standards. As discussed further detail in section 5.3.1.2, DOE 

used compliance report data to establish minimum efficacy requirements for the 4-foot MBP, 8-

5-55
foot SP slimline, and 8-foot RDC HO efficacy levels. Because 4-foot MiniBP SO lamps have 

been not been regulated by DOE in the past, 4-foot MiniBP SO compliance reports do not exist. 

Therefore, to establish appropriate minimum efficacy requirements for each 4-foot MiniBP 

efficacy level, DOE computed the percentage difference between the rated efficacy and 

compliance efficacy for the highest-efficacy 4-foot MBP lamps, and applied that same 

percentage reduction to the 4-foot T5 MiniBP SO rated efficacies. In addition, the DOE test 

procedure for T5 lamps requires the lamps to be tested at 25°C. When operated at 25°C, the 

lumen output of T5 lamps is approximately 10 percent lower than the lumen output of such 

lamps when operated at 35° C. Because the test procedure will be used to determine compliance 

with DOE energy conservation standards, DOE developed EL requirements for T5 standardoutput lamps that take into account 25° C testing. Table 5.3.29 summarizes the resulting 

efficacy levels for 4-foot MiniBP SO lamps with CCTs less than or equal to 4,500K, taking 

compliance data and 25° C testing into account. 

Table 5.3.29 Summary of the ELs for 4-Foot T5 MiniBP SO Lamps With CCTs ≤ 4,500K 

Efficacy Level Efficacy Requirement 

lm/W

EL1 86 

EL2 90 

Section 5.3.4.4 presents additional information on the lamp-and-ballast systems DOE 

develops in the engineering analysis. 

5.3.4.3 System Power Rating 

DOE calculated the system power rating, which represents the energy consumption rate 

of both the lamps and ballast, using published catalog information. For each lamp wattage and 

ballast type, DOE applied a linear fit to several points identifying the system power rating of a 

lamp on a ballast and the ballast factor of the ballast. The fit follows the form of Eq. 5.1 where 

SPR = m * BF + b. DOE used a linear form because the relationship is approximately linear 

over the range of BFs and wattages considered. 

The ballasts DOE used typically have a total harmonic distortion (THD) less than 10 

percent, power factors (PF) greater than 0.95, and typical ballast efficacy factors (BEF). Because 

ballast efficiencies naturally increase as lamp wattages decrease, there is a natural progression to 

higher typical BEFs at lower wattages. Also, because there is less manufacturer literature on 

system power ratings of ballasts with lower wattage lamps, DOE used fewer points to develop a 

linear fit for the energy-saving lamp wattages. Figure 5.3.31 to Figure 5.3.32 show the linear fit 

and ballast characteristics DOE used to derive the system power rating for 2-lamp, 4-foot T5 SO 

lamps on electronic ballasts. 

5-56
50.0

55.0

60.0

65.0

70.0

75.0

80.0

0.85 0.95 1.05 1.15

Ballast Factor

System Power Rating (W)

Linear Fit: m=47.3, b=16.3

Figure 5.3.31 Two-Lamp 28W T5 Ballasts with THD <10 percent, PF >0.95, and BEF 1.52-

1.67 

50.0

55.0

60.0

65.0

70.0

75.0

0.85 0.95 1.05 1.15

Ballast Factor

System Power Rating (W)

Linear Fit: m=52.4, b=7.2

Figure 5.3.32 Two-Lamp 26W T5 Ballasts with THD <10 percent, PF >0.95, and BEF 1.67-

1.71 

5.3.4.4 Results 

For the 4-foot T5 MiniBP SO with CCTs ≤ 4,500K product class, DOE assessed one 

model baseline lamp. DOE considered only energy-saving options that result in approximately 

the same light output as the baseline lamp system. Energy savings could either be achieved 

5-57
5-58

through lamp or lamp and ballast replacements. Appendix 5A provides information on the 

additional lamp-and-ballast designs DOE uses in the NIA. 

Table 5.3.30 presents the engineering characteristics of lamp replacement options for a 

baseline 28W 4-foot T5 MiniBP SO, 4,100K lamp. Table 5.3.31 presents the engineering 

characteristics of lamp and ballast replacement options for the same lamp. As discussed earlier, 

DOE adjusted the BF so that the combination of lamp and ballast maintains light output so that 

potential light output is equal to, greater than, or no more than 10 percent less than the light 

output of the baseline system. All T5 ballasts that DOE considered are electronic. 
Table 5.3.30 Lamp Replacement Engineering Analysis for a Two-Lamp 28W T5, 4,100K System 

Nominal 

Wattage Rated 

Wattage 

Rated 

Efficacy 

(at 35° 

C) 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr 

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T5 28 27.8 86.0 2,391 1,674 20,000 Electronic 1.15 70.7 

EL2 T5 26 26.0 111.5 2,900 2,660 25,000 Electronic 1.15 67.5 

Table 5.3.31 Lamp and Ballast Replacement Engineering Analysis for a Two-Lamp 28W T5, 4,100K Syst

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

(at 35° 

C) 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy Level 

Lamp 

Diameter 

W W Lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T5 28 27.8 86.0 2,391 1,674 20,000 Electronic 1.15 70.7 

EL1* T5 28 27.8 104.3 2,900 2,660 20,000 Electronic 0.96 61.2 EL2* T5 28 27.8 109.7 3,050 2,898 20,000 Electronic 0.90 109.7 EL2* T5 26 26.0 111.5 2,900 2,660 25,000 Electronic 0.90 54.4 

* These systems are used in the new construction/renovation scenario in the LCC analysis. Under this event, slightly less (between 0.7systems are installed where there would have been one baseline system to be within 10 percent mean lumens of the baseline system. Thlumen output of these systems are multiplied by a factor (between 0.74 and 0.80) in the LCC analysis. 

5-59
5.3.5 Four-foot T5 MiniBP HO GSFL With CCTs ≤ 4,500K 

5.3.5.1 Baseline Models 

Similar to 4-foot T5 MiniBP SO lamps, currently, only 4-foot T5 MiniBP HO lamps 

utilizing rare-earth phosphors are sold on the US market. DOE recognizes, however, that 4-foot 

T5 MiniBP HO halophosphor lamps may be introduced to the US market and purchased widely 

by consumers if efficacy standards for 4-foot T5 MiniBP HO lamps are not established. Because 

4-foot T5 halophosphor MiniBP HO lamps do not exist currently, DOE developed a baseline 

model 4-foot T5 MiniBP HO halophosphor lamp by applying efficacy data from shorter length 

halophosphor fluorescent T5 lamps that are currently available in the market and creating a 

relationship between length and efficacy. The baseline 4-foot T5 MiniBP HO lamp that DOE 

modeled is a 54W halophosphor lamp with an efficacy of 76.6 lm/W at 35° C operation. The 

lamp has a CCT of 4,100K, a CRI of 62, and a rated lifetime of 20,000 hours. Although this 

lamp is not commercially available today, it is the least efficacious lamp that may be 

commercially available when standards take effect. For further information on the development 

of the 4-foot T5 MiniBP HO halophosphor baseline, see appendix 5B of this TSD. 

DOE found that the most common ballast is a 2-lamp ballast with a 1.0 ballast factor. 

Thus, DOE paired its baseline 4-foot T5 MiniBP HO lamp with a 1.00 ballast factor programmed 

start electronic ballast. Together, the 54W lamps and 1.00 BF ballast combination creates a 

lumen package of 5,770 mean lumens (and 8,244 initial lumens). 

Table 5.3.32 Baseline Unit of Analysis for 4-Foot T5 MiniBP High-Output Lamps 

Nominal 

Wattage CCT 

Rated 

Efficacy 

(at 35° 

C)* 

Initial Light 

Output 

Mean Light 

Output Lamp Life 

Diameter 

W 

CRI 

K lm/W lm Lm hr 

T5 54 62 4,100 76.6 4,122 2,885 20,000 

* Rated efficacy is based on the rated wattage of the lamp, which is 53.8W. 

5.3.5.2 Efficacy Levels 

In selecting ELs, DOE considered two paths to energy savings. The first concentrated on 

reduced wattage replacement lamps that could be installed in a socket and operate on the existing 

ballast. These lower-wattage replacement lamps have a higher efficacy and therefore produce 

approximately the same light output as the baseline lamp (i.e., light output never drops below 10 

percent of the baseline system). The other path to energy savings involves installing a higher 

efficacy lamp on the same ballast factor ballast to increase light output. For new construction, 

users can install fewer lamp-and-ballast systems in the case of a standard due to their higher light 

output. DOE could not consider installing a lamp on a lower ballast factor ballast to save energy 

as ballasts with a ballast factor lower than 1.0 are not commercially available. 

For the 4-foot T5 miniature bipin HO with CCTs ≤ 4,500K product class DOE analyzed 

one efficacy level preventing the introduction of less efficacious halophosphor lamps on the 

market. For the 4-foot T5 MiniBP HO with CCTs ≤ 4,500K product class, DOE found that only 

5-60
one full-wattage (54W) lamp exists on the market today. Because DOE based its ELs on fullwattage lamps due to the limited utility of reduced-wattage lamps, DOE did not analyze an 

additional EL for this product class. DOE, however, was able to identify a reduced-wattage lamp 

and a full-wattage 4-foot T5 MiniBP HO lamp featuring 800-series phosphors. 

The following discussion identifies the steps and technologies associated with the EL 

DOE considered. Because DOE believes that many T5 high-output lamps are operated at 35° C, 

DOE developed an efficacy level that reflects 35° C operation. As discussed in the screening 

analysis (chapter 4), DOE used design options with highly-emissive electrode coatings, higherefficacy lamp fill gas composition, higher-efficacy phosphors, glass coatings, or higher-efficacy 

lamp diameter to achieve higher efficacy levels for GSFL. For 4-foot T5 MiniBP HO lamps, the 

primary design option DOE assessed was the usage of higher-efficacy phosphors. DOE also 

identified the phosphor associated with the EL: 

EL1. This efficacy level is characterized by lamps that use 800-series phosphors. There 

is a full-wattage (54W) lamp with a rated catalog efficacy (initial lamp lumens divided by ANSI 

rated wattage) of 92.9 lm/W at 35° C and a reduced-wattage (51W) lamp with a rated catalog 

efficacy of 98.0 lm/W at 35° C. 

Figure 5.3.33 illustrates an initial EL based on catalog values of commercially-available 

fluorescent lamps on a plot of selected fluorescent lamps. A square box and a label identify the 

baseline lamp. The plot also shows the high-efficacy replacement lamps DOE considered for the 

baseline lamp. One is at the same wattage, but has a higher efficacy; the other has a combination 

of lower wattage and higher efficacy. 

5-61
EL1

75.0

80.0

85.0

90.0

95.0

100.0

105.0

110.0

45 47 49 51 53 55 57 59

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

54W T5 Baseline

Figure 5.3.33 Initial Efficacy Level for 4-Foot T5 MiniBP HO Fluorescent Lamps With 

CCTs ≤ 4,500K, 35° C Operation 

Table 5.3.33 provides detailed information on the 4-foot T5 MiniBP HO lamp designs 

used in the engineering analysis and subsequent analyses. 

Table 5.3.33 4-Foot T5 MiniBP HO Lamp Designs 

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

(at 35° C)

Initial Light 

Output 

Mean Light 

Output Life CRI 

EL 

Lamp 

Diameter 

W W lm/W lm lm hr

Baseline/0 T5 54 53.8 76.6 4,122 2,885 20,000 62 

1 T5 54 53.8 92.9 5,000 4,600 20,000 85 

1 T5 51 51.0 98.0 5,000 4,600 20,000 85 

As seen above, DOE used commercially-available lamps and their associated rated 

efficacies (rated initial lumen output divided by the ANSI rated wattage) to determine the design 

options required to meet each efficacy level. However, similar to previously discussed product 

classes, these rated efficacy values do not necessarily correspond to how these lamps may 

comply under energy conservation standards. As discussed further detail in section 5.3.1.2, DOE 

used compliance report data to establish minimum efficacy requirements for the 4-foot MBP, 8-

foot SP slimline, and 8-foot RDC HO efficacy levels. Because 4-foot MiniBP HO lamps have 

5-62
5-63

been not been regulated by DOE in the past, 4-foot MiniBP HO compliance reports do not exist. 

Therefore, to establish appropriate minimum efficacy requirements for each 4-foot MiniBP 

efficacy level, DOE calculated the percentage difference between the rated efficacy and 

compliance efficacy for the highest-efficacy 4-foot MBP lamps, and applied that same 

percentage reduction to the 4-foot T5 MiniBP HO rated efficacies. In addition, the DOE test 

procedure for T5 lamps requires the lamps to be tested at 25°C. When operated at 25°C, the 

lumen output of T5 lamps is approximately 10 percent lower than the lumen output of such 

lamps when operated at 35° C. Because the test procedure will be used to determine compliance 

with DOE energy conservation standards, DOE developed EL requirements for T5 high-output 

lamps that take into account 25° C testing. Table 5.3.34 summarizes the resulting efficacy level 

for 4-foot MiniBP HO lamps with CCTs less than or equal to 4,500K. 

Table 5.3.34 Summary of the ELs for 4-Foot T5 MiniBP HO Lamps With CCTs ≤ 4,500K 

Efficacy Level Efficacy Requirement 

lm/W

EL1 76 

Section 5.3.5.4 presents additional information on the lamp-and-ballast systems DOE 

develops in the engineering analysis. 

5.3.5.3 System Power Rating 

The ballasts DOE used typically have a total harmonic distortion less than 10 percent, 

power factors greater than 0.95, and typical ballast efficacy factors. The 54W lamp has one 

available ballast that results in a system power rating of 120.0W during 35° C operation, while 

the 51W lamp has one available ballast that results in a system power rating of 117.0W during 

35° C operation. 

5.3.5.4 Results 

For the 4-foot T5 MiniBP HO with CCTs ≤ 4,500K product class, DOE assessed one 

model baseline lamp. DOE considered only energy-saving options that result in approximately 

the same light output as the baseline lamp system. Energy savings could either be achieved 

through lamp or lamp and ballast replacements. 

Table 5.3.35 presents the engineering characteristics of lamp replacement options for a 

baseline 54W 4-foot T5 MiniBP HO, 4,100K lamp. Table 5.3.36 presents the engineering 

characteristics of lamp and ballast replacement options for the same lamp. As discussed earlier, 

DOE adjusted the BF so that the combination of lamp and ballast maintains light output that is 

equal to, greater than, or no more than 10 percent less than the light output of the baseline 

system. All T5 ballasts that DOE considered are electronic. 
Table 5.3.35 Lamp Replacement Engineering Analysis for a Two-Lamp 54W T5, 4,100K System 

Nominal 

Wattage Rated 

Wattage 

Rated 

Efficacy 

(at 35° 

C) 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

Efficacy 

Level 

Lamp 

Diameter 

W W lm/W lm lm hr 

Ballast 

Type 

Ballast 

Factor 

W 

Baseline T5 54 53.8 76.6 4,122 2,885 20,000 Electronic 1.00 120.0 

EL1 T5 51 51.0 98.0 5,000 4,600 25,000 Electronic 1.00 117.0 

Table 5.3.36 Lamp and Ballast Replacement Engineering Analysis for a Two-Lamp 54W T5, 4,100K Syst

Nominal 

Wattage 

Rated 

Wattage 

Rated 

Efficacy 

(at 35° 

C) 

Initial 

Light 

Output 

Mean 

Light 

Output 

Life 

System 

Power 

Rating 

System 

Initial 

Light 

Output 

Efficacy Level 

Lamp 

Diameter 

W W Lm/W lm lm hr

Ballast 

Type 

Ballast 

Factor 

W lm 

Baseline T5 54 53.8 76.6 4,122 2,885 20,000 Electronic 1.00 120.0 8,244 

EL1* T5 54 53.8 92.9 5,000 4,600 20,000 Electronic 1.00 120.0 6,272 

EL1 T5 51 51.0 98.0 5,000 4,600 25,000 Electronic 1.00 117.0 10,000 

EL1* T5 51 51.0 98.0 5,000 4,600 25,000 Electronic 1.00 117.0 6,272 

* These systems are used in the new construction/renovation scenario in the LCC analysis. Under this event, slightly less (0.63) of thes

installed where there would have been one baseline system to be within 10 percent mean lumens of the baseline system. Therefore, the 

lumen output of these systems are multiplied by a factor (0.63) in the LCC analysis. 

5-64
5.4 INCANDESCENT REFLECTOR LAMPS 

As discussed in chapter 3, the market and technology assessment, DOE created eight 

separate incandescent reflector lamp product classes with three subdivisions: standard-spectrum 

IRL and modified-spectrum IRL, diameter greater and less than or equal to 2.5 inches, and 

voltage less than and greater than or equal to 125V. DOE chose to analyze the standardspectrum, voltage less than 125V, diameter greater than 2.5 inches IRL product class due to its 

prevalence in the market. Discussions with industry experts and a review of manufacturer 

literature for IRL revealed that standard-spectrum lamps represent the vast majority of IRL. 

Discussions also revealed that the majority of consumers purchase 120V PAR30 or PAR38 IRL 

(the most common lamps with a diameter greater than 2.5 inches). Modified-spectrum IRL, 

PAR20 IRL (the most common lamps with a diameter less than or equal to 2.5 inches) and IRL 

that operate at 130V are not as common in the marketplace. Thus, DOE extrapolated its findings 

on standard-spectrum 120V IRL with diameters greater than 2.5 inches to the other product 

classes. Section 5.5.2 provides details on this extrapolation. 

Each IRL product class considered spans the full range of wattages covered. DOE 

considered ELs for each product class with efficacy that varies with wattage. Given that the IRL 

product classes are not divided by wattage, DOE did not choose a representative wattage bin for 

IRL. However, rather than selecting one baseline lamp, DOE chose to analyze lamps of multiple 

wattages in the standard-spectrum product class to prevent oversimplification of the analysis. 

DOE concentrated on analyzing the most popular reflector lamps in terms of lamp size, wattage, 

and lumen package. DOE examined existing product on the market at multiple wattages to select 

baseline lamps. DOE used product at multiple wattages to derive efficacy equations that span 

wattage. Therefore, DOE was able to apply the analysis performed on the most popular lamps to 

the other, less-common lamps. Section 5.4.2 provides further details on the ELs DOE developed 

for IRL. 

Table 5.4.1 Product Classes for Incandescent Reflector Lamps 

Lamp Type Diameter Voltage 

≥ 125 > 2.5 inches 

< 125 (representative) 

≥ 125 

Standard-spectrum 

≤ 2.5 inches 

< 125 

≥ 125 > 2.5 inches 

< 125 

≥ 125 

Modified-spectrum 

≤ 2.5 inches 

< 125 

 

As with GSFL, DOE analyzed lamp designs for the LCC that both save energy and 

maintain comparable light output. DOE considered lamp designs that emit initial lumens equal 

to the light output of the baseline system, or less than that system by no more than 10 percent. 

DOE maintained light output across efficacy levels to ensure that products supply equivalent 

service under the base case and standards case scenarios. To account for the purchase of more5-65
efficacious lamps at the same wattage as the baseline lamp wattage (thus with greater light 

output), DOE considered non-energy-saving lamps in the NIA. Appendix 5A shows lamp 

designs considered in the NIA. 

 In assessing light output, DOE distinguished between mean and initial lumens. DOE 

used initial lumens in its test procedures for incandescent lamps to measure compliance with a 

standard. This is consistent with consensus industry standards on efficacy measurements. 

Therefore, DOE used initial lumens to calculate efficacy. For incandescent lamps, DOE also 

used initial lumens when predicting consumer purchase decisions. Consumers generally make 

purchase decisions based on initial lumens and not mean lumens for incandescent lamps. 

Therefore, DOE lists initial lumens in its tables. Over time, the light output of an incandescent 

lamp decreases slightly. To account for this real-world depreciation in lumens, DOE also 

monitored mean lumens in the NIA. 

5.4.1 Baseline Models for IRL With Diameters Greater Than 2.5 Inches and Operating 

Voltages Less Than 125V 

DOE selected three baseline lamps of varying wattage and shapes to provide a 

comprehensive understanding of consumer economics. DOE included parabolic reflector (PAR) 

halogen baseline lamps of three different wattages. These baseline lamps are currently regulated 

by EPCA and meet the EPCA standard. 

DOE identified three IRL lumen packages that are popular in the commercial and 

residential sectors. DOE also identified power ratings and lifetime characteristics of these lamps, 

as listed in Table 5.4.2. The three light output packages are 630, 1050, and 1,310 lumens, 

corresponding to a 50W PAR30, 75W PAR38, and 90W PAR38 lamp, respectively. These 

lamps represent the most common reflector lamps sold and used today; thus, they represent highvolume wattages and diameters. Since these lamps capture a range of wattages, lumen packages, 

and lamp diameters, they cover a range of applications. Table 5.4.2 presents the representative 

product class and the three baseline lamps DOE selected for its IRL analysis. 

Table 5.4.2 IRL Representative Product Class and Baseline Lamps 

Representative Product Class 

Lamp Baseline Lamps 

Category 

Representative 

Product Class 

Descriptor Wattage 

W

Efficacy 

lm/W 

Initial Light Output 

lm

Lifetime 

hr

IRL 

StandardSpectrum, 

Voltage < 

125V, Diameter 

> 2.5 Inches 

PAR30 

PAR38 

PAR38 

50 

75 

90 

12.6 

14.0 

14.6 

630 

1,050 

1,310 

3,000 

2,500 

2,500 

5.4.2 Efficacy Levels 

For IRL with diameters greater than 2.5 inches and operating voltages less than 125V, 

DOE observed natural efficacy divisions in the marketplace corresponding to a variety of design 

options utilized to increase lamp efficacy. DOE considered these efficacy divisions in selecting 

ELs by using the efficacy levels of commercially-available lamps as a guide. However, 

5-66
commercially-available product does not exist at all of the ELs for all of the lumen packages. 

For example, the 50W PAR30 baseline lamp with 630 lumens only has commercially-available 

product at two of the five ELs. Because it is technically feasible to incorporate the 

commercially-available technologies in lamp types that correspond to all of the baseline lamps, 

and to have a continuous range of efficacies to analyze, DOE developed some model IRL based 

on commercially-available lamp lumen packages. Using efficacy information for the 

commercially-available lamp designs (which substitute for certain baseline lamps) or efficacy 

information from manufacturer interviews, DOE developed a relationship between efficacy and 

wattage. This allowed DOE to develop lamp designs that are not commercially available for 

certain wattages, but that would be substitutes for other baseline lamps. Generally, the lamp 

design substitutes for baseline lamps are based around the lumen output of the baseline lamp, 

plus or minus 10 percent. 

 In reviewing published catalog data, DOE observed that higher-efficacy, reduced-wattage 

IRL, which maintain light output within 10 percent, can substitute for a number of baseline 

lamps. Furthermore, these reduced-wattage designs span a range of design options considered in 

this rule. These design options, discussed in the screening analysis (chapter 4), include the 

tungsten-halogen regenerative cycle (hereafter “halogen”) and halogen infrared (HIR) 

technologies that uses both halogen and glass coatings that reflect infrared light. 

 The commercially-available halogen IRL fall within three tiers of efficacy. To 

distinguish the efficacies of these halogen IRL, DOE designated them as halogen and improved 

halogen. Improved halogen can be achieved using xenon, a higher-efficacy inert fill gas. In 

addition, an even-more-efficacious improved halogen can be achieved by using a silverized 

reflector, a higher-efficiency reflector coating. The baseline halogen IRL employ neither xenon 

nor the higher-efficiency reflector coating. DOE also observed four tiers of efficacy for HIR 

IRL. To distinguish the efficacies of these IRL, DOE designated them as long-life HIR, HIR, 

improved HIR (4,000 hour), and improved HIR plus (4,200 hour). HIR is more efficacious than 

long-life HIR due to the higher operating temperature. Improved HIR (4,000 hour) can be 

achieved by using the additional design options discussed in the screening analysis. These 

design options include higher-efficacy filaments as well as efficient filament coiling, filament 

configuration, capsule design, high-pressure capsules, or higher-efficacy reflector coating. 

Improved HIR plus (4,200 hour) can be achieved with further use of these design options. DOE 

observed lifetime changes across these reduced-wattage IRL. For example, a halogen IRL 

typically has a lifetime of around 2,000 to 3,000 hours, while an HIR IRL typically lives for 

3,000 to 6,000 hours. DOE maintained the lifetime attributes of the commercially available 

product for its analysis. DOE also considered the possibility that manufacturers would not 

produce more efficacious improved HIR or HIR plus products with longer lifetimes than the 

baseline lamps analyzed by DOE. To incorporate this possibility into its analysis, DOE modeled 

lamps at EL4 and EL5 that have shorter lifetimes and lower prices than the 4,000 hour and 4,200 

hour lamps at these efficacy levels. For the lifetimes, see the efficacy level presentation below. 

For a discussion of prices, see chapter 7 of this TSD. 

 DOE established ELs for IRL using an approach similar to the one it uses for GSFL. 

DOE developed continuous equations that set a minimum efficacy requirement across wattage. 

Each equation represents the potential efficacy a lamp achieves using a particular design option. 

5-67
These “technology contour lines” represent the same IRL design option across the wattage range 

of a product class. For example, an EL based on a halogen design option is a curve rather than a 

step function, and denotes a halogen standard at all wattages. In general terms, DOE based the 

ELs on the following progression of design options: 

EL1. This efficacy level can be achieved by an improved halogen lamp which utilizes 

xenon, a higher-efficiency inert fill gas. Such a lamp is currently not commercially available at 

any of the three lumen packages that DOE analyzed, but is technologically feasible to produce. 

To create EL1, DOE developed a model of a lamp with xenon gas using information from 

technical literature and confidential information from manufacturers. 

EL2. This efficacy level can be achieved by two lamps: the long-life HIR lamp and the 

improved halogen lamp with a silver reflector coating. The long-life HIR lamp employs a 

halogen capsule with an infrared reflective coating and a lamp lifetime of 6,000 hours. An 

improved halogen lamp that utilizes a silver reflective coating has a lifetime of 3,000 hours. 

EL3. This efficacy level can be achieved with an HIR lamp (a lamp containing a halogen 

capsule with an infrared reflective coating) with a lamp lifetime of 3,000 hours. Decreasing the 

lamp lifetime from 6,000 to 3,000 hours with higher temperature operation effectively improves 

the efficacy of the tungsten filament. 

EL4. This efficacy level can be achieved by an improved HIR lamp that may employ 

improved reflector coatings, improved HIR coatings or improved capsule designs. This level is 

based on an HIR lamp with a lifetime of 4,000 hours. DOE also models an EL4 lamp for the 

Baseline Lifetime scenario (see chapter 10) that utilizes the same technology but features the 

same lifetime as the baseline lamp in each lumen package (2,500 hours, 2,500 hours, and 3,000 

hours for the 90W, 75W, and 50W lumen packages, respectively). 

EL5. This efficacy level can be achieved by the improved HIR plus lamps that may 

utilize additional improvements in reflector coatings, HIR coatings, or filament and capsule 

designs that produce higher-temperature operation. This level is based on an HIR lamp with a 

lifetime of 4,200 hours. DOE also models an EL5 lamp for the Baseline Lifetime scenario that 

utilizes the same technology as the commercially-available EL 4 lamp but features a lifetime of 

2,500 hours for all lumen packages. 

Figure 5.4.1 plots the results of the IRL engineering analysis for the three lumen 

packages (represented by 50W, 75W, and 90W baseline lamps) along with five initial ELs. 

Square boxes and labels represent the three baseline lamps in the plot; triangles represent higherefficacy lamp designs. Maintaining light output on this plot of efficacy versus wattage means 

that lamp designs are always higher in efficacy than the baseline lamp (i.e., moving up on the yaxis) and lower in wattage (i.e., moving to the left on the x-axis). This trend is evident for all 

three lumen packages analyzed As illustrated in Table 5.4.4 through Table 5.4.6, the Els 

correspond to efficacy levels associated with lamps with particular design options. 

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Baseline

EPCA

EL 1

EL 2

EL 4

EL 3

EL 5

9.0

11.0

13.0

15.0

17.0

19.0

21.0

23.0

20 30 40 50 60 70 80 90 100 110

Lamp Efficacy (lm/W)

Lamp Power (W)

Baseline/EPCA: Halogen (2,500 hr; 3,000 hr for 

50W lumen package)

EL1: Improved Halogen (Xenon) (3,000 hr)

EL2: Long-Life HIR (6,000 hr) 

Improved Halogen (Silver) (3,000 hr)

EL3: HIR (3,000 hr)

EL4: Improved HIR (4,000 hr)

Short-Life Improved HIR (2,500 hr; 

3,000 hr for 50W lumen package)

EL5: Improved HIR Plus (4,200 hr)

Short-Life Improved HIR Plus (2,500 hr)

PAR38 90W Baseline

PAR38 75W Baseline

PAR30 50W Baseline

Figure 5.4.1 Initial Efficacy Levels for Standard-Spectrum IRL With Diameters Greater 

Than 2.5 Inches and Operating Voltages Less Than 125V 

As seen above, DOE used the efficacies of commercially-available lamps and model 

lamps to determine the design options required to meet each efficacy level. However, to 

establish the minimum efficacy requirements for each efficacy level, DOE coupled catalog data 

on commercially-available lamps with data submitted to DOE by manufacturers for the purpose 

of compliance with existing energy conservation standards for incandescent reflector lamps. By 

analyzing manufacturer compliance reports, DOE found that efficacies of lamps when reported 

for the purpose of compliance often vary from catalog values. 

For these reasons, DOE adjusted the initial efficacy levels for IRL such that 

commercially available IRL using design options associated with each EL comply with those 

ELs. Specifically, DOE adjusted EL4 based on the reported efficacy of a PAR38 improved HIR 

lamp. Also, DOE adjusted EL5 based on the reported efficacies of a PAR38 improved HIR plus 

lamp as well as a PAR38 improved HIR lamp that DOE analytically increased in efficacy by 

modeling what the efficacy of the improved HIR lamp (EL4 lamp) would be if the manufacturer 

shortened the life of the lamp. DOE found that all of the lamps incorporating EL2 and EL3 

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design options complied with the initial EL2 and EL3 levels, respectively, when the compliance 

reports for these lamps were taken into account. Thus, DOE did not adjust the initial EL2 or EL3 

levels. Because EL1 is based on a model lamp (and thus there are no compliance reports for 

lamps incorporating the EL1 design options), DOE also did not adjust the EL1 level. Figure 

5.4.2 presents the compliance report data used to develop the IRL efficacy levels. Table 5.4.3

shows the resulting efficacy levels for standard-spectrum IRL with diameters greater than 2.5 

inches and operating voltages less than 125V. 

10.0

12.0

14.0

16.0

18.0

20.0

22.0

24.0

35 45 55 65 75 85 95 105

Reported Efficacy

Reported Wattage

EL1

EL5

EL4

EL3

EL2

Figure 5.4.2 Compliance Report Data for Standard-Spectrum IRL With Diameters 

Greater Than 2.5 Inches and Operating Voltages Less Than 125V 

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Table 5.4.3 Summary of the ELs for Standard-Spectrum IRL With Diameters Greater 

Than 2.5 Inches and Operating Voltages Less Than 125V 

Efficacy Level Efficacy Requirement 

lm/W 

EL1 4.6P0.27

EL2 4.8P0.27

EL3 5.4P0.27

EL4 5.9P0.27

EL5 6.4P0.27

P = rated wattage 

5.4.3 Results 

After selecting baseline lamps and ELs, DOE selected lamp designs associated with the 

ELs for each of the three baseline lamps. Like GSFL, DOE considered IRL that produce more 

light but do not save energy in the NIA. This reflects the fact that DOE cannot require 

consumers to switch to a reduced-wattage lamp. Appendix 5A shows the characteristics of lamp 

designs that both meet the EL and exhibit a higher wattage than or the same wattage as the 

baseline lamp. 

The following table presents the engineering analysis for the 50W PAR30 IRL baseline 

lamp. This baseline lamp is based on a 630-lumen lamp, plus or minus 10 percent. The 40W 

improved PAR30 HIR lamp at EL4 and the 46W long-life HIR at EL2 are the only lamps that are 

commercially available. The 47.8W PAR30 improved halogen (xenon) lamp (EL1), 45W 

PAR30 improved halogen (silver) lamp (EL2), 41.8W PAR30 HIR (EL3), baseline-life 40.0W 

PAR30 improved HIR (EL4), and basline- and non-baseline-life 40.0W PAR30 improved HIR 

plus lamps (EL5) are model lamp designs.e

 These lamps are designed to have approximately the 

same lumen package as the baseline lamp (i.e., 630 lumens), and to have a minimum efficacy 

just above each efficacy level. 

The 40W improved HIR plus PAR30 produces 21 percent more light output than the 

50W PAR30. For the technology employed in these lamps at this efficacy level, DOE believes 

lamps employing similar design options could not be manufactured (and still achieve similar 

performance) at wattages below 40W.f

 Therefore, DOE analyzes a 40W lamp that produces 

greater lumen output at EL5. 

 

e

 Model lamp designs represent lamps that are not commercially available at this time. DOE developed these lamps 

based on technical literature and confidential information from manufacturers on incandescent design lamp options. 

DOE developed these model lamp designs in order to have a more-continuous range of ELs to analyze across the 

three lumen packages. DOE differentiates between model lamp designs and commercially-available lamp designs 

by showing the wattage of the model lamp design to the tenths decimal place. Commercially-available lamps are 

shown in the same way they appear in the product catalogs, with wattages rounded off to the nearest whole number. f

 Through conversations with technical experts, DOE believes that when operating at 120V, an incandescent 

filament must become thinner as the wattage of the lamp decreases. When operating at 120V below 40 watts, the 

filament becomes so thin that its structural integrity becomes compromised. In an HIR lamp, this lower structural 

integrity causes the filament to produce light in a spot of the reflector lamp that is not ideal for optimum light 

5-71
Table 5.4.4 IRL Engineering Analysis 50W PAR30 

Wattage Efficacy Initial Light 

Output 

Lamp 

Life Efficacy 

Level 

Design 

Option 

Lamp 

Descriptor 

W lm/W lm hr 

Baseline Halogen PAR30 50 12.6 630 3,000 

EL1 

Improved 

Halogen 

(Xenon)* 

PAR30 47.8 13.2 630 3,000 

EL2 Long-Life HIR PAR30 46 13.5 620 6,000 

EL2 

Improved 

Halogen 

(Silver)* 

PAR30 45.0 14.0 630 3,000 

EL3 HIR* PAR30 41.8 15.1 630 3,000 

EL4 Improved HIR PAR30 40 17.0 680 4,000 

EL4 Baseline-Life 

Improved HIR* PAR30 40.0 17.0 680 3,000 

EL5 Improved HIR 

Plus* PAR30 40.0 19.1 765 4,200 

EL5 

Baseline-Life 

Improved HIR 

Plus* 

PAR30 40.0 19.1 765 2,500 

*IRL lamp designs with an asterisk are model lamp designs. 

The following table presents the engineering analysis for the 75W PAR38 IRL baseline 

lamp. This baseline lamp and its lamp design substitutes are based on a 1,050-lumen lamp, plus 

or minus 10 percent. DOE developed three model lamps that match the lumen package of this 

baseline lamp. The 71.7W improved halogen (xenon) PAR38 at EL1 is a model lamp design. 

DOE used information from technical literature and confidential information from manufacturers 

to develop this model lamp. In addition, the 68.8W long-life HIR PAR38 lamp at EL2 is a 

model lamp design. This lamp is based on a 6,000 hour HIR lamp with a different wattage and 

lumen package. DOE used information from technical literature in order to develop a 6,000 hour 

HIR lamp with a 1,050-lumen package. The baseline-life improved 55.0W HIR lamp at EL4 is a 

model lamp design based on a commercially-available improved HIR lamp. The 51.7W 

improved HIR plus PAR38 lamp at EL5 is a model lamp design that DOE created based on 

commercially-available HIR lamps with the same lifetime (4,200 hours). Finally, the baselinelife 51.7W improved HIR plus PAR38 lamp at EL5 is a model lamp design that DOE created to 

have the same lamp lifetime as the baseline lamp (2,500 hours). The improved halogen lamp at 

EL2 and the lamps at EL3 and EL4 are commercially available. 

 

extraction. Because of the loss in efficacy due to the placement of the filament in the HIR capsule, it is not practical 

to produce an HIR IRL below 40W. 

5-72
Table 5.4.5. IRL Engineering Analysis for 75W PAR38 

Wattage Efficacy Initial Light 

Output 

Lamp 

Life Efficacy 

Level 

Design 

Option 

Lamp 

Descriptor 

W lm/W lm hr 

Baseline Halogen PAR38 75 14.0 1,050 2,500 

EL1 

Improved 

Halogen 

(Xenon)* 

PAR38 71.7 14.6 1,050 2,500 

EL2 Long-Life HIR* PAR38 68.8 15.3 1,050 6,000 

EL2 Improved 

Halogen (Silver) PAR38 66 15.9 1,050 3,000 

EL3 HIR PAR38 60 17.5 1,050 3,000 

EL4 Improved HIR PAR38 55 19.1 1,050 4,000 

EL4 Baseline-Life 

Improved HIR* PAR38 55.0 19.1 1,050 2,500 

EL5 Improved HIR 

Plus* PAR38 51.7 20.3 1,050 4,200 

EL5 

Baseline-Life 

Improved HIR 

Plus* 

PAR38 51.7 20.3 1,050 2,500 

*IRL lamp designs with an asterisk are model lamp designs. 

The following table presents the engineering analysis for the 90W PAR38 IRL baseline 

lamp. This baseline lamp and its substitute lamp designs are based on a 1,310-lumen lamp, plus 

or minus 10 percent. The 85.7W improved halogen (xenon) PAR38 at EL1 is a model lamp 

design. DOE used information from technical literature and confidential information from 

manufacturers to develop this model lamp. In addition, the 82.5W long-life HIR PAR38 model 

lamp at EL2 is a model lamp design. This lamp is based on a 6,000 hour HIR lamp with a 

different wattage and lumen package. DOE used information from technical literature in order to 

develop a 6,000 hr HIR lamp with a 1,310 lumen package. The baseline-life and non-baselinelife 66.0W improved HIR PAR38 lamps at EL4 are also model lamp designs. DOE scaled these 

lamp designs from a relationship between the 75W halogen PAR38 and the 55W improved HIR 

PAR38. The improved halogen lamp (silver) at EL2, the HIR lamp at EL3, and the nonbaseline-life improved HIR plus lamp at EL5 are commercially available. The baseline-life 

improved HIR plus lamp at EL5 is a model lamp based on the commercially-available improved 

HIR plus lamp. 

5-73
Table 5.4.6 IRL Engineering Analysis for 90W PAR38 

Wattage Efficacy Initial Light 

Output 

Lamp 

Life Efficacy 

Level 

Design 

Option 

Lamp 

Descriptor 

W lm/W lm hr 

Baseline Halogen PAR38 90 14.6 1,310 2,500 

EL1 Improved 

Halogen* PAR38 85.7 15.3 1,310 2,500 

EL2 Long-Life HIR* PAR38 82.5 15.9 1,310 6,000 

EL2 Improved 

Halogen PAR38 79 16.6 1,310 3,000 

EL3 HIR PAR38 70 18.0 1,260 3,000 

EL4 Improved HIR* PAR38 66.0 19.8 1,310 4,000 

EL4 Baseline-Life 

Improved HIR* PAR38 66.0 19.8 1,310 2,500 

EL5 Improved HIR 

Plus PAR38 60 21.0 1,260 4,200 

EL5 

Baseline-Life 

Improved HIR 

Plus* 

PAR38 60.0 21.0 1,260 2,500 

* IRL lamp designs with an asterisk are model lamp designs. 

5.5 SCALING TO PRODUCT CLASSES NOT ANALYZED 

DOE identified and selected certain product classes as “representative” product classes to 

concentrate its analytical effort. DOE chose these representative product classes primarily due to 

their high market volumes. The following section discusses how DOE scales ELs from the 

analyzed product classes to those product classes that it did not analyze. 

5-74
5.5.1 General Service Fluorescent Lamps 

5.5.1.1 2-foot U-Shaped GSFL With CCTs ≤ 4,500K 

Two-foot U-shaped lamps generally are less efficacious than 4-foot MBP lamps due to 

the bend of a 2-foot U-shaped lamp. This drop in efficacy often depends on the wattage and 

diameter of the lamp in question. DOE assessed manufacturer catalogs containing 

commercially-available 2-foot U-shaped lamps with CCTs less than or equal to 4,500K to 

develop standard levels with a similar technology impact at each EL as 4-foot MBP lamps (see 

section 5.3.1.2 for these technology impacts). DOE used compliance report data for 2-foot Ushaped lamps to determine the efficacies at which commercially-available products would 

comply with standards. Figure 5.5.1 shows all compliance report data for 2-foot U-shaped lamps 

with CCTs less than or equal to 4,500K. The points within the gray circles represent compliance 

report data submitted in 2007 or 2008. 

60.0

65.0

70.0

75.0

80.0

85.0

90.0

95.0

28.0 30.0 32.0 34.0 36.0 38.0 40.0

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

2ft U-Shaped <=4500 HALO

2ft U-Shaped <=4500, 700 SERIES

2ft U-Shaped <=4500, 800 SERIES

Figure 5.5.1 All Compliance Report Data for 2-Foot U-Shaped Lamps with CCTs ≤ 4,500K 

When considering recent compliance report data, as described in section 5.3.1.2, DOE 

found that not enough data existed from compliance reports submitted in 2007 and 2008 to 

justify some of its proposed efficacy levels. Specifically, DOE did not have any compliance 

reports from those years that contained data for U-shaped 34W T12 lamps. Therefore, DOE 

adjusted EL1 through EL3 to reflect the levels proposed by NEMA in response to the March 

5-75
2008 ANOPR. (NEMA, No. 26 at p. 7) For EL4 and EL5, NEMA did not propose levels for Ushaped lamps. Thus, DOE used NEMA’s suggested 8-percent value as a scaling factor from the 

linear 4-foot medium bipin efficacy levels. (NEMA, Public Meeting Transcript, No. 38.4 at pp. 

123-124) The final efficacy levels for 2-foot U-shaped lamps with CCTs less than or equal to 

4,500K are summarized in Table 5.5.1. 

Table 5.5.1 Efficacy Requirements for 2-Foot U-Shaped Lamps With CCTs Less Than or 

Equal To 4,500K 

Efficacy Requirement (lm/W) EL 4-foot MBP 2-foot U-Shaped Reduction 

1 78 70 10.3% 

2 81 72 11.1% 

3 85 76 10.6% 

4 89 84 5.6% 

5 93 87 6.5% 

5.5.1.2 Lamps With CCTs Above 4,500K 

As discussed in section 5.3, DOE did not analyze GSFL with a CCT above 4,500K and 2-

foot U-shaped lamps. As discussed in the market and technology assessment, the efficacy of 

lamps with higher CCT values is lower due to the quality of blue light emitted. A technical 

committee of the National Electrical Manufacturers Association analyzed efficacy levels for 

GSFL product classes and recommended efficacy levels for high CCT lamps.4 DOE assessed 

compliance report data for high-CCT lamps when available and compared compliance report 

data to NEMA’s suggestions. For lamps where there was not sufficient compliance report data, 

DOE adopted NEMA’s suggestions. Utilizing this approach, DOE modified its proposed 

efficacy levels as described below. 

Figure 5.5.2 shows all compliance report data for 4-foot MBP lamps with CCTs greater 

than 4,500K. 

5-76
70.0

75.0

80.0

85.0

90.0

95.0

100.0

24.0 26.0 28.0 30.0 32.0 34.0 36.0 38.0 40.0

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

4ft MBP >4500, 700 SERIES

4ft MBP >4500, 800 SERIES

TSL1 4ft MBP

Figure 5.5.2 All Compliance Report Data for 4-Foot MBP Lamps with CCTs > 4,500K 

Although DOE obtained compliance reports submitted over the past 15 years, DOE only 

considered the most recent data when verifying efficacy levels. DOE believes that data 

contained in compliance reports submitted 2007 and 2008 accurately account for adjustments 

over the past 15 years to photometry facilities used for NIST and NVLAP testing that have 

resulted in a reduction of reported lumens for some products. Figure 5.5.3 only shows 

compliance report data submitted in 2007 and 2008 for 4-foot MBP lamps with CCTs greater 

than 4,500K. 

5-77
70

75

80

85

90

95

100

24.0 26.0 28.0 30.0 32.0 34.0 36.0 38.0 40.0

Rated Lamp Efficacy (lm/W)

Rated Wattage (W)

4ft MBP >4500, 700 SERIES

4ft MBP >4500, 800 SERIES

Figure 5.5.3 2007 and 2008 Compliance Report Data for 4-Foot MBP Lamps with CCTs > 

4,500K 

DOE believes that sufficient data was submitted in 2007 and 2008 to justify its selection of 

efficacy levels for this representative product class and therefore did not adopt the levels 

proposed by NEMA. Table 5.5.2 summarizes the resulting efficacy levels for 4-foot MBP lamps 

with CCTs greater than 4,500K. 

Table 5.5.2 Efficacy Requirements For 4-Foot MBP Lamps With CCTs Above 4,500K 

Efficacy Requirement (lm/W) EL 

CCT ≤ 4,500K CCT > 4,500K 

Reduction 

1 78 77 1.3% 

2 81 79 2.5% 

3 85 82 3.5% 

4 89 88 1.1% 

5 93 92 1.1% 

When considering recent compliance report data for 8-foot lamps, DOE found that not 

enough data existed from compliance reports submitted in 2007 and 2008 to justify some of its 

proposed efficacy levels. Specifically, DOE identified EL1, EL2, and EL5 for 8-foot SP slimline 

5-78
lamps and EL2 for 8-foot RDC HO lamps as lacking sufficiently current data. Therefore, DOE 

adjusted these levels to reflect those levels proposed by NEMA. Table 5.5.3 and Table 5.5.4

summarize the resulting efficacy requirements for 8-foot SP slimline lamps and 8-foot RDC HO 

lamps with CCTs greater than 4,500K, after accounting for compliance data. 

Table 5.5.3 Efficacy Requirements For 8-Foot SP Slimline Lamps With CCTs Above 

4,500K 

Efficacy Requirement (lm/W) EL 

CCT ≤ 4,500K CCT > 4,500K 

Reduction 

1 86 83 3.5% 

2 92 87 5.4% 

3 95 91 4.2% 

4 97 93 4.1% 

5 98 94 4.1% 

Table 5.5.4 Efficacy Requirements For 8-Foot RDC HO Lamps With CCTs Above 4,500K 

Efficacy Requirement (lm/W) EL 

CCT ≤ 4,500K CCT > 4,500K 

Reduction 

1 83 80 3.6% 

2 86 83 3.5% 

3 88 84 4.5% 

4 92 88 4.3% 

5 95 91 4.2% 

NEMA did not provide efficacy level recommendations for 4-foot T5 MiniBP SO and 

HO lamps with color temperatures greater than 4,500K. For this reason, DOE reviewed product 

literature for 4-foot T5 MiniBP SO and HO lamps. By comparing catalog ratings for 4-foot T5 

MiniBP SO and HO lamps with a CCT of 4,100K with similar T5 lamps of a 6,500K CCT, DOE 

determined average efficacy reductions for 4-foot T5 MiniBP SO and HO lamps of high CCT. 

For 4-foot T5 MiniBP SO lamps of high CCT, DOE reduced EL1 by 6.0 percent to 81 lm/W and 

EL2 by 6.0 percent to 85 lm/W. For 4-foot T5 MiniBP HO lamps of high CCT, DOE reduced 

EL1 by 5.0 percent to 72 lm/W. Table 5.5.5 and Table 5.5.6 show the efficacy levels for these 

lamps. 

5-79
Table 5.5.5 Efficacy Requirements For 4-Foot T5 MiniBP SO Lamps With CCTs Above 

4,500K 

Efficacy Requirement (lm/W) EL 

CCT ≤ 4,500K CCT > 4,500K 

Reduction 

1 86 81 6.0% 

2 90 85 6.0% 

Table 5.5.6 Efficacy Requirements For 4-Foot T5 MiniBP HO Lamps With CCTs Above 

4,500K 

Efficacy Requirement (lm/W) EL 

CCT ≤ 4,500K CCT > 4,500K 

Reduction 

1 76 72 5.0% 

For 2-foot U-shaped lamps with CCTs above 4,500K, DOE lacked sufficiently current 

compliance report data to justify its proposed efficacy levels. NEMA recommended minimum 

efficacy requirements for EL1 through EL3 only. NEMA, however, also suggested a general 

scaling factor from linear 4-foot medium bipin levels for U-shaped lamps.5

 DOE used NEMA’s 

suggestions to derive the efficacy levels for 2-foot U-shaped lamps with CCTs greater than 

4,500K, as DOE did not have enough compliance data for such lamps to adequately assess 

manufacturing variability of existing products on the market. 

Table 5.5.7 Efficacy Levels For 2-Foot U-Shaped Lamps With CCTs Greater Than 4,500K 

Efficacy Requirement (lm/W) EL 

CCT ≤ 4,500K CCT > 4,500K 

Reduction 

1 70 65 7.1% 

2 72 67 6.9% 

3 76 71 6.6% 

4 84 81 3.6% 

5 87 85 2.7% 

5.5.2 Incandescent Reflector Lamps 

5.5.2.1 Modified-Spectrum IRL 

DOE analyzed standard-spectrum lamps, but set separate standards for modifiedspectrum IRL. As with higher CCT GSFL, modified-spectrum IRL achieve their modified 

spectra through selective filtering of the spectra, thereby inherently lowering their efficacies. 

Manufacturers achieve this specific spectrum in modified-spectrum IRL by applying a coating, 

or introducing neodymium or other additives into the cover glass of the IRL. Manufacturers may 

change the thickness of the coating or the content of neodymium to modify the spectrum to 

different degrees, and this modification changes the lumen output of the IRL. DOE assessed the 

efficacy differences between standard- and modified-spectrum IRL by measuring the efficacies 

5-80
of commercially-available standard- and modified-spectrum lamps. DOE correlated the 

measured color point data of the lamps with lamp light output reduction and lamp spectral power 

distribution. By analyzing the data, DOE established that a reduction of 15% from the standardspectrum efficacy levels would be appropriate for modified-spectrum IRL. Table 5.5.8 shows a 

summary of the ELs for modified-spectrum IRL with diameters greater than 2.5 inches and 

operating voltages less than 125V. See appendix 5C for further details on DOE’s modifiedspectrum IRL analysis. 

Table 5.5.8 Summary of the ELs for Modified-Spectrum IRL With Diameters Greater 

Than 2.5 Inches and Operating Voltages Less Than 125V 

Efficacy Requirement (lm/W) EL 

Standard Spectrum Modified Spectrum Reduction 

1 4.6P0.27 3.9P0.27 15.0% 

2 4.8P0.27 4.1P0.27 15.0% 

3 5.4P0.27 4.6P0.27 15.0% 

4 5.9P0.27 5.0P0.27 15.0% 

5 6.4P0.27 5.4P0.27 15.0% 

P = rated wattage 

5.5.2.2 IRL With Diameters Less Than or Equal To 2.5 Inches 

A smaller-diameter IRL has an inherently lower optical efficacy than a larger-diameter 

lamp given a similar filament size. To determine an appropriate scaling factor for IRL with 

diameters less than or equal to 2.5 inches, DOE examined the inherent efficacy differences 

between the PAR20 lamp and its PAR30 or PAR38 counterpart by comparing catalog efficacy 

data of each lamp type from several lamp manufacturers. In its analysis, DOE found that the 

reduction in efficacy caused by the reduction in lamp diameter was approximately 12 percent for 

IRL. DOE thus established EL1 through EL3 small-diameter IRL requirements that are 12 

percent less than the efficacy requirements for large-diameter IRL. 

DOE developed EL4 and EL5 for large-diameter IRL based on IRL that featured a 

double-ended HIR capsule. Single-ended capsules feature a lead wire inside of the capsule that 

carries current between the filament and the electrical connection in the IRL’s base. The 

presence of this wire inside of the capsule prevents a certain amount of energy from reaching the 

capsule wall and being reflected (recycled) back to the capsule filament. A double-ended burner, 

on the other hand, features a lead wire outside of the capsule, where it does not interfere with the 

reflectance of energy from the capsule wall back to the capsule filament. The double-ended HIR 

capsule configuration does not generally fit into a PAR20 lamp due to its reduced size, however. 

Thus, DOE developed the EL4 and EL5 efficacy requirements for small-diameter IRL by 

assuming that the double-ended burner technology could not be used. In order to determine the 

efficacy reduction that would result from using a single-ended burner instead of a double-ended 

burner in a lamp, DOE obtained a commercially-available single-ended HIR capsule and 

measured the location of the lead wire inside of the capsule. DOE then developed a model that 

computed how much energy is prevented from being reflected against the capsule wall and 

recycled due the the “shadowing effect” of the lead wire inside of the capsule. DOE was also 

5-81
able to determine the slight change in IRL power consumption due to the reduction in energy 

recycling. Finally, DOE simulated manufacturing variability by modeling the effects of 

changing the capsule dimensions and lead wire positioning by small amounts. Using the 

modeled data, DOE computed that an efficacy reduction of approximately 3.5 percent would 

result from the usage of a single-ended burner instead of a double-ended burner in a lamp. This 

3.5-percent reduction is in addition to the 12-percent-lower optical efficacy featured by smalldiameter IRL in comparison with large-diameter IRL. 

Table 5.5.9 shows a summary of the ELs for standard-spectrum IRL with diameters less 

than or equal to 2.5 inches and operating voltages less than 125V. 

Table 5.5.9 Summary of the ELs for Standard-Spectrum IRL With Diameters Less Than 

or Equal To 2.5 Inches and Operating Voltages Less Than 125V 

Efficacy Requirement (lm/W) EL 

≥ 2.5 Inches < 2.5 Inches 

Reduction 

1 4.6P0.27 4.0P0.27 12.0% 

2 4.8P0.27 4.2P0.27 12.0% 

3 5.4P0.27 4.8P0.27 12.0% 

4 5.9P0.27 5.0P0.27 15.5% 

5 6.4P0.27 5.4P0.27 15.5% 

P = rated wattage 

5.5.2.3 IRL With Operating Voltages Greater Than or Equal to 125 Volts 

As discussed in chapter 3, the Market and Technology Assessment, 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. In 

consideration of the different test procedures for IRL rated at 130V than those rated at 120V, and 

by using published manufacturer literature, confidential information on incandescent design, and 

equations from the IESNA Lighting Handbook,

6

 DOE derived an efficacy scaling factor which 

would result in equivalent performance of both classes of IRL when operating under the same 

voltage conditions (as they most often are). The equations DOE used from the IESNA lighting 

handbook are as follows: 

d

volts

VOLTS

LIFE

life  )( Eq. 5.2 

k

VOLTS

volts

LUMENS

lumens  )( Eq. 5.3

n

VOLTS

volts

WATTS

watts  )( Eq. 5.4

Capital letters represent normal rated values while lower-case letters represent changed 

values. By using published manufacturer literature on IRL lumen, wattage, and voltage ratings, 

5-82
DOE found that the most typical values for d, k, and n in the above equations for the IRL 

analyzed are as follows: d=8.7, k=3.4, n=1.6. From this information and confidential 

information on incandescent lamp design, DOE was able to determine that a lamp operating at 

130V would be 15-percent more efficacious than a lamp of a similar wattage operating at 120V. 

Therefore, DOE implements a 15-percent increase in the efficacy requirement for lamps rated 

with a voltage greater than or equal to 125V. Table 5.5.10 shows a summary of the ELs for 

standard spectrum IRL with diameters greater than 2.5 inches and operating voltages greater than 

or equal to 125V. 

Table 5.5.10 Summary of the ELs for Standard Spectrum IRL With Diameters Greater 

Than 2.5 Inches and Operating Voltages Greater Than or Equal to 125V 

Efficacy Requirement (lm/W) EL 

< 125 Volts ≥ 125 Volts 

Increase 

1 4.6P0.27 5.3P0.27 15.0% 

2 4.8P0.27 5.5P0.27 15.0% 

3 5.4P0.27 6.2P0.27 15.0% 

4 5.9P0.27 6.8P0.27 15.0% 

5 6.4P0.27 7.4P0.27 15.0% 

P = rated wattage 

5.6 SUMMARY OF ALL EFFICACY LEVELS FOR COVERED PRODUCTS 

5.6.1 Summary of All Efficacy Levels for Covered GSFL 

Table 5.6.1 shows a summary of the efficacy levels for all general service fluorescent 

lamps affected by this rulemaking. The table shows the ELs for GSFL with CCTs less than as 

well as greater than/equal to 4,500K; the table also shows the associated ELs for 2-foot U-shaped 

lamps. “N/A” is shown where no ELs exist, such as for T5 lamps (which do not have five ELs). 

Representative product classes are shown in grey squares. 

5-83
Table 5.6.1 Summary of All Efficacy Levels for Covered GSFL 

Efficacy Level CCT Lamp Type 1 2 3 4 5 

4-foot medium bipin 78 81 85 89 93 

2-foot U-shaped 70 72 76 84 87 

8-foot single pin 

slimline 86 92 95 97 98 

≤ 4,500K 8-foot recessed double 

contact HO 83 86 88 92 95 

4-foot T5 miniature 

bipin SO 86 90 N/A N/A N/A 

4-foot T5 miniature 

bipin HO 76 N/A N/A N/A N/A

4-foot medium bipin 77 79 82 88 92 

2-foot U-shaped 65 67 71 81 85 

8-foot single pin 

slimline 83 87 91 93 94 

> 4,500K 8-foot recessed double 

contact HO 80 83 84 88 91 

4-foot T5 miniature 

bipin SO 81 85 N/A N/A N/A

4-foot T5 miniature 

bipin HO 72 N/A N/A N/A N/A

5.6.2 Summary of All Efficacy Levels for Covered IRL 

Table 5.6.2 shows a summary of the coefficients of the efficacy levels for all 

incandescent reflector lamps affected by this rulemaking. The various combinations of IRL 

features such as standard-spectrum vs. modified-spectrum, diameters greater than or less 

than/equal to 2.5 inches, and operating voltages greater than/equal to or less than 125V are 

shown in the table. The representative IRL product class is shown in grey squares. 

5-84
Table 5.6.2 Summary of Coefficients for All Efficacy Levels for Covered IRL 

Efficacy Level Lamp Type Diameter Voltage 1 2 3 4 5 

≥ 125V 5.3 5.5 6.2 6.8 7.4 

> 2.5 inches 

< 125V 4.6 4.8 5.4 5.9 6.4 

≥ 125V 4.7 4.9 5.5 5.7 6.2 

Standardspectrum 

≤ 2.5 inches 

< 125V 4.0 4.2 4.8 5.0 5.4 

≥ 125V 4.5 4.7 5.3 5.8 6.3 

> 2.5 inches 

< 125V 3.9 4.1 4.6 5.0 5.4 

≥ 125V 4.0 4.1 4.6 4.9 5.3 

Modifiedspectrum 

≤ 2.5 inches 

< 125V 3.4 3.6 4.0 4.2 4.6 

5-85
5-86

 

REFERENCES 

1 National Electrical Manufacturers Association. 2006. No. 12 at p. 7. This written comment, 

Document Number 12, is available in Docket #EE–2006–STD–0131. For more information, 

contact Brenda Edwards-Jones at (202) 586-2945. 

2

 U.S. Department of Energy, Energy Efficiency and Renewable Energy Office of Building 

Research and Standards. U.S. Department of Energy, Office of Energy Efficiency and 

Renewable Energy. Energy Conservation Program for Consumer Products: Technical Support 

Document: Energy Efficiency Standards for Consumer Products: Fluorescent Lamp Ballast 

Proposed Rule. Appendix B. Marginal Energy Prices and National Energy Savings. Table B.6. 

January, 2000. Washington, D.C. 

<http://www.eere.energy.gov/buildings/appliance_standards/residential/pdfs/appendix_b.pdf. 

3

 Codes and Standards Enhancement (CASE) Initiative For PY2008: Title 20 Standards 

Development. Analysis of Standards Options for Linear Fluorescent Fixtures. Prepared for: 

PG&E Prepared by: ACEEE, Lighting Wizards, and Energy Solutions Last Modified: May 14, 

2008. 

4 National Electrical Manufacturers Association. 2008. No. 26 at p. 7. This written comment, 

Document Number 26, is available in Docket #EE–2006–STD–0131. For more information, 

contact Brenda Edwards-Jones at (202) 586-2945. 

5 National Electrical Manufacturers Association. 2009. No. 37 at pp. 123-124. This public 

meeting transcript, Document Number 37, is available in Docket #EE–2006–STD–0131. For 

more information, contact Brenda Edwards-Jones at (202) 586-2945. 

6

 Rea, M. S., ed., The IESNA Lighting Handbook: Reference and Application, 9th Edition. New 

York: Illuminating Engineering Society of North America. IESNA (2000).