5A-i

APPENDIX 5A. FOUR-FOOT T5 MINIATURE BIPIN HIGH OUTPUT MODEL 

LAMP 

TABLE OF CONTENTS 

5A.1 INTRODUCTION .................................................................................................. 5A-1

5A.2 METHODOLOGY AND RESULTS ..................................................................... 5A-1

LIST OF TABLES 

Table 5A.2.1 Four-foot T5 MiniBP HO Baseline Lamp .......................................................... 5A-2

Table 5A.2.2 Reduced Wattage Four-Foot T5 MiniBP HO Analyzed ..................................... 5A-2

Table 5A.2.3 Performance Characteristics for Modeled Higher Efficacy, Full Wattage 

Four-Foot T5 MiniBP HO Lamp ................................................................ 5A-3
5A-1

APPENDIX 5A. FOUR-FOOT T5 MINIATURE BIPIN HIGH OUTPUT MODEL 

LAMP 

5A.1 INTRODUCTION 

 As discussed in chapter 5 of this preliminary technical support document (TSD), the U.S. 

Department of Energy (DOE) selects higher efficacy lamps as replacements for each baseline 

lamp identified in the engineering analysis. After identifying more efficacious substitutes, DOE 

develops candidate standard levels (CSLs). For this rulemaking DOE only considered CSLs at 

which a full wattage version of the lamp type was available because reduced wattage lamps have 

limited utility. Manufacturer feedback indicated that reduced wattage lamps have problems 

starting in cold temperature applications below 60-65 °F and may also exhibit striations in this 

temperature range. In manufacturer interviews, it was noted that striations remain an issue for 

reduced wattage lamps because not all ballasts contain striation control circuitry, and those that 

are equipped with striation control circuitry do not completely eliminate striation. After 

conducting a review of commercially available products, DOE determined that only reduced 

wattage versions of 4-foot T5a miniature bipin (MiniBP) high output (HO) lamps are available at 

efficacies higher than the baseline. Because DOE believes a higher efficacy, full wattage T5 

MiniBP HO lamp can be manufactured using commercially available technologies, DOE 

developed a higher efficacy, full wattage T5 MiniBP HO model lamp for this product class. The 

following section describes in greater detail how DOE developed performance characteristics for 

this product. 

5A.2 METHODOLOGY AND RESULTS

 General service fluorescent lamps (GSFLs) with T5 diameters exist in a variety of lengths 

and wattages. Market research indicates that 4-foot T5 MiniBP HO lamps are offered with a 

wattage of 54 watts (W) and reduced wattages of 50 W, 49 W, and 47 W. DOE’s market 

research and feedback from manufacturers indicate that the primary drivers of 4-foot T5 MiniBP 

HO market growth are their use as replacement lamps for 8-foot recessed double contact (RDC) 

HO and high intensity discharge (HID) lamps in the industrial sector. 

 As stated in chapter 5 of this TSD, DOE selected a 54 W 4-foot T5 MiniBP HO lamp as a 

baseline because it is representative of the most common, least efficacious lamp in the 4-foot T5 

MiniBP HO representative product class. Table 5A.2.1 lists the characteristics of the 54 W 4-foot 

T5 MiniBP HO baseline lamp. 

 

a

 Fluorescent lamp diameter is given in eighths of an inch. Thus, a T5 lamp is 5/8 of an inch in diameter. 
5A-2

Table 5A.2.1 Four-foot T5 MiniBP HO Baseline Lamp

Lamp 

Diameter

Nominal 

Wattage

Rated 

Wattage

Rated 

Efficacy

(at 35 °C)

Initial 

Light 

Output

(at 35 °C)

Mean 

Light 

Output

(at 35 °C)

Rated 

Life

(PS) CRI

CCT

W W lm/W lm lm hr K

T5 54 53.8 92.9 5,000 4,850 24,000 82 4,100

 DOE surveyed the product offerings for the 4-foot T5 MiniBP HO product class and 

found that no full wattage (54 W) lamps exist with efficacies higher than the baseline. However, 

DOE noted that several reduced wattage lamps with efficacies higher than the baseline are 

commercially available. DOE utilized the characteristics of these commercially available 

reduced wattage T5 MiniBP HO lamps to model an improved full wattage lamp. 

 After reviewing all reduced wattage products, DOE decided to model a more efficacious 

54 W T5 MiniBP HO lamp with an efficacy equivalent to the least efficacious, commercially 

available reduced wattage lamp. DOE only considered lamps that had all performance 

specifications available (i.e., wattage, initial lumen output at 35 °C, mean lumen output at 35 °C, 

rated lifetime, color rendering index [CRI], and correlated color temperature [CCT]) for this 

analysis. Of these lamps, DOE selected the reduced wattage lamp with the lowest efficacy (based 

on rated initial lumen output at 35 °C) to develop the model lamp. Table 5A.2.2 shows the 

specifications of the 47 W reduced wattage lamp with an efficacy of 97.3 lumens per watt 

(lm/W), which was the least efficacious commercially available reduced wattage lamp identified. 

Table 5A.2.2 Reduced Wattage Four-Foot T5 MiniBP HO Analyzed

Lamp 

Diameter

Nominal 

Wattage

Rated 

Wattage

Rated 

Efficacy

(at 35 °C)

Initial 

Light 

Output 

(at 35 °C)

Mean 

Light 

Output 

(at 35 °C)

Rated 

Life

(PS) CRI

CCT

W W lm/W lm lm hr K

T5 47 47 97.3 4,575 4,255 30,000 82 4,100

 DOE then calculated the initial lumen output required to achieve a rated efficacy 

equivalent to that of the selected reduced wattage lamp (i.e., 97.3 lm/W) given a rated wattage of 

53.8 W (the ANSI rated wattage for a 54 W T5 MiniBP HO lamp). Rated efficacy is calculated 

as catalog initial lumen output divided by ANSI rated wattage. For lamp types that do not have a 

defined ANSI rated wattage (e.g., the 47 W 4-foot T5 MiniBP HO), DOE utilized the lamp’s 

nominal wattage to calculate rated efficacy. Next, DOE determined the mean lumen output of the 

modeled lamp by applying the ratio of mean lumen output to initial lumen output of the reduced 

wattage lamp at 35 °C to the initial lumen output of the modeled higher efficacy, full wattage 

lamp. DOE assumed the same lifetime, CRI, and CCT for the modeled lamp. The resulting 

specifications of the higher efficacy, full wattage 4-foot T5 MiniBP HO lamp are shown in Table

5A.2.3.
5A-3

Table 5A.2.3 Performance Characteristics for Modeled Higher Efficacy, Full Wattage 

Four-Foot T5 MiniBP HO Lamp

Lamp 

Diameter

Nominal 

Wattage

Rated 

Wattage

Rated 

Efficacy

(at 35 °C)

Initial 

Light 

Output 

(at 35 °C)

Mean 

Light 

Output 

(at 35 °C)

Rated 

Life

(PS) CRI

CCT

W W lm/W lm lm hr K

T5 54 53.8 97.3 5,237 4,871 30,000 82 4,100