Lighting Research Center Lighting Research Center
    Volume 6 Issue 1
July 2002    
What T5 lamps are available?

T5 lamps are available for standard output and high output. The wattages for standard T5 lamps are 14, 21, 28, and 35 watts. The high-output T5 (T5 HO) lamps are available in 24, 39, 54, and 80 watts (49-watt T5 HO lamps are also available from GE Lighting). Table 1-2 summarizes the features of the standard T5 and T5 HO lamps available in the United States. A four-foot long, 54-watt version that delivers 5,000 lumens is popular in the United States. The high light output allows fewer luminaires to achieve the same illuminance levels as when using other fluorescent lamps. As Table 1-2 shows, however, T5 HO lamps are slightly less efficacious than standard T5 lamps.

Table 1-3 illustrates features of four-foot standard T8 and T12 lamps. Standard T5 and T5 HO lamps have a rated average lamp life of 20,000 hours, the same as most standard T8 and T12 lamps. New prolonged-life T8 and T12 lamps have lives of 4,000 to 10,000 hours longer than T5 lamps. (Table 1-3 excludes these lamps.) The lamps in Table 1-2 all use RE80, a rare earth phosphor with a color rendering index (CRI) value of 85.

Table 1-2. T5 and T5 HO Lamps
(From manufacturers' catalogs; Philips Lighting 2001/2002; GE Lighting 2001/2002)

Lamp Type Nominal Length CCT Light Output* (lm) Lamp Efficacy**
   (in) (K)
(lm/W)
  Initial Mean  

T5 14W 22 3,000-6,500 1,350 1,269-1,275 96
T5 21W 34 3,000-6,500 2,100 1,974-2,000 100
T5 28W 46 3,000-6,500 2,900 2,726-2,750 104
T5 35W 58 3,000-6,500 3,650 3,431-3,450 104

T5 HO 24W 22 3,000-6,500 2,000 1,880-1,895 83
T5 HO 39W 34 3,000-6,500 3,500 3,290-3,320 90
T5 HO 54W 46 3,000-6,500 5,000 4,700-4,740 93
T5 HO 80W 58 3,000-6,500 7,000 6,580-6,650 88



Table 1-3. Four-Foot T8 and T12 Lamps
(From manufacturers' catalogs; Philips Lighting 2001/2002; GE Lighting 2001/2002)

Lamp Type Nominal Length Phosphor* CCT CRI Light Output** (lm) Lamp Efficacy**
  (K)  
  (in)   Initial Mean (lm/W)

T12 40W 48 RE70 3,000-6,500 70-75 3,050-3,250 2,775-2,950 81

48 RE80 3,000-5,000 80-82 2,200-3,400 1,775-3,090 85

T12 34W 48 RE70 3,000-6,500 70-75 2,650-2,800 2,430-2,520 82

48 RE80 3,000-5,000 80-82 2,025-2,900 1,775-2,610 85

T8 32W 48 RE70 3,000-6,500 75-78 2,700-2,850 2,550-2,710 89

48 RE80 3,000-5,000 86 2,800-2,950 2,660-2,800 92



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