26mm-Diameter Linear Fluorescent Lamps
(also called T8)
The most standard linear fluorescent lamps in Europe. Diameter of 26 mm.
Performance: The T8 is among the most efficient fluorescent source. In addition, their cost is now lower than the costs for T12 lamps.
T8 lamps are available with three different types of phosphor coatings:
Coating with halophosphate phosphors: The halophosphates have been used for many years, but have the disadvantage that good colour rendering can only be achieved at the expense of reduced efficacy. Colour rendering ranges from 50 to 75.
Coating with three-band phosphors (or triphosphors): these phosphors achieve both good colour rendering and high efficacy; however they are more expensive than the older halophosphates. Colour rendering ranges from 80 to 85.
Coating with multiband phosphors: very high colour rendering, but this has only been achieved with some reduction in efficacy compared with the triphosphor lamps. Colour rendering of 90 and above.
During the life of a fluorescent lamp, the phosphors age and the light output decreases. The two latter coatings age more slowly than the halophosphates; these lamps therefore have improved lumen maintenance.
The halophosphate type 26mm lamps produce approximately the same light output as the 38 mm diameter lamps of the same length and colour, but consume around 8% less energy. The Triphosphor type version not only consumes around 8% less energy but also produces approximately 10% more lumens and has a higher Colour Rendering Index. This latter version shall therefore be preferred.
Applications: The 26 mm diameter fluorescent tubes have replaced the 38 mm diameter tubes as the standard for new installations.
The T8 triphosphor lamps are suitable for applications where good colour rendering is required (e.g. offices).
The very high colour rendering multiband phosphor lamps are most suitable for lighting in galleries, museums, art shops, etc. and other applications where very high colour rendering is required.
10 – 58 Watt
2700 – 6500 Kelvin
50 – 98
100 lm/W (triphosphor on electronic ballast)
97 lm/W (triphosphor on electromagnetic ballast)
77 lm/W (halophosphate on electromagnetic ballast)