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Business: Industrial


High-Bay Lighting

Purchasing Tips

Tip No. 1

Because of the variability in costs over time and across markets, the key is to have a knowledgeable person without a vested interest in one of the light options analyse the relative cost-effectiveness of high-bay lighting options when selecting systems.

Tip No. 2

Design a system that meets the specific needs of your space and the financial parameters of the project.

Tip No. 3

Avoid the tendency to use a familiar set of hardware rather than taking advantage of new technology where costs and benefits warrant.

Tip No. 4

T5 lamps should not be retrofitted into luminaires designed for other fluorescent lamps such as T8 and T12. The lamps use different ballasts.

Tip No. 5

Compare not only the lamp efficiency, but also the lumen maintenance and the colour rendering. Table 2 ranks lamps according to their energy efficiency and provides information on lumen maintenance, colour rendering index and rated life.

Table 2
Ranking of lamps from most efficient to least efficient, with typical characteristics


Efficacy (lumens/watt) Lumen Maintenance Colour Rendering Index Rated Life (hours)
High-pressure sodium 110 0.9 20 18 000 to 30 000
T5 HO 80 0.94 82 20 000
Metal halide 78 0.82 or less 65–70 15 000 to 20 000
Mercury Vapour 60 0.70 45 24 000+

Lumen maintenance is a measure of how well the lamp maintains its brightness over time. The higher the lumen maintenance, the better.

The colour rendering index is a measure to compare colour quality among lamps that emit light in the same colour range. The index has a maximum value of 100. A value of 85 or better is preferable where colour distinction is significant. This can be important in commercial and industrial spaces (e.g., when working with coloured products or colour-coded wiring). Although high-pressure sodium lights have the highest efficiency, the colour rendering is poor.

Next: Operation and Maintenance Tips