Illuminating DC Lighting

Apr 01, 2007 9:30 PM  By

A brightly lit facility not only helps reduce fatigue and errors, but it also helps foster a friendlier and more orderly work environment.

Early distribution center lighting was provided by traditional incandescent bulbs. These bulbs were replaced by more energy-efficient and brighter fluorescent tubes. While still used in some older facilities, tube lighting was largely replaced by larger round lights known as metal halide fixtures.

More recently, there has been a transition to a newer generation of energy-efficient fluorescent tube lights known as T5HO lighting (the “HO” stands for “high output”). These lights differ from their predecessors in two important ways: The bulbs have a smaller diameter and use less energy than comparable bulbs from the older lights, and the reflectors are designed to direct the light to exactly and only the places where it is needed, reducing the overall number of lights required.

The new fluorescent tube lights have several advantages over the metal halide lights. They require 30%-70% less power to produce the same lighting levels and need hardly any time or energy to warm up to a reasonable brightness level. For this reason, motion sensors can be deployed in low-travel areas to further reduce power consumption. And if there is a momentary power glitch, the lights come right back on, rather than taking several minutes.

Another advantage of the tube lights is that they retain their lumen levels much longer than the metal halide lights do, retaining 95% of their efficiency over their rated life. Metal halide lights lose about 33% of their brightness after running for just 40% of their rated life.

The new T5HO lights can be engineered to provide even more light for less money by combining different reflector patterns and varying number of tubes in each light. They are also much easier to replace than the metal halide type.


Sam Flanders is president of Durham, NH-based Warehouse Management Consultants.