Task Lighting Solutions: Their Economic and Ergonomic Benefits

Supported by human factors research and driven by demand for energy savings, task lighting is a critical component of efficient and effective workplace lighting solutions.
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Karin Tetlow

Lighting Needs Change As We Age

Equally significant to the fact that different tasks require different amounts of lighting is that actual lighting needs vary among individuals.

The older we get, the more light we need to see. Research indicates that the visual performance of those in their 20s is about eight times better than those in their 60s, almost four times better than those in their 50s. In fact, persons in their 60s require 250 percent more contrast than persons in their 20s.

The increased need for light is due to a number of physiological changes in our visual system, which occur as we age. The term presbyopia means "old eye" and is a vision condition involving the loss of the eye's ability to focus on close objects. An additional symptom is the declining ability of the eye to receive light. Symptoms are usually noticeable by age 45 and continue to develop until the process stabilizes some 10−20 years later.

Eyestrain and accompanying headaches, which can result from working under inadequate illumination, are aggravated by aging. Eye fatigue may result in blurry vision and dim lighting aggravates the problem. Task lighting allows us to achieve the correct levels of illumination, regardless of the task or vision requirements, by changing the distance between the light source and the lit object-closer for more light, further away for less. It also allows us to correctly position the angle of light to eliminate glare and ceiling reflections.

Bulb Options and Energy Effciency

Today's task lights utilize one of four types of lighting: incandescent, halogen, compact fluorescent or light-emitting diode (LED or solid-state lighting), which works by running electricity through a chemical chip, causing the chip to glow. Compact fluorescents burn cooler and have proven to be more energy efficient than any other available task light source. A regular incandescent or halogen bulb works by heating a metal wire to a temperature at which it glows. This requires high temperatures, relatively large amounts of energy, and creates a hot bulb surface. In fact, halogen bulbs can reach temperatures of 1,800 degrees Fahrenheit and have, therefore, been banned from many university dormitories because of their risk as a fire hazard.

A compact fluorescent bulb is a low-pressure mercury, electric- discharge lamp in which phosphor coating transforms ultraviolet energy, created by electric discharge, into visible light. The fluorescent bulb remains much cooler and uses less energy than a regular fluorescent or halogen bulb, while providing the same amount of light.

Lower ambient lighting plus a task lamp provides appropriate lighting for viewing computer screens and reading documents.

The first practical electric lamp, developed by Thomas Edison in 1879, converted less than one percent of electricity into light. Today's household incandescent bulbs convert 6−7 percent of their electrical input into light. The rest is wasted as heat. Classic 4-ft fluorescent systems convert approximately 19 percent of their energy into light.

Today's compact fluorescent lamps, five inches in length, or less, can be 50 times more efficient than Edison's original lamp and far more efficient than an incandescent light source capable of the same light output. For example, a 13-watt compact fluorescent task light will produce the same light output as a 60-watt incandescent light, burn cooler and consume only one-quarter of the electricity.

 

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Originally published in Architectural Record.
Originally published in November 2007

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