Oh Say, Can You See?

By Gersil N. Kay | Apr 15, 2003




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A closer look at fiber optic lighting

Now that energy conservation, with mandated controls and wattage restrictions, is the law of the land (ASHRAE/IESNA Standard 90.1), electrical contractors will seek the most practical ways to save electricity. The lighting alone in commercial/institutional/industrial buildings can use up to 45 percent of a structure’s available electricity.

Today, in addition to the conventional lighting products mentioned in the standard, there are newer energy-efficient technologies. When the most energy-efficient sources available are used for the application, then, even if the limitations are ignored or avoided, energy will still be saved. If some practitioners are unaware of these recent developments, and they are not yet mentioned in the standard, they will not be used, causing non-compliance.

These exceptionally energy-efficient lighting methods include rigid light pipe, for ambient or decorative light in large areas; and flexible glass fiber optics for both directional and ambient illumination. Either can be used indoors or out. Savings in installation, maintenance and operation can be obtained as quickly as two to four years, depending upon the sophistication of design.

Also, there is the recent European-developed DALI (Digital Addressable Lighting Interface), designed to conserve energy by selective dimming either when daylight is available, or when the space becomes unoccupied. Local room control and interfacing with building management systems are features. But ceilings filled with these fixtures only give ambient (general), not task illumination. So far, DALI is best suited for very large installations, which require complicated wiring. If used, the “green” DALI fixtures themselves contain digital dimming ballasts.

The glass fiber optics technology, based on the physical principle of total internal reflection, offers the easiest way of compliance where directional (spotlight) rays are needed for task or display. This source/system is well-suited for pre-1940 buildings. Historically, those structures have plenty of interstitial space (between walls, floors and ceilings) within which to insert modern mechanical/electrical systems. Actually, because glass fiber optics is so thin and flexible, and employs miniaturized collimating and diffusing fittings, it does not impact any décor, new or old.

Light is essential to see or do anything, so providing good lighting almost always guarantees profitable repeat business. Bad lighting is ubiquitous, unproductive, uncomfortable and costly. For example, if the illumination is inadequate, people viewing exhibitions complain about light dimmed to protect from prolonged exposure from destructive infrared and ultraviolet rays on fugitive organic materials (wood, paper, textiles, leather, lacquer, etc.). There are no such emissions from long-lasting glass or temporary plastic fiber optics. In fact, its use substantially delays the inevitable drying out and fading by all light. How many office workers go home with headaches from glare on computer screens or flickering overhead fluorescents? Under poor illumination, shoppers may not be able to accurately discern the color of the items they consider purchasing. Quality suffers if factory staff on a production line has to work under hot lights that still don’t allow them to see details closely. Maintenance everywhere is usually expensive and disruptive.

Contrary to the rest of the world, in the United States, when someone mentions fiber optics, the communications type is presupposed. The lighting version is completely different. That is why the National Electrical Contractors’ Association (NECA) has requested a Standard (NEIS #503) for the installation of glass fiber optics lighting. This document is intended to assist energy conservation by acquainting contractors and designers with this practical lighting tool, and codifying the criteria for its installation.

While installation of glass fiber optics is just another lighting job, knowing the differences between it and conventional products before design and installation, will save the installing contractor considerable time, money and problems. For one thing, the harnesses of glass light guides are delivered completely assembled, ready to be inserted into the illuminator. There is no cutting, polishing or slicing involved. The estimator only has to calculate the finite figure of how long it will take to fish the glass “tails.” This is the same effort required for copper wire in any traditional system.

Often, the electrical contractor, rather than a supposedly “expensive” lighting designer, is called upon to design/build the lighting. Even then, initially using a competent outside fiber optics consultant to guide the contractor will be rewarding. This is because first-time users may make unnecessary and unprofitable mistakes until they pass the learning curve and get initial experience with the components.

Echoing NECA, and recognizing the huge potential market in retrofitting to comply with the new energy restrictions, the Philadelphia Chapter of the International Brotherhood of Electrical Workers (IBEW) has developed a Lighting Demonstration lab for hands-on experience with glass fiber optics. Electricians readily take to this technology, and enjoy working with it because they can freely use their innate curiosity and inventiveness. Knowing the team approach is the best solution, the IBEW has opened the lab to contractors, architects, engineers, interior and lighting-designers for introductory free courses in the system. The American Society of Interior Designers (ASID) has had a course for years.

- Fiber optics employs a two-part system, rather than a single lamp as the source. With this technology, the lamp alone is useless without the light guides bringing the illumination to exactly where needed. Similarly, the harness of light guides is no good without the lamp providing the light. Thus, both components are essential to give light, making this system a source. It stands to reason that one lamp powering multiple points of equal-level light conserves more energy than using many such lamps for the same purpose.

-The metal halide lamp, usually used in light pipe and fiber optics, is the type that sends all light rays directly straight ahead. It is much more energy-efficient than most other known sources.

-Realistically, at least two levels of light are needed in every area—one, so as not “to fall over the furniture,” and the other for functional task and display. In addition to the usual retail, office work and museum applications, varying light levels are needed for other purposes like storage, cleaning, security, circulation and even restrooms. In effect, having directional and ambient illumination (one lower than the other) offers yet another way of conserving energy.

-While the physical principle of total internal reflection has been known for centuries, and employed abroad for decades, it has not been widely adopted, where suitable, in this country, even though it is the most energy-efficient system yet known.

In some states, as well as profit for the installer, there are customer rewards for installing energy-efficient lighting, either through money up front, or with monthly rebates. Therefore, it is worthwhile to investigate incentives from utilities and local, state or federal agencies. However, energy conservation must always be balanced with productivity. This can be represented by increased sales, job performance, attendance, and personal comfort, all of which lead to the contractor’s future business and profits. EC

KAY is president of Conservation Lighting International Ltd. in Philadelphia. She can be reached at 215.568.0923.


About The Author

Gersil Kay is president of Conservation Lighting International Ltd. in Philadelphia. She can be reached at 215.568.0923.





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