Beyond the Basics: Holistic Lighting Solutions

By Barbara Horwitz-Bennett, Contributing Editor -- Consulting-Specifying Engineer, 3/1/2005

Experts discuss the next dimension of fluorescent lighting design, highlighting the latest in technology and emphasizing the importance of quality lighting to building owners.

CSE: How can a lighting designer break out beyond routine specs and design more functional, energy-efficient and aesthetic spaces?

KOYLE: The answer is education. Lighting designers must keep up to date with the latest trends, techniques and products. This might be through courses, expositions and periodicals offered by manufacturers, research centers and organizations such as the Illuminating Engineering Society of North America and the International Assn. of Lighting Designers. These may take the form of web-based training, classroom training and trade magazines and journals.

HARAN: Designers need to have a fundamental understanding of the functional, spatial and aesthetic characteristics of the space they are designing. Consequently, he or she must be involved early in the design process to communicate with the architect and interior designers.

It's important to show these folks some examples of past projects and how newer technologies can achieve more effective spaces than routine specifications. For example, in a recent warehouse project, T5HO and high-efficiency T8 systems were considered as a replacement for a high-intensity discharge (HID), high-bay system. The goal was to provide the most functional and energy-efficient solution, regardless of technology. Since savings gleaned from occupancy sensor controls were the compelling factor in the project, T5HO fixtures with programmed start ballasts were specified because they maximize lamp life in frequently switched operations.

CSE: These sound like good strategies, but being that lighting dollars are often among the first to be value engineered out of a project, how can lighting designers best advocate to owners the importance of an adequate lighting budget?

CLANTON: When daylight, electric lighting and controls are integrated with all building systems, it is harder to line-item veto or value engineer out any component. If and when productivity and user satisfaction are factored in the design, quality lighting will be mandated.

KOYLE: The lighting designer also needs to first and foremost understand what the owner values in terms of the lighting and then address those concerns head on. For example, if an owner is concerned about cost, the lighting designer should provide a detailed energy analysis explaining how yearly energy savings would offset a potentially higher initial cost.

HARAN: It is also important for the owners to realize a "human factor payback." Use of advanced lighting techniques and systems including new light sources, controls and daylighting improve occupants' enjoyment of the spaces. Improved productivity and perception of the space environment can then result in notable improvements to the bottom line.

As Mr. Koyle mentioned, when cost is a concern, the lighting designer, when he or she proposes a lighting solution, should show the owner the payback analysis. For example, on one project for a large office building space, a payback analysis showed how indirect fluorescents with T5HOs provided cost savings over direct parabolic fluorescents while reducing glare, brightening the ceiling and improving uniformity.

YORGEY: There are numerous ways that a lighting designer can emphasize to owners the importance of lighting. From an aesthetics angle, proper lighting enhances the architectural detail that the owner is spending money on. Further, the appearance of the fixtures adds to the overall look of the building. If it is value engineered, that look can be compromised.

But it's lighting control that is sometimes the first area of lighting earmarked for elimination in an effort to save cost. However, controls are often an integral part of the well-designed lighting systems, and the designer is often counting on the ability to adjust the various lighting elements to provide for the varied light levels that most spaces in a building require. These variations are needed as functions of the space change for adjusting to the time of day and for accommodating the preferences of the people using the space.

And this leads to a key issue driving the need for quality lighting control: energy efficiency. The majority of states have now adopted some form of energy code requiring efficient lighting that is automatically controlled. Consequently, value engineering the lighting by going to less efficient fixtures may result in the installed lighting exceeding mandatory limits.

As far as addressing cost concerns, it is often helpful to look at the total cost of the lighting system. The total cost consists of several elements including first cost, which is part of a capital or construction budget, and the cost of maintenance and energy, which is paid for from operating budgets. This is one of the more difficult elements to have the owner recognize since the two sources of money are typically controlled by different people in a company. The fact is that an efficient, well-designed lighting and control system will pay for itself with reduced lamp replacement, cleaning expense and reduced energy costs.

In terms of the human factor payback that Mr. Haran mentions, there are several studies that are beginning to directly relate improved lighting and control systems to more satisfied and productive people. Examples of such research are now being offered by the LightRight Consortium, the National Research Council of Canada and the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute.

CSE: What's the latest as far as lamps and ballasts that can translate into improved lighting design schemes?

CLANTON: The latest are lamps and ballasts that provide superior performance, reduce maintenance, use minimal energy, provide user flexibility, respond to controls, decrease the size of luminaires, increase luminaire photometric performance and reduce environmental impact. These include T5HO, induction and ceramic metal-halide lamps, and high-performance, intelligent electronic ballasts that allow for individual addressing and controls.

YORGEY: T8 lamps, 1-in. in diameter, are the most common today, and the major lamp companies have introduced versions with improved color, in terms of both color rendering index and color temperature. These new lamps have also reduced amounts of mercury, meeting state and federal requirements that make the lamps safer for disposal. T5 lamps, 5/8-in. in diameter, are the newest type to see general use in many applications. They have similar efficiency characteristics as the T8 lamps. Because of their reduced diameter, they allow smaller and more appealing fixtures to be produced. T4, 1/2-in. diameter, compact-fluorescent lamps are replacing more and more incandescent lamps in downlight and wall sconce applications. The newest higher-wattage 57-watt, 70-watt and 120-watt compact-fluorescent lamps are being applied in high-bay applications that traditionally use high-wattage HID lamps. At the same time, new developments in HID lamps are lowering the wattage of ceramic metal-halide versions, but providing improved color. They are being applied as great replacements for incandescent fixtures for retail display and other similar applications.

HARAN: Metal-halide lamps are also shrinking incredibly in size, providing more versatile and compact luminaires. Pulse-start metal halide can replace a standard lamp resulting in fewer fixtures, faster re-strike time and improved color uniformity. Ceramic metal-halide lamps provide greater light output, improved color rendering and limited color shift.

In the fluorescent market, high-efficiency T8 lamps with new phosphorous coatings make it possible to get more light from less wattage, and new barrier coatings reduce the amount of mercury in linear T8 fluorescent lamps. The newest T8 electronic ballast designs have features like end-of-life sensing, automatic shut-off and the ability to soft start to extend life. When a programmed-start ballast is used with an occupancy sensor, this makes it the best choice for frequently switched circuits.

T5 lamps are showing up more and more in pendant-mounted linear luminaries used in commercial and institutional spaces. T5 provides markedly improved control and optimal efficiency. Dimming ballasts for T5HOs are becoming readily available, enabling designers to use daylight harvesting in conjunction with skylights and other peak load shedding strategies. Universal input voltage, 120/277, is a new feature in electronic ballasts, which saves valuable maintenance time.

CSE: On the subject of ballast improvements, how are things developing with digital addressable lighting interface (DALI)?

HARAN: Although DALI is still new, use of this system is on the rise. All major ballast manufacturers have DALI ballasts now, and NEMA is expected to issue a DALI-control device protocol this year.

KOYLE: DALI is becoming a more mature technology. With demonstration sites becoming widespread throughout North America, this exemplifies the potential of this exciting control methodology.

CLANTON: DALI desperately needs to develop a better reputation before it is accepted as mainstream. The DALI story is fabulous, but in order for it to become a reality, it must be more than just a protocol. (For more on DALI see "Turned on by DALI," CSE 04/03 p. 40, or search for the story under Issue Archives at csemag.com.)

CSE: How about LEDs? They were all the rage at last year's Lightfair.

CLANTON: LEDs will eventually offer the best and the worst in a light source. They will be the best when it comes to innovative designs that graze large surfaces, producing lighting exactly where it is needed and offering endless color combinations with minimal operation and maintenance. But in instances where LEDs are used to replace traditional light sources, they fall short of good color rendering and are too bright when viewed directly.

HARAN: LEDs are a low-heat, low-energy and long-lasting way to add different effects to displays. Over the past decade, LED energy efficiency has increased four-fold and allowed for more cost-effective and creative designs. As the technology advances and our profession becomes more educated on its applications, it is only a matter of time before this type of light becomes more standard in use as LED costs are decreasing while performance is increasing.