Specifying LEDs for commercial use
Good lighting enhances design, conserves energy, and increases productivity, safety, security, personal comfort, sales, attendance, and profit.
Gersil N. Kay, IESNA, Conservation Lighting International Ltd., Philadelphia
The philosopher Albert Borgmann said, “Technology is most celebrated when it is most invisible—when the machinery is completely hidden, combining the simplicity of godlike effortlessness with blissful ignorance about the mechanisms that operate.”
Lighting, essential to see or do anything for life, work, or play, is such a basic technology. Today it is expected to be present everywhere, including the still-in-use 30 million commercial/ institutional structures erected in the United States prior to 1940, and even more residential units of that age. It is also the easiest discipline with which to conserve energy and reduce CO2 emissions. Unfortunately, lighting is often the last considered in planning and the first to be jettisoned in the budget crunch, when it should be designed as early as possible.
Good lighting enhances all design, conserves energy, and increases productivity, safety, security, personal comfort, sales, attendance, and profit. On the other hand, artificial illumination could consume up to 40% of a commercial structure’s energy, and prolonged exposure to harmful infrared (IR) and ultraviolet (UV) rays emitted by all light, natural and artificial, could accelerate disintegration of fugitive organic material components and contents (anything that once grew, like wood, paper, textiles, leather, ivory, lacquer, feathers, or bone).
In lighting, one size/type does not fit all. There are many tools of differing energy efficiency available for the lighting designer. However, only if all the most energy-efficient technologies best suited to the particular application are known and used, can affordable, sustainable sophisticated illumination be created within the increasing energy conservation regulations. The best practice: Keep the design of task and atmospheric lighting as simple as possible.
Advances in lighting
Every day, there are many revolutionary developments in lighting. Light-emitting diodes, or LEDs, are one. Semiconductor LEDs are solid state lighting (SSL) and, like glass fiber optics (GFO) functional architectural lighting, based on total internal reflection, they differ completely from conventional incandescent, fluorescent, halogen, and metal halide lamps.
LEDs are no longer an evolving topic but are now becoming mainstream for commercial or retail use, such as colleges/universities, data centers, laboratories and research facilities, high-rise multipurpose buildings, offices, hospitals, hospitality, recreation, factory/storage facilities, theaters/assembly, museums, water features, landscapes, libraries, retail stores, and other nonresidential facilities.
Illumination with LEDs could be functional (task, display, ambient, architectural features) or decorative. It may be interior or exterior, directional (spotlight), or ambient (general); automated or manually operated; wireless or wired; individually or centrally controlled with adjacent systems; or have special effects of color, motion, and dimming. Existing lighting fixtures may be retrofitted or historic light levels and colors recreated.
Sustainability is based on each component’s life expectancy, not just that of the chip. Binning (assembly of chips) determines distance of light thrown, resolution, and angle of visibility.
Color temperature of light is crucial. Higher Kelvin temperatures (4,100 K) allow older eyes to see better with less energy consumed. The color temperature selected depends upon the décor, with lower Kelvin degrees (2,700 K) to enhance warm colors (red/yellow/orange), and higher ones for cool colors (blue/green, etc.). A new Color Rendering Index (CRI) from the National Institute of Science and Technology (NIST, part of the U.S. Department of Commerce) is based on vibrant rather than pastel colors.
With LEDs, the metric sought is lumens (visible light output) rather than wattage (energy consumed). Lighting designers also should learn the light distribution, color quality and appearance, and shape and size of the bulb if retrofitting into an existing socket, as well as electrical compatibility with an existing system (transformer, dimmer, and connected load).
This article is not about photons, charts, or W/sq ft. Instead, it suggests using a thoughtful out-of-the-box mixture of art, science, and imagination to create and specify attractive, practical, and sustainable lighting for commercial/retail use with LEDs.
Where to start
Initially, a realistic lighting budget must be created so it will not be halved later, emasculating an originally good plan. Every area should have at least two light levels, to provide contrast and direction. “Value engineering” should not cheapen the design beyond expected usability. If specs are so reduced, the whole activity is a waste of effort and money. Better to do it right, in phases, when funds are available.
To create clear, precise specifications, there is a learning curve to understand LED equivalency compared to conventional systems. Some of the LED differences from conventional lighting systems are:
- Standards for comparison with conventional products are still not complete.
- Price is high, but will decrease with increased quantities marketed.
- Sustainability and dependability: Although very energy-efficient, current LEDs could lose 30% of light level in only 25,000 hours (five years). Then this most expensive lighting may have to be replaced, making it less sustainable for permanent functional architectural uses. As an example, substitution with LED T8s has a proposed payback of two years, but today’s stock-assembled components may only last for five years before light levels decrease below 70%, leaving a relatively short life, after which the illumination no longer performs as designed.
- Smartest product decisions are made not on just the initial cost of the equipment alone, but on the total estimate for design, installation, interfaces, controls, programming, maintenance, operation, and final disposal of the system for the first five years of the source/system. This actual payback time is the deciding factor.
- The SSL lifecycle length is based on the durability of all the LED components and how they are put together, not just the chips. The cheapest LEDs won’t perform adequately because of this great disparity in quality of LEDs. You get what you pay for.
- Binning is based on required resolution, distance of thrown light, and viewing angles.
- Unless specifically designed, all lighting is vulnerable to temperature, vibration, electromagnetic interference, moisture, and voltage drops. Some, like compact fluorescents lights (CFLs), cannot be repeatedly turned on and off, or have to be burned in a certain position.
- Additional energy may be needed with present LEDs to dissipate the excessive heat from the driver (ballast). Newer methods of disposing of heat produced by light could extend the designed LED light levels for much longer periods than now anticipated.
- Extra air conditioning may be required
- In retrofitting existing lighting fixtures with LEDs, there may not be sufficient space for dissipating heat.
- Some LEDs, like halogen, are too glaring,
- All LEDs may not be dimmable, and some marked dimmable are not dimmable, even with the right controller.
- Flicker in dimming could be annoying or even physically sickening to some.
- Some present LED light levels are still not high enough for some applications.
- Is there sufficient color selection?
- Replacement of individual chips could be noticeable among older ones.
- Some current white LEDs may change color unexpectedly.
- Low-voltage LEDs require proper ballasts for fluorescent replacements.
- Compatible interfaces and controls must be included.
- With the speed of research and development, some present LEDs may be obsolete before installed.
The person specifying lighting could be anyone, from the carpenter to the architect. The trick is to make the lighting an asset for the client. Thus, a combination of psychiatrist, technician, and imaginer has to discover the client’s lighting goals and evaluate capabilities of resources to achieve them. There must be awareness of the possibilities afforded, while remaining open-minded to avoid shoehorning the same old signature modus operandi into every job. The lighting designer/specifier is the customer’s representative, and should think “we,” not “me.”
Are LED replacement lamps and ballasts merely being put into existing fixtures, or is a whole new lighting system needed? Today’s LEDs need conversion from ac to dc. Their design may have to include programming, in which case full lighting and electrical services rather than just ordering bulb/lamps and ballasts are needed. Controls are now more than just on/off. Thus, LEDs are not a do-it-yourself job. The more complicated the design, the more experienced the designer has to be.
Whether it is upgrading existing venues or installing anew, the lighting specifier has to know where to search for interstitial spaces in walls, ceilings, floors, landscapes, or even furniture within which to conceal lighting hardware and controls. Appropriate decorative fixtures, color, and light levels for the décor have to be chosen. It is amazing how few educated people know what professional lighting designers are, or do, or their value to the building industry.
Sometimes the client, dazzled by fanciful but misleading advertising, insists on a particular product or method that may not be the best lighting solution for that project. Diplomatic attempts should be made to dissuade such unwise choices. Likewise, aggressive energy conservation without an equal increase in productivity will inevitably fail. People always find ways to circumvent unwanted or impractical restrictions.
Before starting any lighting design specs, there are preliminary steps. Resources should be consulted such as the National Electrical Code (NEC); International Assn. of Electrical Inspectors (IAEI); National Fire Protection Assn. (NFPA); UL; Illuminating Engineering Society of North America (IESNA); International Assn. of Lighting Designers (IALD); New York’s State Historic Preservation Office (SHPO); National Park Service; Internal Revenue Service (IRS); National Electrical Contractors Assn. (NECA) and non-union groups; Lighting Controls Assn. (LCC); International Energy Conservation Code (IECC); U.S. Green Building Council; Green Globes; Americans with Disabilities Act (ADA); Building Owners and Managers Assn. International (BOMA); U.S. Dept. of Energy (DOE); International Building Code (IBC); and federal, state, and local requirements. In certain geographical areas, seismic, wind, or water issues should be considered. Compare detailed photometric performance data using LM-79 and LM-80 for equivalency between conventional sources and newest technologies. Additional research may have to be made.
Always seek third-party objective sources for information on and comparison of LED directionality, efficacy, and other properties. Check groups like the DOE’s CALiPER program, Energy Star, and LED Lighting Facts for independent testing, and investigate commissioning authorities’ experience on performance. Don’t forget to question previous users.
Caveat: There are many makers of LEDs, some better than others in brightness, binning, rendering color, lamp life, heat dissipation, scalability/interchangeability, dimming, and durability. Much higher priced than incandescent bulbs, not all LEDs provide the same quality and dependability. Look for good manufacturing methods, warranty, and expected life.
In every case, to keep safety and dependability uppermost, existing electric power and service initially should be checked for capacity and condition. Provisions for near-future (within five years) anticipated additions should be included in design to save further labor and cost later. Savvy owners have an energy audit of the entire building/complex to see where savings can be made, even if it is done in phases.
To decide if LEDs are the best decision for the usage, ask such practical questions as:
- Are they affordable for the available budget?
- Do they provide adequate performance for the specific lighting task: color, light level, special effects?
- Is there sufficient space for heat dissipation in retrofitting?
- Are they convenient for occupants to operate, control, and maintain?
- Will they be sustainable for the expected length of time needed?
- Can interchangeable components from varying makers be used?
- Are there interfaces and controls compatible with LEDs?
- Can sufficient energy be stored effectively for emergency operation?
- Are they attractive to enhance both architectural design and contents?
- What is the length of their warranty?
Keeping it all together
After understanding the client’s “lighting wish list” and deciding that LEDs are the best choice for the particular project, a design is created, specs written, walk-throughs taken, and bids made and contracted out. Before hitting the first nail, specs should call for an initial meeting with the entire construction team to make everyone—from owner/developer and architect to first-year apprentice—aware of the goals of the project and how to achieve them. This is the time to begin discussing any expected problems, getting everyone’s suggestions for flexible solutions.
It goes without saying that the three Cs of construction—communication, coordination, and cooperation—have to be present for a successful outcome. Specifications for each job should be unique for its LED lighting requirements. Establish priorities in scheduling work to avoid duplication of effort. There has to be a central authority in charge of the whole operation to monitor schedules, reject unauthorized substitutions, and expedite necessary change orders.
Every company involved should have the latest drawings so no one arrives on the job and finds the construction changed without notice. For example, if air conditioning ducts are now where lighting was originally shown, unexpected expensive change orders will occur.
Specs should call for a neat, workmanlike installation with adequate protection for existing features. To avoid accidents and lawsuits, good housekeeping practices should be written in the specs. Spell out detailed installation instructions in the documents instead of merely copying stock boilerplate clauses. Combining theatrical with architectural lighting techniques often adds special, unique lighting effects. Similar to that for HVAC, commissioning for major commercial lighting schemes is a factor.
Specialists should be on hand to repair penetrations in existing decorative features made for the lighting. The entire project should be treated holistically, not by each trade/discipline separately. Full integration of the lighting system within a building means daily supervision to ensure that the intention of the lighting is carried out correctly. If individual plans and specs are not created for each commission, and the same old stock lighting that ignores the client’s ongoing economic welfare is proposed, it will only waste money and create great customer dissatisfaction.
Of course, the project is not complete until a scheduled maintenance program is in place and occupants are taught correct operating instructions.
Lighting by building type
It is assumed that the reader is familiar with accepted lighting techniques used with conventional lighting equipment. Working with LEDs is just another lighting job employing those same methods, but adjusted for SSL. Those techniques won’t be repeated here because they can be found in IESNA publications and many other sources. Here are some directional and ambient details to be addressed with all types of lighting, including LEDs:
Offices: Some offices have artwork or collections displayed museum-style. Such items are treated just like museum exhibits. The caveat: Over-exuberant energy conservation without an increase in productivity will ultimately fail. If the office staff has to wear miners’ caps to see, they won’t be profitable. The back of cubicle desks is not where the light is needed. Who can find correct files in dim lighting?
Private offices, cubicles, large open spaces, food service areas, restrooms, storage, or corridors may each use different types of lighting. However, adequate light levels and controls for the particular purpose must be provided, even for maintenance. Individual controls pertaining to the task are needed. Otherwise, people will always find ways to circumvent unwanted or impractical lighting.
Institutional: Museums and libraries have an added requirement of protecting fugitive organic materials (anything that once grew, like wood, paper, textiles, leather, ivory, lacquer, feathers) from prolonged exposure to harmful IR and UV rays emitted by all light, natural and artificial. Both LEDs and GFO delay damage from IR and UV. They may be used together or separately.
Theaters/assembly areas: Theatrical critics often mention the lighting, both on stage and in the front-of-house. It is part of the ambiance. Poor lighting could diminish the efforts of the performers or the enjoyment of the building. Sports stadium lighting is a whole new ballgame. LED outdoor displays replicate fireworks and other special effects. Be sure that any lights that will be used outdoors (and all connections) are made for outdoor use, because indoor versions will be ruined by the elements.
Poorly designed LED fixtures will cause glare; don’t use them. Eliminate glare also when retrofitting LEDs into existing fixtures. Moreover, be sure there is room to dissipate heat.
Medical: Hospitals and nursing homes deserve a whole article of their own. Patients, already feeling under par, often have to deal with hot, hard-to-reach bedside reading light, and many hospitals have glaring spots in examining rooms, and dreary hallway and cafeteria illumination. MRI and operating rooms require special lighting including explosion- and shock-proof equipment not affected by electromagnetic interference, voltage surges, harmonics, or other such problems. Adequate energy storage for emergency generation is vital.
Retail: Retail merchandising should attract customers with well-lit displays in a comfortable environment that directs traffic easily, points out special features, and represents correct colors. The smart store offers more than expected to make shopping easier and more convenient. Just stepping over a shop’s threshold indicates the quality of merchandise. A jumbled mass of goods badly lit screams low quality.
During renovation, every effort should be made to keep the store open by careful scheduling of work. Hot counters, glaring, bad color, misfocused, or too dim lighting chases prospective clients away. Every kind of lighting, from electronic signage and e-commerce kiosks to theatrical special effects, could be employed to keep the client in the building and attentive to the goods.
Hospitality/food service: “Cooking” restaurant patrons like the food under hot lighting is as bad as plunging them in darkness so they can’t see the menu, the food, or their companions. Keeping them in the dark is not “intimate”; it is simply bad lighting. How many people have to hang over the side of the hotel bed to read by the distant light on the nightstand? Who has found they can’t see to shave or apply makeup in a poorly lit hotel or restaurant bathroom? Is it difficult to read room numbers in the low yellowish light in the hospitality’s hallway?
Because the same lighting techniques used with traditional products have to be tailored to the different characteristics of the SSL, there has to be design innovation such as noticing how viewers perceive lighting, associating dissimilar factors that might possibly work together, constant questioning, observing surroundings to note how good and bad SSL lighting conserves energy and diminishes CO2 emissions, and making mock-ups in labs or on-site, like Thomas Edison did to find ideas that have practical use. Lighting, similar to music, should have rhythm and contrast: fast and slow, loud and soft.
For large projects, consider integrated operation of lighting with other disciplines, now that sensors and connectivity are no longer one-way isolated procedures. They now communicate uses centrally, and interact with adjoining systems and the Internet. Advanced controls connected to the BAS can predict failures in a timely manner to avoid costly shutdowns. Therefore, lighting controls cannot be carelessly hidden behind pillars or other architectural features so that they cannot operate properly. Wireless controls are eminently suited for existing structures, saving labor and material, but make sure that frequencies are not disrupted by outside interference.
An even more exciting version of LEDs is organic LEDs, or OLEDs. For more than a decade, Germany, Japan, South Korea, and forward-thinking companies here and abroad have been developing this technology. It could very well change lighting and architectural design drastically. Bendable OLEDs are sheets of very thin carbon-based polymer sandwiched with electric current. The process is known epitaxy. Properties include energy efficiency, fast response, wide view angles, exceptional color reproduction, outstanding contrast levels, and high brightness.
Manufactured roll-to-roll, similar to newspaper printing, OLEDs will be much cheaper to produce than automobile-like assembling of LEDs with many components from various sources. OLEDs can be inserted into windows to be either transparent or translucent with changing color. Interior designers could use them in straight or curved surfaces or as wallpaper. Emergency crews could have safety clothing that is lit with OLEDs. Indeed, applications are limited only by the designer’s imagination. One of the biggest drawbacks so far is the life of the battery or other movable power source. Latest lithium-ion batteries use 1/10 the energy and last 10 times as long as previously.
With the rapid developments in lighting technology, as soon as the designer gets used to LEDs, there will probably be an even newer technique to learn, so stay tuned.
Lighting designer’s checklist
Here is a partial checklist for designing and specifying LEDs:
- Suitable applications for LEDs?
- Indoor or outdoor use?
- Total system price and payback time?
- Transition from ac to dc?
- Voltage: high or low?
- Range of dimming ability?
- Dimming without color shift?
- Lamp life?
- Light levels? Some specifiers slightly over-design and initially under-run to extend lamp life.
- Relative price compared to expected length of service?
- Uniform light distribution?
- Range of colors and dependable white?
- Physical effects of lighting on certain people?
- Photometrics compared to conventional luminaires?
- Suitable “open” controls (fully functional interoperability between devices of different manufacturers)? Programs like ZigBee may not yet be suitable for large installations.
- Unintentional color shift and stability?
- Color rendition?
- Replacement issues for individual failed chips?
- Heat dissipation for the driver?
- Effects of voltage change, harmonic and electromagnetic interference?
- Selecting of compatible interfaces and controls?
- Adequate space for retrofitting LEDs into existing fixtures?
- Possible additional air conditioning loads required?
- Temperature of the surrounding environment?
- Affected by adjacent lighting/HVAC/life safety systems?
- Architectural impediments for lighting operation?
- Appropriate resolution (high or low) for the application?
- Provisions for emergency lighting?
- Special conditions like seismic areas or wind?
- Combining several lighting products and techniques for exceptional effects?
- Is there LM-79 and LM-80 performance data?
Kay is president and founder of Conservation Lighting International and Building Conservation International. She is a member of the IESNA Board of Directors and is a past member of professional affiliations and societies including IAEI, AIA's Historic Resources Committee, ICOMOS, and International Council on Art Deco Societies. She is a member of the Consulting-Specifying Engineer editorial advisory board.