Everyone should be well aware of the fact that lighting load in a commercial or educational type building runs at about 30% to 40% of the total building load. These percentages have been promoted in articles, white papers, and all types of technical brochures and research papers for many years now. Reducing these percentages has been an agenda item in recent years for a number of standards developers, “green” type organizations, legislators, and regulators. As these groups continue to ratchet down the allowable lighting power density levels in various types of buildings and structures, the pressure builds on the design and manufacturing community to develop products, systems, and solutions to meet these new guidelines.
One of the goals of lighting professionals, electrical engineers, electrical contractors, and energy services specialists has been to work on ways to drive down lighting load as much as possible, without jeopardizing the comfort and safety of building occupants. To accomplish this goal, they must do so in conjunction with the most efficient products and systems being developed and brought to market by the manufacturing community.
On the product development front, the introduction of reduced wattage lamps based on fluorescent and LED technologies has been a key driver of change — so has the use of lighting control devices and systems as well as building management and metering/monitoring systems. Fortunately, these new technologies have allowed the design and construction community to keep pace with these increasingly stringent standards.
But as states like California continue to push building efficiency standards toward an ultimate goal of zero net energy buildings, others will follow. As a result, architects, engineers, and construction professionals will continue to face further design challenges. So where will they find their next round of relief or inspiration? A small change in the 2014 NEC could be a key driver in the evolution of reduced lighting power levels in new buildings across the United States.
A new Exception has been added to Sec. 220.12 that offers designers and installers a new option when calculating lighting loads for specified occupancies where the building is designed and constructed to comply with an energy code adopted by the local authority. Although there are some conditions that must be met prior to taking advantage of this Exception (mainly centered on the use of a power monitoring system), it does present electrical designers with intriguing new options. For example, a designer who takes advantage of this Exception could choose to use smaller transformers, distribution gear, and conductors that would result in a more affordable power system, which might even be safer to work on. But will designers be willing to push transformer load factors to levels above what they’ve traditionally designed to in the past?
For a much more detailed review of this seemingly simple Code change — and its potential far-reaching effects on the design community — read this month’s cover story, “Lightening Up on Lighting Loads,” written by three seasoned electrical engineers. After you’ve read what they have to say, head to the EC&M website and share your thoughts and opinions in our new Discussion Forum (EC&MTalk).
