ALTERNATIVE ENERGY SOURCES, green technology, sustainability, smart grid, energy codes — they’re all terms that are becoming increasingly familiar in today’s society. But where do safety codes — particularly the NEC® — fit into our movement toward cleaner, greener, and more reliable energy sources and systems? A revision to a 2014 NEC requirement on lighting load calculations is a great example of how energy codes and safety codes, while aimed at very different objectives, can be made compatible when the right balance of interests is struck.
Energy conservation features are a key component of today’s built environment, and energy codes adopted by state and local government entities impact all facets of building construction, including the electrical system. Take for instance the California Energy Commission’s Building Energy Efficiency Standards. According to the Commission’s website (energy.ca.gov), its policies on electrical energy conservation and efficiency are responsible for saving California residents more than $74 billion on their electric utility bills since 1975. These measures are not only saving consumers money, they are also reducing the burden on the electrical generating and distribution infrastructure.
Similar to the California requirements, model energy codes such as the International Code Council’s International Energy Conservation Code are being adopted and enforced throughout the U.S. One way these codes reduce electric power consumption is by limiting a building’s lighting loads to a specified wattage per square foot of space. New lighting technology such as compact fluorescent lamps and LED-type luminaires are helping meet these requirements without sacrificing the desired or required level of illumination.
The NEC also includes requirements on the minimum lighting load for a building, requirements that also assign a specified power allowance per square foot of building space. But here’s the rub: The load per square foot assigned by the model energy codes for the purpose of energy conservation is significantly lower than that assigned by the NEC, which for years has provided adequate capacity with a modest amount of room to grow without overburdening the electrical distribution infrastructure.
Since the 1970s, when the first energy codes came into existence, proposals have been made to amend the NEC load requirements to align them more closely with energy code requirements. These proposals indicated that the NEC minimum load calculation requirements exceeded the lighting load levels permitted by the adopted energy code. However, there was a reluctance to accept such proposals among members of the code-making panel, who believed that, while the proposals were well-intentioned, acceptance would diminish the level of safety established by the NEC requirements.
A new exception to Section 220.12 in the 2014 NEC is a great example of a solution to make the NEC compatible with energy code requirements while providing a safe electrical system. The lighting load values required by the NEC were not reduced, but an exception allows the lighting load to be calculated based on the value prescribed by the “energy code adopted by the local authority.” The exception imposes certain checks to maintain the level of safety intended by the NEC. In order to use this provision, for example, power monitoring equipment must be installed to provide continuous information on a building’s general lighting load. When the general lighting load exceeds the value determined by the energy code, an alarm is required to alert the building owner/management of the condition.
This new exception not only offers a safe alternative, it may also provide the additional benefit of considerable cost savings in the electrical distribution infrastructure — a win-win approach for everyone involved.