A primary driver in commercial lighting design is the energy code.
Energy policy acts have mandated more efficient lamps, banning some types of lamps entirely. Across the country, energy codes have been adopted for the Department of Energy’s (DOE) stated purpose of achieving “the maximum practicable, cost-effective improvements in energy efficiency while providing safe, healthy buildings for occupants” .
The State of Texas has adopted the 2009 International Energy Conservation Code (IECC) as the minimum standard – meaning that local Authorities Having Jurisdiction (AHJs) are free to adopt or devise more stringent codes, but whatever an AHJ adopts must be at least as stringent as the 2009 IECC.
What does this mean to lighting construction design? It means a project must conform to the code adopted by the local AHJ as part of the permitting process.
The development of more and more efficient lighting has influenced energy code writers to tighten the wattage allowances for different types of buildings. Codes adopted by various AHJs across Texas range from 2009 IECC to 2015 IECC / ASHRAE 90.1-2013. Some AHJs have their own exterior lighting ordinances. There may be “green building” or LEED requirements added to the basic energy code.
Before a lighting design advances very far it is important for all of the decision makers in the design process – owners, architects, developers, interiors, and landscape- to be aware of code requirements/restrictions. This will help avoid time consuming, costly, or painful redesign at late stages of the project.
In the interior lighting budget for all commercial spaces, incandescent screw shell socket fixtures are counted in COMcheck at the wattage rating of the socket, not the wattage of the lamp installed in the socket. This means we can only use these type fixtures if quantities are very limited.
Example: A porcelain medium base screw shell socket from Lowes’ is about $0.29, but the socket is rated at 660W. COA kindly allows us to count it at 300W since they are well aware that 660W medium base incandescent lamps are not available.
TIP: If the manufacturer will provide ‘derate” labels for the fixture, we are allowed to use that wattage in the calculation.