There's a code for that: inside the International Energy Conservation Code
March 26, 2012
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If you want to get a head start on what may be coming down the pike for building energy codes, you might peruse the International Energy Conservation Code (IECC). Produced by the International Code Council and first published in 1998, the IECC was updated earlier this year. It is often used as a template for legal jurisdictions that want to implement energy codes.
Today, most states have energy codes based on IECC and the ASHRAE/IES 90.1 energy standard, which IECC references as an alternative standard. The IECC lists guidelines for the design of lighting and other energy-using systems inside buildings.
According to the Lighting Controls Association, the 2012 version of the spec incorporates a stronger differentiation between commercial and residential buildings. Provisions for residential lighting dictate that at least 75% of the lamps in permanent light fixtures must be high-efficacy, defined as T8 or smaller-diameter linear fluorescent lamps, or lamps with a minimum efficacy of 40 L/W for below 15 W, 50 L/W for 16to 40-W lighting, and 60 L/W for lamps exceeding 40 W.
The commercial section of the code dictates tandem wiring in certain fluorescent applications, a maximum wattage for exit signs, circuiting for daylight harvesting control, and automatic shutoff, light level reduction and other controls.
Other highlights: The standard now requires occupancy sensors in spaces that include classrooms, conference/meeting rooms, employee lunch and break rooms, private offices, restrooms, storage rooms, custodial closets, and other enclosed spaces 300 sq.ft. or smaller. Further, the sensor must switch off lights within 30 min of vacancy. It also requires that general lighting in areas that get a lot of daylight be separately controlled from other general lighting in the space. IECC 2012 also limits the maximum size of these control zones to 2,500 sq.ft. Options for automatic daylight harvesting control include continuous dimming down to less than 35% of the light output range or multilevel controls offering 100%, a step between 50% and 70%, and another step between OFF and 35%.
There are also specifications for interior lighting power allowances, expressed as W/ft.², or lighting power density (LPD), that are largely unchanged from the 2009 IECC, with the exception of small tweaks in office, retail, fire stations, and warehouse space.
Finally, there were major changes in a section covering additional efficiency package options, which requires the building to either optimize its HVAC efficiency beyond code, optimize lighting efficiency beyond code, produce renewable energy onsite.
The Lighting Controls Association has an in-depth article on the changes: http://lightingcontrolsassociation.org/iecc-2012-decoded/
The code itself is available here: http://www.iccsafe.org/Pages/default.aspx