Decoding the Code
The ANSI/ASHRAE/IES 90.1 energy standard provides a model energy code to jurisdictions interested in regulating the energy-efficient design of commercial buildings. ASHRAE recently published the 2016 version, which supersedes the 2013 version.
The U.S. Department of Energy recognizes the 2013 version as the national energy reference standard. Starting in October 2016, all states were required to have an energy code in place at least as stringent as 90.1-2013 or justify why they could not comply.
Based on past code adoption, a majority will select the 2013 version of the International Energy Conservation Code, some ASHRAE/IES 90.1, and a few states, such as California, will produce their own state-specific codes. While 90.1 was adopted in relatively few states, it provides a baseline for federation construction and programs such as the Leadership in Energy and Environmental Design.
2013 version
ASHRAE/IES 90.1-2013 adjusted lighting power density allowances, established more stringent control requirements and created a table-based formula for determining LPD and control requirements in individual spaces. Due to concerns about what the effect of further pressing LPD allowances could have on lighting quality, the code’s writers focused on energy-saving lighting controls instead of squeezing further reductions out of LPD.
Notable changes from 90.1-2010 include:
Shortened the occupancy-sensor time delay from 30 to 20 minutes;
Required partial-off to 50% of design power for spaces where lights are intermittently used but have to stay on, such as corridors and stairwells;
Required daylight-responsive controls in secondary as well as primary daylight zones, with an additional control reduction point for greater flexibility in reduction; and
Imposed more detailed lighting control functional testing requirements.
2016 version
ASHRAE/IES 90.1-2016 contains few, but significant, modifications, notably in the area of reduced lighting power allowances. The biggest change is in interior and exterior LPD allowances, as advances in LED technology have put significant LPD reductions back on the table.
The standard reduces maximum allowable LPD in all but four building types: hospitals, dormitories, motion picture theaters and museums.
The standard reduces LPD by 16% in retail buildings (1.06W/sq. ft.) and 27% in warehouses (0.48W/sq. ft.). The LPD allowance for merchandise accent lighting in retail buildings — applicable to the space-by-space compliance method — is also reduced for all retail area types.
Exterior
The 2016 standard reduced exterior LPD allowances as well, again based on modeling heavy on the use of LED technology. (The 90.1 lighting subcommittee relies on modeling to determine whether a given space could save energy without compromising lighting quality using cost-effective, commercially available technology.)
The new standard reduces base-site power allowances by 30% for Zone 1 (developed land within parks, rural areas, etc.), 33% for Zone 2 (residential, light industrial/commercial, etc.), 33% for Zone 3 (all other areas), and 31% for Zone 4 (high-activity commercial districts in major metro areas).
In some cases, such as parking areas and drives, the standard further reduces additional LPD allowances applicable to individual space types.
Apart from the aforementioned changes, 90.1-2016 mainly contains clarifications. For example, the new standard:
Allows light sensor calibration in daylight-responsive control systems to occur without a person being present, which recognizes the utility of auto-commissioning sensors;
Requires all lighting to be automatically turned off when not in use, including “night lighting” on emergency circuits not required by life/safety statute; and
Requires dusk-to-dawn exterior lighting to be capable of reducing lighting power by at least 50% when not being used based either on a schedule or occupancy sensors. This is an increase from 30% in the 2013 version of the standard.
Also, some parking area luminaires must use an occupancy sensor, with control zoning restricted to 1,500W per sensor.
Future
Energy codes have made a big impact on energy efficiency in new buildings and product development while having a halo effect on existing construction. DOE continues to update the national energy reference standard to promote maximum energy savings in complying states. As the department recognizes 90.1 as the national energy reference standard, it is likely that 90.1-2016 will become the new national energy reference standard at some point after 2019.
Overall, the 2016 version of 90.1 significantly reduces lighting power allowances, indicating the energy-saving potential and widespread utility of LED technology. It ensures that night lighting not required by statute should be turned off to eliminate energy waste. It also contains significant clarifications to remove potential roadblocks to adoption of intelligent lighting controls.
The 2019 version is expected to show even greater LPD reductions as technology continues to mature and may contain further provisions encouraging networked controls.
Craig DiLouie, LC, CLCP, is the education director of the Lighting Controls Association