By February 2020, the 2016 version of ANSI/ASHRAE/IES 90.1, Energy Standard for Buildings except Low-Rise Residential Buildings, takes effect as the national energy reference standard, based on a 2018 Department of Energy (DOE) ruling. By that time, all states must adopt a commercial building energy code at least as stringent as the standard, or justify why they cannot comply.
Commercial building energy codes regulate the energy-efficient design of nonresidential buildings. Though some are state-specific (such as California, which has Title 24 Part 6), most are based on a model code (in whole or in part). Some have no statewide code (such as Colorado, whose home-rule constitution results in adoption at the county and city level).
The primary model codes are ANSI/ASHRAE/IES 90.1 and the International Energy Conservation Codes (IECC), each updated every three years. Of the two, the IECC is more popular, though it references 90.1 as an alternative compliance standard; 90.1 influences IECC development due to pressure to harmonize; and 90.1 is referenced by legislation such as the Commercial Buildings Tax Deduction and building rating systems such as LEED.
The DOE ruling is likely to result in gradual adoption of either the 2016 or 2019 version (which was recently released) of 90.1 or an updated version of the IECC (2018 or 2021). Once robust, compliance with these rulings has become fragmented and slow, resulting in the United States being a patchwork of codes based on whether it’s a state-specific or a model code, which model code has been adopted, and which version of that model code is used.
As of December 2018, only 10 states had complied with the previous DOE ruling recognizing 90.1-2013 as the national standard, according to EnergyCodes.gov, which unfortunately stopped tracking energy code adoption that month. Having codes more stringent than 90.1-2013, California, Florida, Massachusetts, Nevada, and Washington were the most progressive states at the time.
In this article, we will explore two key areas of 90.1-2016’s lighting section, which regulate lighting power and use of lighting controls, and then drill into major changes from the 2013 version.
The general trend here has been steadily declining power density. Based on the increasing proliferation and cost-effectiveness of LED technology, the 2016 version of 90.1 reduced maximum allowable lighting power density (LPD, measured in W/sq.ft.) in all but four building types, based on the Building Area Method. The additional power allowance for merchandise accent lighting is also reduced for retail buildings. Exterior lighting power allowances are similarly reduced, with base-site power allowances reduced by as much as a third. The standard also reduces additional power allowances for individual exterior space types.
The majority of commercial building energy codes require mandatory lighting controls throughout commercial buildings, with few exemptions. ANSI/ASHRAE/IES 90.1-2016 requires that each space have at least one control device for general lighting, which can be a manual switch, occupancy sensor, or manual-ON timer switch. Manual controls must be capable of light reduction.
Beyond that, control devices must be installed to ensure that all lighting is automatically turned OFF when not in use. Options include scheduling, occupancy sensing, and signaling from another building system. In many spaces, occupancy sensors are specifically required for automatic shutoff; these devices must feature an integral ON/OFF switch and have a maximum time delay of 20 minutes.
For general lighting in daylight zones, the lighting must be independently controlled from other general lighting in response to available daylight. Independent control is also required for special lighting types.
ANSI/ASHRAE/IES 90.1-2016 provides an additional lighting power allowance incentive to go beyond these mandatory controls with a list of options that accelerate energy savings. Applicable to common building types, strategies include manual or programmable dimming, multilevel occupancy sensors, workstation-specific controls, and automatic control in secondary daylight zones.
Exterior lighting must also be turned OFF when it isn’t being used, based on an astronomical time switch, photosensor, or a combination of the two. Dusk-to-dawn and other lighting must be reduced afterhours.
All installed controls must be functionally tested, with appropriate documentation on the lighting and control system turned over to the owner.
Major changes compared to 2013
The most significant changes in the 2016 version of 90.1 compared to the 2013 version are:
- Reduced interior and exterior lighting power allowances.
- Threshold for LPD and automatic shutoff requirements applying to lamp-plus-ballast and one-for-one luminaire replacement retrofits is increased from 10 to 20 percent of connected lighting load.
- All non-exempted lighting must be turned OFF when not in use, including “night lighting” on emergency circuits not required by life/safety statute.
- Dusk-to-dawn exterior lighting must be capable of reducing lighting power by at least 50% (up from 30%) when not being used, based on scheduling or occupancy sensors. Certain parking area luminaires must be occupancy sensor-controlled.
- Light sensors installed with daylight-responsive control systems must be able to be calibrated without the operator doing the setup being present in the controlled space.
- Lighting in open-plan offices can automatically turn ON to more than 50 percent of connected power, as long as the control zone is no larger than 600 sq.ft., which supports adoption of luminaire-integrated occupancy sensors.
Over time, energy codes and standards have become far more stringent in terms of both lighting power allowances and mandatory lighting controls, while adding new functional testing and documentation requirements and incentivizing more advanced controls. This has led to commercial buildings steadily becoming more efficient. Due to the DOE ruling taking effect, it is likely we will see greater adoption of ANSI/ASHRAE/IES 90.1-2016, beginning in the states that are the most progressive in terms of energy efficiency.
For more information, consult the authority having jurisdiction and the energy code applicable to your jurisdiction. You may also take the Lighting Controls Association’s Education Express course covering the standard, and purchase the standard at the ASHRAE bookstore.