Measure Overview
This measure proposes the following revisions to the mandatory control requirement section in the code (Section 130.1) and the associated acceptance test (NA 7.6 in the Reference Appendices). The proposed changes include both updates in the requirements and code language clean-up. Many of the proposed measures also bring the requirements in Title 24, Part 6 into better alignment with the national standards (ASHRAE 90.1) and other model codes (IECC). The first five proposed changes would generate savings and may incur additional costs in implementing the updated requirements; therefore, a full CASE Report will be developed to demonstrate cost-effectiveness. The last proposed changes are code language cleanup and are not likely to result in additional savings or costs. Energy savings estimates and cost and cost-effectiveness analysis will not be performed for these three proposed changes as part of the CASE Report development.
- Require nighttime dimming in parking garage daylight adaptation zones. This measure ensures proper visual adaptation for drivers entering parking garages at night by requiring lighting in the daylight adaptation zones to reduce the light level to that of the general parking zone from sunset to sunrise.
- Require partial or full OFF occupant sensing controls in more spaces. The space types currently being considered include lounges, breakrooms, waiting areas, auditorium areas, hotel function areas, financial transaction areas, lobbies in certain building types, museum exhibition/display areas, and rooms that house server racks in data centers. Additionally, the requirement would trigger occupied standby controls in spaces where ventilation is allowed to be shut off and temperature set back when no occupant is detected. This would result in energy savings from HVAC systems.
- Reduce occupant sensing control time delay to 15 minutes. This measure would reduce the time delay for occupant sensing controls from the current 20 minutes to 15 minutes.
- Clarify the definition and reduce the threshold for requiring multilevel lighting controls. The 0.5 W/ft2 exception to the multilevel lighting controls requirement is an artifact of when expensive fluorescent ballasts were required for each controlled fixture. The added cost for dimming of LED fixtures is negligible, and this update would reflect the new market conditions. This section was developed in 2013 to clarify when light sources were required to have dimming capability, and other mandatory control sections were to define when dimming was applied to various controls. This is no longer clear. Thus, in addition to clarifying when light sources must be capable of dimming, this proposal would also add a manual dimming control section to Section 130.1(a), “Manual Controls,” to provide greater clarity on when manual dimming controls are required.
- Require continuous dimming for all required daylight responsive controls and not be subject to Section 130.1(b) LPD exception. Daylight responsive controls are cost-effective when the controlled wattage exceeds 75 Watts and is not dependent on the lighting power density (LPD) of the space. This 0.5 W/ft2 exception to the multilevel lighting controls requirement is an artifact of when expensive fluorescent ballasts were required for each controlled fixture. The added cost for dimming of LED fixtures is negligible, and this update would reflect the new market conditions.
- Require manual overrides of daylight responsive controls to be timed or reset at the next ON cycle. When the design of the lighting control system allows the daylight responsive control to be manually over ridden and increase lighting power above the control setpoint, the proposed measure would require this type of override to reset after a defined duration or be reset the next time the lights are turned on again after being turned off by manual switching, time-based controls, or occupant sensing controls.
- Make the Alternate Partial Daylight Test the only test method for the Daylight Responsive Control Acceptance Test. This proposed measure would remove the Partial Daylight Test method and make the Alternate Partial Daylight Test the only test method. This simplifies the acceptance test procedure and promotes better compliance with the daylight responsive controls requirements.
- Improve the lighting controls acceptance test methods for luminaire-level lighting controls (LLLC). The proposed measure would improve the acceptance test methods by providing instructions for testing LLLCs when they are used as the control solution to meet the mandatory lighting controls requirements. The improved test method would reduce test burden and increase effectiveness for the Acceptance Test Technicians.
Provide Feedback
This measure page will be updated as the 2028 code cycle progresses. For questions or suggestions, email [email protected]. Please include the measure name in the subject line.
Scope of Proposed Code Change
| Building Type(s) | Construction Type(s) | Type of Change | Updates to Compliance Software | Third Party Verification |
| Nonresidential, Multifamily | New construction, additions, alterations | Mandatory | Update existing feature, add new feature | Update existing verification requirements, add new verification requirements |
Justification for Proposed Change
Several of the proposed revisions to the mandatory control requirements would bring Title 24 into alignment with ASHRAE 90.1 lighting requirements and increase energy savings. The nighttime adaptation compensation controls for the parking garage daylight adaptation zone are an existing requirement in ASHRAE 90.1, and such controls are considered a best practice to increase safety from an illuminating engineering standpoint. ASHRAE 90.1 also requires more spaces to implement partial or full OFF occupant sensing controls, and some of those spaces are currently either not required to have occupant sensing controls or not included as an area category in Title 24. Reducing the maximum time delay of occupant sensing controls to 15 minutes saves energy and aligns with the publication of Addendum BD to ASHRAE 90.1-2022, as well as the default settings for many brands of occupant sensors.
The 0.5 watts per square foot threshold for requiring multilevel lighting controls has been in place since the pre-LED era and was based on traditional light sources. With LEDs’ high efficacy and being continuously dimmable with no or minimal additional cost, it would be prudent to recalibrate and revise the threshold based on current technologies. Furthermore, the code language for multilevel lighting controls has been ambiguous as to whether it pertains to continuous dimming that other controls can utilize or a physical dimmer for manual dimming. Since several other mandatory control sections reference multilevel lighting controls, it is essential to clean up the multilevel lighting controls code language to ensure those references are consistent and coherent. The current exception for multilevel lighting controls also creates a conflict with daylight responsive controls when a space is exempted from multilevel lighting controls but is required to implement daylight responsive controls. Without continuous dimming provided by multilevel lighting controls, daylight responsive controls would not be effective, and the resulting behavior could be perceived negatively by the occupant. The proposal of requiring continuous dimming for daylight responsive controls regardless of the multilevel lighting controls exception aims to address this conflict.
Requiring manual overrides of daylight responsive controls to be timed or reset at the next ON cycle is a code cleanup effort to address ambiguity in the current code language that does not clearly specify whether daylight responsive controls can be overridden by any user and how and when daylight responsive controls should resume when overridden.
The Alternate Partial Daylight Test was proposed and adopted in the 2022 T24 energy code as an alternative to the original Partial Daylight Test, as creating a proper test condition for performing the original Partial Daylight Test is often difficult. The intent was for the two test methods to coexist for a few code cycles, allowing Acceptance Test Technicians’ (ATTs’) to make a smooth transition to the Alternate Partial Daylight Test. It is time to formally remove the less effective Partial Daylight Test to improve acceptance test effectiveness and increase the compliance rate.
Current lighting controls acceptance test methods were designed for zone-based controls, where the lights in the entire zone, e.g., a daylit zone, are controlled by a single sensor. When luminaire-level lighting controls (LLLC) are used as the control solution to meet mandatory control requirements, the sampling rules in current test methods create a test burden, as too many controls would need to be tested. Additionally, the current test methods need to consider the independentedness of each LLLC luminaire in responding to changing daylight conditions and provide specific instructions for correctly and effectively performing the Full Daylight Test.
Relevant Documents
Round One Utility-Sponsored Stakeholder Meeting Materials
-
Use the form above to provide feedback on this measure.
Give Us Your Feedback
The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.