California has been a historical leader in terms of state energy codes. California’s Title 24 has led the way by restricting allowable LPDs (Lighting Power Density) as well as mandating specific types of lighting controls. However, in the past 5-10 years, other codes have made great strides in catching up to the stringency of California’s Title 24. Both ASHRAE 90.1-2016 as well as IECC 2015 have provisions that are much more closely aligned with Title 24 than they used to be. This should make life easier for both specifiers as well as manufacturers since required control equipment doesn’t vary as much based on the project location as it used to.
Maximum allowable LPDs have dropped substantially in the past decade or so. This is largely due to the increases in efficacy and effectiveness of LED lamps and luminaires. As LPD limits have come down, authors of energy codes have had to rely on beefing up requirements for lighting controls in order to continue the push for reduced energy use. Energy codes are often revised on a 3-year cycle (e.g., ASHRAE 90.1 has been revised in 2007, 2010, 2013 and now 2016). In each code cycle, changes in the market allow the state to mandate equipment or techniques that were not previously required. There are a variety of reasons for this:
• Changes in technology – Lighting and controls technology changes so rapidly that, in any given 3-year code cycle, new and improved equipment comes onto the market.
• Financial viability – Mandating certain control equipment or techniques that may not have been financially viable in the previous code cycle may now be viable simply due to changes in equipment cost (and/or associated labor costs for installation).
As stipulated by California law, specific lighting control (or other) code provisions cannot be required unless they 1.) meet a minimum payback requirement as defined by the CEC (California Energy Commission), 2.) can be met with technology readily available in the marketplace during the lifetime of the code cycle, and 3.) “move the needle” (are impactful toward delivering energy savings in California). These code requirements establish a good baseline for energy savings, but it is probable that going beyond the minimum code requirements will garner the maximum energy savings or operational benefits in a specific facility.
Because networked lighting control systems are not yet financially viable based on the California Energy Commission’s threshold, they are not specifically required in Title 24. However, once you understand the minimum requirements for code-compliant lighting controls on a new construction project (and even on many retrofit projects), you will probably agree that trying to meet codes with “unit” equipment would be a very difficult task.
What are the requirements for lighting controls on a new construction project in Title 24-2016? Following is a summary of Title 24 requirements for interior lighting controls for the 2016 code version. Official code documents may be found on-line and downloaded for your use.
• Area controls:
o All luminaires shall be functionally controlled with manual ON and OFF lighting controls. Each area enclosed by ceiling-height partitions shall be independently controlled.
o Up to 0.2 Watts/ft2 of lighting in any area within a building may be continuously illuminated to allow for means of egress illumination, if the path of egress is designated on plans (for normal egress lighting – not “emergency egress”). This is an exemption from any local switching requirement; this provision is different than the exemption noted for automatic shutoff controls.
• Multi-level lighting controls:
o The general lighting of any enclosed area 100 square feet or larger, with a connected lighting load that exceeds 0.5 Watts/ft2 shall provide multi-level lighting control that meets the following requirements: [based on light source or fixture type, as listed on TABLE 130.1A]. For example:
– LED lamps and fixtures must be continuously dimmable in a range of 10-100%.
– CFL lamps must be continuously dimmable in a range of 20-100%.
– Linear fluorescent lamps greater than 13 watts must be capable of operating somewhere in each the following ranges: 20-40%, 50-70%, 75-85% (plus full ON and full OFF). Full-range dimming meets this requirement.
– Track lighting fixtures must be capable of operating somewhere in the range of 30-70% (in addition to full ON and full OFF). Full-range dimming meets this requirement. Separately switching multiple circuits in multi-circuit track also meets this requirement without requiring dimming.
– HID (MH, HPS, etc.), induction and all other light sources must be capable of operating somewhere in the range of 50-70% (in addition to full ON and full OFF). Separately switching lamps in multi-lamp fixtures meets this requirement without requiring dimming.
• Automatic shutoff controls:
o All installed indoor lighting shall be controlled with an occupant sensing control, automatic time-switch control, or other control capable of automatically shutting OFF all of the lighting when the space is typically unoccupied (unless exempted below).
o Separate shutoff controls are required for different floors, each partitioned space, and for any area greater than 5,000 ft2.
o In certain space types, automatic shutoff controls must specifically be occupant-sensing devices; e.g., offices 250 ft2 or smaller, multipurpose rooms of less than 1,000 ft2, classrooms of any size, and conference rooms of any size.
o Certain space types require “partial ON”, “partial OFF” or “full OFF” automatic shutoff control devices (see official code text for details). The partial On and partial Off terms were created by the CEC to describe specific sequences of operation.
o Up to 0.1 Watt/ft2 of lighting in any area within a building may be continuously illuminated, provided that the area is designated for means of egress on the plans and specifications submitted to the enforcement agency. (for normal egress lighting – not “emergency egress”)
o A variety of other specific requirements and exceptions apply (see official code text for details).
o If “manual override” devices are provided, these are allowed to override the normal operation of the automatic shutoff devices (e.g., automatic time switch) for up to 2 hours before reverting to normal operation.
• Daylight harvesting controls:
o All interior general lighting in “primary sidelit” and “skylit daylit” zones shall be automatically controlled by photosensors if there is more than 120W of general lighting in the zone. “Secondary sidelit” must also be considered for automatic daylighting control if the prescriptive method of meeting the energy requirements are used (as opposed to a performance method).
o At a minimum, all luminaires/lamps must be controllable based on the requirements for multi-level lighting control as previously mentioned. Continuous dimming of luminaires/lamps automatically meets this requirement.
o Luminaires/lamps in each zone (“primary sidelit”, “secondary sidelit” and “skylit daylit”) shall be separately controlled.
o A variety of other specific requirements and exceptions apply (see official code text for details).
• Demand responsive controls:
o Buildings larger than 10,000 ft2, excluding spaces with a lighting power density of 0.5 Watts/ft2 or less, shall be capable of automatically reducing lighting power in response to a Demand Response Signal so that the total lighting power of non-excluded spaces can be lowered by a minimum of 15%.
o The important word in this description is … “capable”. That means that the lighting controls must be capable of responding to an ADR (automated demand response) signal, but an actual connection to an external ADR signal doesn’t actually have to be made.
o During inspection by code inspectors, some provision must be available to test the ability of the installed lighting controls to achieve this reduction. Note that the code actually requires the installed equipment to have the ability to handle some form of “standards based protocol”. How this is verified during an actual code inspection is a different matter entirely!
This is only a summary of the code requirements for interior lighting. Code requirements also exist for exterior lighting controls. The advent of LEDs for both interior as well as exterior luminaires has made it much more practical to incorporate cost-effective controls, so the codes now reflect this change in the market.
As previously mentioned, networked lighting control systems are not yet financially viable based on the stringent thresholds imposed by the California Energy Commission’s methodology. Therefore, at least in theory, it is still possible to install code-compliant controls on a new or retrofit project using “unit” equipment. However, when you consider the very complex set of requirements – for area controls, multi-level lighting, automatic shutoff devices, daylight harvesting, and demand response – it’s easy to see how using a networked lighting control system would make your life substantially easier. In fact, if only because of the automated demand response code provision, the use of a networked lighting control system is almost a given.
Having said that, the individual code provisions currently in Title 24-2016 are not written with the expectation that you would use such a system to control the luminaires in your space. Networked lighting control systems typically offer a wide range of variables that can be set for many options. For example, time delays for occupancy sensors and photosensors are often simply typed into the system’s software. A system may also allow for complex behavioral interactions based on the complexity of zoning that is allowed. For example, if a system allows for “nested” zoning, then smaller “subzones” may behave based on local equipment whereas a higher-level zone may override the subzone’s operation (for example for scheduled shutoff). These more complex behavior interactions have not really been incorporated into the code language even of the 2016 version.
Besides specifiers and installers, people such as code inspectors have a bit of a learning curve to understand the complexity of modern control systems, and to understand how these systems may achieve code compliance.
As we speak, potential changes to the current code are already being considered by “stakeholders” (utility companies, California-based lighting specifiers, installers, etc.). Meetings to discuss potential changes are typically open to the generally public and you are encouraged to get involved in this process if you are interested. One of the big things on the horizon is better alignment with ASHRAE 90.1 code language. So – as previously mentioned – over time the various codes have started to mirror each other much more significantly than they used to.
The provisions for mandatory lighting controls in Title 24-2016 may sound complex. But when you consider what the major requirements are, they all make sense. Remember that using newer equipment such as networked lighting control systems will allow you to navigate the code-compliance process a lot more easily than using “unit” equipment.