On July 1, 2014, the new California Title 24, Part 6 of the 2013 Building Energy Efficiency Standards, which covers lighting controls and other electrical equipment, process and HVAC equipment, and window treatment, will go into effect. Typically, each revision of the T-24 standard increases the stringency of requirements by an average of 15%. However, the 2013 edition boosts that number up to 33%! Through the continuous development of these regulations since 1978 — along with other programs and economic changes — California has held its per capita energy use almost flat over the last 30 years while the rest of the country has seen per capita energy use increase by almost 50%.
Focusing on both new construction and the renovation of homes and buildings, the new law takes advantage of energy-efficient and renewable energy technologies that have already proved cost-effective and are likely to create further economies of scale. The standards make extensive use of information technologies that monitor and control a building and equip them for real-time pricing arrangements.
Similar to the requirements of the ASHRAE/IESNA 90.1 2010 standard, which took effect in October 2013, requirements of Title 24, Part 6 are an incremental step toward achieving zero net energy (ZNE). A ZNE building uses only as much energy on an annual basis as can be generated with an on-site (or nearby-site) renewable energy system or systems. Toward that same end, the California Public Utilities Commission, in its Long Term Energy Efficiency Strategic Plan, has a target of making all new residential buildings net-zero by 2020 and commercial buildings by 2030.
Seeing the light
Of primary interest to electrical contractors and engineers is the greatly expanded use of building energy sensing/control systems — and lighting control in particular. Additionally, new buildings have to be wired so that electric energy use can easily be measured for each type of load, such as lighting (Photo 1), plug loads, and charging stations used by electric vehicles. The meter type installed depends on the kVA rating of the electric service. Demand response control systems are also required in all buildings 10,000 sq ft or larger, so that the time-dependent valuation of electric energy will become increasingly important. When a building receives a demand response signal from the electric utility provider, the total lighting power has to be lowered a minimum of 15% below the maximum level.
Lighting designers, engineers, and electrical contractors have important new tasks to follow with regard to the Title 24 standard. In addition to the requirement for the separation of specific electrical loads in new buildings, Title 24 requires a commissioning report to be created for the building owner. This includes reports on all the functional performance tests for the various areas described later in the article.
Six categories of lighting controls require acceptance testing, and these categories may change with each new edition of Title 24, Part 6. After July 1, 2014, any project issued a building permit on or after this date must undergo these acceptance tests. For example, occupancy sensor time-out and sensitivity have to be confirmed along with the performance of photocontrols and demand response systems. A new type of professional certification — the Certified Lighting Controls Acceptance Test Technician (ATT) — will eventually define the professional who does the commissioning and acceptance testing. The requirement for ATTs will begin as soon as the number of trained technicians reaches a specific threshold (see Net Zero Energy Building Training Ground).
Taking control
As a way of satisfying various types of structures and occupancies, Title 24 reduces lighting energy usage in two main ways: (1) It mandates automated lighting controls to cut wasted electrical consumption (for example, a wider use of automatic shutoffs); (2) It prescriptively requires maximum lighting power densities (watts/sq ft). The allowed lighting power densities for office and retail buildings have been reduced for the 2013 standards. However, the prescriptive requirement for lighting power density can be exceeded if the designer claims certain “power adjustment factors” for advanced lighting controls (for example, occupancy sensors used on a closely spaced grid or “partial-ON” occupancy sensors).
Three methods can be used to determine the allowed lighting power density: The Complete Building method, where the building has a single use or a single tenant; the Area Category method — where a building has a variety of different uses; and the Tailored method for malls, auditoriums, retail stores, and similar spaces that have multiple layers of light for specific purposes.
The new law covers:
1) Area controls — All interior luminaires in non-residential buildings must have manual ON/OFF controls, and each area must be independently controlled. Dimmer switches must allow manual ON/OFF functionality, with some exceptions. In areas greater than 100 sq ft, luminaires must incorporate multi-level lighting controls or, in most cases, continuous dimming, depending on the lamp type. They must also meet specific uniformity requirements, and must have at least one of the following types of controls for each luminaire: manual continuous dimming, lumen maintenance, tuning, automatic daylighting controls, or demand-response controls.
2) Multi-level controls — Indoor lighting controls now must operate with either a continuous dimming function or have three intermediate levels between on and off settings (the previous requirement was one intermediate level or “bi-level”). Because fluorescent lighting is the dominant source in non-residential buildings, the California energy code-makers see mandating of fluorescent dimming ballasts in daylit spaces and elsewhere. LEDs, which are expected to become dominant for new construction during the life of this Code, are required to be continuously dimmable.
3) Shutoff requirements — In all buildings, except offices, lighting must be shut off completely during unoccupied times. This even includes lighting that is designated “emergency,” “egress,” or “security” lighting (though it does not include exit signage). Offices can maintain some lighting 24/7, but only along designated paths of egress — and at a reduced maximum of just 0.05W per square foot.
Warehouses, library stacks, and all corridors and stairwells must incorporate “partial off” control that dims the lights whenever the space is unoccupied. Guest rooms in hotels must have occupancy controls linked to both HVAC equipment and all lighting fixtures, including table lamps and other plug-in lighting.
4) Automatic daylighting controls — Automatic daylighting controls are mandatory in all primary daylit zones that have at least 120W of installed load, with few exceptions. This change significantly expands the number of spaces required to use photosensor controls, affecting virtually every office or commercial space with skylights or windows. Two separate zones are established in the regulations, with the primary zone starting at the window plane and extending one window head height back into the space, while a newly defined secondary zone starts at the back edge of the primary zone and extends a further one window head height back.
Photocontrols are now prescriptively required for the secondary zone, and must have the same level of functionality as those in the primary zone. Additionally, the two zones must be controlled separately. This control strategy, called daylight harvesting, uses light sensors (e.g. photosensors or daylight sensors) to automatically reduce electric lighting when sufficient daylight is present.
5) Demand response — Title 24 code requires non-residential buildings larger than 10,000 sq ft, regardless of space type, to have a demand-response (DR) function, such as the OpenADR (automated demand response) messaging protocol. A signal from the local electric utility is able to automatically reduce lighting power consumption by at least 15% below the building’s maximum lighting power during peak demand times.
Two types of demand response conditions can be considered. The primary type is an emergency situation where a reduction in the building’s electric load is needed to prevent the power grid from being stressed to the point of jeopardizing reliability. The second type is when the value of using electricity is less than its cost. HVAC systems aren’t required to be demand-response-compliant under the new code, but building owners may decide to connect these systems as well.
6) Renovation requirements — The threshold for when lighting alterations must comply with the standard has been reduced from when 50% of the luminaires in a space were altered (such as lamp and ballast retrofits) or replaced to when 10% of the luminaires are moved or replaced, consistent with changes to ASHRAE 90.1-2010. This greatly expands application of the standard into existing buildings because automatic shutoff control is no longer limited to buildings larger than 5,000 sq ft.
However, if you’re only changing out lamps and ballasts, a new category has been added, called “luminaire modification-in-place.” In that case, the trigger for compliance is 40 luminaires per tenant space, which is more forgiving in most circumstances (especially in smaller buildings). For projects in which more than 40 luminaires are altered, the altered luminaires must have multi-level control, if applicable, and generally the space must have most, or all, of the lighting controls that are required for new construction projects.
7) Controllable receptacles — The plug loads in some spaces in commercial buildings must now have the same automatic shutoff function as lighting loads. This requirement calls for both controlled and uncontrolled power outlets in certain space types. The controlled outlets can serve computer monitors, cellphone chargers, fan heaters, and other appliances that can be switched off at night. One method of compliance is to have the lighting control system also operate the controlled outlets.
8) Security/safety lighting — Security and egress lighting must be switched off automatically when buildings are unoccupied (this does not include exit signage). Corridor and stairwell lighting must now have a control device that automatically reduces lighting power by at least 50% when the area is unoccupied. Offices can maintain lighting 24/7, but only along designated paths of egress — and at a reduced maximum of just 0.05W per square foot. The occupancy sensors and controls for aisles and open areas of a warehouse have to reduce lighting power by at least 50% during unoccupied periods.
9) Extending sensing and controls — For the first time, lighting in parking garages, lots, and loading/unloading areas must have photocontrols and incorporate occupancy sensors that allow lighting to be switched off or turned to a low level when no one is present. Automatic daylighting controls must use multi-level, continuous dimming, or ON/OFF control.
10) Outdoor lighting — Power densities are reduced for a full range of outdoor luminaires. In addition to photocontrols and automatic scheduling, occupancy sensing devices (controls) are needed for certain outdoor lighting applications — luminaires mounted up to 24 ft above ground and for any incandescent luminaire rated more than 100W. In general, controls must reduce lighting power to each luminaire by at least 40% when the area is unoccupied.
Most outdoor lighting equipment, such as street luminaires, creates some form of glare in the nighttime darkness, and code bodies have developed light pollution/trespass rules to reduce this problem. The new Title 24 law eliminates the old method for classifying outdoor luminaires up to 175W. Instead, luminaires up to 150W must comply with the uplight and glare portions of the IESNA’s BUG assessment system for outdoor lighting.
The individual lighting power allowances for building exteriors are based upon the applicable lighting zone (one of four) for the building site, which permits more lighting in urban zones and less lighting in suburban and rural zones. The four lighting zones cover from undeveloped areas (such as national and state parks) to high-activity commercial districts.
Residential lighting changes are not numerous, but they do introduce requirements for high-efficacy sources as well as vacancy sensors and controls in bathrooms, utility rooms, and other spaces. The 2013 rules also call for better skylights and high-performance windows.
In working toward greater building operation efficiencies with the newest version of Title 24 regulations, the state of California is urging building design teams to assess the applicable codes, standards, and criteria (recognizing that they are all interrelated) and to find the best way to meet, or surpass, the lighting code requirements.
Author’s Note: A special thanks to Owen Howlett, lighting specialist at the California Energy Commission, for assisting in the development of this article.
SIDEBAR: Net-Zero Energy Building Training Ground
The National Electrical Contractors Association (NECA) and the International Brotherhood of Electrical Workers (IBEW) opened a zero net training facility in San Leandro, Calif., last June. Located south of Oakland, the Alameda County Joint Apprenticeship and Training Committee (JATC) training facility serves NorCal NECA and IBEW Local 595.
The 46,000-sq-ft building is on track to become the first net-zero retrofit building, and it should achieve the U.S. Green Building Council’s LEED Platinum certification. Energy-saving features include: LED light sources and fluorescent luminaires circuited through daylight and occupancy sensor-initiated controls; integrated variable refrigerant flow (VRF) systems control room temperature and software initiated monitoring systems verify the building’s performance. Electricians will be trained to understand, install, and maintain many of these energy-saving features.
With its multiple energy conservation measures, the ZNE Center consumes less than 140kW of electrical energy, while a similar commercial building of the same size would use more than 550kW. In addition to DOE net-zero status, the center also exceeds California’s 2030 energy efficiency effort by meeting the zero net goal 17 years in advance. According to Local 595 Business Manager Victor Uno, “This facility shows our commitment to future generations of highly trained and skilled electrical workers.”
