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Title 24, Part 6, Energy Efficiency Standards: Indoor Lighting Changes

Elizabeth Drew, San Francisco Design Engineer

Today when we refer to Title 24, it is taken for granted that we are referring to California’s Energy Code. However, Title 24 is actually The California Building Code and is one of 28 Titles under The California Code of Regulations. This building code is made up of 12 parts, including Mechanical (Part 4), Electrical (Part 3), and Plumbing (Part 5). What we consider the Energy Code is officially titled "California Code of Regulations Title 24, Part 6, Energy Efficiency Standards for Residential and Nonresidential Buildings." The California Energy Commission updates the Energy Efficiency Standard every three years. The present standard is commonly referred to as the 2005 Standard or simply Title 24, and has been in effect since October of 2005. The next version will be referred to as the 2008 Standard, although it will not take effect until August 2009.

The Energy Efficiency Standard is divided into sections and sub-sections, and after being divided between Residential and Non-Residential, it can be further divided by Building Design industry disciplines or sub-disciplines; Architectural (Envelope), Mechanical (HVACR), and Electrical (Lighting). A typical non-residential lighting project, submitted to the Building Department after August 1, 2009, will be affected by the changes in Sections 119, 130-134 and 146. A brief summary of some of the changes to the Electrical Indoor Lighting sections are described as follows:

Section 119 The Mandatory Requirements for Lighting Control Devices has been expanded to include Ballasts and Luminaries. Also under this section, Occupancy, Motion, and Vacancy Sensors are now required to have visible status signals to show they are operating properly; although they are permitted to have override switches to turn the signals off. Multi-level occupant sensors are to be capable of automatically turning all lights off, automatically or manually turning 30 to 70 percent of lights on, manually turning all lights on, and manually turning all lights off. Another change to this section is under Track Lighting Integral Current Limiters. The limiters are to be visibly labeled with their VA rating, have a warning label inside wiring compartments against alterations. The limiter compartment is to be permanently attached to the luminaries such that there will be irreparable damage at attempted removal.

Section 130 has been greatly expanded to cover more than medium screw-base sockets. It addresses all line-voltage sockets and track; establishes minimum wattage allowances for recessed fixtures; and address sockets that can be converted between screw-based and pin-based sockets where the housing and wiring remain unchanged. New methods are dealt with to determine wattage for luminaries with ballasts, transformers, LED systems, and also the devices utilizing GU-24 sockets. This section also constricts the factory installed labels, listing the maximum wattage for the fixture or system; they must be pre-printed, and can not be peel-off or peel-down layers.

Section 131 reduces the Exceptions under Area Lighting Controls and Shut-off controls down to 0.3 W/sf from 0.5 W/sf. Newly added to the Shut-off section is the new requirement to use occupant sensors in offices less than or equal to 250 sf, multi-purpose rooms less than 1000 sf, and all classrooms and conference rooms. The commission has added a lighting control requirement separating general lighting from ornamental and display type lighting when using tailored method for calculating the allowed indoor lighting power density. There is also a demand response lighting control requirement added for retail spaces with sales floor areas over 50,000 sf.

The Daylighting area of the Standard under Section 131 has been re-written, and the daylight area divided into three parts; Primary Sidelit, Secondary Sidelit and Skylit. Primary and Secondary Sidelit area widths are the width of the window plus the least of; 2 ft on either side of the window, or nearest five foot or higher permanent vertical obstruction, or half way to the next window. The floor plan depth of the Primary Sidelit area is equal to the height from floor to window header, and the depth of the Secondary Sidelit area is twice the Primary depth. The Skylit area is the "footprint" of the skylight opening plus 70% of the ceiling height around the "footprint," unless blocked by a permanent obstruction. Daylight areas can not be double counted if they cross. Where the Primary Daylit and Skylit daylight area in a room is greater than 250 sf, the general lighting within the Daylight area is required to be separately circuited and controlled. If this area is greater than 2,500 sf the general lighting is required to have automatic Daylighting controls. Separate controls are not required within the Secondary Daylit area, however control credits can be gained by controlling the Secondary daylit general lighting separately. Buildings requiring Skylights are addressed under section 146.

A significant change under Section 132 is an exception for replacement of existing pole mounted luminaries. New control requirements have been added for Sign Lighting under section 133, and for control acceptance requirements of outdoor lighting under section 134.

Several Power Density values have changed under the Area Category Method in Table 146F. Office Occupancy has been split between office sizes. Offices less than or equal to 250 sf are allowed 1.1 W/sf, and offices more than or equal to 250 sf are allowed 0.9 W/sf. Parking Garage and Theater Categories have also been divided. Parking Garage has been split between Parking Area with 0.2 W/sf and Ramps & Entries with 0.6 W/sf. Theater has been split into Motion Picture at 0.9 W/sf and Performance at 1.4 W/sf. Several of the Categories have very small allowances that can be added, usually based on task space.

Skylight requirements have been modified under section 146 to be required in climate zones 2 thru 15, in low rise buildings with three or less floors and with at least 8,000 sf on the floor directly below the roof. Also under section 146, a non-programmable double throw switch is now required to qualify for the interlocked lighting option, where only the highest wattage system is counted when two lighting systems are installed within one space. Control Credits are added for combined and automatic multi-level control sensors, and manual dimming.

Most of the changes to the new 2008 Standard are modifications and clarifications to the existing requirements. And many of the adjustments are based on questions called in or emailed to the Energy Commission from Architects, Engineers and Contractors. These changes will affect every project from the largest to the smallest. There are many changes within the new Standard which will affect all building disciplines, which will become clearer through study and application. The California Energy Commission publishes the Standard, as well as the compliance manuals which give a much more in depth explanation of the requirements and how to comply with them.


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