The Energy Code limits the amount of lighting power that may be installed in a building. The following are the general rules for calculating allowed indoor lighting power.
1. There shall be no lighting power allotment trade-offs between the separate conditioned and unconditioned indoor function areas. Indoor conditioned and indoor unconditioned lighting power allotments must each be separately determined on compliance documentation.
2. There shall be no lighting power allotment trade-offs between the separate indoor and outdoor function areas. Indoor and outdoor lighting power allotments must each be separately determined on compliance documentation.
3. Some areas of a building may use the Tailored Method, while other areas of the same building may use the Area Category Method. However, no single area in a building shall be allowed to use both the Tailored Method and the Area Category Method.
4. The Tailored Method shall not be used in any building using the Complete Building method for compliance.
The Complete Building Method shall only be applied when lighting will be installed throughout the entire building. The building must consist of one type of use for a minimum of 90 percent of the floor area of the entire building.
The allowed indoor lighting power allotment for the entire building shall be calculated as follows:
1. For a conditioned building, multiply the entire conditioned floor area of the building by the applicable lighting power density (LPD, watts per sq. ft.) provided in Table 140.6-B.
2. For an unconditioned building, multiply the entire unconditioned floor area of the building by the applicable LPD provided in Table 140.6-B.
The Complete Building Method shall be used only for building types, as defined in §100.1, that are specifically listed in Table 140.6-B (for example, retail store buildings and office buildings.)
The Complete Building Method shall be used only on projects involving:
a. Entire buildings with one type of use occupancy.
b. Mixed occupancy buildings where one type of use makes up at least 90 percent of the entire building (in which case, when applying the Complete Building Method, it shall be assumed that the primary use is 100 percent of the building).
c. A tenant space where one type of use makes up at least 90 percent of the entire tenant space (in which case, when applying the Complete Building Method, it shall be assumed that the primary use is 100 percent of the tenant space).
A few more notes as follows:
•Use the Complete Building Method only when the applicant is applying for a lighting permit and submits plans and specifications for the entire building or the entire tenant space.
•Use the Complete Building Method only when the lighting power allotment in Table 140.6-B is available for the entire building. There are no additional lighting power allowances available when using Complete Building Method. Also, there are no mounting height multipliers available when using the Complete Building Method.
•For buildings including a parking garage plus another type of use listed in Table 140.6-B, the parking garage portion of the building and other type of use portion of the building shall each separately use the Complete Building Method.
Example 5-18: Mixed-Occupancy Parking Garage Building
Question
A building is to be constructed with 95 percent of it consisting of a parking garage, and the remaining 5 percent consisting of offices and support spaces such as an electrical room. What is the assumed building type under the complete building method?
Answer
Since parking garage makes up at least 90 percent of the entire building, the building shall be considered a parking garage when applying the Complete Building Method.
When using the Complete Building Method, qualifying building types are those in which a minimum of 90 percent of the building floor area functions as one of the building types listed in Table 140.6-B, (as defined below), and which do not qualify as any other building occupancy type more specifically defined in §100.1 (the occupancy type information are provided below), and which do not have a combined total of more than 10 percent of the area functioning as any nonresidential function areas specifically defined in §100.1.
Definitions of Nonresidential Building Occupancy Types (Below are partial list from §100.1):
Assembly Building is a building with meeting halls in which people gather for civic, social, or recreational activities. These include civic centers, convention centers and auditoriums.
Grocery Store Building is a building with building floor areas used for the display and sale of food.
Gymnasium Building is a building with building floor areas used for physical exercises and recreational sport events and activities.
Healthcare Facility is any building or portion thereof licensed pursuant to California Health and Safety Code Division 2, Chapter 1, section 1204 or Chapter 2, section 1250.
Industrial/Manufacturing Facility Building is a building with building floor areas used for performing a craft, assembly, or manufacturing operation.
Office Building is a building of CBC Group B Occupancy with building floor areas in which business, clerical or professional activities are conducted.
Parking Garage Building is a building with building floor areas used for parking vehicles and consists of at least a roof over the parking area enclosed with walls on all sides. The building includes areas for vehicle maneuvering to reach designated parking spaces. If the roof of a parking structure is also used for parking, the section without an overhead roof is considered an outdoor parking lot instead of a parking garage.
Religious Facility Building is a building with building floor areas used for assembly of people to worship.
Restaurant Building is a building with building floor areas in which food and drink are prepared and served to customers in return for money.
Retail Store Building is a building with building floor areas used for the display and sale of merchandise except food.
School Building is a building used by an educational institution. The building floor area can include classrooms or educational laboratories, and may include an auditorium, gymnasium, kitchen, library, multipurpose room, cafeteria, student union, or workroom. A maintenance or storage building is not a school building.
The Area Category Method is more flexible than the Complete Building Method because it can be used for multiple tenants or partially completed buildings. Under the Area Category Method, an "area" is defined as all contiguous spaces that accommodate or are associated with a single primary function as listed in Table 140.6-C|tag=TABLE_140_6_C. For primary function areas not listed, selection of a reasonably equivalent type shall be permitted. When the lighting in these areas is completed later under a new permit, the applicant may show compliance with any of the lighting options except the Complete Building Method.
The Area Category Method divides a building into primary function areas. Each function area is defined in §100.1. The allowed lighting power is determined by multiplying the area of each function times the lighting power density for that function. Where areas are bounded or separated by interior partitions, the floor space occupied by those interior partitions shall be included in any area. The total allowed watts are the summation of the allowed lighting power for each area covered by the permit application.
When using this method, each function area in the building must be included as a separate area. Boundaries between primary function areas may or may not consist of walls or partitions. For example, kitchen and dining areas within a fast food restaurant may or may not be separated by walls. For purposes of compliance, they must still be separated into two different function areas. However, it is not necessary to separate aisles or entries within primary function areas. When the Area Category Method is used to calculate the allowed total lighting power for an entire building however, the main entry lobbies, corridors, restrooms, and support functions shall each be treated as separate function areas.
Requirements for using the Area Category Method include all of the following:
1. The Area Category Method shall be used only for primary function areas, as defined in §100.1, that are listed in Table 140.6-C|tag=TABLE_140_6_C.
2. Primary Function Areas in Table 140.6-C|tag=TABLE_140_6_C shall not apply to a complete building. Each primary function area shall be determined as a separate area.
3. For purposes of compliance with §140.6(c)2, an "area" shall be defined as all contiguous areas which accommodate or are associated with a single primary function area listed in Table 146.0-C.
4. Where areas are bounded or separated by interior partitions, the floor area occupied by those interior partitions may be included in a Primary Function Area.
5. If at the time of permitting for a newly constructed building, a tenant is not identified for a multitenant area, a maximum of 0.4 watts per sq. ft. shall be allowed for the lighting in each area in which a tenant has not been identified. The area shall be classified as Unleased Tenant Area.
6. Under the Area Category Method, the allowed indoor lighting power for each primary function area is the lighting power density value in Table 140.6-C|tag=TABLE_140_6_C multiplied by the square footage of the primary function area. The total allowed indoor lighting power for the building is the sum of the allowed indoor lighting power for all areas in the building.
In addition to the allowed indoor lighting power calculated according to §140.6-B through F, the building may add additional lighting power allowances for qualifying lighting systems as specified in the Qualifying Lighting Systems column in Table 140.6-C|tag=TABLE_140_6_C under the following conditions:
1. Only primary function areas having a lighting system as specified in the Qualifying Lighting Systems column in Table 140.6-C|tag=TABLE_140_6_C and in accordance with the corresponding footnote of the table shall qualify for the additional lighting power allowances.
2. The additional lighting power allowances shall be used only if the plans clearly identify all applicable task areas and the lighting equipment designed to illuminate these tasks.
3. Tasks that are performed less than two hours per day or poor-quality tasks that can be improved are not eligible for the additional lighting power allowances.
4. The additional lighting power allowances shall not utilize any type of luminaires that are used for general lighting in the building.
5. The additional lighting power allowances are used only for areas complying with the Area Category Method. The allowances shall not be used when using the Complete Building Method or when the Tailored Method is used for an area in the building.
6. The additional lighting power allowed is the smaller of:
i. The lighting power density listed in the “Allowed Additional Lighting LPD” column in Table 140.6-C|tag=TABLE_140_6_C, times the sq. ft. of the primary function, or
ii. The adjusted indoor lighting power of the applicable lighting.
7. In addition to meeting §140.6(c)2Gi through vi, additional lighting power for videoconferencing as specified in Table 140.6-C|tag=TABLE_140_6_C shall be allowed in a videoconferencing studio, as defined in §100.1, provided the following conditions are met:
i. Before the Additional Videoconference Studio Lighting power allotment will be allowed for compliance with §140.6|topic=SECTION 140.6 – PRESCRIPTIVE REQUIREMENTS FOR INDOOR LIGHTING of the Energy Code, the person who is eligible under Division 3 of the Business and Professions Code to accept responsibility for the construction or installation of features, materials, components, or manufactured devices shall sign and submit the certificate of installation.
If any of the requirements in this certificate of installation are not met, the Additional Videoconference Studio Lighting installation shall not be eligible for the additional lighting power allotment.
ii. The Videoconferencing Studio is a room with permanently installed videoconferencing cameras, audio equipment, and playback equipment for both audio-based and video-based two-way communication between local and remote sites.
iii. General lighting is controlled in accordance with Table 130.1-A.
iv. Wall wash lighting is separately switched from the general lighting system.
v. All of the lighting in the studio, including general lighting and additional lighting power allowed by §140.6(c)2Gvii is controlled by a multi-scene programmable control system (also known as a scene preset control system).
Lighting Terms:
(related to both Area Category Method and Tailored Method)
Accent Lighting is directional lighting to emphasize a particular object or surface feature, or to draw attention to a part of the field of view. It can be recessed, surface mounted, or mounted to a pendant, stem, or track, and can be display lighting. It shall not provide general lighting.
Decorative Lighting/Luminaires is lighting or luminaires installed only for aesthetic purposes and that does not serve as display lighting or general lighting. Decorative luminaires are chandeliers, sconces, lanterns, neon or cold cathode, light emitting diodes, theatrical projectors, moving lights, and light color panels, not providing general lighting or task lighting.
Dim-to-warm (also known as warm dim) light source is capable of simultaneously decreasing its correlated color temperature as its light output decreases, typically resembling the change in color temperature of an incandescent lamp as it dims.
Floor Display Lighting is supplementary lighting that provides a higher level of illuminance to a specific area than the level of surrounding ambient illuminance required to highlight features, such as merchandise on a clothing rack or sculpture or free standing of artwork, which is not displayed against a wall.
General Lighting is installed electric lighting that provides a uniform level of illumination throughout an area, exclusive of any provision for special visual tasks or decorative effect, exclusive of daylighting, and also known as ambient lighting.
Special Effects Lighting is lighting installed to give off luminance instead of providing illuminance, which does not serve as general, task, or display lighting.
Tunable white light source is capable of adjusting its correlated color temperature while maintaining its relative light output and capable of adjusting its light output while maintaining its correlated color temperature.
Wall Display Lighting is supplementary lighting that provides a higher level of illuminance to a specific area than the level of surrounding ambient illuminance required to highlight features, such as merchandise on a shelf or wall-mounted artwork, which is displayed on perimeter walls.
Window Display Lighting is lighting that provides a higher level of illuminance to a specific area than the level of surrounding ambient illuminance of objects such as merchandise, goods, and artifacts, in a show window, to be viewed from the outside of a space through a window.
Example 5-19: Lighting Power Allowance for Special Effect Lighting and Non-General Lighting
There is lighting power allowance for special effects lighting in the Decorative/Special Effects Lighting additional power allowance in the tailored method to lighting power compliance in Table 140.6-D where both terms are combined.
Both the area category method (Table 140.6-C|tag=TABLE_140_6_C) and the tailored method (Table 140.6-D) provide additional lighting power allowances for lighting that is not considered general lighting; however, to claim these allowances, the other lighting systems must be separately switched.
Under layered lighting design scenarios with multiple luminaire types, compliance documentation will require allocating some or all of non-general lighting power to the additional lighting power allowances and the rest of the lighting wattage to the general lighting power allowance. Only the general lighting power allowance is able to be shared across different spaces.
When there is only one lighting system type in a space, such as is the case when a monolithic design approach is taken, that system type will be treated as general lighting. Thus, light fixtures that might ordinarily be considered ornamental or display luminaires are considered general lighting luminaires if they are the only system type in a given enclosed space.
Example 5-20: Corridor With Accent Lighting and General Lighting
A corridor may have a lighting system to provide both accent lighting and general lighting as illustrated in the following images about three different corridor scenarios.
Figure 5-22: Corridors With Accent Lighting and General Lighting: A Corridor With Wall Washer and Accent Luminaires (left image), a Corridor With Recessed Troffer Luminaires (center image), and a Corridor With Scone Luminaires (right image)
Image Source: Bernie Bauer
Corridor A has two lighting systems: forward wall-washers which provides the primary illumination and recessed accent lights for highlighting artwork. Wall-washers (asymmetric optics) are generally used as accent or feature lighting. However, in this scenario since they provide the general or ambient illumination the lighting power for these luminaires per Table 140.6-C|tag=TABLE_140_6_C Area Category Method are allowed up to the 0.40 W per sq. ft general lighting allowance for corridor spaces. The artwork recessed accent lights are providing focal illumination to highlight the art. Therefore, the lighting power for these luminaires may be assigned to the 0.25 W per sq. ft. decorative/display lighting allowance listed under the “Additional Lighting Power” column of Table 140.6-C|tag=TABLE_140_6_C.
One option: provided the total lighting power of the wall-washers and accent lights is equal to or less than the allowed 0.4 W per sq. ft. general lighting power allowance for corridor spaces under Table 140.6-C|tag=TABLE_140_6_C, both luminaires may use the general lighting power allowance.
Another option: if the total lighting power of the wall-washers and accent lights exceeds the 0.4 W per sq. ft. general lighting power allowance for corridor spaces under Table 140.6-C|tag=TABLE_140_6_C, an additional 0.25 W per sq. ft. decorative/display lighting allowance may be used for the accent lights provided that the accent lights are separately switched from the wall washers. The additional lighting power allowed will be the lower of the calculated additional allowance for decorative/display lighting or the proposed wattage of the accent lighting.
Corridor B has one lighting system (2 by 4 recessed LED basket troffers) which provides all the illumination for the space. Basket troffers (symmetric wide distribution optics) are primarily to provide general or ambient illumination. Therefore, the lighting power for these luminaires must be assigned to the 0.4 W per sq. ft. general lighting power allowance for corridor spaces listed in Table 140.6-C|tag=TABLE_140_6_C. The 0.25 W per sq. ft. decorative/display lighting allowance does not apply in this scenario as there are no luminaires providing directional illumination.
Corridor C has one lighting system: wall sconces that provide up-lighting on the ceiling for general /ambient illumination, but the sconces also include a downlight element. However, in this scenario since they provide the general or ambient illumination the lighting power for these luminaires are assigned the 0.40 W per sq. ft. general lighting power allowance for corridor spaces as listed in Table 140.6-C|tag=TABLE_140_6_C. If needed, the 0.25 W per sq. ft. decorative/display lighting allowance could also apply in this scenario. However, the up-light and downlight components of the luminaries must be placed on separate circuits.
Example 5-21: Calculating the Allowed Lighting Power Using Area Category Method
Question
What is the allowed lighting power for a 10,000-ft² multi-use building with the following area types?
- Main entry lobby of 500 ft²,
- Corridors of 1,500 ft²,
- Grocery store (Grocery Sales) of 3,000 ft²,
- Retail store (Retail Merchandise Sales) of 2,500 ft²
- Restrooms of 500 ft²
- Future development of 2,000
ft²
Answer
Most of the functional area types and corresponding lighting power density values can be found in Table 140.6-C|tag=TABLE_140_6_C. The future development area type is unknown with no built-out plan at the time of permitting, therefore the function area type is designated as “All other” with LPD of 0.4 W/ft².
Area LPD Size in ft² Allowed Lighting Power
1) Main Entry 0.7 W/ft² 500 ft² 350 W
2) Corridors 0.4 W/ft² 1,500 ft² 600 W
3) Grocery Store (Grocery Sales) 1 W/ft² 3,000 ft² 3,000 W
4) Retail Store (Merchandise Sales) 0.95 W/ft² 2,500 ft² 2,375 W
5) Restrooms 0.65 W/ft² 500 ft² 325 W
6) Future Development (All other) 0.4 W/ft² 2,000 ft² 800 W
TOTAL 10,000 ft² 7,450 watts
Example 5-22: Tunable-White and Dim-to-Warm Luminaires
Question
Which tunable-white and dim-to-warm luminaires qualify for the additional lighting power allowance for applications in healthcare facilities?
Answer
There is additional lighting power allowance for tunable-white and dim-to-warm luminaires for most of the healthcare/hospital function areas as specified in Table 140.6-C|tag=TABLE_140_6_C.
The qualified tunable-white luminaires shall be capable of color change ≥ 2000K CCT.
The qualified dim-to-warm luminaires shall be capable of color change ≥ 500K CCT.
A dim-to-warm luminaire product capable of color tune from 2700K to 1800K is acceptable and qualifies for the additional light power.
The Tailored Method is a lighting compliance approach which establishes an allowed lighting power budget on a room-by-room or area-by-area basis.
Use of tailored method could be helpful when more general lighting power is required for the listed primary function areas in Table 140.6-D that have a high room cavity ratio (RCR).
In addition to providing a lighting power budget for general illumination, the tailored method provides additional lighting power budgets for illuminating wall displays, floor displays, task lighting, and decorative/special effects lighting. These additional layers of lighting power have been informally referred to as “use-it-or-lose-it” lighting power allowances because these additional allowances cannot be traded-off to other areas or applications. If a lighting design does not include these additional layers of lighting power, the total lighting power budget using the Tailored Method may be less than if the Area Category Method or Complete Building Method of compliance is used.
§140.6(c)3G thru 3H; Table 140.6-D, F, G
Compliance tools such as compliance software programs can be used to document trading-off Tailored Method lighting power allotments. Trade-offs are available only for general lighting and only under the following circumstances:
1. From one conditioned primary function area using the Tailored Method, to another conditioned primary function area using the Tailored Method.
2. From one conditioned primary function area using the Tailored Method, to another conditioned primary function area using the Area Category Method.
3. From one unconditioned primary function area using the Tailored Method, to another unconditioned primary function area using the Tailored Method.
4. From one unconditioned primary function area using the Tailored Method, to another unconditioned primary function area using the Area Category Method.
A. Calculating Tailored Method General Lighting Power Allotments
The Energy Code defines general lighting as installed electric lighting that provides a uniform level of illumination throughout an area, exclusive of any provision for special visual tasks or decorative effect, exclusive of daylighting. To qualify as general lighting for the Tailored Method, the lighting system shall not use narrow beam direction lamps, wall-washers, valance, direct cove, or perimeter linear slot types of lighting systems.
Section 140.6(c)3F shall be used to determine the general lighting power density allotments as follows:
1. Using Table 140.6-D and 140.6-G to Determine General Lighting Power Allotments:
a. Find the appropriate Primary Function Area in column 1 of Table 140.6-D that fits one of the Nonresidential Function Area definitions in §100.1.
b. Find the corresponding General Illumination Level (Lux) in column 2.
c. Determine the room cavity ratio (RCR) for that primary function area, according to the applicable equation in Table 140.6-F. Use the nonresidential certificate of compliance to document the RCR calculation.
d. Refer to Table 140.6-G, using the General Illumination Level (Lux, determined according to item b), and the RCR (determined according to item c), to determine the allowed general lighting power density value.
e. Multiply the allowed general lighting power density value by the square footage of the primary function area. The product is the allowed general lighting power for general lighting for that primary function area.
2. How to calculate Room Cavity Ratio (RCR)
•The room cavity ratio must be determined for any primary function area using the Tailored Lighting Method.
•The lighting level in a room is affected in part by the configuration of the room, expressed as the room cavity ratio (RCR). Rooms with relatively high ceilings typically are more difficult to light and have a high RCR. Because luminaires are not as effective in a room with a high RCR, §140.6 allows a greater LPD to compensate for this effect.
•The RCR is based on the entire space bounded by floor-to-ceiling partitions. If a task area within a larger space is not bounded by floor to ceiling partitions, the RCR of the entire space must be used for the task area. The exception to this rule allows for imaginary or virtual walls when the boundaries are established by “high stack” elements (close to the ceiling structure and high storage shelves) or high partial walls defined as “permanent full height partitions” described in §140.6(c)3Gii wall display. These permanent full height partitions are only applicable when claiming additional lighting power for wall display lighting.
•The RCR is calculated from one of the following formulas:
Equation 5-3 (Table 140.6-F) Rectangular Shaped Rooms
Where:
RCR = The room cavity ratio
H = The room cavity height, vertical distance measured from the work plane to the center line of the luminaire
L = The room length using interior dimensions
W = The room width using interior dimensions
A = The room area ( L x W )
Equation 5-4 (Table 140.6-F) Non-Rectangular Shaped Rooms
Where:
RCR = The room cavity ratio
H = The room cavity height (see equation above)
A = The room area
P = The room perimeter length
•For rectangular rooms, these two methods yield the same result and the second more general form of calculating RCR may be used in all instances, if desirable.
•It is not necessary to document RCR values for rooms with an RCR less than 2.0. Rooms with a RCR higher than 2.0 are allowed higher LPDs under the Tailored Method.
•A special situation occurs when illuminating stacks of shelves in libraries, warehouses, and similar spaces. In this situation, the lighting requirements are to illuminate the vertical stack rather than the horizontal floor area. In stack areas the RCR is assumed to be greater than seven. The non-stack areas are treated normally.
Example 5-23: Calculating Room Cavity Ratio (RCR)
Question
A small retail shop “Personal Shopper” room is 14 ft. wide by 20 ft. long by 8 ft. high. The lighting system uses recessed ceiling fixtures. The task surface is at desk height (2.5 ft. above the floor). What is the room cavity ratio?
Answer
The room cavity height is the distance from the ceiling (center line of luminaires) to the task surface (desk height). This is 8 ft. -2.5 ft. = 5.5 ft.
RCR = 5 x H x (L + W) / Area
RCR = 5 x 5.5 (14+20) / (14 x 20) = 3.34
§140.6(c)3G thru 3J; Table 140.6-D and E
When using the Tailored Method for lighting compliance, there are additional lighting power allowances for the following lighting applications:
•Wall display lighting
•Floor display lighting and task lighting
•Decorative/special effects lighting
•Very valuable display case lighting
The additional lighting power values and adjustment factor values are listed in Table 140.6-D, E, F, and G. These additional layers of lighting power are not available when using §140.6(c)3F to determine the general Lighting Power allotment and are not available for any primary function areas using the Complete Building or Area Category methods of compliance.
All of the additional lighting power allowances are “use-it-or-lose-it” allowances that cannot be traded-off. That is, if the installed watts are less than the allowed watts, the difference in watts is not available to trade off anywhere else in the building.
Use the appropriate compliance form to document the additional lighting power for wall display lighting, floor display lighting and task lighting, decorative/special effects lighting, and very valuable display case lighting.
Lighting Terms:
(related to Tailored Method and Area Category Method)
Floor Display Lighting is supplementary lighting that provides a higher level of illuminance to a specific area than the level of surrounding ambient illuminance required to highlight features, such as merchandise on a clothing rack or sculpture or free standing of artwork, which is not displayed against a wall.
Wall Display Lighting is supplementary lighting that provides a higher level of illuminance to a specific area than the level of surrounding ambient illuminance required to highlight features, such as merchandise on a shelf or wall-mounted artwork, which is displayed on perimeter walls.
Display Case Lighting is lighting that provides a higher level of illuminance to a specific area than the level of surrounding ambient illuminance of small art objects, artifacts, or valuable collections which involves customer inspection of very fine detail from outside of a glass enclosed display case.
Task Lighting is lighting directed to a specific surface or area, providing illumination for visual tasks. Task lighting is not general lighting.
17. Wall display lighting is defined as supplementary lighting required to highlight features such as merchandise on a shelf or other wall features such as graphics, artwork, or product presentation; and that provides a higher level of illuminance to a specific area than the level of surrounding ambient illuminance.
18. Additional allowed power for wall display lighting is available only for lighting that illuminates walls having wall displays or wall features, and only when there is a watt per linear foot allowance in column 3 of Table 140.6-D for the primary function area.
1. The additional allowed power for wall display lighting shall be the smaller of:
i. The wall display lighting power density values (column 3 of Table 140.6-D) multiplied by the wall display length.
ii. The adjusted lighting power used for the wall display luminaires.
19. Calculate the adjusted lighting power by multiplying the maximum rated wattage of the wall display luminaires with the appropriate mounting height adjustment factor from Table 140.6-E.
20. Note that mounting height adjustment factor is available for wall display luminaires mounted greater than 10 feet 6 inches from the finished floor. Mounting height is the distance from the finished floor to the bottom of the luminaire.
2. To qualify for the additional wall display lighting power:
i. The lighting system shall be a type that is appropriate for creating a higher level of illuminance on the wall display. Lighting systems appropriate for wall display lighting are lighting track adjacent to the wall, wall-washer luminaires, luminaires behind a wall valance or wall cove, or accent light. (Accent luminaires are adjustable or fixed luminaires with PAR, R, MR, AR, or luminaires providing directional display lighting.)
ii. The qualifying wall display lighting shall be mounted within 10 feet of the wall having the wall display.
iii. The lighting system shall not be a general lighting system type.
21. Note: Lighting internal to display cases that are attached to a wall or directly adjacent to a wall are counted as wall display. All other lighting internal to display cases are counted as floor display lighting, or as very valuable display case lighting.
3. The length of display walls shall include the length of the perimeter walls including but not limited to closable openings and permanent full height interior partitions.
22. Permanent full height interior partitions are those that meet the following conditions:
i. Extend from the floor to within two feet of the ceiling or are taller than ten feet; and
ii. Are permanently anchored to the floor.
4. The additional wall display lighting power is not available for the following:
i. For any function areas using the Complete Building or Area Category methods of compliance.
ii. General lighting systems.
23. Note that floor displays shall not qualify for wall display lighting power allowances.
24. Floor display lighting is defined as supplementary lighting required to highlight features, such as merchandise on a clothing rack or floor mounted artwork and featured architectural elements, which are not displayed against a wall. Floor display lighting provides a higher level of illuminance to this specific area than the level of surrounding ambient illuminance.
25. Task Lighting is defined as lighting that specifically illuminates a location where a task is performed, but not general lighting.
26. Additional allowed power for floor display lighting and additional allowed power for task lighting may be used only for qualifying floor display lighting systems, qualifying task lighting systems, or a combination of both, for the listed primary function areas in Table 140.6-D.
27. Lighting internal to display cases that are not attached to a wall and not directly adjacent to a wall, shall be counted as floor display lighting or very valuable display case lighting.
1. The additional allowed power for the floor display and task lighting shall be the smaller of:
a. The floor display and task lighting power density values (column 4 of Table 140.6-D) multiplied by the square footage of floor display or task area.
b. The adjusted lighting power used for floor display lighting or task lighting.
28. Calculate the adjusted lighting power by multiplying the maximum rated wattage of the floor display or task luminaires with the appropriate mounting height adjustment factor from Table 140.6-E.
29. Note that mounting height adjustment factor is available for floor display luminaires mounted greater than 10 feet, 6 inches from the finished floor. Mounting height is the distance from the finished floor to the bottom of the luminaire.
2. To qualify for additional floor display lighting power:
a. The floor display lighting system shall be mounted no closer than 2 feet to a wall. When track lighting is used for floor display lighting, and where portions of that lighting track are more than 2 feet from the wall and other portions are within 2 feet of the wall, only those portions of track more than 2 feet from the wall shall qualify for the floor display lighting power allowance.
b. The floor display lighting system consists of only directional lamp types, such as PAR, R, MR, AR, or of luminaires providing directional display light.
c. If track lighting is used, only track heads that are classified as directional lighting types.
3. To qualify for additional task lighting power:
a. The task lighting system shall be located immediately adjacent to and capable of illuminating the task for which it is installed.
b. The lighting system shall be of a type different from the general lighting system.
c. The lighting system shall be separately switched from the general lighting system
4. To qualify for the additional power for floor display and task lighting, the lighting system shall be a type that is appropriate for creating a higher level of illuminance on the floor display or task.
5. The additional power for floor display and task lighting is not available for the following:
a. Any function areas using the Complete Building or Area Category methods of compliance.
b. Displays that are installed against a wall shall not qualify for the floor display lighting power allowances.
c. Any floor area designed to not have floor displays or tasks, such as floor areas designated as a path of egress, shall not be included for the floor display allowance.
6. For floor areas qualifying for both floor display and task lighting power allowances, the additional allowed power shall be used only once for the same floor area so that the allowance shall not be additive.
Special effects lighting is defined as lighting installed to give off luminance instead of providing illuminance, which does not serve as general, task, or display lighting.
Qualifying decorative lighting includes luminaires such as chandeliers, sconces, lanterns, neon and cold cathode, light-emitting diodes, theatrical projectors, moving lights, and light color panels when any of those lights are used in a decorative manner that does not serve as display lighting or general lighting.
Additional allowed power for decorative/special effects lighting may be used only for the listed primary function areas in Table 140.6-D.
1. The additional allowed power for decorative/special effects lighting shall be the smaller of:
a. The allowed decorative/special effects lighting power values (column 5 of Table 140.6-D) multiplied by the square footage of the floor areas having decorative/special effects lighting.
b. The adjusted lighting power used for decorative/special effects lighting.
2. Additional decorative and special effects lighting power is not available for any function area using the Complete Building or Area Category methods of compliance.
3. Additional decorative/special effects lighting power shall be used only in areas having decorative/special effects lighting.
30. Any floor area not designed to have decorative or special effects lighting shall not be included for the decorative/special effects lighting allowance.
Case lighting is defined as lighting of small art objects, artifacts, or valuable collections that involves customer inspection of very fine detail from outside a glass enclosed display case.
Additional allowed lighting power for very valuable display case lighting shall be available only for display cases in retail merchandise sales, museum, and religious worship areas.
1. The additional allowed power for very valuable display case lighting shall be the smallest of one of the following:
a. The product of the area of the primary function and 0.50 watt per sq. ft.
b. The product of the area of the display case and 7 watts per sq. ft.
c. The adjusted lighting power used for very valuable display case lighting.
2. To qualify for additional allowed power for very valuable display case lighting, a case shall contain jewelry, coins, fine china, fine crystal, precious stones, silver, small art objects and artifacts, and/or valuable collections, the display of which involves customer inspection of very fine detail from outside a locked case.
3. The additional very valuable display case lighting is not available for any function areas using the complete building or area category methods of compliance.
4. Qualifying lighting includes internal display case lighting or external lighting employing highly directional luminaires specifically designed to illuminate the case or inspection area without spill light and shall not be fluorescent lighting unless installed inside of a display case.
Example 5-24: Decorative Lighting and Very Valuable Display Lighting — Tailored Method (Five Parts) (Part 1)
Question
A 5,500-ft² retail store has:
5,000 ft² of gross retail sales area (merchandise sales) with a RCR of 2.5
200 ft² of restrooms (with a RCR of 6.0)
300 ft² of corridors (with a RCR of 6.5)
100 ft² of very valuable merchandise case top with 1,200 W of light sources
As part of the retail scheme in the sales floor area, the following lighting is being used.
- Wall display lighting of 300 linear feet of perimeter wall including closeable openings
- Floor display lighting
- Decorative/special effects lighting.
What is the allowed lighting power for general lighting in this store using the Tailored Method?
Answer
The general illumination level is 500 Lux per Table 140.6-D for merchandise sales and showroom area in retail. Per Table 140.6-G, the lighting power density (LPD) is 0.90 W/ft² for a 500 Lux space with an RCR of 2.5. Therefore, the allowed general lighting power for the retail sales area is 0.90 W/ft² X 5,000 ft² = 4,500 W.
Corridors and restrooms are not included in the Tailored Method tables and therefore must comply under the area category method. Look up Table 140.6-C|tag=TABLE_140_6_C for the allowed LPD for these spaces. Table 140.6-C|tag=TABLE_140_6_C allows general lighting power LPD of 0.40 W/ft2 for corridors and 0.65 W/ft2 for restrooms. (The RCR is not used for the area category method)
The allowed power for the restrooms is 200 ft² x 0.65 W/ft² = 130 W.
The allowed power for the corridors is 300 ft² x 0.40 W/ft² = 120 W.
Note that for the Tailored Method, the allowed wattage for each lighting task other than general lighting is of the use-it-or-lose-it variety, which prohibits trade-offs among these wattages and different tasks or areas. Only the General Lighting component of the Tailored Method is tradable between areas using tailored method or areas using area category method.
Example 5-25: Wall Display Lighting – Tailored Method (Continue – Part 2)
Question
If the adjusted lighting power of the floor display luminaires is 3,000 watts, what is the allowed wall display lighting power for the retail sales area in this store?
Answer
The wall display lighting is computed from the entire wall perimeter, including all closeable openings, multiplied by the wall display power allowance. The allowed lighting power density value (for wall display lighting in merchandise sales and showroom areas of retail sales) is 11.5 W/ft as indicated in column 3 of Table 140.6-D. Therefore, the wall display lighting is 300 ft. x 11.5 W/ft. = 3,450 W..
Note that in the Tailored Method, the wall display lighting allowance is a use-it-or-lose-it allowance.
The additional allowed power for wall display lighting is the smaller of:
- The wall display lighting power allowance of 3,450 W, as calculated from above.
- The adjusted lighting power used for the wall display lighting, 3,000 W.
Since the smaller of 3,450 W and 3,000 W is 3,000 W, the additional allowed power for wall display lighting is 3,000 W for the retail sales area in this store.
Example 5-26: Floor Display Lighting – Tailored Method (Continue – Part 3)
Question
If the adjusted lighting power of the floor display luminaires is 4,000 watts, what is the allowed floor display lighting power for this store?
Answer
The floor display allowance is computed from the area of the entire space with floor displays multiplied by the floor display lighting power density. Therefore, the allowed wattage is 5,000 ft² x 0.7 W/ft² = 3,500 W. The allowance is taken from column 4 of Table 140.6-D.
Note that in the Tailored Method, the floor display power allowance is a use-it-or-lose-it allowance.
The additional allowed power for floor display lighting is the smaller of:
- The floor display lighting power allowance of 3,500 W, as calculated from above.
- The adjusted lighting power used for the floor display lighting, 4,000 W.
Since the smaller of 3,500 W and 4,000 W is 3,500 W, the additional allowed power for floor display lighting is 3,500 W for the retail sales area in this store.
Example 5-27: Decorative/Special Effect Lighting – Tailored Method (Continue – Part 4)
Question
If the adjusted lighting power of the decorative/special effect luminaires is 4,000 watts, what is the allowed decorative/special effect lighting power for this store?
Answer
The decorative/special effect allowance is computed from the area of the entire space with floor displays times the decorative/special effect lighting power density. Therefore, the allowed wattage is 5,000 ft² x 0.35 W/ft² = 1,750 W. The allowance is taken from column 5 of Table 140.6-D.
Note that in the Tailored Method, the decorative/special effect lighting allowance is a use-it-or-lose-it allowance.
The additional allowed power for decorative/special effect lighting is the smaller of:
- The decorative/special effect lighting power of 1,750 W, as calculated from above.
- The adjusted lighting power used for the decorative/special effect lighting, 4,000 W.
Since the smaller of 1,750 W and 4,000W is 1,750 W, the additional allowed power for decorative/special effect lighting is 1,750 W for the retail sales area in this store. The decorative/special effect lighting must be redesigned so that the adjusted wattage is reduced to no more than 1,750 W or the excess wattage must be taken from the general lighting power allowance provided there is extra wattage available.
Example 5-28: Very Valuable Display Case Lighting – Tailored Method (Continue – Part 5 of 5)
Question
If the adjusted lighting power of the very valuable display case lighting is 1,200 watts, what is the allowed very valuable display case lighting power for this store?
Answer
The allowed wattage for very valuable display case top is smaller of the product of 0.50 W/ft² and the gross sales area (5,000 ft²) or the product of 7 W/ft² and the actual area of the case tops (100 ft²) or the adjusted lighting power of the very valuable display case lighting.
The allowed lighting power is the smaller of one of the following:
- 0.50 W/ft² X 5,000 ft² = 2,500 watts
- 7 W/ft² X 100 ft² = 700 watts
- The adjusted lighting power of very valuable display case lighting, 1,200 watts.
Therefore, the additional allowed power for very valuable display case lighting is 700 W.
The very valuable display case lighting will need to be redesigned to reduce the adjusted wattage to no more than 700 W, or the excess wattage must be taken from the general lighting power allowance provided there is extra wattage available.
Example 5-29: Retail Space – Full Height Partitions
Question
A large retail store with a sales area that has a 14-foot high ceiling and full height perimeter wall also has several other walls and a high fixture element in the space. Based on the definition of “full-height” interior partitions (per §140.6[c]3Giii), which components qualify for the wall display lighting allocation?
Answer
The figure below shows full height interior partitions and partial height interior partitions.
Figure 5-23: (Example 5-29) Retail Lighting in Application — Partitions Qualifying for Wall Display Lighting Power Under Tailored Method
Image Source: California Energy Commission
Full height interior partitions extend from the floor to within two feet of the ceiling or are taller than 10 feet. Full height partitions must also be permanently anchored to the floor.
Example 5-30: Wall Display Lighting in a Retail Store – Tailored Method
Question
In the following figure, Condition A has 2 x 4 troffers placed 3 feet from a perimeter sales wall as well as fluorescent wall-washers 5 feet from the sales wall. Condition B has fluorescent wall-washers 3 feet from the wall and PAR adjustable accent lights 5 feet from the wall. Which luminaires qualify for the wall display lighting allocation?
Answers
Figure 5-24: (Example 5-30) Retail Lighting in Application — Walls Qualifying for Wall Display Lighting Power Under Tailored Method
Image Source: California Energy Commission
Per §140.6(c)3Giia, qualifying lighting must be mounted within 10 feet of the wall and must be an appropriate wall lighting luminaires. (Luminaires with asymmetric distribution toward the wall or adjustable directed toward the wall).
CONDITION A
While both luminaires are within 10 feet of the wall only the wall-washer qualifies for the wall display allocation. The 2 x 4 troffer is a general lighting luminaire with symmetric distribution and does not qualify for the allocation.
CONDITION B
Both luminaires are within 10 feet of the wall, and both qualify for the wall display allocation. The fluorescent wall-washer has an asymmetric distribution and the PAR accent light at 5 feet from the wall provides directional light.
Example 5-31: Lighting Power Adjustments for Luminaire Mounting Height – Tailored Method
Figure 5-25: (Example 5-31) Lighting Power Adjustments for Luminaire Mounting Height
Image Source: California Energy Commission
Question
A high ceiling space with allowed display lighting has wall-washers mounted on the ceiling near the wall and accent lights mounted on suspended track in the center of the space. Because of the 14-foot high ceiling, does the display lighting qualify for a mounting height factor adjustment?
Answer
Per §140.6(c)3Givand 3Hviii, both the wall-washers and accent lights qualify for the mounting height adjustment as they are mounted at height greater than 10 feet 6 inches and they also provide directional light.
If the track is suspended at 10 feet instead of 11 feet, it is excluded from an adjustment factor and must use the default factor of one with the allowed LPD as shown in column four in Table 140.6-E.