PRESCRIPTIVE APPROACH
1. Actual and Allowed LPD
2. Complete Building Method
3. Area Category Method
4. Tailored Method
SECTION 9
THE COMPLIANCE PROCESS
There are two major steps to Title 24 compliance:
1. Meet all mandatory requirements by installing required controls and
devices and ensuring that they have all of the required functionality.
2. Meet all prescriptive or performance requirements by ensuring that the
actual lighting power installed in a space is less than the allowed lighting
power for that space.
SLIDE 173
SECTION 9
ACTUAL LIGHTING POWER
The actual indoor lighting power of the proposed building area is the
total wattage of all planned, permanent and portable lighting systems,
adjusted by the following:
1. Reduction of wattage through controls
2. Lighting wattage exclusions
3. Up to 0.3 W/ft2 of portable lighting for office areas ONLY is excluded
SLIDE 174
SECTION 9
ACTUAL LIGHTING POWER: REDUCTION THROUGH CONTROLS
If you exceed the mandatory controls
requirements by installing a control where
it is not required, you are eligible for a
Power Adjustment Factor (PAF). This
will result in a lower calculated lighting
power use for the installed system.
( Controlled W ) X ( PAF from 140.6-A )
= Lighting Power Reduction
For example, a 480 ft2 open office plan
with an occupancy control is eligible for a
PAF of 0.2. Given that the controlled
lighting in that space totaled 100W :
(100W) X (0.2) = 20W of excluded
lighting power (80W total)
SLIDE 175
SECTION 5
T24 2013 Power Adjustment Factors
SLIDE 176
SECTION 9
ACTUAL LPD: LIGHTING WATTAGE EXCLUDED
Wattage of many lighting applications may be excluded, including:
• Studio lighting for film or photography and for a videoconferencing studio
• Equipment that is for sale and for demonstration
• Lighting installed by the manufacturer in vending machines, scientific and
industrial equipment, refrigerated cases, walk-in freezers, and food
preparation equipment
SLIDE 177
Photo: Jessie Whiteman
SECTION 9
ALLOWED LIGHTING POWER
The allowed indoor lighting power for each building or area is
calculated using one of the following methods:
• Complete Building
• Area Category
• Tailored Method
Each of these methods involves multiplying the square footage of a space by
the allowed wattage per square foot for that space.
SLIDE 178
COMPLETE BUILDING METHOD
SECTION 9
COMPLETE BUILDING METHOD
The Complete Building Method may only be used on projects involving entire
buildings with one primary type of use or in mixed-use buildings or tenant spaces
where 90% of the spaces have one primary use.
This is the simplest way to comply with the Standards, and many will attempt this
method first before trying one of the two more complex methods.
(TABLE 140.6-B ) X (floor area of entire building ) = Allowed Lighting Power
SLIDE 180
SECTION 5
CHANGES TO 140.6-B
SLIDE 181
TYPE OF BUILDING
ALLOWED LIGHTING POWER DENSITY
(WATTS PER SQUARE FOOT)
2013 2008
Office Building
0.85
0.8
0.8 0.85
SECTION 9
COMPLETE BUILDING METHOD EXAMPLE
A 3,000 square foot office building uses a total of 2,500W of lighting, 500W of
which is portable lighting on desks. More than 90% of the building is used for
office space. Does this space comply using the Complete Building Method?
Step 1: 0.3 W/ft2 of portable lighting for office areas is excluded.
0.3W x 3,000ft2 = up to 900W excluded (all 500W in our case)
Adjusted actual installed lighting = 2,500W – 500W = 2,000W
SLIDE 182
SECTION 9
COMPLETE BUILDING METHOD EXAMPLE
A 3,000 square foot office building uses a total of 2,500W of lighting, 500W of
which is portable lighting on desks. More than 90% of the building is used for
office space. Does this space comply using the Complete Building Method?
Step 2: Determine allowed lighting using Table 140.6-B
Offices = 0.8W/ft2 allowed
3,000ft2 x 0.8W/ft2 = 2,400W allowed
SLIDE 183
SECTION 9
COMPLETE BUILDING METHOD EXAMPLE
A 3,000 square foot office building uses a total of 2,500W of lighting, 500W of
which is portable lighting on desks. More than 90% of the building is used for
office space. Does this space comply using the Complete Building Method?
Step 3: Does it comply?
2,400W allowed
2,000W installed after adjustments
YES! This space is compliant!
SLIDE 184
SECTION 5
FORMS FOR COMPLETE BUILDING METHOD
SLIDE 185
CEC-NRCC-LTI-01-E
SECTION 5
FORMS FOR COMPLETE BUILDING METHOD
SLIDE 186
CEC-NRCC-LTI-03-E
SECTION 5
FORMS FOR PORTABLE LIGHTING IN OFFICES
SLIDE 187
NRCC-LTI-01-E
AREA CATEGORY METHOD
SECTION 9
AREA CATEGORY METHOD
The total allowed lighting power for the building is the sum of all allowed lighting power
calculations for all areas in the building. An “area” is defined as all adjacent spaces
which are associated with a single function type, as listed in TABLE 140.6-C.
(TABLE 140.6-C ) X (floor area) = Allowed Lighting Power for that area
SLIDE 189
SECTION 5
CHANGES TO 140.6-C
SLIDE 190
PRIMARY FUNCTION AREA
ALLOWED LIGHTING
POWER (W/ft2)
2013 2008
Office Area > 250 ft2 0.75 0.9
Office Area ≤ 250 ft2 1 1.1
AREA CATEGORY METHOD EXAMPLE
SLIDE 191
SECTION 5
LIGHTING SCHEDULE
Luminaire Type Example Wattage Quantity
Classroom
1x8 linear pendant Linear Fluorescent T8 Finelite series 12-ID 56 6
Corridor
Recessed downlight Integral LED Cree CR6 12 13
Conference Room
Recessed downlight Integral LED Cree CR6 12 4
1x8 linear pendant Integral LED Finelite series 12-ID 56 1
Controls: 1. Both the conference room and classroom have manual dimmer switches
2. corridors are controlled with occupancy sensors that dim to 40% when vacant
3. Linear pendants are equipped with integral occupancy sensors that shut off lighting
completely when vacant and allow partial-on control.
SLIDE 192
SLIDE 193
Conference Room
265 ft.2
Classroom
643 ft.2
Corridors
512 ft.2
SECTION 9
CONFERENCE ROOM
Step 1: Calculate actual installed wattage
Step 2: Adjust actual wattage using Power Adjustment Factors
Step 3: Calculate allowed wattage
Step 4: Determine compliance (actual < allowed)
SLIDE 194
SECTION 9
CONFERENCE ROOM
Step 1: Calculate actual installed wattage
Step 2: Adjust actual wattage using Power Adjustment Factors
Step 3: Calculate allowed wattage
Step 4: Determine compliance (actual < allowed)
4x Recessed Downlight 4 x 12W = 48W
1x Linear Pendant 1 x 56W = 56W
TOTAL 104W
SLIDE 195
104W
SECTION 9
CONFERENCE ROOM
Step 1: Calculate actual installed wattage
Step 2: Adjust actual wattage using Power Adjustment Factors
Step 3: Calculate allowed wattage
Step 4: Determine compliance (actual < allowed)
Are the installed controls all mandatory? Do any exceed the standards?
The conference room has partial-on capable integral occupancy controls in
the linear pendants that are not required by the code. They are eligible for a
Power Adjustment Factor of 0.2 from Table 140.6-A.
We can reduce the installed wattage by:
56W x 0.2 PAF = 1W (93W installed after adjustment)
SLIDE 196
104W
93W
SECTION 9
CONFERENCE ROOM
Step 1: Calculate actual installed wattage
Step 2: Adjust actual wattage using Power Adjustment Factors
Step 3: Calculate allowed wattage
Step 4: Determine compliance (actual < allowed)
Allowed wattage is determined by multiplying the square footage of the
space by the allowed watts per square foot in Table 140.6-C.
265 ft2 x 1.4W per ft2 = 371 W allowed
SLIDE 197
104W
93W
371W
SECTION 9
CONFERENCE ROOM
Step 1: Calculate actual installed wattage
Step 2: Adjust actual wattage using Power Adjustment Factors
Step 3: Calculate allowed wattage
Step 4: Determine compliance (actual < allowed)
Does the space comply? Is our adjusted installed wattage less than the
allowed wattage?
Yes! We have 93W installed and are allowed 371W. This portion of the floor
plan is compliant with Title 24.
SLIDE 198
104W
83W
371W
SECTION 9
CLASSROOM
Actual installed: 56W linear pendants x 6 = 336W
PAF Adjustment: 0.2 (partial on occupancy control in a classroom)
Adjusted Installed: 269W
Allowed: 643 ft2 x 1.2W per ft2 = 772W
Does it comply?
Yes! We have 269W installed and are allowed 772W.
SLIDE 199
SECTION 9
CORRIDORS
Actual installed: 12W recessed down light x 13 = 156W
PAF Adjustment: None
Adjusted Installed: 156W
Allowed: 512 ft2 x 0.6W per ft2 = 307W
Does it comply?
Yes! We have 156W installed and are allowed 307W.
SLIDE 200
SECTION 9
BRINGING IT ALL TOGETHER
Conference Room: 93W / 371W
Classroom: 269W / 772W
Corridors: 156W / 307W
TOTAL: 518W / 1450W
Our space complies with quite a bit of room to spare.
SLIDE 201
SECTION 5
FORMS FOR AREA CATEGORY METHOD
SLIDE 202
CEC-NRCC-LTI-01-E
SECTION 5
FORMS FOR AREA CATEGORY METHOD
SLIDE 203
CEC-NRCC-LTI-03-E
SECTION 5
FORMS FOR AREA CATEGORY METHOD
SLIDE 204
CEC-NRCC-LTI-03-E
SECTION 5
FORMS FOR MANDATORY CONTROLS REQUIREMENTS
SLIDE 205
CEC-NRCC-LTI-02-E
SECTION 5
FORMS FOR MANDATORY CONTROLS REQUIREMENTS
SLIDE 206
CEC-NRCI-LTI-05-H
TAILORED METHOD
SECTION 9
TAILORED METHOD
• Allowances for each area (just like area category)
• Allowances for display and task lighting within an area
Allowed lighting power is determined by the space’s occupancy type
and physical characteristics (e.g., ceiling height).
See Table 140.6-D for details.
SLIDE 208
SECTION 5
CHANGES TO 140.6-D
SLIDE 209
1 2 3 4 5
Primary Function Area
General
Illumination
Level (Lux) Wall Display
Allowed
Combined
Allowed
Ornamental
2013 2013 2008 2013 2008 2013 2008
Financial Transaction Area 300 3.15 3.15 0.2 0.2 0.5 0.6
Malls and Atria 300 3.5 3.5 0.5 0.5 0.5 0.6
Retail Merchandise Sales,
and Showroom Areas 400 14 17 1 1.2 0.5 0.7
SECTION 9
ALLOWANCES UNDER THE TAILORED METHOD
The Tailored Method adds additional lighting power allowances for:
• Wall displays
• Floor displays
• Task lighting
• Ornamental/special effects lighting
• Very valuable display cases
These lighting power allowances cannot be used in any space other
than the display or task area. Any wattage not covered by these
allowances must be deducted from the general lighting allowance for
that area.
SLIDE 210
SECTION 9
EXTERIOR SPACES
SLIDE 211
Photo: Cree
EXTERIOR SPACES
SECTION 9
LIGHTING ZONES
Lighting Zone 1: Government parks, recreation areas and wildlife preserves
Ambient Illumination: Dark
The local entity with authority over the property will know if the property is a
government designated park, recreation area or wildlife preserve. If the park is
within a rural or urban area, it might have a higher lighting zone classification.
Lighting Zone 2: Rural Areas
Ambient Illumination: Low
Rural areas are populated with fewer than 2,500 people.
SLIDE 212
SECTION 9
LIGHTING ZONES
Lighting Zone 3: Urban Areas
Ambient Illumination: Medium
An urban area is a densely settled core of a census tract that
contains at least 2,500 people.
Lighting Zone 4: Special Use District
Ambient Illumination: High
This zone may only be created by a local government through
application to the California Energy Commission and is used for
special area types that require a particularly high amount of light.
SLIDE 213
SECTION 9
LIGHTING POWER ALLOWANCES
The allowed lighting power for a space is determined by measuring
the area of the installation and multiplying this number by the lighting
power allowance for that space.
The actual lighting power is equal to the total watts of all non-
exempt lighting systems (including ballast, driver, transformer).
SLIDE 214
SECTION 9
LIGHTING POWER ALLOWANCES
When determining allowed lighting power, the number of luminaires, their
mounting heights, and their layout affect the size of the illuminated area
and thus the allowed lighting power for a space.
The illuminated area is any hardscape area within a square around
each luminaire or pole, less any obstructions. The size of this square is
10 times the luminaire mounting height, with the luminaire in the
middle of the square.
SLIDE 215
SECTION 5
CALCULATING THE ILLUMINATED AREA
SLIDE 216
For a pole with a 20 ft. mounting
height, our illuminated area
would be a square with:
20ft. x 10ft. = 200 ft. sides
20 ft. pole at the center
of illuminated area
200 ft. sides
100 ft. from pole to
edge of illuminated area
SECTION 9
LIGHTING POWER ALLOWANCES
Three major areas are considered when determining the allowed
lighting power for a space:
Area Wattage Allowances (AWA)
Determined for the total illuminated hardscape area.
Linear Wattage Allowances (LWA)
Determined for the total perimeter length of the hardscape, not
including areas that are not illuminated.
Initial Wattage Allowances (IWA)
This may be used once per project site to provide additional
wattage for small sites or unusual hardscape geometries.
SLIDE 217
SECTION 9
LIGHTING POWER ALLOWANCES
SLIDE 218
SECTION 9
PLANTERS AND LANDSCAPE AREAS
Planters and small landscape areas are included within the general
hardscape area as long as the width or length of the inclusion is less
than 10 ft, and the inclusion is bordered on at least three sides.
Landscape areas that are greater than 10 ft in both width and length
are excluded from the general hardscape area calculation, but the
perimeter of these exclusions may be included in the linear wattage
allowance (LWA) calculation.
SLIDE 219
SECTION 9
STEP 1: DETERMINE THE ILLUMINATED AREA
The illuminated area is 10x the mounting height of the pole.
The mounting height of our poles is 25’, so the illuminated area for each pole
is 10 x 25, or 250ft x 250ft.
The corner planters are excluded from the illuminated area because they are
larger than 10 ft in both width and length.
The center island is included because it has a width of only 5 ft.
SLIDE 221
SECTION 9
STEP 2: CALCULATE THE AREA AND PERIMETER
The total included hardscape area is:
Entire square: (100 x 100) = 10,000 ft2
- Corner cutouts: 4 x (20 x 20) = -1,600 ft2
+ Entryway: (15 x 10) = +150 ft2
TOTAL = 8,550 ft2
The total perimeter area is:
3 Long Sides = 3 x 60 = 180 ft
8 Cutout Sides = 8 x 20 = 160 ft
1 Short Side = 1 x 45 = 45 ft
2 Entry Sides = 2 x 10 = 20 ft
TOTAL = 405 ft
SLIDE 222
SECTION 9
STEP 3: CALCULATE ALLOWANCES
Using Table 140.7-A we can determine the Initial, Area and Perimeter
Wattage Allowances for the area.
SLIDE 223
ALLOWANCE
TYPE ALLOWANCE SPACE SIZE
POWER
ALLOWANCE
Initial 770W - 770W
Area 0.09 W/sq. ft. 8,550 sq. ft. 770W
Perimeter 0.60 W/ft. 405 ft. 243W
SECTION 9
EXTERIOR EXERCISE: STEP 4 – DOES IT COMPLY?
Assuming each pole is using 300W of lighting power, does the space
comply?
Initial: 770W
Area: 770W
Perimeter: 243W
TOTAL: 1,783W
Yes, this space complies. It is allowed to use 1,783W of lighting
power and is only using 600W.
SLIDE 224