prescriptive approach

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





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





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

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





Are the installed controls all mandatory? Do any exceed the standards?

SLIDE 195

104W

SECTION 9

CONFERENCE ROOM





Allowed wattage is determined by multiplying the square footage of the

space by the allowed watts per square foot in Table 140.6-C.

SLIDE 196

104W

93W

SECTION 9

CONFERENCE ROOM





Does the space comply? Is our adjusted installed wattage less than the

allowed wattage?

SLIDE 197

104W

83W

371W

SECTION 9

CLASSROOM

Actual installed: 56W linear pendants x 6 =

PAF Adjustment: (partial on occupancy control in a classroom)

Adjusted Installed:

Allowed: 643 ft2 x 1.2W per ft2 =

Does it comply?

SLIDE 198

SECTION 9

CORRIDORS

Actual installed: 12W recessed down light x 13 =

PAF Adjustment:

Adjusted Installed:

Allowed: 512 ft2 x 0.6W per ft2 =

Does it comply?

SLIDE 199

SECTION 9

BRINGING IT ALL TOGETHER

Conference Room:

Classroom:

Corridors:

TOTAL:

SLIDE 200

SECTION 5

FORMS FOR AREA CATEGORY METHOD

SLIDE 201

CEC-NRCC-LTI-01-E

SECTION 5


SLIDE 202

CEC-NRCC-LTI-03-E

SECTION 5


SLIDE 203

CEC-NRCC-LTI-03-E

SECTION 5

FORMS FOR MANDATORY CONTROLS REQUIREMENTS

SLIDE 204

CEC-NRCC-LTI-02-E

SECTION 5

FORMS FOR MANDATORY CONTROLS REQUIREMENTS

SLIDE 205

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 207

SECTION 5

CHANGES TO 140.6-D

SLIDE 208

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 209

SECTION 9

EXTERIOR SPACES

SLIDE 210

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 211

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 212

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 213

SECTION 9


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 214

SECTION 5

CALCULATING THE ILLUMINATED AREA

SLIDE 215

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


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 216

SECTION 9


SLIDE 217

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 218

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 220

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 221

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 222

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:

SLIDE 223

prescriptive approach

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