PRESCRIPTIVE APPROACH · SLIDE 209 CEC-NRCI-LTI-05-H 7/31/2014 PRESCRIPTIVE METHOD . TAILORED...

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 175 7/31/2014 PRESCRIPTIVE METHOD

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


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)


SECTION 5

T24 2013 Power Adjustment Factors


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 179

Photo: Jessie Whiteman

7/31/2014 PRESCRIPTIVE METHOD

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.


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


SECTION 5

CHANGES TO 140.6-B

SLIDE 183

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 ft2 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 3,000 ft2 = up to 900W excluded (all 500W in our case)

Adjusted actual installed lighting = 2,500W – 500W = 2,000W


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


SECTION 9





Step 3: Does it comply?

2,400W allowed

2,000W installed after adjustments

YES! This space is compliant!


SECTION 5

FORMS FOR COMPLETE BUILDING METHOD

SLIDE 187

CEC-NRCC-LTI-01-E


SECTION 5

FORMS FOR COMPLETE BUILDING METHOD

SLIDE 188

CEC-NRCC-LTI-03-E


SECTION 5

FORMS FOR PORTABLE LIGHTING IN OFFICES

SLIDE 189

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.

(Allowed W/ft2 per Table 140.6-C ) X (ft2 of the area)

= Allowed Lighting Power for that area


SECTION 5

CHANGES TO 140.6-C

SLIDE 192

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 193

SECTION 5

LIGHTING SCHEDULE

Luminaire Source Type Product Example Installed Power Quantity

Classroom

1x8 linear pendant Linear Fluorescent T8 Finelite series 12-ID 59W 6

Corridor

Recessed downlight Integral LED Cree CR6 12W 13

Conference Room

Recessed downlight Integral LED Cree CR6 12W 4

1x8 linear pendant Linear Fluorescent T8 Finelite series 12-ID 59W 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 lights off

completely when the area is vacant and allow partial-on control


Conference Room

265 ft2

Classroom

643 ft2

Corridors

512 ft2

SECTION 9

CONFERENCE ROOM

Step 1: Calculate actual installed power (watts)

Step 2: Adjust actual power using Power Adjustment Factors

Step 3: Calculate allowed power (watts)

Step 4: Determine compliance (actual < allowed)


Photo: Cree, Inc.

SECTION 9

CONFERENCE ROOM

Step 1: Calculate actual installed power

Step 2: Adjust actual wattage using Power Adjustment Factors

Step 3: Calculate allowed power


4x Recessed Downlight 4 x 12W = 48W

1x Linear Pendant 1 x 59W = 59W

TOTAL 107W

SLIDE 197

107W


SECTION 9

CONFERENCE ROOM


Step 2: Apply Power Adjustment Factors

Step 3: Calculate allowed wattage


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

The linear pendant in the conference room has integral occupancy controls

with partial-on capability that are not required by the code, making it eligible

for a Power Adjustment Factor of 0.2 from Table 140.6-A.

We can therefore adjust the installed wattage:

59W x 0.2 PAF = 12W

107W - 12W = 95W after adjustment

SLIDE 198

107W

95W


SECTION 9

CONFERENCE ROOM



Step 3: Calculate allowed power


Allowed lighting power is determined by multiplying the square footage

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

Allowed Wattage = ft2 of the space x allowed W/ft2 in Table 140.6-C

265 ft2 x 1.4W/ft2 = 371 W allowed

SLIDE 199

107W

95W

371W


SECTION 9

CONFERENCE ROOM

Step 1: Calculate actual installed wattage


Step 3: Calculate allowed wattage


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

allowed wattage?

Yes! We have 95W installed and are allowed 371W. This portion of the floor

plan is compliant with Title 24.

SLIDE 200

107W

95W

371W


SECTION 9

CLASSROOM

Actual installed: 59W linear pendants x 6 = 354W

PAF Adjustment: 0.2 (partial-on occupancy control)

Adjusted Installed: 283W

Allowed: 643 ft2 x 1.2W per ft2 = 772W

Does it comply?

Yes! We have 283W installed and are allowed up to 772W.


SECTION 9

CORRIDORS

Actual installed: 12W recessed downlight 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.


SECTION 9

BRINGING IT ALL TOGETHER

Conference Room: 95W / 371W

Classroom: 283W / 772W

Corridors: 156W / 307W

TOTAL: 518W / 1450W

Our space complies and is well below the maximum allowed power.


Photo: Acuity Brands Photo: Cree, Inc.v Photo: Cree, Inc.

SECTION 9

WHAT IF IT DIDN’T COMPLY?

Let’s assume that our space used less efficacious products instead of the

LEDs. In this case, it is possible that our space would not comply. What

happens if…

1. The conference room was over its power allowance, but the other

spaces were under?

OR

2. All of the spaces are over their allowed lighting power limits?


SECTION 5

FORMS FOR AREA CATEGORY METHOD

SLIDE 205

CEC-NRCC-LTI-01-E


SECTION 5


SLIDE 206

CEC-NRCC-LTI-03-E


SECTION 5


SLIDE 207

CEC-NRCC-LTI-03-E


SECTION 5

FORMS FOR MANDATORY CONTROLS REQUIREMENTS

SLIDE 208

CEC-NRCC-LTI-02-E


SECTION 5

FORMS FOR MANDATORY CONTROLS REQUIREMENTS

SLIDE 209

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.


SECTION 5

CHANGES TO 140.6-D

SLIDE 212

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.


SECTION 9

EXTERIOR SPACES

Photo: Cree

EXTERIOR SPACES

Photo: Cree, Inc.

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.


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

LZ4 designation is only granted when the California Energy

Commission approves a local government’s application. LZ4 is used

for special area types that require exceptionally high light levels.


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).


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.


SECTION 5

CALCULATING THE ILLUMINATED AREA

SLIDE 219

For a pole with a 20 ft mounting

height, our illuminated area

would be 200 sq. ft.

20 ft pole at the center

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.


SECTION 9



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 over 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.


Photo Credit: Cree

SECTION 9

STEP 1: DETERMINE THE ILLUMINATED AREA

The illuminated area is 10x the mounting height of the pole.

Our two poles are both mounted at a height of 25 ft, so the

illuminated area for each pole is 10 x 25, or 250 ft x 250 ft.

The corner planters are excluded from the illuminated area because

they are longer than 10 ft in both width and length.

The center island is included because, at 5 ft wide, it falls under the

10 ft requirement.


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


SECTION 9

STEP 3: CALCULATE ALLOWANCES

Using Table 140.7-A we can determine the Initial, Area and Perimeter

Power Allowances for the area.

SLIDE 226

ALLOWANCE

TYPE

POWER

ALLOWANCE SPACE SIZE

AREA POWER

ALLOWANCE

Initial 770W – 770W

Area 0.09 W/ft2 8,550 ft2 770W

Perimeter 0.60 W/ft2 405 ft 243W


SECTION 9

EXTERIOR EXERCISE: STEP 4 – DOES IT COMPLY?

Assuming each of the two poles in our hardscape area uses 300W of

lighting power, does the lighting in this space comply?

Initial: 770W

Area: 770W

Perimeter: 243W

TOTAL: 1,783W

Yes, the lighting in this area complies. The area is allowed 1,783W

of lighting power and only uses 600W.


PRESCRIPTIVE APPROACH · SLIDE 209 CEC-NRCI-LTI-05-H 7/31/2014 PRESCRIPTIVE METHOD . TAILORED...

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