modelling for potential increases in lighting power ... · cynthia jolley-rogers is a lighting...

AIRAH and IBPSA’s Australasian Building Simulation 2017 Conference, Melbourne, November 15-16.

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MODELLING FOR POTENTIAL INCREASES IN LIGHTING POWER

DENSITY STRINGENCY IN SECTION J6 OF THE NCC

CYNTHIA JOLLEY-ROGERS Secretary, Canberra branch IESANZ, NSW Chapter

Energy Action Australia Pty Ltd

Suite H, 59-69 Lathlain Street

Belconnen ACT 2617

[email protected]

LYNLEY BOLAND Energy Action Australia Pty Ltd


Belconnen ACT 2617

[email protected]

PAUL BANNISTER, F.AIRAH, FIEAUST, MIPENZ Energy Action Australia Pty Ltd


Belconnen ACT 2617

[email protected]

ABOUT THE AUTHOR

Cynthia Jolley-Rogers is a lighting consultant with Energy Action and Secretary of the ACT branch

of the IESANZ. She has worked in lighting for 30 years, and in energy efficiency for 8 years.

Cynthia designs lighting upgrades, provides analysis on lighting energy efficiency policies,

strategies and training courses, and peer review for lighting designs for clients from a wide range of

industries, bodies and government departments. Cynthia has previously presented a paper at the

Improving Energy Efficiency in Commercial Buildings 2016 in Frankfurt on the pros and cons of

using LED in lighting upgrades.

ABSTRACT

Energy Action was engaged to provide analysis and recommendations on updating Section J for the

2019 version of the NCC (National Construction Codes), including Section J6 for Artificial

Lighting. The analysis involved running 20 lighting simulations across 14 models to test the

existing lighting IPD (W/m2) which were based on existing fluorescent and metal halide technology

and establish a baseline. A further 20 lighting simulations were run across the 14 models to provide

a test case exploring the possible stringency of new requirements which could be developed based

on current LED technology. This paper presents the results of these simulations and discusses some

of the insights revealed by our analysis of those results regarding the potential stringency of Section

J6 as LED technology increasingly becomes the main player in lighting efficiency.


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1. INTRODUCTION

1.1 Background

The National Construction Code (NCC) is seen as a major policy instrument which may address

rising energy prices and pressure for improved energy productivity and reduced greenhouse gas

emissions.

The NCC provides two methods for complying with energy efficiency requirements. The first is by

building simulation which provides an opportunity to calculate an entire building’s energy

efficiency including all services and the building fabric. This means that trade-offs between more or

less efficient services or structures can be made, but the building must meet the energy efficiency

requirements as a whole. The second method for complying with NCC energy efficiency

requirements is by complying with the Deemed to Satisfy clauses.

The provisions of NCC Volume 1 Section J – Energy Efficiency Deemed to Satisfy clauses

comprise parts 1 through 8. This paper is concerned with Section J6 which deals with the energy

efficiency of artificial lighting in commercial building interiors and perimeters and includes many

technical concepts which are specific to lighting. Definitions are provided for words and concepts in

the Nomenclature section of this paper. All words with definitions provided have been italicised.

Section J6 covers interior lighting and perimeter lighting in separate sections, and using different

methods. Interior lighting energy efficiency is primarily addressed through maximum requirements

for Illumination Power Density (IPD) as described in Table J6.2a of the Code, and adjustment

factors for unusual room aspect ratios (RAR) and for lighting controls. Some alternative

requirements are described for specific lighting situations such as track lighting and perimeter

lighting.

Section J6 was first introduced along with the rest of Section J in 2006. Parts of Section J were

updated in 2009, but the improved efficiencies afforded by electronic ballasts and T5 fluorescent

tubes prompted only marginal improvements to the efficiency requirements of lighting. This is clear

from the maximum IPDs still required by the 2017 code which are very easily achieved using

technology which was in wide use in 2009.

Since 2009, lighting technology has advanced at such a rate that the industry is now barely

recognisable as the same industry which functioned at the time that Section J6 was first introduced.

In fact, lighting technology has advanced to such an extent that in 2017 the maximum IPDs

required by the existing code are regularly double the IPDs achieved in the most routine lighting

designs.

The key brief for the current project was therefore to investigate the viability of increasing the

stringency of Section J6 through data collection, simulation, calculation and analysis to match

current economic, construction and environmental circumstances for updates in the 2019 version of

the NCC.

For lighting this meant that a base case was required in order to understand where the industry had

arrived in terms of pre-LED technology’s performance against the existing code. The base case was

set up via a series of simulations using pre-LED technology and the results of these simulations

were compared to the requirements of the existing code.


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The question of how LED would perform compared with pre-LED technology was then analysed

using a series of test case simulations and the results of these simulations were used to propose new

IPD requirements for the code.

2. METHODOLOGY

2.1 Simulations

A base case simulation was created in AGi32 version 17.4 with 16 standard rooms. Each standard

room is a model – numbered 1 through 16. The 16 models are defined by their Room Aspect Ratio

(RAR).

Section J6 defines the equation for Room Aspect Ratio (RAR) as: 𝐴

𝐻 𝑥 𝐶

where A= the area of the room, H= ceiling height and C=the perimeter of the room.

The first 11 models have an RAR below 1.5, and qualify under the existing rules for use of an

adjustment factor to increase the required IPD. The last 5 have an RAR above 1.5 and do not qualify

for the use of an adjustment factor under the existing rules.

Section J6 defines the equation for the RAR adjustment factor as:

0.5 + (𝑅𝐴𝑅/3)

The maximum required IPD is divided by result of this equation to increase the maximum allowed

IPD for that space.

Standard room shapes were selected to represent space types typically encountered in most

buildings. The standard room shapes were:

• a long thin rectangle representing a corridor or a long thin room;

• a short fat rectangle representing a square or nearly square room, and

• an L-shape room representing a room with unusual shapes or which contains corners.

Each room area was allocated a room shape which correspondended to the typical shape or use for a

room of that size for most buildings. Table 1 lists the range of standard room models with their

corresponding room areas, room aspect ratios (RAR) and room shapes which were used in the

simulations.


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Model number Room area (m2)

Ceiling heights (m)

RAR Room shape

1 15 10.0 0.05 Long thin rectangle

2 15 10.0 0.10 Short fat rectangle


4 100 5.0 0.33 L-shape



7 100 2.7 0.62 L-shape

8 100 2.4 0.69 L-shape









Table 1. Standard rooms simulated in AGi32

To deliver the project within the required timelines some trade offs were required. To prevent the

calculation speed of the simulations from running overly long, the impact of windows, furniture and

furnishings absorbing light was compensated for by setting the rooms surface reflectances to very

low levels.

The first group of simulations were used to establish models which could achieve:

• the targeted maximum IPD for

• a maintained average of 320 lux

• on a working plane of 0.7m with

• AGi32 pre-set surface reflectances of Floor = 0.2, Walls = 0.5, Ceiling = 0.8

• A maintenance factor of 0.8 using

• T8 fluorescent recessed troffers.

The maintained averages achieved were well above the recommended levels.

A number of simulations were run, gradually reducing the surface reflectance’s to a level where the

IPD became more difficult to achieve and the average maintained illuminance levels dropped by 12-

18%, but still achieved the target. From this point all models used the very poor surface reflectance’s

of Floor = 0.1, Walls = 0.2, Ceiling = 0.2, which would essentially be an almost black room.

Models 1 and 2 were discarded from further simulations because their geometry was unrealistic;

their ceiling heights for such small areas not being representative of any space which would require

artificial lighting.

Table 2 lists the simulations run for each of the illuminance targets in each model. Notice in Table 2

that average maintained illuminance levels recommended in AS/NZS1680 relate to specific tasks or


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work spaces, and most of these spaces come in a range of shapes. However the target of 800 lux

relates only to the daylight adjustment zone of car park entry ramps which are all long thin spaces

by their nature.

Note also in Table 2 that the NCC mandates a minimum illuminance for safe movement, which is

described in AS/NZS1680.0 as 20 lux, however since targeting an average of 40 lux generally

achieves a minimum of 20 lux no extra simulations were run for the target of 20 lux minimum.

Illuminance targets per room shape

Long thin

rectangle

Short fat

rectangle L-shape

2016 maximum

illumination

Power Density

(W/m²)

1 N/A N/A

20 20 N/A

40 40 40 6

80 80 80 5

160 160 160 7

240 240 240 8

320 320 320 9

600 600 600 15

800 N/A N/A 25

Retail Retail Retail N/A

Table 2. Illuminance targets simulated for each room shape.

A base case was created for all maintained average illuminance targets to find the capacity of pre-

LED technology to meet existing IPD requirements and ensure that the simulations could achieve

those existing requirements.

The base cases used the following technology types:

• T5 and T8 linear fluorescent troffers and battens

• Metal halide (MH) high bays (HB)

• Compact fluorescent (CFL) down lights (DL)

• Metal halide (MH) down lights (DL)

Linear fittings and downlight scenarios were modelled separately. For models with very high

ceilings in simulations where high illuminance levels where required, linear fittings were

inadequate for the job so high bay fittings were used.

Existing adjustments for RAR were applied to achieve the required IPD in rooms with an RAR that

qualified for that adjustment, where required, though at all times the maximum IPD without

recourse to the adjustment for RAR was targeted.

A further series of test case simulations was run to test how low the IPD could be reduced while

achieving the target maintained illuminance using LED technology for each model and illuminance

target, using adjustments for RAR only where absolutely necessary.


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The test cases used the following LED luminaire types:

• Troffers and battens

• High bays (HB)

• Down lights (DL)

2.2 Retail simulations

Retail lighting posed its own issues. There are no Australian Standards on which to base target

illuminance for retail. To source target illuminance levels for retail lighting we measured the

average illuminance of the shops at the local mall and compared the results to the recommended

retail illuminance targets provided in the CIBSE SLL Lighting Guides. The Society of Light and

Lighting (SLL) are part of CIBSE in the UK.

Table 3 shows the results of illuminance measurements taken in shops at Belconnen Mall in

Canberra in January 2017 using a calibrated Hagner brand illuminance (lux) meter. The technology

in the first 4 shops was predominantly linear fluorescent, and in the last shop was LED. This audit

indicated that illuminance levels in Australian shops with fluorescent technology range between 330

to 1,000 lux and that at least some shops using LED technology are exessively bright with

illuminance levels above 2,000 lux.

Retailer Average vertical

illuminance on a

selection of shelves

Average horizontal

illuminance on

merchandise

Average illuminance

on floor

Supermarket 1 336, 373 986 465, 483

Supermarket 2 332, 389 666 498

Department store 1 446, 1175 822 796

Department store 2 332, 375, 378, 723 585 609

Jewellery store 1830, 1720, 1320 1254, 2206

Table 3. Average illuminances measured in retailers at Belconnen Mall, January 2017

The Society of Light and Lighting (SLL) recommend between 500-1,000 lux vertical illuminance on

merchandise for low budget shops, 100 – 200 lux plus accent lighting on merchandise in high

budget shops, and 250- 500 lux on merchandise with some accent lighting on merchandise in value

for money and quality profile shops.

In arriving at a target illuminance for the retail sector for use in simulations for this project,

consideration was given to the difference in recommended illuminance between Australian offices

and European offices. The Australian Standards recommend a maintained average of 320 lux on the

task in an office, while European standards call for 500 lux. Given the existing Australian retail

illluminance levels tend to be around the 300-400 lux range, with some spikes up to 700 or 1,000

lux, and CIBSE’s recommendations sit between 500 and 1,000 lux for their brighter shops, a

recommended target of between 250-500 lux on the merchandise could be reasonably interpolated

for Australia, with circulation style levels of 160-240 lux on the floor.


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In order to achieve the various horizontal and vertical illuminance targets the lighting technology

types were combined in the retail lighting simulations. The base case retail simulation used the

following technology types in the one simulation:

• T5 linear fluorescent battens

• Metal halide (MH) high bays (HB)

• Metal halide (MH) down lights (DL)

The LED retail simulation used LED down lights (DL) and shop lighters.

3. RESULTS

Table 4 shows the IPD results achieved in the simulations with pre-LED technology and with LED

technology for each of the illuminance targets (lux levels) recommended in AS/NZS1680.

Item 40 lux 80 lux 160

lux

240

lux

320

lux

400

lux

600

lux

Retail

250-

500

lux

800

lux

Existing max

basic IPD 6 5 7 8 9 10 15 22 25

Base case

Fluorescent,

CFL & MH

max basic IPD

1.58 2.16 4.03 6.3 7 8.5 14 22 16.9

Test case

LED max

basic IPD

0.83 1.04 2.3 2.9 4.2 5.8 9.6 13.8 11.2

Recommended

new max basic

IPD

1 1.5 2.5 3 4.5 6 10 14 11.5

Table 4. IPD results achieved in base & test cases.

From the simulation results it was determined that the current code requirements could be readily

surpassed with pre-LED technology, and that the use of LED fittings allows the extent of

improvement to be increased further.

The bottom row of Table 4 shows the proposed new maximum IPDs based on the simulation

results.

Table J6.2a in Section J6 of the NCC lists the maximum required IPD requirements for a range of

space types and tasks based on recommended illuminance levels from AS/NZS1680. Table 5.

Proposed revised stringencies based on an update of Table J6.2a from the Deemed to Satisfy clauses

of Section J of the NCC

of this report shows Table J6.2a with the existing maximum IPD requirements next to the proposed

maximum IPD requirements. The proposed maximum IPD listed in Table 5 are all derived from the

recommended new maximum basic IPD in Table 4.


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Space types

Illuminance

target

2016

maximum

illumination

Power

Density

(W/m²)

Proposed 2019

maximum

illumination

Power Density

(W/m²)

Auditorium, church and public hall 160 10 2.5

Board room and conference room - during AV

presentation

Minimum of

20 lux 10 1

Board room and conference room -

intermittent use, minimal note taking or

reading

240 10 3

Board room and conference room - regular or

constant use, regular note taking or reading 320 10 4.5

Carpark – general 40 6 1

Carpark - entry zones (first 20m of travel

during the day) 800 25 11.5

Carpark - entry zones (first 20m of travel at

night) 160 25 2.5

Common rooms, spaces and corridors in a

Class 2 building 160 8 2.5

Control room, switch room and the like -

intermittent monitoring 240 9 3

Control room, switch room and the like -

constantly monitoring 320 9 4.5

Corridors 160 8 2.5

Courtroom 320 12 4.5

Dormitory of a Class 3 building used for

sleeping only 80 6 1.5

Dormitory of a Class 3 building used for

sleeping and study

160 in the

room, 320

on the desk

9 4.5

Entry lobby from outside the building 160-400 15 6

Health care - children's ward, infants wards,

emergency dept to operating room, bed head

reading

240 10 3

Health care - examination room 320 10 4.5

Health care - examination room in intensive

care and high dependency wards (use of task

lighting)

400 10 6

Health care - patient ward 160 7 2.5

Health care - other patient care areas including

corridors where cyanosis lamps are used -

wards and general transit areas

160 13 2.5

Health care - other patient care areas including

corridors where cyanosis lamps are used -

emergency dept to operating room

240 13 3

Kitchen and food preparation area 240 8 3


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Space types

Illuminance

target

2016

maximum

illumination

Power

Density

(W/m²)

Proposed 2019

maximum

illumination

Power Density

(W/m²)

Laboratory - artificially lit to an ambient level

of 400 lx or more 400 12 6

Library - stack and shelving area 160 12 2.5

Library - reading room 320 9 4.5

Lounge area for communal use in a Class 3 or

9c building 240 10 3

Museum and gallery - circulation, cleaning

and service lighting 160 8 2.5

Office - artificially lit to an ambient level of

200 lx or more 320 9 4.5

Office - artificially lit to an ambient level of

less than 200 lx 160 7 2.5

Plant room 80 5 1.5

Restaurant, café, bar, hotel lounge and a space

for the serving and consumption of food and

drinks

80-400 18 6

Retail space including a museum and gallery

whose purpose is the sales of objects 250-500 22 14

School - general purpose learning areas and

tutorial rooms

320 on

desks 8 4.5

Sole occupancy unit of a Class 3 building 160 5 2.5

Sole occupancy unit of a Class 9c building 160 7 2.5

Storage with shelving higher than 75% of the

height of the aisle lighting 80 8 1.5

Service area, cleaner's room and the like 80 10 1.5

Toilet, locker room, staff room, rest room and

the like 80 5 1.5

Wholesale storage and display area 80 6 1.5

Stairs 80 10 1.5

Fire stairs used only for emergency egress 1 10 1

Table 5. Proposed revised stringencies based on an update of Table J6.2a from the Deemed to

Satisfy clauses of Section J of the NCC

For other spaces or illuminance levels, the required stringency should be set based on 1.4W/m² per

100 lux.

4. CONSULTATION STAGE

A consultation stage is in progress involving stakeholders throughout the lighting industry in

particular the representatives and members of the Lighting Council of Australia (LCA), the

Illuminating Engineers Society (IESANZ) and the Dark Sky Association (DSA). The original


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analysis report was made available to these stakeholders, and several drafts of the proposed Section

J 2019 have been issued and consulted on. Feedback has been primarily around concern that the

proposed maximum IPD may be too low to achieve good quality lighting as defined by experienced

designers of lighting for complex spaces with complex lighting design needs such as high-end

offices, lobbies, retail, hospitality and the like. Concerns were raised around the following issues:

• The ability to achieve adequate lighting quality and levels in corridors, and in amenities with

high partitions, especially without adjustments for controls.

• The ability to achieve adequate light levels on ceilings and walls in line with LG7. It has

long been postulated that upcoming versions of the Australian Standards will include similar

requirements and the concern is that the proposed maximum IPD s will not allow for that.

• The ability to achieve IPD requirements using light sources with a colour temperature of

3,000K or below, or tunable white light sources.

• The tendency for very cool colour temperature lights to be used both externally and

internally to achieve the required IPD resulting in high levels of blue content lighting. Cool

colour temperature lights have a higher lm/W efficacy than warm colour temperature lights,

but as a result are often used in unsuitable applications instead of more appropriate warm

colour temperature lighting.

• The tendency for high glare luminaires to be used to achieve the required IPD as opposed to

luminaires with well screened LEDs which will make the luminaire more pleasant and more

suitable for use, but less efficient.

• The loss of an adjustment factor for controls. The original draft removed the IPD adjustment

factors for controls in an attempt to encourage designers to achieve the maximum IPD and

then add controls rather than using controls as a method to increase the IPD allowance.

However, it was considered that this would more likely discourage people from using

controls at all, which was not the intention.

• The impact on designs using high colour rendering (CRI) light sources which are typically

less efficient than standard CRI light sources.

• The efficacy stringency around perimeter lighting being so strict that decorative

architectural external luminaires which are heavily baffled to strategically target lighting and

protect the surrounding environment from excessive light spill will not qualify.

• The requirements to prevent external light from spilling direct beams of light into the sky

which would disqualify the use of low level orientation up-lights such as path lights and up-

lights on deciduous trees.


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In response to these issues raised further analysis has been conducted and amendments made to the

drafts as follows:

• IPD adjustments for the use of controls has been re-instated with some tweaks to allow for

modern developments in dimming technology.

• IPD adjustments for lighting quality have been added including upward adjustments for the

use of warm white and high colour rendition light sources, and a penalty for using colour

temperatures over 5,300K.

• The minimum perimeter luminaire efficacy which was proposed for 105lm/W has been

reduced to 85lm/W and will be reviewed again after more data has been provided by the

LCA on the range of efficacies of architectural luminaires.

• Continuing work on the wording of requirements for the control of obtrusive exterior

lighting.

• Max IPD in Table J6.2a for corridors and amenities was adjusted up to 2.5W/m2 to correlate

with the illuminance target of 160 lux.

• The ABCB has agreed to engage interested stakeholders in the lighting industry to produce

case studies to prove or disprove the achievability of the proposed maximum IPDs and their

adjustment factors during 2018.

CONCLUSIONS

The results of the base case simulations using pre-LED technology which was available in 2009

show that it would have been possible to increase the stringency of maximum IPDs in Section J by

between 14% to 64% in 2009.

The results of the test case simulations which use LED technology available in 2017 show that it is

possible to increase the stringency of maximum IPDs in Section J by between 17% to 83% in 2019.

Industry consultation has raised issues around more complex spaces and lighting design issues

which the initial simulations and analysis did not have the opportunity to investigate. As more data

becomes available and further analysis is done on architectural luminaire efficacy and case studies

of complex spaces and lighting designs further drafts of the 2019 Section J will be produced which

should lead to an effective and useful tool for guidance on energy efficient and good quality lighting

design.

NOMENCLATURE

AGi32 – a lighting industry simulation software package produced by the US company Lighting

Analysis and distributed in Australia by Lighting Lab.


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Average illuminance – the average light level calculated from a group of at least 3 measurements

taken on a working plane in a space as per measurement guidelines in AS/NZS1680.3

Ballast – an electrical device used in fluorescent and HID luminaires to limit the amount of current

in the circuit. Originally ballasts consisted of copper wire wound around an iron core. These are

known as magnetic ballasts and are still used to run high powered HID luminaires. Magnetic

ballasts in fluorescent luminaires and lower powered HID luminaires are still present in legacy

lighting equipment. Electronic ballasts are more efficient than magnetic ballasts and are used to run

modern fluorescent luminaires and low powered HID luminaires.

Batten - a surface mounted light fitting comprised solely of a lamp holder/s and a bare lamp. A

linear fluorescent batten comes with control gear included and may incorporate a diffuser.

CFL – Compact fluorescent Lamp

CIBSE – Chartered Institute of Building Services Engineers, London

Colour Rendering Index (CRI) – a meaurement out of 100 of the accuracy of the colour of an object

as it is percieved under a light source. Daylight is rated as having a CRI of Ra=100, as is a halogen

or an incandescent lamp. A typical fluorescent tube in Australia has a CRI of Ra = >80, and a

typical metal halide has a CRI of Ra=>70.

Colour Temperature (CCT) – the perceived colour of a white light source measured in according to

the Kelvin scale. 2,700K is the colour of incandescent light globes, while a warm white fluorescent

lamp of LED is typically 2,900K - 3,200K. 4,000K is a nuetral white colour popular in office

fluoresent lighting, 5,000K is a more natural daylight colour, 6,000K is a cool daylight colour and

8,000K is a very blue, white daylight colour more commonly used in the Europe than Australia. A

white LED is created by coating a blue LED with phosphor. The more phosphor, the warmer the

colour temperature of the light, hence the warmer the colour temperature, the less efficient the

LED chip becomes.

Warm colour temperature lighting is used in spaces to enhance feelings of relaxation and calm such

as hospitality and entertainment spaces and break out spaces in hospitals and commercial buildings.

Some major retail chains specify that warm white lighting must be used throughout their stores.

Cool colour temperature light sources are useful to increase alertness and help to see more clearly

when working on a detailed task but if used indiscriminately they have can have a detrimental

impact on our circadian rhythms and when used for exterior lighting, on plant and animal life

including pollination, biodiversity and food security.

Tunable white light sources are also less efficient but can be used to achieve balance in our

circadian rhythm by changing the colour temperature over the course of the day. Tunable white

LEDs can be preset to suit the needs of the occupants of the same space with varied needs at

different times –for example a cool colour temperature for older people playing bingo in a hall will

help them to see more clearly and stay alert, while a warm colour temperature will provide a calm

atmosphere for doing yoga and winding down at the end of the day in the same hall.

Daylight adjustment zone – AS/NZS1680 recommends that the first 15m of a car park entrance

ramp is lit to a maintained average of 800 lux during the day to provide a distance of travel into the


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car park where the eyes are able to adjust from the bright daylight outside which can be well over

2,000 lux to the dimmer interior light levels for which the standard recommends a maintained

average of 40 lux.

Design life – the length of time that a system is designed to meet specified requirements. This

differs from the actual life of the system which may be forced to run much longer than it is designed

to do while decreasing in efficacy as it ages.

Down light – a square or circular luminaire typically using a halogen lamp, a CFL or a HID. It may

be recessed into the ceiling or mounted on the surface.

Electronic ballast – refer to the definition for “ballast”.

Fluorescent - an electric tube that produces light by creating an electric arc through a gaseous

mixture thus exciting a layer of phosporous powder on the inside of the tube causing the powder to

fluores. The original linear fluorescent tube was also made into a more compact form by reducing

the diameter and bending and twisting the tube to form compact fluorescent lamps. Original

fluorescent lamps and tubes contained only 1 layer of phosphor, but tri-phosphor technology was

developed in the 1990s which increased the performance to such a degree that single phosphor or

halo phosphor tubes were outlawed in Australia for tubes above 15W under the MEPS legislation.

Horizontal illuminance – the amount of light falling on a horizontal plane, measured in lumens per

square metre (lm/m2).

Illuminance - the amount of light that falls on a surface. This is measured in lumens per square

metre (lm/m2) and is commonly referred to as the lux level (lx).

IPD – Illumination Power Density is the term used in the NCC to express the amount of power used

to illuminate a particular space. IPD calculations are based on luminaire system wattage. Expressed

as W/m2

Lamp – commonly referred to as a light globe in technical lighting nomenclature a lamp is a light

source. A table lamp or standard lamp are not technically lamps, but are referred to as luminaires.

LED – an electronic lamp which produces light through the interaction of electrons passing through

layers of a semi-conductor.

Linear fitting – a long thin luminaire, usually housing a fluorescent tube or linear array of LEDs.

Luminaire – commonly referred to as a light fitting or fixture, a luminaire is a system which

includes a lamp, a lamp holder, and/or a reflector and/or a diffuser and/or control gear.

LPD- Lighting Power Density or LPD is the more commonly used term for the amount of power

used to light a particular space. Technically LPD is based on lamp wattage, but it is more

commonly used interchangeably with the term IPD where luminaire system wattage is used.

Expressed as W/m2. Green Star uses LPD and bases its calculations on luminaire system wattage.

Green Star LPD is expressed as W/m2/100 lux.


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LUX (lx) - the unit of measurement used for illuminance - the number of lumens on a surface per

m2.

MEPS – Minimum Energy Performance Standards. These govern the efficiency of electrical

products available in Australia including lamps equipment and white goods.

Halogen lamp - an incandescent lamp with a halogen gas to improve its efficiency. These lamps

produce 70% heat and 30% light, and so are an inefficient light source compared to fluorescent,

HID or LED.

HID – High Intensity Discharge - a family of lamps which includes metal halide, sodium and

mercury vapour.

High bay – a luminaire used to light from heights typically using CFL or HID lamps combined with

a bell shaped reflector. LED versions are also available.

Incandescent lamps - a family of lamps which uss a filament that glows, or incandesces to produce

light. A filament lamp is easy to control because it will switch on and off instantly, and can dim.

These lamps produce 90% heat and 10% light, and so are a very inefficient light source compared to

fluorescent, HID or LED.

Maintained average –the average illuminance measured in a space at the end of the lighting systems

design life.

Maintenance factor – a percentage expressed as a decimal applied to the lumen output of a

luminaire to represent its lumen depreciation at the time it is expected to fail or be replaced. A

maintenance factor of 1 represents a new lamp or luminaire.

Metal halide – an electric lamp that produces light by creating an electric arc through a gaseous

mixture of vaporized metal compounds. The most commonly used type of HID lamp.

Perimeter lighting - lighting affixed to the exterior walls or soffits of a building used to light the

entrances, signage, exterior walls, paths or car parks around the building.

RAR (Room Adjustment Factor) – the ratio of a rooms volume to its perimeter and height,

expressed as a decimal. The RAR of a room impacts on the quality of the distribution of light in the

room, especially when the room is very narrow or the ceiling is very high.

RAR adjustment factor - the maximum required IPD of the space is divided by the adjustment

factor to increase the allowed maximum IPD of the space. To qualify for use of the adjustment

factor a room must have an RAR below 1.5.

Recessed luminaire – a luminaire inserted into a ceiling so that the front face sits flush with the

ceiling and the body of the luminiare is recessed into the ceiling cavity.

Recessed troffer– a square or rectanglar recessed box shaped luminaire typically using a linear

fluorescent tube or a linear array of LEDs.

SLL – Society for Light and Lighting – part of CIBSE


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Recessed down light – a square or circular recessed luminaire typically using a halogen lamp, a

CFL or a HID.

T5 fluorescent tube – a fluorescent tube with a diameter of 5/8ths of an inch or 26mm. T5 tubes are

the latest development in fluorescent technology and only run on electronic control gear. The T5

tube was developed by reducing the diameter of the T8 tube, thus achieving a lower powered

alternative. For instance a 1200mm 36W T8 tube was reduced to a 1200mm 28W T5 tube, with a

corresponding drop in light output.

T8 fluorescent tube – a fluorescent tube with a diameter of 8/8ths of an inch or 16mm. A T8 tube

may run on magnetic or electronic control gear. The T8 tube was developed by reducing the

diameter of the original T12 tube, thus achieving a lower powered alternative. For instance a

1200mm 40W T12 tube was reduced to a 1200mm 36W T8 tube with a corresponding drop in light

output. However the development of tri-phophor technology which occurred several years later

improved the light output significantly.

Track lighting – a lighting system comprised of a track or a bar containing a power feed suspended

from or affixed to a ceiling. Individual light fittings are easily clipped in or out of the track to

provide a flexible system for lighting displays or merchandise which may change position regularly.

Surface reflectance – the proportion of light reflected from the surfaces in the room including walls,

ceiling and floor, and furnishings. This is influenced by the colour and texture of the surfaces. For

instance a tile floor is more reflective than carpet, and a white painted plaster wall is more reflective

than a wood panelled wall.

Troffer– a square or rectanglar box shaped luminaire typically using a linear fluorescent tube or a

linear array of LEDs. May be mounted directly on a ceiling or recessed into the ceiling cavity.

Working plane – the surface at which a task is performed. If the task is writing at a desk the

working plane is the desktop. If the task is walking down a corridor the working plane is the floor.


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REFERENCES

1. Section J6 NCC 2016, Deemed to Satifsy clauses

2. AS/NZS1680.0 Australian/New Zealand Standard, Interior and Workplace Lighting, Safe

movement

3. AS/NZS1680.2.1 Australian/New Zealand Standard, Interior and Workplace Lighting, Specific

applications – Circulation spaces and other general areas


applications – Office and screen based tasks


applications – Educational and training facilities


applications – Industrial tasks and processes


applications – Hospital and medical tasks

8. AS/NZS1680.3 Australian/New Zealand Standard, Interior and Workplace Lighting,

Measurement, calculation and presentation of photometric data

9. AS/NZS4282 CIBSE Lighting Handbook Section 12.3 Retail Lighting recommendations

10. Artificial light at night as a new threat to pollination, Nature 10 August 2017, Page 206, Eva

Knopp, Leana Zoller, Remo Ryser, Christopher Gerpe, Moran Horler, Colin Fontaine,

University of Bern, Institute of Ecology and Evolution.

modelling for potential increases in lighting power ... · cynthia jolley-rogers is a lighting...

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