Light and lighting -- Energy performance of lighting in buildings

This document specifies the methodology for evaluating the energy performance of lighting systems for providing general illumination inside non-residential buildings and for calculating or measuring the amount of energy required or used for lighting inside buildings. This document does not cover lighting requirements, the design of lighting systems, the planning of lighting installations, the characteristics of lighting equipment (lamps, control gear and luminaires) and systems used for display lighting, desk lighting or luminaires built into furniture. This document does not provide any procedure for the dynamic simulation of lighting scene setting.

Lumière et éclairage -- Performance énergétique de l'éclairage des bâtiments

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Status
Published
Publication Date
23-Jan-2019
Current Stage
6060 - International Standard published
Start Date
15-Dec-2018
Completion Date
24-Jan-2019
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ISO/CIE 20086:2019 - Light and lighting -- Energy performance of lighting in buildings
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INTERNATIONAL ISO/CIE
STANDARD 20086
First edition
2019-01
Light and lighting — Energy
performance of lighting in buildings
Lumière et éclairage — Performance énergétique de l'éclairage des
bâtiments
Reference number
ISO/CIE 20086:2019(E)
ISO/CIE 2019
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ISO/CIE 20086:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/CIE 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
ii © ISO/CIE 2019 – All rights reserved
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ISO/CIE 20086:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviations ....................................................................................................................................................................... 2

4.1 Symbols ......................................................................................................................................................................................................... 2

4.2 Subscripts .................................................................................................................................................................................................... 4

5 Description of the methods ....................................................................................................................................................................... 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Output of the method 1— Comprehensive method ................................................................................................ 5

5.3 Optional methods ................................................................................................................................................................................. 5

5.3.1 Method 2 — Quick calculation method ........................................................................................................ 5

5.3.2 Method 3 — Direct metering method............................................................................................................ 5

6 Method 1 — Calculation of the energy required for lighting .................................................................................. 6

6.1 Output data ................................................................................................................................................................................................ 6

6.2 Calculation time steps ....................................................................................................................................................................... 6

6.3 Input data .................................................................................................................................................................................................... 6

6.3.1 Lighting system data ........................................................................................................................................... .......... 6

6.3.2 Product data ...................................................................... ................................................................................................... 7

6.3.3 System design data .................. ......................................................................................................................... .............. 8

6.3.4 Operating conditions .................................................................................................................................................... 8

6.3.5 Constants and physical data................................................................................................................................... 8

6.4 Calculation procedure ....................................................................................................................................................................... 9

6.4.1 Applicable time step ..................................................................................................................................................... 9

6.4.2 Operating conditions calculation ....................................................................................................................... 9

6.4.3 Energy calculation .......................................................................................................................................................... 9

6.5 Expenditure factors for lighting systems ......................................................................................................................13

7 Method 2 — Quick calculation of the energy required for lighting ..............................................................16

7.1 Output data .............................................................................................................................................................................................16

7.2 Calculation time steps ....................................................................................................................................................................16

7.3 Input data .................................................................................................................................................................................................17

7.3.1 Lighting system data ........................................................................................................................................... .......17

7.3.2 Luminaire data ...............................................................................................................................................................17

7.3.3 System design data .................. ......................................................................................................................... ...........17

7.3.4 Operating conditions .................................................................................................................................................17

7.3.5 Constants and physical data................................................................................................................................17

7.4 Calculation procedure ....................................................................................................................................................................17

7.4.1 Applicable time step ..................................................................................................................................................17

7.4.2 Operating conditions calculation ....................................................................................................................18

7.4.3 Energy calculation .......................................................................................................................................................18

7.5 Expenditure factors for lighting systems ......................................................................................................................20

8 Method 3 — Metered energy used for lighting ...................................................................................................................20

8.1 Output data .............................................................................................................................................................................................20

8.2 Calculation time steps ....................................................................................................................................................................20

8.3 Input data .................................................................................................................................................................................................20

8.4 Calculation procedure of annual energy ........................................................................................................................20

9 Quality control .....................................................................................................................................................................................................21

9.1 Method 1....................................................................................................................................................................................................21

9.2 Method 2....................................................................................................................................................................................................21

9.3 Method 3....................................................................................................................................................................................................21

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ISO/CIE 20086:2019(E)

10 Compliance check .............................................................................................................................................................................................22

10.1 General ........................................................................................................................................................................................................22

10.2 Method 1....................................................................................................................................................................................................22

10.3 Method 2....................................................................................................................................................................................................22

10.4 Method 3....................................................................................................................................................................................................22

Annex A (informative) Input data sheet with default values and choices ..................................................................23

Annex B (normative) Simplified method for installed power estimation ..................................................................28

Annex C (normative) Assessment of the installed power for lighting systems in existing

buildings ....................................................................................................................................................................................................................31

Annex D (normative) Occupancy estimation ............................................................................................................................................32

Annex E (informative) Expenditure factors for lighting systems .........................................................................................36

Annex F (normative) Constant illuminance ...............................................................................................................................................56

Bibliography .............................................................................................................................................................................................................................58

iv © ISO/CIE 2019 – All rights reserved
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ISO/CIE 20086:2019(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso

.org/iso/foreword .html.

ISO collaborates closely with the International Commission on Illumination (CIE) on all matters of

standardization for light and lighting.

This document was prepared by Technical Committee ISO/TC 274, Light and lighting. The document has

been jointly prepared with CIE JTC 6, Energy performance of lighting in buildings.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
© ISO/CIE 2019 – All rights reserved v
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ISO/CIE 20086:2019(E)
Introduction

It is of paramount importance that correct lighting is provided in buildings. The convention and

procedures in this document assumes that the designed and installed lighting scheme conforms to

good lighting practices. For new and refurbished installations in the non-residential building sector the

design of the lighting system should conform to the requirements in the lighting applications standards

ISO 8995-1/CIE S 008 for indoor workplaces and ISO 30061/CIE S 020 for emergency escape lighting.

This document also assumes that the buildings can have access to daylight to provide all or some of the

illumination required in the rooms or zones and that in addition there will be an adequate amount of

electric lighting installed to provide the required illumination in the absence of daylight.

This document defines the methods for estimating or measuring the amount of energy required or used

for lighting in buildings. The method of separate metering of the energy used for lighting will also give

regular feedback on the effectiveness of the lighting control.

The methodology of energy estimation not only provides values for the Lighting Energy Numeric

Indicator (LENI) but it will also provide input for the heating and cooling load estimations for the

combined total energy performance of building indicator.

Figure 1 gives an overview of the methodology and the flow of the processes involved.

NOTE The dotted line linking preliminary annual LENI to the comprehensive method indicates the required

follow-up of the budget calculation with the comprehensive calculation during the detailed lighting design

process.
Figure 1 — Flow chart illustrating alternative routes to determine energy use
vi © ISO/CIE 2019 – All rights reserved
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INTERNATIONAL STANDARD ISO/CIE 20086:2019(E)
Light and lighting — Energy performance of lighting in
buildings
1 Scope

This document specifies the methodology for evaluating the energy performance of lighting systems

for providing general illumination inside non-residential buildings and for calculating or measuring the

amount of energy required or used for lighting inside buildings.

This document does not cover lighting requirements, the design of lighting systems, the planning of

lighting installations, the characteristics of lighting equipment (lamps, control gear and luminaires)

and systems used for display lighting, desk lighting or luminaires built into furniture. This document

does not provide any procedure for the dynamic simulation of lighting scene setting.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 8995-1/CIE S 008, Lighting of work places — Part 1: Indoor

ISO 10916, Calculation of the impact of daylight utilization on the net and final energy demand for lighting

ISO 30061/CIE S 020, Emergency lighting
IEC 60598 (all parts), Luminaires
CIE S 017, ILV, International Lighting Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in CIE S 017 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
time step
period in which the energy is evaluated
Note 1 to entry: Measured in hour, month, year.
3.2
standby energy

energy required for charging batteries and/or the energy required for lighting controls during the time

the electric lights are switched off

Note 1 to entry: Lighting controls and emergency battery charging circuits are only considered where power is

supplied via a luminaire.
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ISO/CIE 20086:2019(E)
3.3
lighting control
device connected to the luminaire to vary the light output

Note 1 to entry: In this document lighting controls are only considered where power is supplied via a luminaire.

3.4
lighting system

set of light sources and/or lamps with luminaires and related equipment, if any, interacting together to

satisfy lighting application requirements
Note 1 to entry: The lighting system can be dedicated to:

a) the support of (a) specified visual task(s) under specified conditions considering other requirements such as

human comfort, safety, the appearance of the surrounding environment and energy consumption;

b) the support of other than human tasks, such as plant growth or breeding of animals.

Note 2 to entry: The lighting system can include physical components, communication protocols, user interfaces,

software and networks to provide control and monitoring functions.
[SOURCE: CIE DIS 017:2016; Term 17-29-029]
3.5
expenditure factor
expense factor
effort factor

indicator of the energy efficiency of a given lighting system compared to a reference system

4 Symbols and abbreviations
4.1 Symbols
For the purposes of this document, the specific symbols listed in Table 1 apply.
Table 1 — Symbols and units
Symbol Name of quantity Unit
A Total useful area m
A Partial area which is lit by daylight m
A Area not lit by daylight m
A Sum of task areas within the room m
D Daylight factor %
D Daylight availability classification 1
class
e Expenditure factor for lighting systems 1
e Partial expenditure factor for constant illuminance control 1
L,C
e Partial expenditure factor for daylight dependant lighting control 1
L,D
e Partial expenditure factor for the electric lighting system 1
L,ES
e Partial expenditure factor for delivery of electric light 1
L,ES,del
e Partial expenditure factor for distribution of electric light 1
L,ES,dis
e Partial expenditure factor for generation of electric light 1
L,ES,gen
e Partial expenditure factor for occupancy dependant lighting control 1
L,O
E Maintained illuminance lx
E Maintained illuminance on immediate surround of task area lx
sur
E Maintained illuminance on the task area lx
task
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ISO/CIE 20086:2019(E)
Table 1 (continued)
Symbol Name of quantity Unit
F Absence factor 1
f Factor for the efficiency of the operating device 1
F Constant illuminance factor 1
F Factor for reduced power of area 1
F Factor for the efficiency of the constant illuminance control 1
F Daylight dependency factor 1
F Lighting control factor 1
D,C
F Daylight supply factor 1
D,S
F Factor for light source efficiency 1
f Maintenance factor 1
F Correction factor for maintenance factor 1
CMF
F Occupancy dependency factor 1
F Controls function factor 1
F Utilization factor of the luminaire 1
F Utilization factor for determination of the energy use 1
u,e
h Mounting height of luminaire m
K Room Index 1
time period at which x % of the measured initial luminous flux value
L h
is maintained
L Length of room m
N Number of days in month i d
n Number of lamps in the luminaire 1
P Installed electric power density W/m
p Specific electrical evaluation power W/(m lx)
P Control standby power of luminaire i W
c,i
P Electrical evaluation power density for determination of the energy use W/m
P Total emergency standby power W
P Emergency charging power of luminaire i W
e,i
P Power of luminaire i W
P Power density of area j W/m
P Illuminance-normalized power density of area j W/(m lx)
j,lx
P Total power of n luminaires W
P Total controls standby power W
P Lamp rated power W
Q Lighting energy numeric indicator (LENI) for a building kWh/m
LENI
Q Lighting energy numeric indicator for an area or relevant zone kWh/m
LENI,sub
R General colour rendering index 1
t Daylight time h
t Daylight absence time h
t Time step hour, month, year
t Total operating hours h
tot
t Number of hours in a standard year h
W Total annual energy used for lighting kWh
W Annual energy required for lighting for an area or a zone kWh
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ISO/CIE 20086:2019(E)
Table 1 (continued)
Symbol Name of quantity Unit
W Total energy for illumination kWh
L,t
W Metered energy kWh
W Total energy for standby kWh
P,t
w Width of room m
W Energy per time step kWh
W Energy used for lighting Wh
W Energy needed for lighting Wh
Standby energy density for automatic lighting controls of the luminaire
W kWh/m
per year
Standby energy density for battery charging of emergency luminaires
W kWh/m
per year
η Luminaire luminous efficacy lm/W
η Luminaire light output ratio 1
η Utilance 1
4.2 Subscripts

For the purposes of this document, the specific subscripts listed in Table 2 apply.

Table 2 — Subscripts
i Relevant element under consideration
Month number, 1 – 12
j Relevant area under consideration
5 Description of the methods
5.1 General

This document covers three methods for the assessment of the energy required for electric lighting

within a building, either by calculation (method 1 and method 2) or by direct metering of the lighting

circuit (method 3). The calculation method 1 offers two options,
1) for new or refurbished buildings, and
2) for existing buildings.

For new and refurbished buildings it also offers a quick calculation method 2 for the annual energy

estimation.

This document offers calculation methods, with different levels of accuracy for the installed power,

occupancy estimation and daylight availability.

Method 1 provides the most accurate calculation procedure and it relies upon a comprehensive lighting

scheme design as the main input to the energy calculation.

Method 2 provides a quick estimation aimed for pre-design calculations and employs default values.

Default values are provided in Annex A.
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ISO/CIE 20086:2019(E)

Method 3 provides the most accurate energy use for lighting information but can only be used after

the building has been commissioned and occupied. This method can also be linked to the Building

Management System (BMS) of the building to provide continuous smart metering.
5.2 Output of the method 1— Comprehensive method

This method covers the calculation of the energy requirements of lighting systems in non-residential

buildings where a comprehensive lighting system design has been performed. This calculation method

is suitable for use during the design of new or refurbished buildings and for assessing existing buildings.

The method output shall be in terms of kilowatt hours per time step for the building. The output value

shall be normalized for the considered time step to square meters of the useful area to give the sub-

LENI value. If the time-step is yearly this is the Lighting Energy Numeric Indicator LENI.

The time step of the output can be:
— yearly,
— monthly, or
— hourly,
in accordance with the time step of the input data.
5.3 Optional methods
5.3.1 Method 2 — Quick calculation method

This method covers the calculation of the energy requirements of lighting systems for non-residential

buildings where a comprehensive lighting system design has not been performed. The method makes

use of quick calculation and default data and the result gives budget values.

The method output shall be in terms of kilowatt hours per year for the building. This yearly output

value shall be normalized to square meters of the useful area to give the LENI.
The time step of the output shall be yearly.

This method is suitable for use during the conceptual stage of design of new or refurbished buildings.

5.3.2 Method 3 — Direct metering method

This method covers the direct measurement of the energy used by lighting system in non-residential

buildings by segregated direct metering. This method gives the true value of energy used by the lighting

system and can be used to verify the values obtained by the calculation methods.

The method output shall be in terms of kilowatt hours per time step for the building. The yearly output

value shall be normalized to square meters of the useful area to give the LENI.
The time step of the output can be:
— yearly,
— monthly, or
— hourly,
in accordance with the time step of the input data.

This method is suitable for use in existing buildings where the lighting circuit is sufficiently segregated

to allow separate metering.
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ISO/CIE 20086:2019(E)

This method is applicable to buildings with facilities for separate metering of the electricity used for all

lighting within the building. The metering can alternatively be by the BMS arrangement.

The calculated or measured annual energy required for lighting can be normalized to a unit area to

generate the LENI. LENI provides a comparable measure of the energy performance of the lighting

installation in the buildings. When the output value is obtained for other time steps it shall be

normalised to the unit area to give the sub-LENI value.
6 Method 1 — Calculation of the energy required for lighting
6.1 Output data
The output data of this method are listed in Table 3.
Table 3 — Output data of this method
Description Symbol Unit
Specified time step, e.g. hourly, monthly or
t hour, month, year
annually
Energy used for lighting (in kWh) per time
step (e.g. hourly, monthly or annually) within W kWh
rooms or zones
LENI is the area normalized annual energy used for lighting within the b
...

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