ISO/CIE 10916
(Main)Light and lighting – Energy performance of lighting in buildings — Calculation of the impact of daylight utilization
Light and lighting – Energy performance of lighting in buildings — Calculation of the impact of daylight utilization
This document defines the calculation methodology for determining the monthly and annual amount of usable daylight penetrating non-residential buildings through vertical facades and rooflights and the impact thereof on the energy demand for electric lighting. This document is applicable for existing buildings and the design of new and renovated buildings. This document provides the overall lighting energy balance equation relating the installed power density of the electric lighting system with daylight supply and lighting controls (proof calculation method). The determination of the installed power density is not in the scope of this method, neither are controls relating, for instance, to occupancy detection. Provided the determination of the installed power density and control parameters using external sources, the internal loads by lighting and the lighting energy demand itself can be calculated. The energy demand for lighting and internal loads by lighting can then be taken into account in the overall building energy balance calculations: heating; ventilation; climate regulation and control (including cooling and humidification); heating the domestic hot-water supply of buildings. For estimating the daylight supply and rating daylight-dependent electric lighting control systems, a simple table-based calculation approach is provided. The simple method describes the division of a building into zones as required for daylight illumination-engineering purposes, as well as considerations on the way in which daylight supplied by vertical facade systems and rooflights is utilized and how daylight-dependent lighting control systems affect energy demand. Dynamic vertical facades with optional shading and light redirection properties are considered, i.e. allowing a separate optimization of facade solutions under direct insolation and under diffuse skies. For rooflighting systems, standard, static solutions like shed rooflights and continuous rooflights are considered. The method is applicable for different latitudes and climates. For standard building zones (utilizations), operation times are provided. For detailed analysis an approach to calculate the effect of daylight on the lighting energy demand on an hourly or sub-hourly basis is provided. Unlike the simple table-based annual calculation approach, which is regression based, this method relies on an emulation concept. Relevant quantities are modelled explicitly and are then interacting directly with sensors, actuators and functional elements of the BACS or are triggering user interaction. By this approach, model configuration and parametrization from the design stage can seamlessly be used in the BACS configuration. To support overall building performance assessment, additional daylight performance indicators on the overall building level are provided.
Lumière et éclairage — Performance énergétique de l'éclairage des bâtiments — Calcul de l'impact de l'utilisation de la lumière du jour
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FINAL DRAFT
International
Standard
ISO/CIE FDIS
ISO/TC 274
Light and lighting – Energy
Secretariat: DIN
performance of lighting in
Voting begins on:
buildings — Calculation of the
2024-05-17
impact of daylight utilization
Voting terminates on:
2024-07-12
Lumière et éclairage — Performance énergétique de l'éclairage
des bâtiments — Calcul de l'impact de l'utilisation de la lumière
du jour
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MADE IN NATIONAL REGULATIONS.
Reference number
ISO/CIE FDIS 10916:2024(en) © ISO/CIE 2024
FINAL DRAFT
ISO/CIE FDIS 10916:2024(en)
International
Standard
ISO/CIE FDIS
ISO/TC 274
Light and lighting – Energy
Secretariat: DIN
performance of lighting in
Voting begins on:
buildings — Calculation of the
impact of daylight utilization
Voting terminates on:
Lumière et éclairage — Performance énergétique de l'éclairage
des bâtiments — Calcul de l'impact de l'utilisation de la lumière
du jour
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
© ISO/CIE 2024
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
IN ADDITION TO THEIR EVALUATION AS
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
or ISO’s member body in the country of the requester
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
ISO copyright office CIE Central Bureau TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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Published in Switzerland Reference number
ISO/CIE FDIS 10916:2024(en) © ISO/CIE 2024
© ISO/CIE 2024 – All rights reserved
ii
ISO/CIE FDIS 10916:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols, indices, and abbreviated terms . 4
4.1 Symbols .4
4.2 Indices and abbreviated terms .5
5 Proof calculation method . 6
5.1 Energy demand for lighting as function of daylight .6
5.2 Subdivision of a building into zones .8
5.3 Operating time .8
5.4 Electric lighting.8
5.5 Constant illuminance control .8
5.6 Daylight .8
5.7 Occupancy dependency factor F .9
O,n
6 Daylight Performance Indicator. 9
Annex A (informative) Simple calculation method . 10
Annex B (informative) Comprehensive hourly calculation .54
Annex C (informative) Daylight performance indicator .88
Annex D (informative) Examples .89
Bibliography .96
© ISO/CIE 2024 – All rights reserved
iii
ISO/CIE FDIS 10916:2024(en)
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
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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 document should be noted. This document was drafted in accordance with the editorial rules of the
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This document was prepared by Technical Committee ISO/TC 274, Light and lighting, in collaboration with
the International Commission on Illumination (CIE), JTC 06, 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 2024 – All rights reserved
iv
ISO/CIE FDIS 10916:2024(en)
Introduction
This document is part of a set of standards which allows users to rate the overall energetic performance
of buildings. Facades and rooflights have a key impact on the building’s energy balance. This document
supports daylighting and lighting-energy-related analysis and optimization of facade and rooflight systems.
It is specifically devised to establish conventions and procedures for the estimation of daylight penetrating
buildings through vertical facades and rooflights, as well as on the energy consumption for electric lighting
as a function of daylight provided in indoor spaces.
© ISO/CIE 2024 – All rights reserved
v
FINAL DRAFT International Standard ISO/CIE FDIS 10916:2024(en)
Light and lighting – Energy performance of lighting in
buildings — Calculation of the impact of daylight utilization
1 Scope
This document defines the calculation methodology for determining the monthly and annual amount of
usable daylight penetrating non-residential buildings through vertical facades and rooflights and the impact
thereof on the energy demand for electric lighting. This document is applicable for existing buildings and the
design of new and renovated buildings.
This document provides the overall lighting energy balance equation relating the installed power density of
the electric lighting system with daylight supply and lighting controls (proof calculation method).
The determination of the installed power density is not in the scope of this method, neither are controls
relating, for instance, to occupancy detection. Provided the determination of the installed power density and
control parameters using external sources, the internal loads by lighting and the lighting energy demand
itself can be calculated. The energy demand for lighting and internal loads by lighting can then be taken into
account in the overall building energy balance calculations:
— heating;
— ventilation;
— climate regulation and control (including cooling and humidification);
— heating the domestic hot-water supply of buildings.
For estimating the daylight supply and rating daylight-dependent electric lighting control systems, a simple
table-based calculation approach is provided. The simple method describes the division of a building into
zones as required for daylight illumination-engineering purposes, as well as considerations on the way in
which daylight supplied by vertical facade systems and rooflights is utilized and how daylight-dependent
lighting control systems affect energy demand. Dynamic vertical facades with optional shading and light
redirection properties are considered, i.e. allowing a separate optimization of facade solutions under direct
insolation and under diffuse skies. For rooflighting systems, standard, static solutions like shed rooflights
and continuous rooflights are considered. The method is applicable for different latitudes and climates. For
standard building zones (utilizations), operation times are provided.
For detailed analysis an approach to calculate the effect of daylight on the lighting energy demand on an
hourly or sub-hourly basis is provided. Unlike the simple table-based annual calculation approach, which is
regression based, this method relies on an emulation concept. Relevant quantities are modelled explicitly
and are then interacting directly with sensors, actuators and functional elements of the BACS or are
triggering user interaction. By this approach, model configuration and parametrization from the design
stage can seamlessly be used in the BACS configuration.
To support overall building performance assessment, additional daylight performance indicators on the
overall building level are provided.
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.
CIE S 017:2020, ILV: International Lighting Vocabulary
© ISO/CIE 2024 – All rights reserved
ISO/CIE FDIS 10916:2024(en)
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 terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
CIE maintains a terminology database for use in standardization
...
ISO/CIE FDIS 10916:2024(Een)
ISO TC 274/JWG 1
Secretariat: DIN
Date: 2024-03-0619
Light and lighting – Energy performance of lighting in buildings — Calculation of the impact of
daylight utilization
ISO/CIE DIS 10916:2023(E)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no
part of this publication may be reproduced or utilized otherwise in any form or by any means,
electronic or mechanical, including photocopying, or posting on the internet or an intranet, without
prior written permission. Permission can be requested from either ISO at the address below or
ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.orgwww.iso.org
Published in Switzerland
ii © ISO/CIE 2023 – All rights reserved
ISO/CIE DIS FDIS 10916:2023(E2024(en)
Contents
Foreword . vi
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols, indices, and abbreviated terms . 4
4.1 Symbols . 4
4.2 Indices and abbreviated terms . 5
5 Proof calculation method . 5
5.1 Energy demand for lighting as function of daylight . 5
5.2 Subdivision of a building into zones . 7
5.3 Operating time . 8
5.4 Artificial lighting . 8
5.5 Constant illuminance control . 8
5.6 Daylight . 8
5.7 Occupancy dependency factor F . 9
O,n
6 Daylight Performance Indicator . 9
Annex A (informative) Simple calculation method . 10
A.1 General . 10
A.2 Building segmentation: Spaces benefiting from daylight . 12
A.3 Daylight supply factor for vertical facades . 15
A.3.1 Daylight factor classification . 15
A.3.2 Daylight supply factor . 20
A.3.2.1 General . 20
A.3.2.2 Luminous exposure ratios at different sites (climates and latitudes) . 21
A.3.2.3 Relative times, shading activated, shading not activated for vertical facades . 22
A.3.2.4 Determination of daylight supply factor for sunshading not activated F . 24
D,s,SNA,j
A.3.2.5 Determination of daylight supply factor for sunshading activated F . 32
D,s,SA,j
A.4 Daylight supply factor for rooflights . 34
A.4.1 General . 34
A.4.2 Daylight availability factor . 34
A.4.3 Daylight supply factor . 42
A.5 Daylight Responsive Control Systems . 47
A.6 Monthly evaluation method . 49
A.7 Determination of day-time and night-time hours . 50
© ISO/CIE 2023 – All rights reserved iii
© ISO/CIE 2024 – All rights reserved
iii
ISO/CIE DIS 10916:2023(E)
A.8 Exemplary operation times of different building zone . 52
Annex B (informative) Comprehensive hourly calculation . 54
B.1 General . 54
B.2 Time Basis, Building Segmentation, Control Point Allocation, Link to electric lighting . 55
B.2.1 Time Basis . 55
B.2.2 Building Segmentation . 56
B.2.3 Control point Allocation . 56
B.2.4 Link to electric lighting . 56
B.3 Daylight supply and come along solar gain calculation . 57
B.3.1 Algebraic calculation of daylight supply (“3 Phase Method”) . 57
B.3.1.1 Algebraic calculation of photometric quantities: E (t ), L (t ) . 57
Room,Day n Room,Day n
B.3.1.2 Come along Algebraic calculation of solar gains inside and exterior on facade . 59
B.3.1.3 Angular basis (Data resolution) . 61
B.3.2 Requirements for climate data, i.e. sky vector s (n) and outside environment (OE) . 62
v
B.3.2.1 Sky vector s (n) . 62
v
B.3.2.2 Outside environment (OE) . 63
B.3.3 Requirements for T , T , i.e. BSDF data . 63
v e
B.3.4 Requirements for view point connection matrix . 63
B.3.5 Parametrization of typical daylight scenarios . 64
B.4 User Model: Occupancy, lighting requirements and system interaction . 67
B.4.1 General . 67
B.4.2 Occupancy patterns . 67
B.4.3 Lighting requirements for automatic controls . 68
B.4.4 Interaction of user with lighting system . 68
B.4.5 Parametrization of typical occupancy patterns and user requirements . 71
B.5 Building Automation and Control Systems (BACS): Daylighting Control Elements . 71
B.5.1 General . 71
B.5.2 Sensors . 72
B.5.3 Actuators . 74
B.5.4 Operator functions . 74
B.5.5 Application functions . 75
B.5.6 Network application and processing functions . 77
B.5.7 Function extension and synthesis . 78
B.6 Example . 78
B.6.1 General . 78
iv © ISO/CIE 2023 – All rights reserved
ISO/CIE DIS FDIS 10916:2023(E2024(en)
B.6.2 Boundary conditions and model description . 78
B.6.3 Driving quantities (weather, user). 84
B.6.4 Daylight emulation . 85
B.6.5 Calculation results . 85
Annex C (informative) Daylight performance indicator. 92
Annex D (informative) Examples . 93
D.1 General . 93
D.2 Space with vertical facade . 93
D.3 Space with rooflights . 96
D.3.1 General . 96
D.3.2 Determination of the daylight availability factor F . 97
D,s
D.3.2.1 Mean daylight factor for strip-type rooflights. 97
D.3.2.2 Mean daylight factor for shed rooflights . 97
D.3.2.3 Daylight availability factor F for strip-type rooflights . 98
D,s
D.3.2.4 Daylight availability factor F for shed rooflights . 98
D,s
D.3.3 Determination of the annual and monthly final energy demand for lighting . 98
D.3.3.1 Annual final energy demand for strip-type rooflights . 98
D.3.3.2 Annual final energy demand for shed rooflights. 99
D.3.3.3 Monthly energy demand for strip-type rooflights . 99
D.3.3.4 Monthly final energy demand for shed rooflights . 100
Bibliography . 101
Foreword .
...
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