oSIST prEN 12665:2023
(Main)Light and lighting - Basic terms and criteria for specifying lighting requirements
Light and lighting - Basic terms and criteria for specifying lighting requirements
This document defines basic terms and definitions for use in all lighting applications. This document also sets out a framework for the specification of lighting requirements, giving details of aspects that are to be considered when setting those requirements.
Licht und Beleuchtung - Grundlegende Begriffe und Kriterien für die Festlegung von Anforderungen an die Beleuchtung
Dieses Dokument definiert grundlegende Begriffe für alle lichttechnischen Anwendungen. Dieses Dokument legt auch Rahmenbedingungen für die Festlegung der Anforderungen an die Beleuchtung fest. Dabei werden Einzelheiten zu den Gesichtspunkten dargestellt, die bei Festlegung dieser Anforderungen zu berücksichtigen sind.
Lumière et éclairage - Termes de base et critères pour la spécification des exigences en éclairage
Le présent document définit les termes et définitions de base à utiliser dans toutes les applications d’éclairage. Le présent document définit également un guide pour la spécification d’exigences en éclairage et fournit certains détails relatifs aux aspects à prendre en compte lors de l’établissement desdites exigences.
Svetloba in razsvetljava - Osnovni izrazi in merila za specifikacijo zahtev za razsvetljavo
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 12665:2023
01-januar-2023
Svetloba in razsvetljava - Osnovni izrazi in merila za specifikacijo zahtev za
razsvetljavo
Light and lighting - Basic terms and criteria for specifying lighting requirements
Licht und Beleuchtung - Grundlegende Begriffe und Kriterien für die Festlegung von
Anforderungen an die Beleuchtung
Lumière et éclairage - Termes de base et critères pour la spécification des exigences en
éclairage
Ta slovenski standard je istoveten z: prEN 12665
ICS:
01.040.91 Gradbeni materiali in gradnja Construction materials and
(Slovarji) building (Vocabularies)
91.160.01 Razsvetljava na splošno Lighting in general
oSIST prEN 12665:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 12665:2023
DRAFT
EUROPEAN STANDARD
prEN 12665
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2022
ICS 01.040.91; 91.160.01 Will supersede EN 12665:2018
English Version
Light and lighting - Basic terms and criteria for specifying
lighting requirements
Lumière et éclairage - Termes de base et critères pour Licht und Beleuchtung - Grundlegende Begriffe und
la spécification des exigences en éclairage Kriterien für die Festlegung von Anforderungen an die
Beleuchtung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 169.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12665:2022 E
worldwide for CEN national Members.
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Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
3.1 Eye and vision . 5
3.2 Light and colour . 8
3.3 Lighting equipment . 25
3.4 Daylight . 35
3.5 Lighting installations . 36
3.6 Lighting measurements . 49
4 Framework for the specification of lighting requirements . 50
4.1 General . 50
4.2 Illuminance . 51
4.3 Luminance . 51
4.4 Glare . 51
4.4.1 Disability glare . 51
4.4.2 Discomfort glare . 51
4.5 Colour . 51
4.5.1 Colour rendering . 51
4.5.2 Light source colour . 51
4.6 Energy. 51
4.7 Maintenance . 52
4.7.1 Maintenance . 52
4.7.2 Maintenance factor . 52
4.8 Measurements and calculations . 52
Annex A (informative) Additional explanation of defined terms . 53
Annex B (informative) Index of terms . 56
Bibliography . 65
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European foreword
This document (prEN 12665:2022) has been prepared by Technical Committee CEN/TC 169 “Light and
lighting”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12665:2018.
The main technical changes in this revision of EN 12665:2018 are through harmonisation with the
revised CIE International Lighting Vocabulary, CIE S 017:2020.
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Introduction
This document specifies a basic framework intended to be used for the specification of lighting
requirements.
Where a term is contained in CIE Publication CIE S 017:2020 ILV, International Lighting Vocabulary or
IEC 60050-845, International Electrotechnical Vocabulary, Chapter 845: Lighting, a reference is given to
the equivalent term where the terms in both documents are, for all practical purposes, identical.
NOTE Definitions from CIE S 017:2020 and IEC 60050-845:2020 contain notes providing information on the
numbering in previous versions of both documents. These notes were generally omitted as they are not necessary
for application in European standards.
For some terms additional explanation is given in informative Annex A. An index of terms is given in
informative Annex B.
The lighting requirements for a space are determined by the need to provide:
— adequate illumination for safety and movement;
— conditions that will facilitate visual performance and colour perception;
— acceptable visual comfort for the occupants in the space.
The relative importance of these factors will vary for different applications. This basic framework covers
aspects in the field of vision, photometry and colorimetry, involving natural and man-made optical
radiation over the UV, the visible and the IR regions of the spectrum, and application subjects covering
all usages of light, indoors and outdoors, including environmental, energy and sustainability
requirements and aesthetics and non- image forming biological aspects.
Peculiar and specific terms can be defined in application standards.
Considerations should also be given to the energy used by lighting and to maintenance.
The parameters that need to be specified to ensure good visual conditions and an efficient lighting
installation are common to many applications. These are dealt with in Clause 4 of this document.
LED terms and definitions already existing within EN 62504 have not been included in this document.
For terms and definitions concerning daylight openings within a building envelope the following
standards may also be consulted:
EN 12216, Shutters, external blinds, internal blinds — Terminology, glossary and definitions
EN 12519, Windows and pedestrian doors — Terminology
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1 Scope
This document defines basic terms and definitions for use in all lighting applications. This document also
sets out a framework for the specification of lighting requirements, giving details of aspects that are to be
considered when setting those requirements.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp/ui
3.1 Eye and vision
3.1.1
adaptation
process by which the state of the visual system is modified by previous and present exposure to stimuli
that can have various luminance values, spectral distributions and angular subtenses
Note 1 to entry: Adaptation to specific spatial frequencies, orientations, sizes, etc. are recognized as being included
in this definition.
Note 2 to entry: The terms light adaptation and dark adaptation are also used, the former when the luminances of
the stimuli are of at least several candelas per square metre, and the latter when the luminances are of less than
some hundredths of a candela per square metre.
[SOURCE: IEC 60050-845:2020 845-22-012 / CIE S 017:2020; 17-22-012, modified - Note 2 to entry
added]
3.1.2
accommodation
adjustment of the dioptric power of the crystalline lens by which the image of an object, at a given
distance, is focused on the retina
[SOURCE: IEC 60050-845:2020 845-22-086 / CIE S 017:2020; 17-22-086]
3.1.3
visual acuity
visual resolution
capacity for seeing distinctly fine details that have very small angular separation
[SOURCE: IEC 60050-845:2020 845-22-077 / CIE S 017:2020; 17-22-077]
3.1.4
brightness
attribute of a visual perception according to which an area appears to emit, transmit or reflect, more or
less light
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Note 1 to entry: The use of this term is not restricted to primary light sources.
[SOURCE: IEC 60050-845:2020 845-22-059 / CIE S 017:2020; 17-22-059]
3.1.5
contrast
perceived contrast
assessment of the difference in appearance of two or more parts of a field seen
simultaneously or successively
EXAMPLE 1 Brightness contrast, lightness contrast, colour contrast, simultaneous contrast, successive contrast.
EXAMPLE 2 By the proportional variation in contrast near the luminance threshold (ΔL/L) or by the ratio of
luminances for much higher luminances (L /L ).
1 2
[SOURCE: IEC 60050-845:2020 845-22-089 / CIE S 017:2020; 17-22-089, modified - example 2 added]
3.1.6
brightness contrast
subjective assessment of the difference in brightness between two or more surfaces seen simultaneously
or successively
3.1.7
colour contrast
subjective assessment of the difference in colour between two or more surfaces seen simultaneously or
successively
3.1.8
glare
condition of vision in which there is discomfort or a reduction in the ability to see details or objects,
caused by an unsuitable distribution or range of luminance, or by extreme luminance contrasts
Note 1 to entry: See also “disability glare”, “discomfort glare”.
[SOURCE: IEC 60050-845:2020 845-22-098 / CIE S 01/E 7:2020; 17-22-098]
3.1.9
flicker
perception of visual unsteadiness induced by a light stimulus the luminance or spectral distribution of
which fluctuates with time, for a static observer in a static environment
Note 1 to entry: The fluctuations of the light stimulus with time include periodic and non-periodic
fluctuations and can be induced by the light source itself, the power source or other influencing factors.
[SOURCE: IEC 60050-845:2020 845-22-092 / CIE S 017:2020; 17-22-092]
3.1.10
visual field
part of an external scene that is perceived when an observer gazes at some point in the scene
[SOURCE: IEC 60050-845:2020 845-22-080 / CIE S 017:2020; 17-22-080]
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3.1.11
visual performance
quality of performance of the visual system of an observer related to central and peripheral vision
Note 1 to entry: Performance of the visual system may be measured for instance by the speed and accuracy with
which a visual task is performed.
[SOURCE: IEC 60050-845:2020 845-29-005 / CIE S 017:2020; 17-29-005, modified – note 1 to entry
added]
3.1.12
visual comfort
subjective condition of visual well-being induced by the luminous environment
3.1.13
reaction time
minimum time interval between the occurrence of an event demanding immediate action and the
response to the event (unit: s)
Note 1 to entry: The reaction time includes the time needed for perception, taking a decision and acting.
3.1.14
visual task
visual elements of the activity being undertaken
Note 1 to entry: The main visual elements are the size of the structure, its luminance, its contrast against the
background, its colour, and its duration.
3.1.15
visual acuity
visual resolution
measure of spatial discrimination such as the reciprocal of the value of the angular
separation in minutes of arc of two neighbouring objects (points or lines or other specified stimuli) which
the observer can just perceive to be separate
[SOURCE: IEC 60050-845:2020 845-02-078 / CIE S 017:2020; 17-22-078]
3.1.16
contrast
quantity intended to correlate with the perceived brightness contrast, usually defined by one
of a number of formulae that involve the luminances of the stimuli considered
EXAMPLE By the proportional variation in contrast near the luminance threshold (ΔL/L) or by the ratio of
luminances for much higher luminances (L /L ).
1 2
3.1.17
field of vision
extent of space in which objects are visible to an eye in a given position
Note 1 to entry: In the horizontal plane meridian the field of vision extends to nearly 190° with both eyes open, the
area seen binocularly is about 120°, and the area seen by one eye only is about 154°.
Note 2 to entry: The extent of the field of vision tends to diminish with age.
[SOURCE: IEC 65050-845:2020 845-22-081 / CIE S 017:2020; 17-22-081]
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3.2 Light and colour
3.2.1
luminous flux
Φ , Φ
v
change in luminous energy with time
dQ
v
Φ =
v
dt
where Q is the luminous energy emitted, transferred or received, and t is time (unit: lm)
v
Note 1 to entry: Luminous flux is a quantity derived from the radiant flux, Φ , by evaluating the radiation according
e
to its action upon the CIE standard photometric observer. Luminous flux can be derived from the spectral radiant
flux distribution by
∞
Φ = KVΦ λ λλd
( ) ( )
vem ,λ
∫
0
where K is maximum luminous efficacy, Φ (λ) is spectral radiant flux, V(λ) is spectral luminous efficiency and λ
m e,λ
is wavelength.
Note 2 to entry: The distribution of the luminous intensities as a function of the direction of emission, e.g. given by
ϕ
the polar angles (ϑ, ), is used to determine the luminous flux, Φ , within a certain solid angle, Ω , of a source:
v
Φ = I ϑϕ, sinϑdϕdϑ
( )
vv
∫∫
Ω
Note 3 to entry: The corresponding radiometric quantity is "radiant flux". The corresponding quantity for photons
is "photon flux".
[SOURCE: IEC 60050-845:2020 845-21-039, CIE S 017:2020; 17-21-039]
3.2.2
luminous intensity
I , I
v
density of luminous flux with respect to solid angle in a specified
direction
dΦ
v
I =
v
dΩ
where Φ is the luminous flux emitted in a specified direction, and Ω is the solid angle containing that direction
v
−1
(unit: cd = lm ⋅ sr )
Note 1 to entry: For practical realization of the quantity, the source is approximated by a point source.
Note 2 to entry: The distribution of the luminous intensities as a function of the direction of emission, e.g. given by
ϕ
the polar angles (ϑ, ), is used to determine the luminous flux, Φ , within a certain solid angle, Ω , of a source:
v
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Φ = I ϑϕ, sinϑdϕdϑ
( )
∬
v v
Ω
Note 3 to entry: Luminous intensity can be derived from the spectral radiant intensity distribution by
∞
IK= I λ V λλd
( ) ( )
vm∫ e,λ
0
where K is maximum luminous efficacy, I (λ)is the spectral radiant intensity at wavelength λ, and V(λ) is spectral
m e,λ
luminous efficiency.
Note 4 to entry: The corresponding radiometric quantity is "radiant intensity". The corresponding quantity for
photons is "photon intensity".
[SOURCE: IEC 60050-845:2020 845-21-045 / CIE S 017:2020; 17-21-045]
3.2.3
luminance
L , L
v
density of luminous intensity with respect to projected area in a specified direction at a specified point
−2 −2 −1
on a real or imaginary surface (unit: cd ⋅ m = lm ⋅ m ⋅ sr )
dI
1
v
L =
v
dA cosα
where I is luminous intensity, A is area and α is the angle between the normal to the surface at the
v
specified point and the specified direction
Note 1 to entry: In a practical sense, the definition of luminance can be thought of as dividing a real or imaginary
surface into an infinite number of infinitesimally small surfaces which can be considered as point sources, each of
which has a specific luminous intensity, I , in the specified direction. The luminance of the surface is then the
v
integral of these luminance elements over the whole surface.
The formula in the definition can mathematically be interpreted as a derivative (i.e. a rate of change of luminous
intensity with projected area) and could alternatively be rewritten in terms of the average luminous intensity, Ī ,
v
as:
I
1
v
L = lim
v
A→0 A cosα
Hence, luminance is often considered as a quotient of averaged quantities; the area, A, should be small enough so
that uncertainties due to variations in luminous intensity within that area are negligible; otherwise, the quotient
I
1
v
L = gives the average luminance and the specific measurement conditions have to be reported with the
v
A cosα
result.
Note 2 to entry: For a surface being irradiated, an equivalent formula in terms of illuminance, E , and solid angle, Ω
v
dE
1
v
, is L = where θ is the angle between the normal to the surface being irradiated and the direction of
v
dΩθcos
irradiation. This form is useful when the source has no surface (e.g. the sky, the plasma of a discharge).
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dΦv
Note 3 to entry: An equivalent formula is L = where Φ is luminous flux and G is geometric extent.
v
v
dG
Note 4 to entry: Luminous flux can be obtained by integrating luminance over projected area, Acosα , and solid angle,
Ω
Φ = L cosα dA dΩ
V ∫∫ v
2
Note 5 to entry: Since the optical extent, expressed by Gn , where G is geometric extent and n is refractive index, is
−2
invariant, the quantity expressed by L n is also invariant along the path of the beam if the losses by absorption,
v
reflection and diffusion are taken as 0. That quantity is called "basic luminance".
Note 6 to entry: The formula in the definition can also be described as a function of luminous flux, Φ . In this case, it
v
is mathematically interpreted as a second partial derivative of the luminous flux at a specified point (x, y) in space
in a specified direction (ϑ,φ) with respect to projected area, Acosα , and solid angle, Ω ,
2
d Φ xy, ,,ϑϕ
( )
v
L xy, ,,ϑϕ =
( )
v
dA x, y cosα dΩ ϑϕ,
( ) ( )
where α is the angle between the normal to that area at the specified point and the specified direction.
Note 7 to entry: The corresponding radiometric quantity is "radiance". The corresponding quantity for photons is
"photon radiance".
[SOURCE: IEC 60050-845:2020 845-21-050/ CIE S 017:2020; 17-71-050]
3.2.4
average luminance
L , , L ,
L L
av v,av v
−2
luminance averaged over a specified surface (unit: cd ⋅ m )
Note 1 to entry: In practice, this may be approximated by an average of the luminances at a representative number
of points on the surface. The number and position of these points should be specified in the relevant application
guide.
[SOURCE: IEC 60050-845:2020 845-29-151 / CIE S 017:2020; 17-29-151, modified - Note 1 to entry
added]
3.2.5
minimum luminance
L
min
−2
lowest luminance of any relevant point on the specified surface (unit: cd ⋅ m )
Note 1 to entry: The relevant points at which the luminances are determined should be specified in the appropriate
application standard.
3.2.6
maximum luminance
L
max
−2
highest luminance of any relevant point on the specified surface (unit: cd ⋅ m )
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Note 1 to entry: The relevant points at which the luminances are determined should be specified in the appropriate
application standard.
3.2.7
maintained average luminance
maintained luminance
L
m
−2
value below which the average luminance of a specified surface is not permitted to fall (unit: cd ⋅ m )
Note 1 to entry: The maintained average luminance is the average luminance of the specified surface at the time
maintenance should be carried out.
[SOURCE: IEC 60050-845:2020 845-29-153 / CIE S 017:2020; 17-29-153, modified - selection of
symbols]
3.2.8
initial average luminance
L
i
−2
average luminance of the specified surface when the lighting installation is new (unit: cd ⋅ m )
[SOURCE: IEC 60050-845:2020 845-29-152 / CIE S 017:2020; 17-29-152, modified - selection of
symbols]
3.2.9
luminance contrast
quantity relating to the difference in luminance between two surfaces
Note 1 to entry: Widely accepted definitions include:
C = (L − L ) / L with L > L (positive contrast),
1 2 1 1 2
C = (L − L ) / L with L < L (negative contrast),
1 2 1 1 2
C = (L − L ) / (L + L2) with L > L ,
1 2 1 1 2
where C is the luminance contrast and L and L are the luminances of the two surfaces.
1 2
Note 2 to entry: Although luminance contrast is intended to correlate with brightness contrast, it is possible that it
does not do so directly because brightness contrast depends on other factors such as the angular separation, the
luminance gradient, and any size difference between the two surfaces.
3.2.10
illuminance
E , E
v
density of incident luminous flux with respect to area at a point on a real or imaginary surface
dΦ
v
E =
v
dA
−2
where Φ is luminous flux and A is the area on which the luminous flux is incident (unit: lx = lm ⋅ m )
v
Note 1 to entry: Illuminance can be derived from the spectral irradiance distribution by
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∞
EK= E λ V λλd
( ) ( )
vm e,λ
∫
0
where K is maximum luminous efficacy, E (λ) is the spectral irradiance at wavelength λ and V(λ) is spectral
m e,λ
luminous efficiency.
Note 2 to entry: The corresponding radiometric quantity is "irradiance". The corresponding quantity for photons is
"photon irradiance".
[SOURCE: IEC 60050-845:2020 845-21-060 / CIE S 017:2020; 17-21-060]
3.2.11
average illuminance
, E , E
E v
v,av
illuminance averaged over a specified surface (unit: lx)
Note 2 to entry: When stating the average illuminance it is necessary to provide a clear indication of the type of
illuminance at the points of the surface, i.e. horizontal, vertical, spherical, cylindrical or semi-cylindrical.
Note 2 to entry: In practice this can be derived either from the total luminous flux falling on the surface divided by
the total area of the surface, or alternatively from an average of the illuminances at a representative number of
points on the surface.
[SOURCE: IEC 60050-845:2020 845-29-155 / CIE S 017:2020; 7-29-155, modified - note 2 to entry
added]
3.2.12
minimum illuminance
E
min
lowest illuminance at any relevant point on the specified surface (unit: lx)
3.2.13
maximum illuminance
E
max
highest illuminance at any relevant point on the specified surface (unit: lx)
3.2.14
maintained average illuminance
maintained illuminance
E , E , E , E
v,av,m av,m
m vm,
value below which the average illuminance over a specified surface is not permitted to fall (unit: lx)
Note 1 to entry: The maintained average illuminance is the average illuminance over the specified surface at the
time maintenance should be carried out.
[SOURCE: IEC 60050-845:2020 845-29-157 / CIE S 017:2020; 17-29-157]
3.2.15
initial average illuminance
E , E , E , E
v,av,i av,i
v,i i
average illuminance on the specified surface when the installation is new (unit: lx)
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[SOURCE: IEC 60050-845:2020 845-29-156 / CIE S 017:2020; 17-29-156]
3.2.16
spherical illuminance
E , E
v,o o
mean value of illuminance on the outer curved surface of a very small (real or imaginary) sphere at a
point in space (unit: lx)
Note 1 to entry: The spherical illuminance can be expressed by
EL= dΩ
v,o v
∫
4π
where Ω is solid angle and L is luminance.
v
Note 2 to entry: The spherical illuminance is the quotient of the luminous flux of all the light incident on the outer
surface of an infinitely small sphere centred at the given point and the area of the diametrical cross-section of that
sphere.
Note 3 to entry: The analogous quantities "spherical irradiance", E , and "photon spherical irradiance" (also
e,o
termed "photon fluence rate"), E , are defined in a similar way, replacing luminance, L , by radiance, L , and
p,o v e
photon radiance, L , respectively.
p
[SOURCE: IEC 60050-845:2020 845-221-066 / CIE S 017:2020; 17-21-066]
3.2.17
hemispherical illuminance
E
hs
total luminous flux falling on the curved surface of a very small hemisphere located at the
specified point divided by the curved surface area of the hemisphere (unit: lx)
Note 1 to entry: The base of the hemisphere is taken to be horizontal unless stated otherwise.
3.2.18
cylindrical illuminance
E , E , E
z v,c c
mean value of illuminance on the outer curved surface of a very small (real or imaginary) sphere that is
oriented vertically at a point in space (unit: lx)
Note 1 to entry: Cylindrical illuminance is sometimes also defined as the arithmetic mean of the vertical illuminance,
E , at a point
v,v
2π
1
EE= dϕ
z v,v
∫
0
2π
where E is the vertical illuminance for an area element with its normal in the direction φ, and φ is the angle in
v,v
the plane perpendicular to the axis of the cylinder.
Note 2 to entry: The
...
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