EN 14501:2021+A1:2025

SLOVENSKI STANDARD
01-marec-2025
Rolete in polkna - Toplotno in vizualno ugodje - Delovne karakteristike in
klasifikacija (vključno z dopolnilom A1)
Blinds and shutters - Thermal and visual comfort - Performance characteristics and
classification
Abschlüsse - Thermischer und visueller Komfort - Leistungsanforderungen und
Klassifizierung
Stores et volets - Confort thermique et visuel - Caractéristiques de performance et
classification
Ta slovenski standard je istoveten z: EN 14501:2021+A1:2025
ICS:
91.060.50 Vrata in okna Doors and windows
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 14501:2021+A1
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2025
EUROPÄISCHE NORM
ICS 91.060.50 Supersedes EN 14501:2021
English Version
Blinds and shutters - Thermal and visual comfort -
Performance characteristics and classification
Stores et volets - Confort thermique et visuel - Abschlüsse - Thermischer und visueller Komfort -
Caractéristiques de performance et classification Leistungsanforderungen und Klassifizierung
This European Standard was approved by CEN on 21 October 2019 and includes Amendment 1 approved by CEN on 20 August
2024.
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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14501:2021+A1:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and symbols . 7
4 Notations used . 9
4.1 General . 9
4.2 Visual or solar properties . 9
4.3 Geometry of the radiation .10
4.4 Optical factors .11
5 Thermal comfort .11
5.1 General .11
5.2 Control of solar gains – Total solar energy transmittance g .11
tot
5.3 Secondary heat gains – Secondary heat transfer factor q .13
i, tot
5.4 Protection from direct transmission – Normal/normal solar transmittance τ .14
e, n-n
6 Visual comfort .14
6.1 General .14
6.2 Darkening performance .16
6.3 Glare control .17
6.4 Night privacy .19
6.5 Visual contact with the outside .20
6.6 Daylight utilization .21
6.7 Rendering of colours .21
Annex A (normative) Reference glazing .22
A.1 General .22
A.2 Reference glazing with integrated data only .22
A.2.1 Glazing A .22
A.2.2 Glazing B .22
A.2.3 Glazing C .23
A.2.4 Glazing D .24
A.2.5 Glazing E .24
A.3 Reference glazing with spectral data .25
A.3.1 General .25
A.3.2 Glazing F .25
A.3.3 Glazing G .26
A.3.4 Glazing H .26
A.3.5 Spectral data for the panes .26
Annex B (informative) The meaning of the secondary internal heat transfer factor q .33
i, tot
Annex C (informative) Example of performance presentation . 34
C.1 Thermal comfort . 34
C.2 Visual comfort . 34
Annex D (informative) Daylight Glare Probability . 36
D.1 General . 36
D.2 Glare . 36
D.3 Daylight Glare Probability . 36
D.3.1 General . 36
D.3.2 Annual evaluation . 37
D.3.3 Simplified annual glare evaluation . 38
Annex E (normative) Opacity performance of curtain material . 44
Bibliography . 45

European foreword
This document (EN 14501:2021+A1:2025) has been prepared by Technical Committee CEN/TC 33 “Doors,
windows, shutters, building hardware and curtain walling”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by July 2025, and conflicting national standards shall be withdrawn at
the latest by July 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document includes Amendment 1 approved by CEN on 20 August 2024.
This document supersedes !EN 14501:2021".
The start and finish of text introduced or altered by amendment is indicated in the text by tags !".
The main modifications of this project of revision are relating to:
— the revision of the performance classification for the darkening performance;
— the revision of the performance classification for the glare control. The new classification is based on DGP
(Daylight Glare Probability) calculations and considers the cut-off angle of the curtain material;
— the addition of a fifth reference glazing (triple glazing);
— the addition of an informative annex giving recommendations on the class for glare control to be used
depending on the location and orientation of the building, as well as on the size of the glazed area, the
distance from the façade and the light transmittance of the glazing.
Any feedback and questions on this document should be directed to the users’ national standards body. A
complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: 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 the United Kingdom.
Introduction
This document is a part of a series of standards dealing with blinds and shutters for buildings as defined in
EN 12216.
The characteristics covered by this document are specific requirements that are complementary to the
intrinsic requirements that internal blinds, external blinds or shutters shall fulfil in accordance with EN 13120,
EN 13561 and EN 13659, respectively.
1 Scope
This document applies to the whole range of shutters, awnings and blinds defined in EN 12216, described as
solar protection devices in this document.
It specifies the corresponding properties and classifications:
— relating to thermal comfort:
— the solar factor (total solar energy transmittance);
— the secondary heat transfer factor;
— the direct solar transmittance;
— relating to visual comfort:
— the darkening performance;
— the night privacy;
— the visual contact with the outside;
— the glare control;
— the daylight utilization;
— the rendering of colours.
NOTE For other purposes, more detailed methods using different parameters can be used.
Some of the characteristics (e.g. g ) are not applicable when solar protection devices are not parallel to the
tot
glazing (e.g. folding-arm awnings).
This document is not applicable to the solar protection devices using fluorescent materials.
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.
EN 410, Glass in building — Determination of luminous and solar characteristics of glazing
EN 12216, Shutters, external blinds, internal blinds — Terminology, glossary and definitions
EN ISO 52022-1, Energy performance of buildings — Thermal, solar and daylight properties of building
components and elements — Part 1: Simplified calculation method of the solar and daylight characteristics for
solar protection devices combined with glazing (ISO 52022-1)
EN ISO 52022-3, Energy performance of buildings — Thermal, solar and daylight properties of building
components and elements — Part 3: Detailed calculation method of the solar and daylight characteristics for
solar protection devices combined with glazing (ISO 52022-3)
EN 14500:2021, Blinds and shutters — Thermal and visual comfort — Test methods

EN ISO 52022-1 supersedes EN 13363-1.
EN ISO 52022-3 supersedes EN 13363-2.
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in EN 12216 and the following apply.
ISO and IEC maintain terminology 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/
3.1
transmittance
τ
ratio of the transmitted flux to the incident flux (see Figure 1)
Note 1 to entry: A more detailed definition is given in EN 14500:2021.
3.2
reflectance
ρ
ratio of the reflected flux to the incident flux (see Figure 1)
Note 1 to entry: A more detailed definition is given in EN 14500:2021.
3.3
absorptance
α
ratio of the absorbed flux to the incident flux (see Figure 1)
Key
1 solar protection device 4 absorbed radiation α ∙ E
2 incident radiation E 5 reflected radiation ρ ∙ E
3 transmitted radiation τ ∙ E
Figure 1 — Representation of the optical factors
3.4
openness coefficient
ratio between the area of the openings and the total area of a fabric
Note 1 to entry: For identical fabrics that differ only by the colour, the openness coefficient is considered as
independent of the colour.
Note 2 to entry: The openness coefficient is determined according to EN 14500:2021.
3.5
solar factor
total solar energy transmittance
g
ratio between the total solar energy transmitted into a room through a window and the incident solar energy
on the window
Note 1 to entry: g is the solar factor of the glazing alone; gtot is the solar factor of the combination of a glazing and a
solar protection device.
3.6
secondary internal heat transfer factor
q
i, tot
part of the total absorbed radiation which is flowing inwards through the glazing and the combined shading
device
3.7
colour rendering index
R
a
index designed to express synthetically a quantitative evaluation of the differences in colour between eight
test colours lit directly by the standard illuminant D and by the same illuminant transmitted through the
solar protection device
3.8
operative temperature
θ
op
uniform temperature of a room in which an occupant would exchange the same amount of heat by radiation
plus convection as in the actual non-uniform environment
Note 1 to entry: For more information on the calculation of θ it is recommended to refer to EN ISO 13791 or
op,
EN ISO 13792.
3.9
light exclusion system
part of the solar protection device intended to reduce peripheral light penetration
Note 1 to entry: A guiding system may qualify as a light exclusion system, but only if the curtain penetrates the guiding
channels.
3.10
cut-off angle
first angle of incidence at which the direct light transmittance is no longer perceivable
Note 1 to entry: A more detailed definition is given in EN 14500:2021.
4 Notations used
4.1 General
For the purpose of this document, the optical factors τ (transmittance), ρ (reflectance) and α (absorptance)
are labelled with subscripts which indicate:
— the visual or solar properties;
— the geometry of the incident and the transmitted or reflected radiation.
4.2 Visual or solar properties
According to the respective spectrum, the following subscripts are used:
— « » solar (energetic) characteristics, given for the total solar spectrum, (wavelengths λ from 300 nm
e
to 2 500 nm), according to EN 410;
— « » visual characteristics, given for the standard illuminant D weighted with the sensitivity of the
v 65
human eye (wavelengths λ from 380 nm to 780 nm), according to EN 410.
4.3 Geometry of the radiation
The following subscripts are used to indicate the geometry of the incident radiation and the geometry of the
transmitted or reflected radiation (see Figure 2):
— « » for directional (fixed, but arbitrary direction θ);
dir
— « » for normal, or near normal in case of reflected radiation, the angle of incidence is θ = 0°,
n
or θ ≤ 8° respectively;
— « » for hemispherical (collected in the half space behind the sample plane);
h
— « » for diffuse.
dif
NOTE A more detailed definition is given in EN 14500:2021.

Key
1 solar protection device
2 incident directional light or solar radiation
3 transmitted direct component of light or solar radiation
4 transmitted diffuse component of light or solar radiation
Figure 2 — Direct and diffuse components of transmitted radiation
4.4 Optical factors
The optical factors are designated as follows:
— τ normal/normal solar transmittance;
e, n-n
— τ normal/normal light transmittance;
v, n-n
— τ normal/diffuse light transmittance;
v, n-dif
— τ normal/hemispherical light transmittance;
v, n-h
— τ diffuse/hemispherical light transmittance.
v, dif-h
5 Thermal comfort
5.1 General
Thermal comfort is mainly governed by the operative temperature θ within the room. θ depends on the air
op op
temperature, the air velocity and the temperature of the surrounding surfaces.
Solar gains shall be controlled in order to limit the operative temperature. The classification of the total solar
energy transmittance g is given in 5.2.4.
tot
Solar protection devices influence the thermal comfort in three aspects:
— the mean operative temperature and/or the cooling loads are influenced by the solar gains which mainly
depend on the size of the windows and the total solar energy transmittance g ;
tot
— the solar protection device may cause higher local values of θ when irradiated by the sun due to higher
op
temperatures on the inner surface of the glazing or solar protection device. This effect is quantified by the
secondary internal heat transfer factor qi, tot;
— the solar protection device may prevent persons and surroundings in the room from being irradiated
directly. This effect is quantified by the direct-direct solar transmittance τ .
e, dir-dir
The performance classes for the thermal comfort used in the following clauses are specified in Table 1.
Table 1 — Definition of classes
Influence on thermal comfort
0 1 2 3 4
Class
very little moderate very good
little effect good effect
effect effect effect
5.2 Control of solar gains – Total solar energy transmittance gtot
5.2.1 General
The limitation of solar gains is one of the most important aspects of summer thermal comfort. It also strongly
reduces the energy consumption of cooling systems. The solar gains are directly proportional to the total solar
energy transmittance g .
tot
g depends on the glazing and the solar protection device. g may be determined using either the
tot tot
methodology given in 5.2.2 or in 5.2.3. When the glazing specifications are unknown, any one of the eight
different reference glazing given in Annex A may be used.
The method and the glazing used for the determination of the g value shall be specified in all reported g
tot tot
values.
For a declaration of performance (independent from the installation conditions), the calculation according to
5.2.2 and the reference glazing C, specified in Annex A, shall be used. For cases not covered by 5.2.2, the method
defined in 5.2.3 shall be used, assuming that:
— for external solar protection devices, the space between the solar protection device and the glazing is
unventilated;
— summer conditions are used.
The solar factor g of glazing alone, needed for the calculation of g shall be calculated according to EN 410.
tot,
For venetian blinds, the values of the total solar factor g shall be specified for at least two positions:
tot
— the fully closed position of the slats at normal incidence;
— the slats tilted at 45° and irradiation with 30° altitude angle, 0° azimuth angle.
In the case of roller shutters with light and ventilation slots, g shall be calculated:
tot
— in the fully extended and closed position at normal incidence;
— in the fully extended and open position at normal incidence.
corr
NOTE 1 For slatted or louvered devices tilted at 45° the values τ specified in EN ISO 52022-1 can be used as the
e
direct-hemispherical solar transmittance except for mirror-finish products and under the boundary condition that there
is no direct solar transmission at the tilt angle of the slats under consideration.
NOTE 2 A direct calorimetric measurement of gtot is given by ISO 19467.
NOTE 3 For a more detailed method for the calculation of the transmittance and the reflectance of slatted devices, see
the calculation method given in EN ISO 52022-3. The view factors given in Annex D of EN ISO 52022-3:2017 are only
applicable for venetian blinds with a ratio of d/l = 1 for slat width l and slat distance d. EN 14500:2021 and ISO TR 52022-
2 provide additional view factors for other configurations.
5.2.2 Determination of g – Simplified method
tot
The simplified method to be applied for the determination of g is EN ISO 52022-1.
tot
The necessary data for the calculation are the following:
— τ solar transmittance of the solar protection device;
e
solar reflectance of the outer surface of the solar protection device;
— ρe
— g solar factor of the glazing;
— U thermal transmittance of the glazing.
5.2.3 Determination of g – Detailed method
tot
The detailed method to be applied for the determination of g is EN ISO 52022-3.
tot
The necessary data for the calculation are the following:
— τ(λ) normal/hemispherical spectral transmittance of the solar protection device;
n-h
— ρ(λ) and ρ’(λ) normal/hemispherical spectral reflectances of the solar protection device for each
n-h n-h
side;
— ε, ε' emissivities of the solar protection device surfaces;
— C openness coefficient as a measure for the size of the openings (fabrics only);
o
— the spectral characteristics of each pane of the glazing;
— the emissivity of each surface of each pane of the glazing;
— the thickness and nature of gas space.
In EN ISO 52022-3, two different sets of boundary conditions are specified: summer conditions and reference
(mean winter) conditions. Care should be taken to choose the correct set of boundary conditions according to
the project specifications and the national regulations.
If spectral data for ρ(λ), ρ´(λ) and τ(λ) are not available, integrated data may be used. This will reduce the
accuracy of the calculations.
5.2.4 Performance classes
The classification of g is specified in Table 2 with the classes quoted in Table 1.
tot
The method and the glazing used for the determination of the g value shall be specified for all reported
tot
classes.
Table 2 — Total solar energy transmittance g — Classification
tot
Class 0 1 2 3 4
g g ≥ 0,50 0,35 ≤ g < 0,50 0,15 ≤ g < 0,35 0,10 ≤ g < 0,15 g < 0,10
tot tot tot tot tot tot
5.3 Secondary heat gains – Secondary heat transfer factor qi, tot
5.3.1 General
The total solar energy transmitted through a facade consists of two parts:
— radiation in the solar range, measured by the solar transmittance τ ;
e, tot
— heat (thermal radiation and convection), measured by the secondary heat transfer factor q .
i,tot
The secondary heat transfer factor q of the combination of glazing and solar protection device shall be
i, tot
calculated with the following formula:
q = g – τ
i, tot tot e, tot
q may be determined for the eight different reference glazing given in Annex A using either the methodology
i,tot
given in 5.3.2 or in 5.3.3. For general product labelling (independent from the installation conditions), the
calculation for q according to 5.3.2 and the reference glazing C, specified in Annex A, shall be used.
i,tot
value shall be specified in all reported q
The method and the glazing used for the determination of the qi,tot i,tot
values.
NOTE An example explaining the meaning of q is given in Annex B.
i, tot
5.3.2 Determination of q – Simplified method
i, tot
The direct solar transmittance τ and the total solar transmittance g of the combination of a glazing and a
e, tot tot
solar protection device shall be calculated according to EN ISO 52022-1.
5.3.3 Determination of q – Detailed method
i, tot
The direct solar transmittance τe, tot and the total solar transmittance gtot of the combination of a glazing and a
solar protection device shall be calculated according to EN ISO 52022-3.
In EN ISO 52022-3, two different sets of boundary conditions are specified: summer conditions and reference
(mean winter) conditions. Care should be taken to choose the correct set of boundary conditions according to
the project specifications and the national regulations.
5.3.4 Performance classes
The classification of q is specified in Table 3 with the classes quoted in Table 1.
i, tot
Table 3 — Secondary Heat transfer factor q — Classification
i, tot
Class 0 1 2 3 4
q q ≥ 0,30 0,20 ≤ q < 0,30 0,10 ≤ q < 0,20 0,03 ≤ q < 0,10 q < 0,03
i, tot i, tot i, tot i, tot i, tot i, tot
5.4 Protection from direct transmission – Normal/normal solar transmittance τ
e, n-n
5.4.1 General
The ability of a solar protection device to protect persons and surroundings from direct irradiation is
measured by the direct/direct solar transmittance τ of the device. For the sake of simplicity, the normal-
e, dir-dir
normal solar transmittance τe, n-n is used as a measure for this property.
5.4.2 Determination
The normal/normal solar transmittance τ shall be determined according to EN 14500:2021.
e, n-n
5.4.3 Performance classes
The classification of τ is specified in Table 4 with the classes quoted in Table 1.
e, n-n
Table 4 — Normal/normal solar transmittance τ — Classification
e, n-n
Class 0 1 2 3 4
τ τ ≥ 0,20 0,15 ≤ τ < 0,20 0,10 ≤ τ < 0,15 0,05 ≤ τ < 0,10 τ < 0,05
e, n-n e, n-n e, n-n e, n-n e, n-n e, n-n

NOTE Slatted or louvered devices with non-perforated slats are class 4 when the slats are tilted in a way that there
is no direct penetration of the sun.
6 Visual comfort
6.1 General
Depending on the geometry of the incident and the transmitted radiation, the components of the light
transmission concern different aspects of visual comfort.
When a solar protection device fitted to a window is directly illuminated by the sun:
— the incident radiation is mainly directional;
— the transmitted radiation is partially directional (τ ), partially diffuse (τ );
v, dir-dir v, dir-dif
— the total transmitted light flow is the sum of these two components:
τ τ τ
v, dir-h = v, dir-dir + v, dir-dif
These characteristics depend on the incidence angle θ.
The value τ is representative of the global reduction of natural light by the solar protection device when
v, dir-h
the light is coming from one specific direction. If an average value is required, τ is representative.
v, dif-h
represents the light passing through the holes in the solar
The direct part of transmitted radiation τv, dir-dir
protection device under incidence θ. It allows recognition of shapes, and has a favourable influence on vision
to the outside, but is unfavourable for night privacy.
It may also be the basis of two factors of visual discomfort:
— direct vision of the solar disc;
— solar spots on the floor or the office furniture.
The diffused part τ of transmitted radiation results in an own luminance of the solar protection device,
v, dir-dif
which appears as a light source.
This may cause discomfort glare, either from an excessive value of the luminance in itself, or from the contrast
between the luminance of the solar protection device and that of its surrounding.
Solar protection devices shall be classified, with regard to the following criteria:
— darkening performance;
— glare control;
— night privacy;
— visual contact with the outside;
— daylight utilization;
— rendering of colours.
These criteria depend on three main optical factors:
— τ normal/normal light transmittance;
v, n-n
— τv, n-dif diffused part of light transmission;
— τ diffuse/hemispherical light transmittance.
v, dif-h
The performance classes for glare control, night privacy, visual contact with the outside, daylight utilization
are quoted in Table 5.
Table 5 — Definition of Classes
Influence on visual comfort
0 1 2 3 4
Class
very good
very little effect little effect moderate effect good effect
effect
In the case of adjustable slatted solar protection devices, e.g. venetian blinds or louvres, the tilting angle of the
slats and the direction of the incident light shall be specified when reporting any value or class.
NOTE 1 The real light transmittance of the solar protection device can be much greater than that of the curtain, due
to the lateral gaps and the guiding system. It is difficult to establish, either by calculation or direct measurement.
NOTE 2 The residual light transmittance of the solar protection device in its fully extended and closed position can be
evaluated, according to the type of solar protection device, from the light transmittance of the constitutive materials. To
some extent, the light transmittance of a completely closed or partially opened slatted or louvered device (e.g. venetian
blind) can be evaluated using the calculation method given in EN ISO 52022-3 from the light characteristics and geometry
of the slats or laths.
NOTE 3 When the window is not directly exposed to the sun it receives diffuse radiation, which can be disturbing
enough to require that the solar protection device remains in the extended position.
NOTE 4 Adjustable slatted solar protection devices provide a variable light control.
NOTE 5 In the case of a venetian blind with unperforated slats, τ can be considered as 0 when the blind is fully
v, n-n
closed. If the slats can be tilted horizontally, τv, n-n can be considered to be greater than 0,5 in that position. This means,
of a venetian blind with unperforated slats can be adjusted to a large extent.
that τv, n-n
NOTE 6 In the case of a venetian blind with fully perforated slats, the minimum value of τ can be considered to be
v, n-n
the measured value of τv, n-n of the perforated area of an individual slat.
NOTE 7 In the case of a venetian blind with partially perforated slats, the minimum value of τv, n-n can be considered
to be 0, when the perforated area can be protected with the unperforated area of the upper slat. If this is not the case, τ
v,
can be considered to be the measured value of τ of the perforated area of an individual slat.
n-n v, n-n
6.2 Darkening performance
6.2.1 General
Darkening performance represents the capacity of an internal blind, external blind or a shutter in the fully
extended and closed position to reduce light penetration.
6.2.2 Determination
The performance is expressed by the level of illuminance when no light is perceivable through the complete
solar protection device. It shall be determined according to EN 14500:2021.
6.2.3 Performance classes
The darkening performance is specified according to the classification given in Table 6. This classification uses
the classification for curtain material specified in Annex E.
Table 6 — Darkening performance of solar protection devices — Classification
No light Curtain material classification
perceived at
Internal
the following
incident
external
0 1 2 3 4
light
incident light
level (L)
A With light exclusion
No 75 000 lx     A.4
system
B With light exclusion
2 mlux 30 000 lx    B.3 B.4
system
C With light exclusion
2 mlux 1 000 lx   C.2 C.3 C.4
system
D With light exclusion
No test D.0 D.1 D.2 D.3 D.4
system
E Without light
No test E.0 E.1 E.2 E.3 E.4
exclusion system
NOTE 1 For some classes, an additional light source is placed in the observer room in order to reproduce a minimal
internal light condition, e.g. light produced by clock face, light passing under the door.
Class A.4 is a technical class intended to cover specific applications such as high grade laboratory work,
advanced optics, photochemical, handling highly light sensitive material.
Class B may be suitable for example for photography work.
NOTE 2 The darkening performance of a solar protection device is based on three elements:
— the opacity performance of the curtain material (e.g. fabric, laths, slats) according to Annex E;
— the choice of the frame;
— the result of the test carried out on the complete solar protection device according to Table 6.
6.3 Glare control
6.3.1 General
The glare control is characterized by:
— the capacity of the solar protection device to control the luminance level of windows, doors and façades
and to reduce the luminance contrasts between different zones within the field of vision due to:
— the solar spot on the work surface and its immediate surrounding;
— the part of the sky seen through a window;
— the direct vision of the solar disk through a solar protection device;
— the luminance of the solar protection device contrasting with its surroundings (in the case of diffusing
materials);
— the capacity of the solar protection device to prevent disturbing reflection on visual display due to the
luminance of the window and the surrounding surfaces.
Frame
NOTE 1 EN 12665:2018, 3.1.8 (CIE ILV 17-492) defines glare as follows: “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 contrasts”.
NOTE 2 EN 12665:2018, 3.2.22 (CIE ILV 17-333) defines discomfort glare as follows: “glare that causes discomfort
without necessarily impairing the vision of objects”.
6.3.2 Determination
Glare control is a function of τ and τ .
v, n-dif v, n-n
τ and τ shall be determined according to EN 14500:2021.
v, n-dif v, n-n
6.3.3 Performance classes
Glare depends on many criteria such as:
— the person (age, visual acuity .);
— the building (location, surroundings .);
— the room (area, position and number of windows, reflectance of walls and furniture.);
— the façade (orientation, glazing transmittance, glazing fraction .);
— the usage of the room (office, computer screens, private use .);
— the position of the person within the room (distance from the façade, viewing direction .);
— the task performed (reading, writing, working at a PC…).
As a consequence, it is not possible to define a classification suitable for every configuration.
Table 7 has been produced to compare intrinsic performances of solar protection devices for glare control
only. It may be used as a guide for selecting a curtain material when the detailed situation is not known or the
glare disturbance not the primary concern. Annex D provides recommended glare control classes for
particular building situations (location, orientation, glazing light transmittance, glazing fraction…).
NOTE In order to develop the classification, several situations have been assessed on an hourly basis over a period
of one complete year with the following boundary conditions:
— location: Frankfurt am Main;
— orientation: south facing;
— offices: W 4 m × D 5 m × H 3 m and W 10 m × D 5 m × H 3 m;
— glazing fraction: 50 % and 100 %;
— glazing light transmittance: 85 % and 30 %;
— distance from the window: 2 m;
— three different qualities of anti-reflective computer screens.
The methodology used is the Daylight Glare Probability (DGP) which is an approach to consider both the
illuminance at eye level and individual glare sources of high luminance to estimate the percentage of persons
affected by discomfort glare. A more detailed presentation of the DGP and its application for specific buildings
is available in EN 17037.
In order to take into account a specific building situation, a detailed study can be carried out (see EN 17037).
The solar protection device shall be classified according to Table 7. The classes are quoted in Table 5.
Table 7 — Glare control — Classification
τ
v, n-n
τ
v, n-dif
0,00 < τ 0,01 < τ 0,02 < τ 0,03 < τ
v, n- v, n- v, n- v, n-
τ = 0,00 τ > 0,05
v, n-n v, n-n
n ≤ 0,01 n ≤ 0,02 n ≤ 0,03 n ≤ 0,05
τ ≤ 0,03 4 4 3 3 1 0
v, n-dif
0,03 < τ ≤ 0,06 4 3 2 2 1 0
v, n-dif
0,06 < τ ≤ 0,10 4 3 2 1 0 0
v, n-dif
0,10 < τ ≤ 0,15 3 2 1 1 0 0
v, n-dif
0,15 < τ ≤ 0,20 2 2 1 1 0 0
v, n-dif
0,20 < τ ≤ 0,25 1 1 0 0 0 0
v, n-dif
0,25 < τ 0 0 0 0 0 0
v, n-dif
Solar protection devices that are inside the grey area of Table 7 may gain a higher class, assuming they can
justify a cut-off angle less or equal to 65° (e.g. a class 3 product will become class 4 in this case). The cut-off
angle shall be determined according to EN 14500:2021.
NOTE 1 τ = 0,00 means that the openness factor is equal to zero.
v, n-n
NOTE 2 Glare control of non-perforated venetian blinds depends on two aspects:
— reflectance of the slats;
— closure of the slats and other gaps.
6.4 Night privacy
6.4.1 General
Night privacy is the capacity of an internal or external blind or a shutter in the fully extended position or fully
extended and closed position to protect persons, at night in normal light conditions from external view.
6.4.2 Determination
Night privacy is quantified by the parameters τ and τ . τ and τ shall be determined according
v, n-dif v, n-n v, n-dif v, n-n
to EN 14500:2021.
6.4.3 Performance classes
The performance of the solar protection device shall be classified according to Table 8. The classes are quoted
in Table 5.
Table 8 — Privacy night — Classification

τv, n-dif
τ
v, n-n
0 ≤ τ ≤ 0,04 0,04 < τ ≤ 0,15 τ > 0,15
v, n-dif v, n-dif v, n-dif
τ > 0,10 0 0 0
v, n-n
0,05 < τ ≤ 0,10 1 1 1
v, n-n
0,00 < τ ≤ 0,05 2 2 2
v, n-n
τ = 0,00 4 3 2
v, n-n
NOTE This table can be used for venetian blinds with fully perforated and closed slats assuming τv, n-dif ≤ 0,04.
6.5 Visual contact with the outside
6.5.1 General
Visual contact with the outside is the capacity of the solar protection device to allow an exterior view when it
is fully extended. This function is affected by different light conditions during the day.
It is characterized by two parameters:
— the normal/normal transmittance τ ;
v,n-n
— the diffuse part of light transmittance τ .
v,n-dif
NOTE 1 High values of τv, n-n are favourable because they allow a shape recognition.
NOTE 2 A high value of τv, n-dif is unfavourable because it distorts the direct vision and generates a parasitic luminance
on the fabric when illuminated by the sun.
NOTE 3 In addition to τ and τ , the distribution and shape of the openings and the reflectance at the inward
v, n-n v, n-dif
face of the solar protection device can have an influence.
6.5.2 Determination
Visual contact with the outside is quantified by the parameters τ and τ . τ and τ shall be
v, n-dif v, n-n v, n-dif v, n-n
determined according to EN 14500:2021.
6.5.3 Performance classes
The performances of the solar protection device shall be classified according to Table 9. The classes are quoted
in Table 5.
Table 9 — Visual contact with the outside — Classification
τ
v,n-dif
τ
v,n-n
0,04 < τ
v,n-
0 < τ ≤ 0,04 τ > 0,15
v,n-dif v,n-dif
≤ 0,15
dif
τ > 0,10 4 3 2
v,n-n
0,05 < τ ≤ 0,10 3 2 1
v,n-n
0,00 < τ ≤ 0,05 2 1 0
v,n-n
τ = 0,00 0 0 0
v,n-n
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