EN 14500:2008

SLOVENSKI STANDARD
01-september-2008
Rolete in polokna - Toplotno in vizualno ugodje - Preskus in računske metode
Blinds and shutters - Thermal and visual comfort - Test and calculation methods
Abschlüsse - Thermischer und visueller Komfort - Prüf- und Berechnungsverfahren
Fermetures et stores - Confort thermique et lumineux - Méthodes d'essai et de calcul
Ta slovenski standard je istoveten z: EN 14500:2008
ICS:
91.060.50 Vrata in okna Doors and windows
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 14500
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2008
ICS 91.060.50
English Version
Blinds and shutters - Thermal and visual comfort - Test and
calculation methods
Fermetures et stores - Confort thermique et lumineux - Abschlüsse - Thermischer und visueller Komfort - Prüf- und
Méthodes d'essai et de calcul Berechnungsverfahren
This European Standard was approved by CEN on 11 April 2008.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14500:2008: E
worldwide for CEN national Members.

Contents
Page
Foreword.4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .6
4 Notations used.10
4.1 General .10
4.2 Visual or solar properties .10
4.3 Geometry of the radiation .10
4.4 Optical factors.11
5 Test and calculation methods to be used according to product - Guidelines .12
5.1 General .12
5.2 Venetian blinds .12
5.3 Roller blinds .13
5.4 Pleated blinds .13
5.5 Projecting awnings.14
5.6 Vertical blinds.14
5.7 Shutters.14
6 Measurement set-up.14
6.1 Measurement principles.14
6.1.1 Spectral and integral characteristics.14
6.1.2 Absolute and relative methods (according to CIE 130) .15
6.2 Measuring equipment .15
6.2.1 General .15
6.2.2 Equipment for irradiation.15
6.2.3 Equipment for detection.17
6.2.4 Reference samples.20
6.3 Test samples.20
6.3.1 General .20
6.3.2 Thick translucent samples .20
7 Measurement procedure .21
7.1 General .21
7.2 Test method A – Single beam instrument (substitution method).21
7.2.1 General .21
7.2.2 Test apparatus for the substitution method .21
7.2.3 Direct-hemispherical transmittance mode .22
7.2.4 Direct-hemispherical reflectance mode .25
7.2.5 Diffuse-hemispherical transmittance mode .28
7.3 Test method B – Double beam spectrophotometer (comparison method).28
7.3.1 General .28
7.3.2 Spectral direct-hemispherical transmittance mode .29
7.3.3 Spectral direct-diffuse transmittance mode .30
7.3.4 Direct-hemispherical reflectance mode .31
7.4 Determination of τ and ρ .35
n-h n-h
7.5 Determination of τ .35
n-n
7.5.1 General .35
7.5.2 Measurement of τ .35
n-n
7.5.3 Determination of τ from the measurement of τ .36
n-n n-dif
7.6 Determination of τ .36
dif-h
7.6.1 General.36
7.6.2 Measurement.36
7.6.3 Calculation.36
7.7 Determination of opacity characteristics for dim-out and black out fabrics or products.37
7.7.1 General.37
7.7.2 Samples.38
7.7.3 Test equipment.38
7.7.4 Test procedure .39
7.7.5 Lighting using natural light.40
8 Additional calculation methods for transmittance and reflectance of products.40
8.1 General.40
8.2 Venetian blinds .40
8.2.1 General.40
8.2.2 Ordinary venetian blind with incomplete closure, normal incidence .41
8.2.3 Ordinary venetian blind with slats tilted at 45°, 45° solar altitude, 0° azimuth .41
8.2.4 Ordinary venetian blind with slats in “Cut-Off” position, 30° solar altitude, 0° azimuth.41
8.2.5 Ordinary venetian blind with slats in horizontal position, 60° solar altitude, 0° azimuth .42
8.3 Vertical blinds .42
8.4 Shutters .42
9 Test report.43
Annex A (informative) Examples of test equipment for opacity characteristics determination.44
A.1 General.44
A.2 Example 1.44
A.3 Example 2.45
Annex B (informative) Determination of openness coefficient .47
B.1 Method for fabrics made from opaque material .47
B.2 Method for venetian blinds .47
Annex C (informative) Determination of infrared properties .48
C.1 General.48
C.2 Determination .48
C.2.1 IR properties of transparent materials.48
C.2.2 IR properties in the case of holes in an opaque layer.49
C.2.3 IR properties of venetian blinds.49
Annex D (informative) Approach in case of projecting solar protection devices .51
D.1 General.51
D.2 Detailed model.51
D.2.1 Reduction factor of direct radiation .52
D.2.2 Reduction factor for diffuse and reflected radiation .52
D.3 Simplified approach for summer.52
D.4 Examples of calculation.53
D.4.1 General.53
D.4.2 Mean values of x for summer.54
D.4.3 Calculations.54

Foreword
This document (EN 14500:2008) 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 November 2008, and conflicting national standards shall be withdrawn
at the latest by November 2008.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Introduction
This European Standard is part of a series of standards dealing with blinds and shutters for buildings as
defined in EN 12216.
This European Standard is mainly based on the European work performed in CEN/TC 89 "Thermal
performance of buildings and building components" relating to solar and light transmittance of solar protection
devices combined with glazing, and the document CIE 130.
1 Scope
This European Standard defines test and calculation methods for the determination of the reflection and
transmission characteristics to be used to determine the thermal and visual comfort performance classes of
external blinds, internal blinds and shutters, as specified in EN 14501.
This European Standard also specifies the method to determine opacity characteristics of dim-out/black-out
external blinds, internal blinds and shutters, as specified in EN 14501.
This European Standard applies to the whole range of shutters, awnings and blinds defined in EN 12216,
described as solar protection devices in this European Standard. Some of the characteristics (e.g. g ) are not
tot
applicable when products are not parallel to the glazing (e.g. folding-arm awnings).
NOTE Informative Annex D presents an approach for the determination of characteristics in case of projectable
products.
Products using fluorescent or retroreflecting materials are outside the scope of this European Standard.
2 Normative references
The following referenced documents are indispensable for the application 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 130:1998, Practical methods for the measurement of reflectance and transmittance
EN 410, Glass in building – Determination of luminous and solar characteristics of glazing
EN 12216:2002, Shutters, external blinds, internal blinds – Terminology, glossary and definitions
EN 13363-1, Solar protection devices combined with glazing – Calculation of solar and light transmittance –
Part 1: Simplified method
EN 13363-2:2005, Solar protection devices combined with glazing – Calculation of total solar energy
transmittance and light transmittance – Part 2: Detailed calculation method
EN 14501:2005, Blinds and Shutters – Thermal and visual comfort – Performance characteristics and
classification
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12216:2002, EN 14501:2005 and
the following apply.
3.1 Processes
3.1.1
reflection
process by which radiation is returned by a surface or medium, without change of frequency of its
monochromatic components
The following sub-processes are defined herewith:
 Specular (or directional or regular) reflection: reflection in accordance with the laws of geometrical
optics, without diffusion
 Diffuse reflection: reflection due to light scattering, in which, on the macroscopic scale, there is no
specular reflection
 Direct-hemispherical (or mixed) reflection: partly specular and partly diffuse reflection. Direct-
hemispherical reflection is the sum of the diffuse and specular reflection
 Isotropic diffuse reflection: diffuse reflection in which the spatial distribution of the reflected radiation
is such that the radiance or luminance is the same in all directions in the hemisphere into which the
radiation is reflected
3.1.2
transmission
passage of radiation through a medium without change of frequency of its monochromatic components
The following sub-processes are defined herewith:
 Directional (or direct-direct) transmission: transmission in accordance with the laws of geometrical
optics, without diffusion or redirection
 Diffuse transmission: transmission due to light scattering, in which, on the macroscopic scale, there
is no direct transmission
 Direct-hemispherical (or mixed or total) transmission: partly directional and partly diffuse transmission.
The direct-hemispherical transmission is the sum of the diffuse and direct transmission
 Isotropic diffuse transmission: diffuse transmission in which the spatial distribution of the transmitted
radiation is such that the radiance or luminance is the same in all directions in the hemisphere into
which the radiation is transmitted
3.1.3
absorption
process by which radiant energy is converted to a different form of energy (e.g. heat) by interaction with
matter
3.2 Characteristics
3.2.1
reflectance
ρρρρ
ratio of the reflected flux to the incident flux
The following sub-characteristics are defined:
 Directional-directional (or direct-direct) reflectance: ratio of the specularly reflected flux to the
directional incident flux
 Directional-diffuse reflectance: ratio of the diffusely reflected flux to the directional incident flux
 Directional-hemispherical (or total) reflectance: ratio of the total reflected flux to the directional
incident flux
 Diffuse-hemispherical reflectance: ratio of the total reflected flux to the ideally diffuse incident flux.
Ideally diffuse irradiation means that the radiance or the luminance is equal for the whole hemisphere
of the incident irradiation
3.2.2
transmittance
ττττ
ratio of the transmitted flux to the incident flux
The following sub-characteristics are defined:
 Directional-directional transmittance: ratio of the directly transmitted flux to the directional incident
flux
 Directional-diffuse transmittance: ratio of the diffusely transmitted flux to the directional incident flux
 Directional-hemispherical transmittance: ratio of the total transmitted flux to the directional incident
flux
 Diffuse-hemispherical transmittance: ratio of the total transmitted flux to the ideally diffuse incident
flux. Ideally diffuse irradiation means that the radiance or the luminance is equal for the whole
hemisphere of the incident irradiation
3.2.3
absorptance
αααα
ratio of the absorbed flux to the incident flux

3.3 Angle definitions
3.3.1 General
All the following angles are defined in a coordinate system which is fixed relative to the orientation of the solar
protection device
3.3.2
angle of incidence
θθθθ
angle between the normal to the plane of the solar protection device and the direction of the incident radiation
(see Figure 1)
3.3.3
altitude angle
αα
αα
s
projection of the angle of incidence on the vertical plane which contains the direction of the incident radiation
(see Figure 1)
3.3.4
azimuth angle
γγγγ
projection of the angle of incidence on a plane which is normal to the plane of the solar protection device. The
intersection of this projection plane and the plane of the solar protection device is horizontal (see Figure 1)
3.3.5
profile angle
αααα
p
projection of the altitude angle on a vertical plane which is perpendicular to the façade under consideration
(see Figure 1). The profile angle is given by the following formula: tg α = tg θ / cos γ
p
Key
1 Direction of the incident radiation
2 Vertical plane normal to the solar protection device
3 Projected direction of the incident radiation
4 Direction normal to the solar protection device
5 Altitude angle (angle in the vertical plane)
6 Azimuth angle (angle in the horizontal plane)
7 Profile angle
8 Angle of incidence
9 Solar protection device
Figure 1 – Angle definitions
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
e
nm to 2 500 nm), according to EN 410;
 « » visual characteristics, given for the standard illuminant D weighted with the sensitivity of
v 65
the 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
n
θ = 0°, or θ ≤ 8° respectively;
 « » for hemispherical (collected in the half space behind the sample plane);
h
 « » for diffuse.
dif
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  direct-hemispherical light transmittance
v, dir-h
 τ  normal-hemispherical solar transmittance
e, n-h
 τ  direct-hemispherical solar transmittance
e, dir-h
 ρ  normal-hemispherical light reflectance
v, n-h
 ρ  direct-hemispherical light reflectance
v, dir-h
 ρ  normal-hemispherical solar reflectance
e, n-h
 ρ  direct-hemispherical solar reflectance
e, dir-h
 τ diffuse-hemispherical light transmittance
v, dif-h
5 Test and calculation methods to be used according to product - Guidelines
5.1 General
The test methods described in this European Standard are intended to be used for testing the characteristics
of the curtain elements of solar protection devices. Curtain elements are for example flat sheets of coated
aluminium for slats for venetian blinds, fabric materials for roller blinds or glass slats with or without patterns
for external glass venetian blinds. The properties of the whole product, which consists of one or more
elements, are then calculated according to EN 13363-1 or EN 13363-2. Also a whole product may be tested, if
the test equipment is sufficiently large so that the whole product fulfils the requirements of test samples as
stated in Clause 6.3.
This European Standard characterises the product performance through the properties of the curtain (centre
of product values). However, peripheral gaps and/or holes and the set-up can have a strong effect on the
performance of the product under real conditions and shall be considered during set-up.
For all solar protection devices, it is assumed that the products are fully extended (not partially retracted)
when solar protection or glare protection is required.
NOTE For building planning it can be useful to take into consideration partially retracted solar protection devices. The
properties of the whole window can then be approximated from the properties of the window area with and without solar
protection devices.
5.2 Venetian blinds
The solar and light characteristics of venetian blinds shall be:
 Either measured directly on a complete product according to Clause 7. The venetian blind shall in
this case fulfil the requirements of test samples specified in Clause 6.3;
 or calculated using the properties of the individual slats. The slats characteristics shall be measured
according to Clause 7 and the calculation method of Annex A of EN 13363-2:2005 shall be used.
Additional information/requirements presented in Clause 8 shall be used.
NOTE If products cannot be appropriately characterised using EN 13363-2 (for example mirror finished and/or
special shaped slats), a more detailed calculation method may be necessary.
The characteristics of the combination of a venetian blind with a glazing may be measured directly according
to Clause 7 if the requirements of test sample specified in Clause 6.3 are fulfilled.
The different possibilities of determination of venetian blind characteristics are presented in Figure 3.
Figure 3 — Options for characterisation of venetian blinds
5.3 Roller blinds
The solar and light characteristics of roller blinds shall be:
 Either measured directly on a complete product according to Clause 7. The roller blind shall in this
case fulfil the requirements of test sample specified in Clause 6.3;
 Or determined using the properties of the fabric. In this case, it is assumed that the properties of the
complete product are the same as those of the fabric.
The characteristics of the combination of a roller blind with a glazing may be measured directly according to
Clause 7 if the requirements of test samples specified in Clause 6.3 are fulfilled.
Opacity characteristics may be tested either on the curtain material or on a complete product if the test
equipment is large enough. In all cases, it is essential to prevent any lateral losses through peripheral gaps.
The different possibilities of determination of roller blind characteristics are presented in Figure 4.

Figure 4 — Options for characterisation of roller blinds
5.4 Pleated blinds
As an approximation the properties of the fabric may be used as properties of the curtain in the same way as
for roller blinds (see Clause 5.3).
When the measurement set-up is sufficiently large, the optical properties of the pleated curtain may be tested
directly.
5.5 Projecting awnings
Fabric properties of projecting awnings may be determined according to Clause 7.
However, existing calculation methods being only applicable to products which are parallel to the glazing, it is
not possible to characterise the performance of a whole product from its fabric properties only.
NOTE Informative Annex D presents an approach for the determination of characteristics in case of projecting
awnings.
5.6 Vertical blinds
Properties of vertical blinds shall be determined according to Clause 8.3.
5.7 Shutters
The solar and light characteristics of shutters shall be:
 Either determined for the curtain material according to Clause 7;
 Or determined for the complete product according to Clause 8.4.
Opacity characteristics may be tested either on the curtain material or on a complete product if the test
equipment is large enough. In all cases, it is essential to prevent any lateral losses through peripheral gaps.
6 Measurement set-up
6.1 Measurement principles
6.1.1 Spectral and integral characteristics
Any characteristic referring to optical properties of materials shall be determined under broad-band conditions
with a specified illuminant (integral method) or spectrally for defined wavelengths λ (spectral method).
Spectral method
The relevant spectral characteristic (e.g. the normal-hemispherical spectral transmittance τ (λ)) is measured
n-h
as a function of the wavelength. Spectral measurements can be made either with monochromatic light or with
a source having a broad spectrum and a spectroradiometer as detector. When a spectral characteristic of a
sample is known, the corresponding integral characteristic can be calculated with the formula given in EN 410.
Integral method
The relevant weighted characteristic is measured directly, using a source with a standard spectral power
distribution S(λ) and a broad-band detector with the required relative spectral weighting function:
 For broad-band measurements of solar properties characteristic (e.g. the normal-hemispherical solar
), the detector system shall have a flat spectral response over the whole solar
transmittance τ
e,n-h
range and the spectral power distribution of the incident irradiation S(λ) shall correspond to the EN
410 solar spectrum;
 For broad-band measurements of the light characteristics (e.g. the normal-hemispherical light
transmittance τ ), the sensitivity of the detector shall correspond to the photopic spectral sensitivity
v,n-h
of the human eye V(λ) and the spectral power distribution S (λ) of the light source shall correspond
D65
with the standard illuminant D65 (according to EN 410);
 For broad band measurements of light characteristics it is also possible to use a light source with a
spectral power distribution S(λ) that corresponds with the standard solar spectrum and to use a
detector with a spectral sensitivity w(λ), so that S(λ)w(λ) = S (λ)V(λ).
D65
Necessary accuracy: A broad-band light-source/detector system is accurate enough, when the solar or light
characteristics for a solar control glazing with a selectivity of τ / τ > 1,5 and the results of a clear glass
v e
sample do not differ more than 4 % relatively from the results determined with a calibrated spectroradiometer
with a relative accuracy of 2 % or better.
6.1.2 Absolute and relative methods (according to CIE 130)
Since they are defined as the ratio of two fluxes, reflectance and transmittance are, in themselves, relative
characteristics, but, whenever their values are measured directly without the use of another material standard
as a reference, the corresponding method is termed absolute.
Reflectance measurements are carried out with the help of a standard and are accordingly classified as
relative methods.
NOTE 1 Absolute methods for reflectance measurements do exist, but they are outside the scope of this standard.
In the case of transmittance, similar considerations apply. Since the flux is transmitted through an unknown
sample it is to be referred to the flux incident on it. This comparison with the incident flux does not,
theoretically, require any standard. It is only necessary to leave a free passage for the flux. According to this
principle, measurements of transmittance are classified as absolute measurements.
NOTE 2 Relative transmittance measurements can be more appropriate in the case of diffusing test samples. Then a
diffusing reference sample can be more accurate.
6.2 Measuring equipment
6.2.1 General
An instrument for measuring the characteristics of materials consists of
 Equipment for irradiation (see Clause 6.2.2);
 Equipment for detection (see Clause 6.2.3);
 Reference samples (see Clause 6.2.4).
6.2.2 Equipment for irradiation
6.2.2.1 Single or double-beam instrument
Two methods of measurement are possible:
 Method A, using a single beam recording instrument;
 Method B, using a double-beam instrument. In double-beam instruments, the beam is switched
between a path which has an incidence on the sample and one which does not.
Method B is recommended because of its inherent correction of drift in source brightness or amplifier gain.
6.2.2.2 Geometric conditions
The equipment for irradiation shall fulfil the following geometric requirements:
 In the case of test samples with directional features (e.g. slatted curtains and some single or
multicoloured fabrics), the angular orientation of these features with respect to the plane of incidence
or the plane of view shall be specified;
NOTE 1 The plane of incidence is the plane that contains the normal to the surface of the test sample and the direction
of the incident radiation.
 In case of homogeneous samples without directional features, it is sufficient to characterise the
direction of the incident irradiation with the angle of incidence θ. θ is the angle between the normal to
the surface and the optical axis of the incident irradiation;
 The size of the irradiated/illuminated area of the sample shall be sufficiently large in comparison to
the structure of the sample, so that the result is independent from the location of the incident beam
on the sample. If this is not possible, the mean value of several measurements at different locations
on the sample shall be used, weighted by the relative size of each area. The irradiance shall be
nearly homogeneous on the relevant area.
NOTE 2 In the case of oblique irradiation/illumination, the size of the irradiated area increases with 1/cos(θ), where θ is
the angle of incidence. For large angles θ, care shall be taken to satisfy the above requirements.
 Stray radiation outside the irradiated area of the sample shall be avoided;
 In the case of directional irradiation, the tolerance of the angle of incidence shall be ± 5° at every
point of the relevant area. The size of the relevant area depends on the type of sample. The “thicker”
the sample, the bigger the relevant area shall be. The definition of the relevant surface is presented
in Figure 5. A definition of thick samples is given in Clause 6.3.2;
 In the case of diffuse irradiation, an integrating sphere shall be used as a light source.
Key
1 Sample
2 Diameter of the aperture
3 Diameter of the relevant area
4 Diameter of the incident beam
Figure 5 — Areas considered
6.2.2.3 Polarisation
The characteristics of solar protection devices or materials for non-normal incidence depend on the state of
polarisation of the irradiating beam. Directional measurements can only be performed with unpolarised
incident irradiation if no polarisation arises from the source or the deflecting or focusing optics (if present) and
if the detector is insensitive to polarisation. Therefore, in general, for non-normal measurements, two separate
measurements shall be made with the incident radiation fully linearly polarised in the plane perpendicular to
the plane of incidence and in the plane parallel to the plane of incidence, respectively. The value of the
characteristic for unpolarised irradiation shall then be calculated as the mathematical average of the two
results.
NOTE 1 The reflected or transmitted radiation is usually partly polarised even if the incident radiation is unpolarised.
NOTE 2 The radiation emitted from a lamp is generally partially polarised. A beam entering an integrating sphere is
depolarised by the multiple reflections inside the sphere.
6.2.3 Equipment for detection
6.2.3.1 General
Photometers, radiometers, spectroradiometers and spectrophotometers are used as detectors. For all types of
detectors care shall be taken about sufficient linearity and low temperature dependence. A sufficient warm-up
period shall be respected.
NOTE Errors may be caused by detectors with a sensitivity that depends on the position of the beam on the
photosensitive area.
6.2.3.2 Integrating sphere
An Integrating (or Ulbricht) sphere is a hollow sphere whose internal surface is a diffuse white reflector. This
optical device is used to collect flux either reflected or transmitted from a sample or to provide isotropic
irradiation of a sample from a complete hemisphere. The hollow sphere has apertures for admitting and
detecting flux and usually having additional apertures over which sample and reference specimen are placed.
An integrating sphere equipped with a radiometer, photometer and/or spectroradiometer is recommended for
the measurement of:
 direct-hemispherical reflectance and transmittance,
 diffuse reflectance and transmittance.
The direct-direct components can then be obtained by subtracting one from the other.
NOTE 1 Special care has to be taken when the transmittance/reflectance of thick translucent samples (e.g. glass slats
with printed patterns) is measured, because of possible lateral losses of transmitted/reflected light.
NOTE 2 Integrating spheres are not suitable for measuring luminescent materials.
NOTE 3 The higher the reflectance of the sphere coating is, the higher is the sensitivity of the detection equipment.
NOTE 4 Common materials for sphere coatings are BaSO and pressed and low-density sintered PTFE.
NOTE 5 The basic idea behind integrating spheres is that the indirect illuminance/irradiance of the inner sphere wall is
assumed to be proportional to the flux transmitted/reflected by the test specimen or reference sample. This is true for
spheres with perfectly isotropic diffuse reflecting walls without openings. The illuminance/irradiance of directly irradiated
parts of the sphere is not proportional to the flux. It is therefore necessary to equip the sphere with baffles as it is
described in Clause 6.2.3.3.
6.2.3.3 Requirements
An integrating sphere together with the detectors shall fulfil the following requirements:
 All detector ports shall be equipped with additional baffle(s) in order to cut the line of sight between
sample/reference port and detector(s). This ensures that the detector is not illuminated directly. The
baffles shall be coated with a diffuse, spectrally non-selective coating with a very high reflectance
(normal-hemispherical spectral reflectance > 92 %).
 Detectors shall either be:
 Radiometers/photometers which are sensitive to light coming from all the different possible
directions in the integrating sphere. Radiometers/photometers shall evaluate the incoming
radiation according to the cosine law;
 Radiance/luminance meters with a narrow viewing angle. In this case it is necessary to
shield/baffle the (small) observed area of the sphere wall which is directly seen by the detector.
No radiation other than that from the observed area shall be allowed to influence the reading of
the detector.
 The outside surface of the sphere shall be painted black in order to avoid inter-reflections between
the sample and the outer surface of the sphere.
NOTE 1 Many matt samples (e.g. opal glass lamellae) are abrasive and may become contaminated if they are allowed
to come into contact with black paint. For these materials a thin sheet of black paper surrounding the sample can prevent
the sample from being contaminated.
 Ports:
 The total area of the sphere ports shall not exceed 1/10 of the internal reflecting sphere area.
Unused ports which are closed and covered with the same coating as the rest of the inner walls
of the sphere do not have to be taken into account;
 The wall surrounding the sample port shall have a sharp edge, so that there is no step between
the inner sphere wall and the sample surface (see Figure 6);

Key
1 Sample
2 Integrating sphere
Figure 6 — Sharp edge on sample port of integrating sphere
NOTE 2 The number, position and diameter of the necessary sphere ports depend on the measurement method, the
type of the sample and the characteristics to be measured. Since ports always disturb the operating conditions in the
sphere, their number and diame
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