ISO/DIS 13837

Road vehicles -- Safety glazing materials -- Method for the determination of solar transmittance

Véhicules routiers -- Vitrages de sécurité -- Méthode de détermination du facteur de transmission du rayonnement solaire

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 13837
ISO/TC 22/SC 35 Secretariat: UNI
Voting begins on: Voting terminates on:
2020-09-25 2020-12-18
Road vehicles — Safety glazing materials — Method for the
determination of solar transmittance

Véhicules routiers — Vitrages de sécurité — Méthode de détermination du facteur de transmission du

rayonnement solaire
ICS: 81.040.30; 43.040.60
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
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NATIONAL REGULATIONS.
ISO/DIS 13837:2020(E)
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PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
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ISO/DIS 13837:2020(E)
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ii © ISO 2020 – All rights reserved
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ISO/DIS 13837:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

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

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

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

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Symbols ......................................................................................................................................................................................................... 2

4 Apparatus ..................................................................................................................................................................................................................... 2

5 Procedure..................................................................................................................................................................................................................... 2

5.1 Sample preparation ............................................................................................................................................................................ 2

5.2 Measurement ............................................................................................................................................................................................ 2

5.3 Calculation method ............................................................................................................................................................................. 3

5.3.1 Visible luminous transmittance[LT ] .......................................................................................................... 3

5.3.2 Solar UV transmittance [T ] .............................................................................................................................. 3

5.3.3 Solar UV transmittance [T (400)] ................................................................................................................ 3

5.3.4 Solar direct transmittance [T ] ........................................................................................................................... 3

5.3.5 Solar direct reflectance [R ] ................................................................................................................................. 3

5.3.6 Solar direct absorbance [a ] ................................................................................................................................. 3

5.3.7 Total solar transmittance[T ] ............................................................................................................................ 3

5.3.8 Colorimetry .......................................................................................................................................................................... 5

6 Expression of results ........................................................................................................................................................................................ 5

Annex A (informative) Derivation of solar weight tables in this International Standard ..........................10

Bibliography .............................................................................................................................................................................................................................12

© ISO 2020 – All rights reserved iii
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ISO/DIS 13837:2020(E)
Foreword

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

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

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

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

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

electrotechnical standardization.

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

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

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

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

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

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

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

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

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iso/ foreword .html.

This document was prepared by Technical Committee [or Project Committee] ISO/TC [or ISO/PC] 22,

Road vehicle, Subcommittee SC 35, Lighting and visibility.

This second edition cancels and replaces the first edition (ISO 13837:2008), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— Unify convention A and B (see clause 5, ISO 13837:2008 clause 6);

— Add calculation methods for visible luminous transmittance, solar direct reflectance, solar direct

absorbance and colorimetry.(see clause 5.3.1, 5.3.5, 5.3.6 and 5.3.8);
— Move the texts of Annex B to clause 5.3.7.

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

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/DIS 13837:2020(E)
Introduction

A review of existing standards and industry specifications and procedures reveals a lack of agreement

with respect to the basis for defining and measuring the ultraviolet (UV), visible (VIS) , infrared (IR)

transmittance and colorimetry(L*, a*, b*) properties of glazing materials. To avoid the continued

preparation and promulgation of conflicting standards by individual entities, there is an interest in the

automotive and glazing industries to harmonize on a worldwide basis the test procedures and protocol

used to assess the solar transmittance properties of glazing materials.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 13837:2020(E)
Road vehicles — Safety glazing materials — Method for the
determination of solar transmittance
1 Scope

This International Standard specifies test methods to determine the visible luminous, the direct, total

solar transmittance and the colorimetry of safety glazing materials for road vehicles.

This International Standard applies to monolithic or laminated, clear or tinted samples of safety glazing

materials. Essentially flat sections of glazing parts can be used in this test, as well as flat samples of the

same 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.

ISO 9845-1:1992, Solar energy — Reference solar spectral irradiance at the ground at different receiving

conditions — Part 1: Direct normal and hemispherical solar irradiance for air mass 1,5

ISO 9050:2003, Glass in building — Determination of light transmittance, solar direct transmittance, total

solar energy transmittance, ultraviolet transmittance and related glazing factors

ISO 11664-1:2007, Colorimetry —Part 1: CIE standard colorimetric observers
ISO 11664-2:2007, Colorimetry — Part 2: CIE standard illuminants
ISO 11664-3:2012, Colorimetry —Part 3: CIE Tristimulus Values
ISO 11664-4:2008, Colorimetry —Part 4: CIE 1976 L*a*b* Color space

ISO 10292, Glass in building — Calculation of steady-state U values (thermal transmittance) of multiple

glazing
3 Terms and definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
standardize

adjust an instrument output to correspond to a previously established calibration, using one or more

homogeneous specimens or reference materials.
3.1.2
transmittance/ reflectance

ratio of transmitted/reflectance flux to incident flux, under specified geometric and spectral conditions.

3.1.3
air mass (ratio)

ratio of the mass of atmosphere in the actual observer-sun path to the mass that would exist if the

observer were at sea level, at standard barometric pressure, and the sun were directly overhead.

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ISO/DIS 13837:2020(E)
3.2 Symbols
Table 1 — Symbol definition
Symbol Symbol Definition
T the transmittance through a glazing at wavelength λ within a specified Δλ
the external reflectance(R) of a glazing at wavelength λ within a specified Δλ

LT the visible luminous transmittance for illuminant A with 2 degree view through a glazing

ultraviolet (UV) direct solar energy transmitted through a glazing

ultraviolet (UV) direct solar energy transmitted through a glazing at a specified upper

T (400)
limit value (400nm)
T direct solar energy (e) transmitted through a glazing
q secondary heat transfer to the inside of a glazing
T total solar energy (T +q ) transmitted to the inside of a glazing
TS e i
direct solar energy (e) reflected by a glazing
a direct solar energy (e) absorbed by a glazing
λ wavelength, in nm
Δλ uniform λ interval
normalized relative spectral distribution of global solar radiation
E (n)
W(λ) values x(λ), y(λ) ,z(λ) times S(λ)
S(λ) relative spectral distribution of global solar radiation

tristimulus values calculated using the CIE 1964 standard colorimetric observer under

X , Y , Z
10 10 10
illuminant D65 spectral power distribution (6500 K correlated color temperature)

the coordinates of the CIE 1976 L*a*b* color space. L*, CIELAB lightness; a*, b*, CIELAB

* * *
L , a , b
coordinates
4 Apparatus

This method requires spectral transmittance data to be obtained from samples of glazing materials

using a scanning spectrophotometer. This instrument, preferably equipped with an integrating sphere,

shall be capable of measuring transmittance over that part of the electromagnetic spectrum in which

the solar energy is transmitted to the earth's surface.
5 Procedure
5.1 Sample preparation

Cut out (if necessary) and clean the flattest area of curved test specimens with distilled water and

reagent grade ethanol, or use an alternate procedure appropriate to the material, if necessary. Cut and

clean flat samples similarly.
5.2 Measurement

Standardize the spectrophotometer in accordance with the manufacturer's instructions. Measure

transmittance/reflectance of cleaned sample and record the sample spectral data in accordance with

the instrument manufacturer's recommendation. Note its film/coating side and curvature orientation,

if applicable.
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ISO/DIS 13837:2020(E)
5.3 Calculation method
5.3.1 Visible luminous transmittance[LT ]

Compute luminous transmittance LT by integration using weight data of visible light of Illuminate A

in Table 2. Transmission (T) for the visible range (380 to 780 nm) determined by the following function:

780
LT =×TW (1)
A λλ
380
5.3.2 Solar UV transmittance [T ]

Compute solar UV transmittance T by integration using the solar weight data in Table 3. Transmission

(T) for solar range (300 nm to 380 nm) is determined by the following functions:
380
TT=×En() (2)
UV λλ
300
5.3.3 Solar UV transmittance [T (400)]

Compute solar UV transmittance T (400) by integration using the solar weight data in Table 4.

Transmission (T) for solar range (300 nm to 400 nm) is determined by the following functions:

400
TT400 =×En (3)
() ()
UV ∑ λλ
300
5.3.4 Solar direct transmittance [T ]

Compute solar direct transmittance T by integration using the solar weight data in Table 5.

Transmission (T ) for solar range (300 nm to 2 500 nm) is determined by the following functions:

2500
TT=×En() (4)
e λλ
300
5.3.5 Solar dir
...