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

ISO 13837:2008 specifies test methods to determine the direct and total solar transmittance of safety glazing materials for road vehicles. Two computational conventions (denoted convention “A” and convention “B”) are included, both of which are consistent with current international needs and practices. ISO 13837:2008 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.

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

General Information

Status
Withdrawn
Publication Date
06-Apr-2008
Withdrawal Date
06-Apr-2008
Current Stage
9599 - Withdrawal of International Standard
Start Date
28-Sep-2021
Completion Date
28-Sep-2021
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INTERNATIONAL ISO
STANDARD 13837
First edition
2008-04-15
Corrected version
2009-06-01
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
Reference number
ISO 13837:2008(E)
ISO 2008
---------------------- Page: 1 ----------------------
ISO 13837:2008(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT
© ISO 2008

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 13837:2008(E)
Contents Page

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

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

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

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

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

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

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

4 Computational conventions ................................................................................................................ 2

4.1 Convention “A” ..................................................................................................................................... 2

4.2 Convention “B”..................................................................................................................................... 2

5 Apparatus .............................................................................................................................................. 2

6 Procedure .............................................................................................................................................. 2

6.1 Sample preparation .............................................................................................................................. 2

6.2 Measurement......................................................................................................................................... 3

6.3 Calculation by computational convention “A” .................................................................................. 3

6.4 Calculation by computational convention “B” .................................................................................. 3

6.5 Total solar transmittance ..................................................................................................................... 4

7 Expression of results ........................................................................................................................... 4

Annex A (informative) Derivation of solar weight tables in this International Standard ............................ 9

Annex B (informative) Determination of total solar transmittance ............................................................. 14

Bibliography ..................................................................................................................................................... 16

© ISO 2008 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 13837:2008(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 committee has been

established has the right to be represented on that committee. International 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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 13837 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 11, Safety

glazing materials.
This corrected version of ISO 13837:2008 incorporates the following correction:
⎯ Equation (B.4) on page 15 has been corrected.
iv © ISO 2008 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 13837:2008(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) and infrared (IR)

transmittance 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.
© ISO 2008 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 13837:2008(E)
Road vehicles — Safety glazing materials — Method for the
determination of solar transmittance
1 Scope

This International Standard specifies test methods to determine the direct and total solar transmittance of

safety glazing materials for road vehicles. Two computational conventions (denoted convention “A” and

convention “B”) are included, both of which are consistent with current international needs and practices.

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 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.

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

CIE 85:1989, Solar spectral irradiance
3 Terms, 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

ratio of transmitted 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

3.1.4
solar indirect transmittance

fraction of the solar radiation absorbed by the safety glazing materials and reradiated to the interior

NOTE The fraction is the secondary heat transfer factor as defined in ISO 9050.
© ISO 2008 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 13837:2008(E)
3.2 Symbols
Symbol Definition
ultraviolet (UV) direct solar energy transmitted through a glazing
direct solar (DS) energy transmitted through a glazing
secondary heat transfer to the inside of a glazing
T total solar energy (T + q ) transmitted to the inside of a glazing
TS DS i
λ wavelength, in nm
uniform λ interval
solar energy within a ∆λ
E′ E in trapezoidal form EE/2, ⋅⋅⋅E ,E /2
( )
λ λ 12 nn−1
⎡ ⎤
E′ (n) normalized EE′′⋅⋅⋅E′
λ λ ∑ 300 2 500
⎣ ⎦

NOTE Additional definitions are specific to the computational convention chosen and are defined with the

appropriate convention.
4 Computational conventions
4.1 Convention “A”

Convention “A” defines the UV range from 300 nm to 400 nm for air mass 1,5 global. This definition is

consistent with ISO 3917 and CIE 20:1972, and the best average solar flux specified in ISO 9845-1:1992,

Table 1, Column 5.
4.2 Convention “B”

Convention “B” defines the UV range from 300 nm to 380 nm for air mass 1,0 global. This definition is

consistent with ISO 9050 and EN 410, and the maximum possible solar flux found in CIE 85:1989, Table 4.

NOTE This International Standard defines each convention and computations are based on established methods

(see Annex A). The tables incorporated in each computational convention simplify the calculations, leading to high

accuracy with minimum effort. Since the results will differ depending on which convention is chosen, it is essential that the

convention chosen be clearly identified when results are reported.
5 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 sun's energy

is transmitted to the earth's surface.
6 Procedure
6.1 Sample preparation

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

grade methanol, or use an alternate procedure appropriate to the material, if necessary. Cut and clean flat

samples similarly.
2 © ISO 2008 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 13837:2008(E)
6.2 Measurement

Standardize the spectrophotometer in accordance with the manufacturer's instructions. Place a clean sample

normal to the measuring beam in the transmittance sample position. Note its film side and curvature

orientation, if applicable. Record the sample spectral data in accordance with the instrument manufacturer's

recommendation.
6.3 Calculation by computational convention “A”
6.3.1 Definitions specific to computational convention “A”
6.3.1.1 Solar UV transmittance [T (400)]

See Table 1. The transmittance is weighted interval by interval and derived from ISO 9845-1:1992, Table 1,

Column 5 (with air mass 1,5 global) from 300 nm to 400 nm, at intervals of 5 nm.
6.3.1.2 Solar direct transmittance [T (1,5)]

See Table 2. The transmittance is weighted interval by interval and derived from ISO 9845-1:1992, Table 1,

Column 5 (with air mass 1,5 global) from 300 nm to 2 500 nm, at intervals of 5 nm, 10 nm and 50 nm.

6.3.1.3 Solar total transmittance [T (1,5)]

The transmittance is the sum of the direct transmittance as defined in 6.3.1.2 and the indirect transmittance as

defined in 3.1.4.
6.3.2 Computation method

6.3.2.1 Compute direct solar transmittance by integration using the solar weight data in Tables 1 and 2.

Transmission (T) for each solar range (λ to λ ) is determined by the following functions:

1 n
400
%TT(400)=×%E′ (n){}Table 1 (1)
UV λ
300
2500
%TT(1,5)=×%E′ (n){}Table 2 (2)
DS λ
300

where (nE′ ) is the normalized solar energy computed trapezoidally in wavelength interval (∆λ).

6.3.2.2 Transmittance shall be measured to at least 2 300 nm. If it is not possible to measure

transmittance to the recommended 2 500 nm, the last value shall be multiplied by the remaining E′ (n)

weight values in Table 2.
6.4 Calculation by computational convention “B”
6.4.1 Definitions specific to computational convention “B”
6.4.1.1 Solar UV transmittance [T (380)]

See Table 3. The transmittance is weighted interval by interval and derived from CIE 85:1989, Table 4 (with

air mass 1,0 global) from 300 nm to 380 nm, at intervals of 5 nm.
6.4.1.2 Solar direct transmittance [T (1,0)]

See Table 4. The transmittance is weighted interval by interval and derived from CIE 85:1989, Table 4 (with

air mass 1,0 global) from 300 nm to 2 500 nm, at intervals of 5 nm, 10 nm and 50 nm.

© ISO 2008 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 13837:2008(E)
6.4.1.3 Solar total transmittance [T (1,0)]

The transmittance is the sum of the direct transmittance as defined in 6.4.1.2 and the indirect transmittance as

defined in 3.1.4.
6.4.2 Computation method

6.4.2.1 Compute direct solar transmittance by integration using the solar weight data in Tables 3 and 4.

Transmission (T) for each solar range (λ to λ ) is determined by the following functions:

1 n
380
%TT(380)=×%E′ (n) Table 3 (3)
UV ∑ λ
300
2500
%TT(1,0)=×%E′ (n) Table 4 (4)
DS ∑ λ
300

where (nE′ ) is the normalized solar energy computed trapezoidally in wavelength interval (∆λ).

6.4.2.2 Transmittance shall be measured to at least 2 300 nm. If it is not possible to measure

transmittance to the recommended 2 500 nm, the last value shall be multiplied by the remaining E′ (n)

weight values in Table 4.
6.5 Total solar transmittance

This International Standard defines the determination of the direct solar transmittance of safety glazing

materials computed by either of two computational conventions (“A” or “B”). If it is necessary to compute total

solar transmittance, use the equations in Annex B and the direct solar transmittance results from 6.3 or 6.4,

whichever is appropriate.
7 Expression of results

Record thickness, type, construction, and curvature orientation if applicable, of the specimen; the instrument

and computational convention used (“A” or “B”); and the specimen's total UV and direct solar transmittance,

and, if necessary, the specimen's total solar properties rounded to 0,1 %, in accordance with the rounding

convention in Reference [6].
4 © ISO 2008 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 13837:2008(E)
Table 1 — Solar global radiation through air mass 1,5 and
partitioned into uniform spectral trapezoidal intervals
E′ (n)
300 0,000 000
305 0,001 045
310 0,004 634
315 0,011 800
320 0,019 807
325 0,027 019
330 0,043 271
335 0,042 703
340 0,047 644
345 0,048 041
350 0,052 948
355 0,054 947
360 0,056 946
365 0,064 930
370 0,072 925
375 0,075 901
380 0,077 991
385 0,075 890
390 0,073 777
395 0,092 335
400 0,055 446
400
%TT(400)=×%E′ (n)
UV ∑ λ
300
NOTE Modified wavelength intervals in
ISO 9845-1:1992, Table 1, Column 5.
© ISO 2008 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO 13837:2008(E)
Table 2 — Solar global radiation through air mass 1,5 and
partitioned into uniform spectral trapezoidal intervals
E′ (n) E′ (n) E′ (n)
λ, nm λ, nm λ, nm
λ λ λ
300 0,000 000 410 0,011 712 850 0,049 016
305 0,000 048 420 0,011 973 900 0,039 872
310 0,000 214 430 0,010 839 950 0,016 652
315 0,000 545 440 0,013 166 1 000 0,037 501
320 0,000 915 450 0,015 431 1 050 0,034 127
325 0,001 248 460 0,016 175 1 100 0,020 859
330 0,001 999 470 0,015 988 1 150 0,012 512
335 0,001 973 480 0,016 466 1 200 0,021 415
340 0,002 201 490 0,015 565 1 250 0,023 934
345 0,002 219 500 0,015 661 1 300 0,018 651
350 0,002 446 510 0,016 043 1 350 0,001 642
355 0,002 538 520 0,015 016 1 400 0,000 136
360 0,002 630 530 0,015 900 1 450 0,003 746
365 0,002 999 540 0,015 681 1 500 0,009 548
370 0,003 369 550 0,015 790 1 550 0,013 934
375 0,003 506 560 0,015 539 1 600 0,012 093
380 0,003 603 570 0,015 184 1 650 0,011 636
385 0,003 506 580 0,014 646 1 700 0,010 440
390 0,003 408 590 0,014 112 1 750 0,008 111
395 0,004 265 600 0,014 568 1 800 0,001 553
400 0,007 684 610 0,015 020 1 850 0,000 231
620 0,014 760 1 900 0,000 000
630 0,014 502 1 950 0,000 682
640 0,014 525 2 000 0,001 878
650 0,014 547 2 050 0,004 040
660 0,014 333 2 100 0,004 507
670 0,014 079 2 150 0,004 134
680 0,012 749 2 200 0,003 604
690 0,011 426 2 250 0,003 583
700 0,012 375 2 300 0,003 468
710 0,013 315 2 350 0,003 242
720 0,010 313 2 400 0,002 251
730 0,011 094 2 450 0,001 070
740 0,012 248 2 500 0,000 433
750 0,012 119
760 0,009 197
770 0,010 675
780 0,011 438
790 0,011 201
800 0,032 812
2 500
%TT(1,5)=×%E′ (n)
DS ∑ λ
300
NOTE Modified wavelength intervals in ISO 9845-1:1992, Table 1, Column 5.
6 © ISO 2008 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 13837:2008(E)
Table 3 — Solar global radiation through air mass 1,0 and
partitioned into uniform spectral trapezoidal intervals
E′ (n)
300 0,000 000
305 0,005 026
310 0,014 169
315 0,027 622
...

INTERNATIONAL ISO
STANDARD 13837
First edition
2008-04-15
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
Reference number
ISO 13837:2008(E)
ISO 2008
---------------------- Page: 1 ----------------------
ISO 13837:2008(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT
© ISO 2008

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 13837:2008(E)
Contents Page

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

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

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

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

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

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

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

4 Computational conventions ................................................................................................................ 2

4.1 Convention “A” ..................................................................................................................................... 2

4.2 Convention “B”..................................................................................................................................... 2

5 Apparatus .............................................................................................................................................. 2

6 Procedure .............................................................................................................................................. 2

6.1 Sample preparation .............................................................................................................................. 2

6.2 Measurement......................................................................................................................................... 3

6.3 Calculation by computational convention “A” .................................................................................. 3

6.4 Calculation by computational convention “B” .................................................................................. 3

6.5 Total solar transmittance ..................................................................................................................... 4

7 Expression of results ........................................................................................................................... 4

Annex A (informative) Derivation of solar weight tables in this International Standard ............................ 9

Annex B (informative) Determination of total solar transmittance ............................................................. 14

Bibliography ..................................................................................................................................................... 16

© ISO 2008 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 13837:2008(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 committee has been

established has the right to be represented on that committee. International 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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 13837 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 11, Safety

glazing materials.
iv © ISO 2008 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 13837:2008(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) and infrared (IR)

transmittance 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.
© ISO 2008 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 13837:2008(E)
Road vehicles — Safety glazing materials — Method for the
determination of solar transmittance
1 Scope

This International Standard specifies test methods to determine the direct and total solar transmittance of

safety glazing materials for road vehicles. Two computational conventions (denoted convention “A” and

convention “B”) are included, both of which are consistent with current international needs and practices.

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 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.

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

CIE 85:1989, Solar spectral irradiance
3 Terms, 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

ratio of transmitted 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

3.1.4
solar indirect transmittance

fraction of the solar radiation absorbed by the safety glazing materials and reradiated to the interior

NOTE The fraction is the secondary heat transfer factor as defined in ISO 9050.
© ISO 2008 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 13837:2008(E)
3.2 Symbols
Symbol Definition
ultraviolet (UV) direct solar energy transmitted through a glazing
direct solar (DS) energy transmitted through a glazing
secondary heat transfer to the inside of a glazing
T total solar energy (T + q ) transmitted to the inside of a glazing
TS DS i
λ wavelength, in nm
uniform λ interval
solar energy within a ∆λ
E′ E in trapezoidal form EE/2, ⋅⋅⋅E ,E /2
( )
λ λ 12 nn−1
⎡ ⎤
E′ (n) normalized EE′′⋅⋅⋅E′
λ λ ∑ 300 2 500
⎣ ⎦

NOTE Additional definitions are specific to the computational convention chosen and are defined with the

appropriate convention.
4 Computational conventions
4.1 Convention “A”

Convention “A” defines the UV range from 300 nm to 400 nm for air mass 1,5 global. This definition is

consistent with ISO 3917 and CIE 20:1972, and the best average solar flux specified in ISO 9845-1:1992,

Table 1, Column 5.
4.2 Convention “B”

Convention “B” defines the UV range from 300 nm to 380 nm for air mass 1,0 global. This definition is

consistent with ISO 9050 and EN 410, and the maximum possible solar flux found in CIE 85:1989, Table 4.

NOTE This International Standard defines each convention and computations are based on established methods

(see Annex A). The tables incorporated in each computational convention simplify the calculations, leading to high

accuracy with minimum effort. Since the results will differ depending on which convention is chosen, it is essential that the

convention chosen be clearly identified when results are reported.
5 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 sun's energy

is transmitted to the earth's surface.
6 Procedure
6.1 Sample preparation

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

grade methanol, or use an alternate procedure appropriate to the material, if necessary. Cut and clean flat

samples similarly.
2 © ISO 2008 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 13837:2008(E)
6.2 Measurement

Standardize the spectrophotometer in accordance with the manufacturer's instructions. Place a clean sample

normal to the measuring beam in the transmittance sample position. Note its film side and curvature

orientation, if applicable. Record the sample spectral data in accordance with the instrument manufacturer's

recommendation.
6.3 Calculation by computational convention “A”
6.3.1 Definitions specific to computational convention “A”
6.3.1.1 Solar UV transmittance [T (400)]

See Table 1. The transmittance is weighted interval by interval and derived from ISO 9845-1:1992, Table 1,

Column 5 (with air mass 1,5 global) from 300 nm to 400 nm, at intervals of 5 nm.
6.3.1.2 Solar direct transmittance [T (1,5)]

See Table 2. The transmittance is weighted interval by interval and derived from ISO 9845-1:1992, Table 1,

Column 5 (with air mass 1,5 global) from 300 nm to 2 500 nm, at intervals of 5 nm, 10 nm and 50 nm.

6.3.1.3 Solar total transmittance [T (1,5)]

The transmittance is the sum of the direct transmittance as defined in 6.3.1.2 and the indirect transmittance as

defined in 3.1.4.
6.3.2 Computation method

6.3.2.1 Compute direct solar transmittance by integration using the solar weight data in Tables 1 and 2.

Transmission (T) for each solar range (λ to λ ) is determined by the following functions:

1 n
400
%TT(400)=×%E′ (n){}Table 1 (1)
UV λ
300
2500
%TT(1,5)=×%E′ (n){}Table 2 (2)
DS λ
300

where (nE′ ) is the normalized solar energy computed trapezoidally in wavelength interval (∆λ).

6.3.2.2 Transmittance shall be measured to at least 2 300 nm. If it is not possible to measure

transmittance to the recommended 2 500 nm, the last value shall be multiplied by the remaining E′ (n)

weight values in Table 2.
6.4 Calculation by computational convention “B”
6.4.1 Definitions specific to computational convention “B”
6.4.1.1 Solar UV transmittance [T (380)]

See Table 3. The transmittance is weighted interval by interval and derived from CIE 85:1989, Table 4 (with

air mass 1,0 global) from 300 nm to 380 nm, at intervals of 5 nm.
6.4.1.2 Solar direct transmittance [T (1,0)]

See Table 4. The transmittance is weighted interval by interval and derived from CIE 85:1989, Table 4 (with

air mass 1,0 global) from 300 nm to 2 500 nm, at intervals of 5 nm, 10 nm and 50 nm.

© ISO 2008 – All rights reserved 3
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ISO 13837:2008(E)
6.4.1.3 Solar total transmittance [T (1,0)]

The transmittance is the sum of the direct transmittance as defined in 6.4.1.2 and the indirect transmittance as

defined in 3.1.4.
6.4.2 Computation method

6.4.2.1 Compute direct solar transmittance by integration using the solar weight data in Tables 3 and 4.

Transmission (T) for each solar range (λ to λ ) is determined by the following functions:

1 n
380
%TT(380)=×%E′ (n) Table 3 (3)
UV ∑ λ
300
2500
%TT(1,0)=×%E′ (n) Table 4 (4)
DS ∑ λ
300

where (nE′ ) is the normalized solar energy computed trapezoidally in wavelength interval (∆λ).

6.4.2.2 Transmittance shall be measured to at least 2 300 nm. If it is not possible to measure

transmittance to the recommended 2 500 nm, the last value shall be multiplied by the remaining E′ (n)

weight values in Table 4.
6.5 Total solar transmittance

This International Standard defines the determination of the direct solar transmittance of safety glazing

materials computed by either of two computational conventions (“A” or “B”). If it is necessary to compute total

solar transmittance, use the equations in Annex B and the direct solar transmittance results from 6.3 or 6.4,

whichever is appropriate.
7 Expression of results

Record thickness, type, construction, and curvature orientation if applicable, of the specimen; the instrument

and computational convention used (“A” or “B”); and the specimen's total UV and direct solar transmittance,

and, if necessary, the specimen's total solar properties rounded to 0,1 %, in accordance with the rounding

convention in Reference [6].
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ISO 13837:2008(E)
Table 1 — Solar global radiation through air mass 1,5 and
partitioned into uniform spectral trapezoidal intervals
E′ (n)
300 0,000 000
305 0,001 045
310 0,004 634
315 0,011 800
320 0,019 807
325 0,027 019
330 0,043 271
335 0,042 703
340 0,047 644
345 0,048 041
350 0,052 948
355 0,054 947
360 0,056 946
365 0,064 930
370 0,072 925
375 0,075 901
380 0,077 991
385 0,075 890
390 0,073 777
395 0,092 335
400 0,055 446
400
%TT(400)=×%E′ (n)
UV ∑ λ
300
NOTE Modified wavelength intervals in
ISO 9845-1:1992, Table 1, Column 5.
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ISO 13837:2008(E)
Table 2 — Solar global radiation through air mass 1,5 and
partitioned into uniform spectral trapezoidal intervals
E′ (n) E′ (n) E′ (n)
λ, nm λ, nm λ, nm
λ λ λ
300 0,000 000 410 0,011 712 850 0,049 016
305 0,000 048 420 0,011 973 900 0,039 872
310 0,000 214 430 0,010 839 950 0,016 652
315 0,000 545 440 0,013 166 1 000 0,037 501
320 0,000 915 450 0,015 431 1 050 0,034 127
325 0,001 248 460 0,016 175 1 100 0,020 859
330 0,001 999 470 0,015 988 1 150 0,012 512
335 0,001 973 480 0,016 466 1 200 0,021 415
340 0,002 201 490 0,015 565 1 250 0,023 934
345 0,002 219 500 0,015 661 1 300 0,018 651
350 0,002 446 510 0,016 043 1 350 0,001 642
355 0,002 538 520 0,015 016 1 400 0,000 136
360 0,002 630 530 0,015 900 1 450 0,003 746
365 0,002 999 540 0,015 681 1 500 0,009 548
370 0,003 369 550 0,015 790 1 550 0,013 934
375 0,003 506 560 0,015 539 1 600 0,012 093
380 0,003 603 570 0,015 184 1 650 0,011 636
385 0,003 506 580 0,014 646 1 700 0,010 440
390 0,003 408 590 0,014 112 1 750 0,008 111
395 0,004 265 600 0,014 568 1 800 0,001 553
400 0,007 684 610 0,015 020 1 850 0,000 231
620 0,014 760 1 900 0,000 000
630 0,014 502 1 950 0,000 682
640 0,014 525 2 000 0,001 878
650 0,014 547 2 050 0,004 040
660 0,014 333 2 100 0,004 507
670 0,014 079 2 150 0,004 134
680 0,012 749 2 200 0,003 604
690 0,011 426 2 250 0,003 583
700 0,012 375 2 300 0,003 468
710 0,013 315 2 350 0,003 242
720 0,010 313 2 400 0,002 251
730 0,011 094 2 450 0,001 070
740 0,012 248 2 500 0,000 433
750 0,012 119
760 0,009 197
770 0,010 675
780 0,011 438
790 0,011 201
800 0,032 812
2 500
%TT(1,5)=×%E′ (n)
DS ∑ λ
300
NOTE Modified wavelength intervals in ISO 9845-1:1992, Table 1, Column 5.
6 © ISO 2008 – All rights reserved
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ISO 13837:2008(E)
Table 3 — Solar global radiation through air mass 1,0 and
partitioned into uniform spectral trapezoidal intervals
E′ (n)
300 0,000 000
305 0,005 026
310 0,014 169
315 0,027 622
320 0,040 070
325 0,049 865
330 0,070 579
335 0,067 061
340 0,072 643
345
...

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