ASTM G24-21

Standard Practice for Conducting Exposures to Daylight Filtered Through Glass

SIGNIFICANCE AND USE
4.1 Since solar radiation, air temperature, relative humidity, and the amount and kind of atmospheric contaminants vary continuously, results from exposures based on elapsed time will sometimes differ. The variations in the results will usually be reduced by timing the exposures in terms of:  
4.1.1 One or more environmental parameters such as solar radiant exposure, or  
4.1.2 A predefined property change of a weathering reference specimen with known performance.  
4.2 Variations in temperature, moisture, and atmospheric contaminants can have a significant effect on the degradation caused by solar radiation. In addition, exposures conducted at different times of the year can cause large differences in the rate of degradation. Different materials generally have different sensitivities to heat, moisture, and atmospheric contaminants, and this could explain differences in rankings of specimens exposed to equivalent solar radiant exposure when other environmental conditions vary.  
4.3 Since the method of mounting has an influence on the temperature and other parameters during exposure of the specimen, there shall be agreement between contractual parties as to the method of mounting the specimen for the particular exposure test under consideration.  
4.4 There are differences among various single strength window glasses in their transmittance in the 300 to 350 nm region. For example, at 320 nm, the percent transmittance for seven different lots of single strength window glass ranged from 8.4 to 26.8 %. At 380 nm, the percent transmittance ranged from 84.9 % to 88.1 %.5  
4.5 Differences in UV transmittance between different lots of glass generally continue even after solarization. The largest differences among window glasses in UV transmittance are in the spectral range of 300 to 320 nm.  
4.6 This practice is best used to compare the relative performance of materials tested at the same time behind the same lot of glass. Because of variability between lots of g...
SCOPE
1.1 This practice describes procedures for conducting exposures of various materials to daylight filtered through glass in passively ventilated and non-vented enclosures. For exposures in under glass enclosures with forced air circulation, refer to Practice G201.  
1.1.1 This practice is not intended for corrosion testing of bare metals.  
1.2 For direct exposures, refer to Practice G7.  
1.3 This practice is limited to the method of conducting the exposures. The preparation of test specimens and evaluation of results are covered in various standards for the specific materials.  
1.4 Exposure conducted according to this practice can use two types of exposure cabinets.  
1.4.1 Type A—A cabinet that allows passive ventilation of specimens being exposed behind glass.  
1.4.2 Type B—Enclosed cabinet with exterior painted black that does not provide for ventilation of specimens exposed behind glass. Exposures conducted using a Type B cabinet are typically referred to as “black box under glass exposures.”  
1.5 Type A exposures of this practice are technically similar to Method B of ISO 877-2.  
1.6 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Nov-2021
• ICS: 59.080.01 - Textiles in general
• Technical Committee: G03 - Weathering and Durability
• Drafting Committee: G03.02 - Natural and Environmental Exposure Tests

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: G24 − 21
Standard Practice for
1
Conducting Exposures to Daylight Filtered Through Glass
ThisstandardisissuedunderthefixeddesignationG24;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 Thispracticedescribesproceduresforconductingexpo-
sures of various materials to daylight filtered through glass in
2. Referenced Documents
passively ventilated and non-vented enclosures. For exposures
2
2.1 ASTM Standards:
in under glass enclosures with forced air circulation, refer to
C1036Specification for Flat Glass
Practice G201.
D4303Test Methods for Lightfastness of Colorants Used in
1.1.1 This practice is not intended for corrosion testing of
Artists’Materials
bare metals.
D6901Specification for Artists’ Colored Pencils
1.2 For direct exposures, refer to Practice G7.
E824Test Method for Transfer of Calibration From Refer-
1.3 This practice is limited to the method of conducting the
ence to Field Radiometers
exposures.Thepreparationoftestspecimensandevaluationof
E903Test Method for Solar Absorptance, Reflectance, and
results are covered in various standards for the specific
Transmittance of Materials Using Integrating Spheres
materials.
G7Practice for Natural Weathering of Materials
G113Terminology Relating to Natural andArtificialWeath-
1.4 Exposure conducted according to this practice can use
ering Tests of Nonmetallic Materials
two types of exposure cabinets.
G147Practice for Conditioning and Handling of Nonmetal-
1.4.1 Type A—A cabinet that allows passive ventilation of
lic Materials for Natural and Artificial Weathering Tests
specimens being exposed behind glass.
G201Practice for Conducting Exposures in Outdoor Glass-
1.4.2 Type B—Enclosed cabinet with exterior painted black
Covered Exposure Apparatus with Air Circulation
that does not provide for ventilation of specimens exposed
3
2.2 ISO Standards:
behind glass. Exposures conducted using a Type B cabinet are
ISO 877-2Plastics – Methods of Exposure to Solar Radia-
typically referred to as “black box under glass exposures.”
tion – Part 2: Direct Weathering and Exposure Behind
1.5 TypeAexposuresofthispracticearetechnicallysimilar
Window Glass
to Method B of ISO877-2.
ISO 9060:2018Solar Energy – Specification and Classifica-
1.6 Units—The values stated in SI units are to be regarded
tion of Instruments for Measuring Hemispherical Solar
as standard. The values given in parentheses after SI units are
and Direct Solar Radiation
4
providedforinformationonlyandarenotconsideredstandard.
2.3 Other Document:
1.7 This standard does not purport to address all of the WMO Guide to Meteorological Instruments and Methods of
Observation WMO No. 8,2014 Edition (2017).
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3.1 Definitions:
1.8 This international standard was developed in accor-
3.1.1 The definitions contained in Terminology G113 are
dance with internationally recognized principles on standard-
applicable to this practice.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
1
ThispracticeisunderthejurisdictionofASTMCommitteeG03onWeathering the ASTM website.
3
and Durability and is the direct responsibility of Subcommittee G03.02 on Natural Available from International Organization for Standardization (ISO), ISO
and Environmental Exposure Tests. Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Current edition approved Dec. 1, 2021. Published December 2021. Originally Switzerland, https://www.iso.org.
4
approved in 1973. Last previous edition approved in 2013 as G24–13. DOI: AvailablefromWorldMeteorologicalOrganization(WMO),7bis,avenuedela
10.1520/G0024-21. Paix,CasePostaleNo.2300,CH-1211Geneva2,Switzerland,http://www.wmo.int.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: G24 − 13 G24 − 21
Standard Practice for
1
Conducting Exposures to Daylight Filtered Through Glass
This standard is issued under the fixed designation G24; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This practice evaluates the resistance of nonmetallic materials to solar radiation describes procedures for conducting exposures
of various materials to daylight filtered through glass in passively ventilated and non-vented enclosures. For exposures in under
glass enclosures with forced air circulation, refer to Practice G201.
1.1.1 This practice is not intended for corrosion testing of bare metals.
1.2 For direct exposures, refer to Practice G7.
1.3 This practice is limited to the method of conducting the exposures. The preparation of test specimens and evaluation of results
are covered in various standards for the specific materials.
1.4 Exposure conducted according to this practice can use two types of exposure cabinets.
1.4.1 Type A—A cabinet that allows passive ventilation of specimens being exposed behind glass.
1.4.2 Type B—Enclosed cabinet with exterior painted black that does not provide for ventilation of specimens exposed behind
glass. Exposures conducted using a Type B cabinet are typically referred to as “black box under glass exposures.”
1.5 Type A exposures of this practice are technically similar to Method B of ISO 877-2.
1.6 Units—The values stated in SI units are to be regarded as the standard. The inch-pound units values given in parentheses are
for information only.after SI units are provided for information only and are not considered standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
1
This practice is under the jurisdiction of ASTM Committee G03 on Weathering and Durability and is the direct responsibility of Subcommittee G03.02 on Natural and
Environmental Exposure Tests.
Current edition approved June 1, 2013Dec. 1, 2021. Published July 2013December 2021. Originally approved in 1973. Last previous edition approved in 20052013 as
G24 – 05.G24 – 13. DOI: 10.1520/G0024-13.10.1520/G0024-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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G24 − 21
2. Referenced Documents
2
2.1 ASTM Standards:
C1036 Specification for Flat Glass
3
D3424 Practice for Evaluating the Relative Lightfastness and Weatherability of Printed Matter (Withdrawn 2020)
D4303 Test Methods for Lightfastness of Colorants Used in Artists’ Materials
D6901 Specification for Artists’ Colored Pencils
E824 Test Method for Transfer of Calibration From Reference to Field Radiometers
E903 Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres
E1084 Test Method for Solar Transmittance (Terrestrial) of Sheet Materials Using Sunlight
G7 Practice for Natural Weathering of Materials
G113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
G173G147 Tables for Reference Solar Spectral Irradiances: Direct Normal and Hemispherical on 37° Tilted SurfacePractice for
Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering Tests
G177 Tables for Reference Solar Ultraviolet Spectral Distributions: Hemispherical on 37° Tilted Surface
G201 Practice for Conducting Exposures in Outdoor Glass-Covered Exposure Apparatus with Air Circulation
2.2 Other Documents:ISO Standards:
4
WMO Guide to Meteorological Instruments and Methods of Observation WMO No. 8, Seventh Edition.
53
ISO 105 B01 Textiles—Tests for Colour Fastness, International Standards Organization,
...