ASTM G7/G7M-13

Standard Practice for Atmospheric Environmental Exposure Testing of Nonmetallic Materials

SIGNIFICANCE AND USE
4.1 The relative durability of materials in natural exposures can be very different depending on the location of the exposure because of differences in ultraviolet (UV) radiation, time of wetness, temperature, pollutants, and other factors. Therefore, it cannot be assumed that results from one exposure in a single location will be useful for determining relative durability in a different location. Exposures in several locations with different climates which represent a broad range of anticipated service conditions are recommended.  
4.2 Because of year-to-year climatological variations, results from a single exposure test cannot be used to predict the absolute rate at which a material degrades. Several years of repeat exposures are needed to get an “average” test result for a given location.  
4.3 Solar ultraviolet radiation varies considerably as a function of time of year. This can cause large differences in the apparent rate of degradation in many polymers. Comparing results for materials exposed for short periods (less than one year) is not recommended unless materials are exposed at the same time in the same location.  
4.4 Defining exposure periods in terms of total solar or solar-ultraviolet radiant energy can reduce variability in results from separate exposures. Solar ultraviolet measurements are typically made using instruments which record broadband UV (for example, 295 to 385 nm) or narrow band UV, as described in 7.2.4 and 7.2.5. An inherent limitation in solar-radiation measurements is that they do not reflect the effects of temperature and moisture, which may also influence the rate or type of degradation.  
4.5 The design of the exposure rack, the location of the specimen on the exposure rack, and the type or color of adjacent specimens can affect specimen temperature and time of wetness. In order to minimize variability caused by these factors, it is recommended that test specimens, control specimens, and any applicable weathering reference mat...
SCOPE
1.1 This practice covers procedures to be followed for direct exposure of nonmetallic materials to the environment. When originators of a weathering test have the actual exposure conducted by a separate agency, the specific conditions for the exposure of test and control specimens must be clearly defined and mutually agreed upon between all parties.  
1.2 For exposures behind glass, refer to Practice G24.  
1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.4 This practice is technically equivalent to the parts of ISO 877 that describe direct exposures of specimens to the environment.  
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-May-2013
• ICS: 19.040 - Environmental testing
• Technical Committee: G03 - Weathering and Durability
• Drafting Committee: G03.02 - Natural and Environmental Exposure Tests

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: G7/G7M − 13
Standard Practice for
Atmospheric Environmental Exposure Testing of
1
Nonmetallic Materials
This standard is issued under the fixed designation G7/G7M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope With Axis Vertical by the Shading Method (Withdrawn
3
2005)
1.1 Thispracticecoversprocedurestobefollowedfordirect
E941 Test Method for Calibration of Reference Pyranom-
exposure of nonmetallic materials to the environment. When
etersWithAxisTiltedbytheShadingMethod(Withdrawn
originators of a weathering test have the actual exposure
3
2005)
conducted by a separate agency, the specific conditions for the
G24 Practice for Conducting Exposures to Daylight Filtered
exposure of test and control specimens must be clearly defined
Through Glass
and mutually agreed upon between all parties.
G113 Terminology Relating to Natural andArtificial Weath-
1.2 For exposures behind glass, refer to Practice G24.
ering Tests of Nonmetallic Materials
G130 Test Method for Calibration of Narrow- and Broad-
1.3 The values stated in either SI units or inch-pound units
Band Ultraviolet Radiometers Using a Spectroradiometer
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each 2.2 ISO Standards:
system shall be used independently of the other. Combining
ISO 877 Plastics—Methods of Exposure to Direct Weath-
values from the two systems may result in non-conformance ering;toWeatheringUsingGlass-FilteredDaylight,andto
with the standard.
Intensified Weathering by Daylight Using Fresnel Mir-
4
rors
1.4 This practice is technically equivalent to the parts of
ISO 9370 Plastics—Instrumental Determination of Radiant
ISO 877 that describe direct exposures of specimens to the
Exposure in Weathering Tests—General Guidance and
environment.
4
Basic Test Method
1.5 This standard does not purport to address all of the
2.3 ASTM Adjuncts:
safety concerns, if any, associated with its use. It is the
5
A Test Rack
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3. Terminology
bility of regulatory limitations prior to use.
3.1 Definitions—The definitions given in Terminology E41
and Terminology G113 are applicable to this practice.
2. Referenced Documents
2
2.1 ASTM Standards:
4. Significance and Use
E41 Terminology Relating To Conditioning
4.1 The relative durability of materials in natural exposures
E824 Test Method for Transfer of Calibration From Refer-
can be very different depending on the location of the exposure
ence to Field Radiometers
because of differences in ultraviolet (UV) radiation, time of
E913 Method for Calibration of Reference Pyranometers
wetness, temperature, pollutants, and other factors. Therefore,
it cannot be assumed that results from one exposure in a single
location will be useful for determining relative durability in a
1
This practice is under the jurisdiction ofASTM Committee G03 on Weathering
different location. Exposures in several locations with different
and Durabilityand is the direct responsibility of Subcommittee G03.02 on Natural
and Environmental Exposure Tests.
Current edition approved June 1, 2013. Published June 2013. Originally
3
approved in 1969. Last previous edition approved in 2011 as G7/G7M – 11. DOI: The last approved version of this historical standard is referenced on
10.1520/G0007_G0007M-13. www.astm.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM 4th Floor, New York, NY 10036, http://www.ansi.org.
5
Standards volume information, refer to the standard’s Document Summary page on Detailed drawings for an acceptable test rack may be obtained from ASTM
the ASTM website. International. Request ADJG0007.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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G7/G7M − 13
climates which represent a broad range of anticipated service be placed on a single test panel or on test panels placed
conditions are recommended. adjacent to each other during exposure.
4.2 Because of year-to-year climatological variations, re- 4.6 It is strongly recommended that at least one control
sults from a single exposure test cannot be used to predict the material be part of an
...

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: G7/G7M − 11 G7/G7M − 13
Standard Practice for
Atmospheric Environmental Exposure Testing of
1
Nonmetallic Materials
This standard is issued under the fixed designation G7/G7M; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope*Scope
1.1 This practice covers procedures to be followed for direct exposure of nonmetallic materials to the environment. When
originators of a weathering test have the actual exposure conducted by a separate agency, the specific conditions for the exposure
of test and control specimens must be clearly defined and mutually agreed upon between all parties.
1.2 For exposures behind glass, refer to Practice G24.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as the standard. The inch-pound units
given in parentheses are for information only.values stated in each system may not be exact equivalents; therefore, each system
shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.4 This practice is technically equivalent to the parts of ISO 877 that describe direct exposures of specimens to the
environment.
1.5 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E41 Terminology Relating To Conditioning
E824 Test Method for Transfer of Calibration From Reference to Field Radiometers
3
E913 Method for Calibration of Reference Pyranometers With Axis Vertical by the Shading Method (Withdrawn 2005)
3
E941 Test Method for Calibration of Reference Pyranometers With Axis Tilted by the Shading Method (Withdrawn 2005)
G24 Practice for Conducting Exposures to Daylight Filtered Through Glass
G113 Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
G130 Test Method for Calibration of Narrow- and Broad-Band Ultraviolet Radiometers Using a Spectroradiometer
2.2 ISO Standards:
ISO 877 Plastics—Methods of Exposure to Direct Weathering; to Weathering Using Glass-Filtered Daylight, and to Intensified
4
Weathering by Daylight Using Fresnel Mirrors
ISO 9370 Plastics—Instrumental Determination of Radiant Exposure in Weathering Tests—General Guidance and Basic Test
4
Method
2.3 ASTM Adjuncts:
5
A Test Rack
1
This practice is under the jurisdiction of ASTM Committee G03 on Weathering and Durabilityand is the direct responsibility of Subcommittee G03.02 on Natural and
Environmental Exposure Tests.
Current edition approved June 1, 2011June 1, 2013. Published July 2011June 2013. Originally approved in 1969. Last previous edition approved in 20052011 as
G7 – 05.G7/G7M – 11. DOI: 10.1520/G0007_G0007M-11.10.1520/G0007_G0007M-13.
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 the ASTM website.
3
The last approved version of this historical standard is referenced on www.astm.org.
4
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
5
Detailed drawings for an acceptable test rack may be obtained from ASTM International. Request ADJG0007.
*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

---------------------- Page: 1 ----------------------
G7/G7M − 13
3. Terminology
3.1 Definitions—The definitions given in Terminology E41 and Terminology G113 are applicable to this practice.
4. Significance and Use
4.1 The relative durability of materials in natural exposures can be very different depending on the location of the exposure
because of differences in ultraviolet (UV) radiation, time of wetness, temperature, pollutants, and other factors. Therefore, it cannot
be assumed that results from one exposure in a single location will be useful for
...