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ASTM G156-97

(Practice)

Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test

Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test

SCOPE
1.1 This standard describes the criterion to be used for selection of a WRM and procedures to be used for determining within lab and between lab tolerances of changes in measured properties of a reference material intended for use in monitoring operating conditions to establish the consistency of exposure tests.
Note 1—Examples of laboratory accelerated tests in which a weathering reference material could be used to monitor consistency are light and water exposure tests such as those described in Practices G 152, G 153, and G 154 G 155and other standards in which tests conducted according to these standards are referenced. Examples of outdoor exposures where a weathering reference material could be used to monitor consistency are those conducted according to Practices G 7, G 24, or G 90. A reference material can also be used to monitor consistency of exposure or conditioning test that do not involve exposure to light.
1.2 This practice does not cover (1) control materials used for comparison of stability with test materials, or (2) standard materials used to time exposures.
1.3 This practice provides an outline of experiments required to determine how the measured properties of the reference material change as a function of exposure to specified test conditions. It includes establishment of reproducible measurement procedures, determination of the critical region in the light source causing the changes, and effects of other critical exposure stresses such as temperature and moisture.
1.4 This practice describes procedures for conducting round-robin tests with the weathering reference material to determine reproducibility of the reference material property change in exposures conducted in different laboratories, and the repeatability when replicate reference material specimens are exposed in a single device and tested in one laboratory.
1.5 This practice describes procedures for using the results from analysis of variance on results from round-robin tests to determine the contribution of the exposure, the measurement device, reference material variability, and operator error to total variability.

General Information

Status
Historical
Publication Date
09-Feb-2002
ICS
19.040 - Environmental testing
Technical Committee
G03 - Weathering and Durability
Drafting Committee
G03.01 - Joint Weathering Projects
Current Stage
Ref Project

Relations

Replaced By
ASTM G156-02 - Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test
Effective Date
10-Feb-2002
Referred By
ASTM G151-19 - Standard Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources
Effective Date
10-Feb-2002
Referred By
ASTM D7238-20 - Standard Test Method for Effect of Exposure of Unreinforced Polyolefin Geomembrane Using Fluorescent UV Condensation Apparatus
Effective Date
10-Feb-2002

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ASTM G156-97 - Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure TestASTM G156-97 - Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test
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ASTM G156-97 - Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: G 156 – 97
Standard Practice for
Selecting and Characterizing Weathering Reference
Materials Used to Monitor Consistency of Conditions in an
Exposure Test
This standard is issued under the fixed designation G 156; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope device, reference material variability, and operator error to total
variability.
1.1 This standard describes the criterion to be used for
selection of a WRM and procedures to be used for determining
2. Referenced Documents
within lab and between lab tolerances of changes in measured
2.1 ASTM Standards:
properties of a reference material intended for use in monitor-
D 3045 Practice for Heat Aging of Plastics Without Load
ing operating conditions to establish the consistency of expo-
D 3980 Practice for conducting an Interlaboratory Study for
sure tests.
Tess of Paints and Related Coatings
NOTE 1—Examples of laboratory accelerated tests in which a weather-
E 177 Practice for Use of the Terms Precision and Bias in
ing reference material could be used to monitor consistency are light and
ASTM Test Methods
water exposure tests such as those described in Practices G 23, G 26, and
E 691 Practice for Conducting an Interlaboratory Study to
G 53 and other standards in which tests conducted according to these
Determine Precision of a Test Method
standards are referenced. Examples of outdoor exposures where a weath-
E 1169 Guide for Conducting Ruggedness Tests
ering reference material could be used to monitor consistency are those
conducted according to Practices G 7, G 24, or G 90. A reference material G 7 Practice for Atmospheric Environmental Exposure
can also be used to monitor consistency of oven aging exposures such as
Testing of Nonmetallic Materials
those described in Practice D 3045.
G 23 Practice for Operating Light-Exposure Apparatus
1.2 This practice does not cover (1) control materials used (Carbon-Arc Type) With and Without Water for Exposure
for comparison of stability with test materials, or (2) standard of Nonmetallic Materials
materials used to time exposures. G 24 Practice for Conducting Exposures to Daylight Fil-
1.3 This practice provides an outline of experiments re- tered Through Glass
quired to determine how the measured properties of the G 26 Practice for Operating Light-Exposure Apparatus
reference material change as a function of exposure to specified (Xenon-Arc Type) With and Without Water for Exposure
test conditions. It includes establishment of reproducible mea- of Nonmetallic Material s
surement procedures, determination of the critical region in the G 53 Practice for Operating Light-Exposure Apparatus
light source causing the changes, and effects of other critical (Fluorescent UV-Condensation Type) for Exposure of
exposure stresses such as temperature and moisture. Nonmetallic Materials
1.4 This practice describes procedures for conducting G 90 Practice for Performing Accelerated Outdoor Weath-
round-robin tests with the weathering reference material to ering of Nonmetallic Materials Using Concentrated Natu-
determine reproducibility of the reference material property ral Sunlight
change in exposures conducted in different laboratories, and G 113 Terminology Relating to Natural and Artificial
the repeatability when replicate reference material specimens Weathering Tests of Nonmetallic Materials
are exposed in a single device and tested in one laboratory. 2.2 SAE Standard:
1.5 This practice describes procedures for using the results SAE J1960, Accelerated Exposure of Automotive Exterior
from analysis of variance on results from round-robin tests to Materials using a Controlled Irradiance Water-Cooled
determine the contribution of the exposure, the measurement Xenon Arc Apparatus
Annual Book of ASTM Standards, Vol 08.02.
1 3
This practice is under the jurisdiction of ASTM Committee G-3 on Weathering Discontinued—See Annual Book of ASTM Standards, Vol 06.02.
and Durability and is the direct responsibility of Subcommittee G03.01 on Joint Annual Book of ASTM Standards, Vol 14.02.
Weathering Projects. Available from Society of Automotive Engineers, 400 Commonwealth Drive,
Current edition approved Dec. 10, 1997. Published March 1998. Warrendale, PA 15096.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
G 156
SAE J1885, Accelerated Exposure of Automotive Interior 4.4.1 The results obtained according to this practice are
Materials Using a Controlled Irradiance Water-Cooled valid only for the exposure cycle used for the round-robin and
Xenon Arc Apparatus cannot be applied to the same weathering reference material
used in a different exposure cycle.
3. Terminology
4.5 The change in characteristic property of a reference
3.1 Definitions—The definitions listed in Terminology
material may be affected by the placement of the reference
G 113 are applicable to this standard.
material in the exposure device. This is often due to variations
in light intensity and temperature within the allowed exposure
4. Significance and Use
area. Random placement of replicate specimens of the weath-
4.1 Weathering reference materials are used in laboratory
ering reference material through-out the allowed exposure area
accelerated exposure tests to establish consistency among tests
provides the best indication of the overall consistency of the
run at different times and in different laboratories in the same
exposure test.
type of device. Specifications defining consistency of exposure
NOTE 5—In some cases, procedures require exposure of a weathering
conditions based on the property change of a reference material
reference material at a specific location within the exposure device or
are usually based on results for a single lot of the reference
chamber. Results for a reference material used in this way may not provide
material. When a new lot of the reference material is intro-
an accurate representation of the exposure conditions in other positions
duced, round-robin studies are necessary to compare the new
within the device.
and old lots and to establish appropriate limits for expected
5. Procedure
performance of the new lot.
5.1 Select a reference material which exhibits a measurable
NOTE 2—An example of the use of a clear polystyrene reference
change in a characteristic property when exposed in the
standard for this purpose is given in SAE J1885 and SAE J1960.
NOTE 3—Some weathering reference materials (for example blue specific type of device and exposure cycle to be monitored.
wools) are also used to define periods of exposure. Although not
5.2 Determine the procedure used that can best measure the
specifically covered by this standard, the procedures described for
change in characteristic property of the reference material.
characterizing a reference material used to monitor consistency of
5.2.1 Conduct a series of experiments to determine the
exposures are also generally applicable to characterizing reference mate-
effect of important factors in the measurement procedure. It is
rials used to define periods of exposure.
recommended that this be done using a ruggedness test
4.2 It is important to test the consistency of exposure in the
according to Guide E 1169 to determine which factors signifi-
laboratory accelerated device with a weathering reference
cantly affect results. The results from this test can be used to
material that responds to the test conditions similar to the way
tighten the test measurement procedures.
the test materials respond. Therefore, the weathering reference
5.2.2 When the results from the ruggedness testing are
material should be sensitive to the spectral region of the light
complete, write a set of instructions for running the test used to
source mainly responsible for producing degradation in the test
determine the level of the characteristic property that is
materials to provide the most meaningful evaluation of expo-
unambiguous and clearly understood by operators who will be
sure test consistency. The weathering reference material should
making the measurement. Have two operators in one labora-
also provide information on consistency of temperature and
tory conduct the measurement on at least three replicate
humidity conditions if the latter are important factors in
specimens of the reference material. Interview the operators to
degradation of the test materials.
determine whether the procedure provides clear and easy to
understand directions. Modify the procedure to remove any
NOTE 4—Material homogeneity can also be an important factor in
selection of a weathering reference material, particularly if weathering is
ambiguity in instructions.
initiated by the radiation absorbed by impurities as is the case in aliphatic
5.3 Determine the homogeneity of the weathering reference
type polymers exposed to radiation longer than 300 nm.
material by measuring the property change of randomly
4.3 The measurement of the characteristic property of a selected replicate specimens that have been exposed to very
weathering reference material can be subject to error depend- tightly controlled test conditions, or by appropriate chemical
ing on the instrument and the procedure used to measure the analysis techniques such as ultraviolet and/or infrared spectro-
property. It is important to develop measurement procedures scopic analysis.
that are clear and which minimize chances for operator 5.4 For any new weathering reference material, determine
the response of the reference material to critical exposure
misinterpretation. It is also important to determine the level of
variability caused by measurement of the characteristic prop- stresses. These results are important to determining whether
the material being considered is appropriate for monitoring the
erty.
4.4 When a reference material is used to monitor or specify specific conditions of the exposure test being used. Tests to
the consistency of an exposure test, it is important that any determine the materials response to exposure stresses should be
specification li
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SIGNIFICANCE AND USE
5.1 As with any accelerated test, the increase in rate of weathering compared to in-service exposure is material dependent. Results from exposures conducted to this practice may provide good rank correlation to results from actual use conditions for one type of material or product. It should not be assumed that this will be true for other materials or products. It is always best to verify the ability of an accelerated exposure test to properly rank the durability of materials with actual use conditions. Guide G141 provides information about using rank correlation.  
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1.1 This practice covers the basic principles and operating procedures for using outdoor glass-covered exposure apparatus with air circulation. This practice is limited to the procedures for obtaining, measuring and controlling conditions of exposure. A number of exposure procedures are listed in Appendix X1; however, this practice does not specify the exposure conditions best suited for the material to be tested.  
1.2 For direct weathering exposures, refer to Practice G7. For exposures behind glass without air circulation, refer to Practice G24.  
1.3 Test specimens are exposed to solar radiation filtered through glass under partially controlled environmental test conditions. Different glass types and operating parameters are described.  
1.4 Specimen preparation and evaluation of the results are covered in ASTM methods or specifications for specific materials. More specific information for determining the change in properties after exposure and reporting these results is described in Practices D5870, D2244 and Test Method D523.  
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SIGNIFICANCE AND USE
4.1 Results obtained from this practice can be used to compare the relative durability of materials subjected to the specific test cycle used. No accelerated test can be specified as a perfect simulation of natural or field exposures. Results obtained from this practice can be considered as representative of natural weathering only when a sufficient magnitude of mathematical correlation exists between exposures.  
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4.3 The relative durability of materials determined by this practice can be used to determine the relative durability of the materials exposed under natural weathering conditions provided the materials have similar acceleration factors. However, even if results from a specific accelerated test condition are found to be useful for comparing the durability of materials exposed in a particular exterior location, it cannot be assumed that they will be useful for determining the relative durability for a different location. The relative durability of materials in n...
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1.1 Linear Fresnel reflector concentrators using the sun as source are utilized in the accelerated outdoor exposure testing of materials.  
1.2 This practice covers a procedure for performing accelerated outdoor exposure testing of materials using a linear Fresnel reflector, accelerated outdoor weathering, test machine. The apparatus (see Fig. 1 and Fig. 2) and guidelines are described herein to minimize the variables encountered during outdoor accelerated exposure testing.    
1.3 This practice does not specify the exposure conditions best suited for the materials to be tested but is limited to the method of obtaining, measuring, and controlling the procedures and certain conditions of the exposure. Sample preparation, test conditions, and evaluation of results are covered in existing methods or specifications for specific materials.  
1.4 The linear Fresnel reflector accelerated outdoor exposure test apparatus described may be suitable for the determination of the relative durability of materials when these materials are exposed to concentrated sunlight, heat, and moisture.  
1.5 This practice establishes uniform sample mounting and in-test maintenance procedures. Also included in the practice are standard provisions for maintenance of the machine and linear Fresnel reflector mirrors to ensure cleanliness and durability.  
1.6 This practice shall apply to specimens whose size meets the dimensions of the target board as described in 8.2.  
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SIGNIFICANCE AND USE
5.1 The use of this apparatus is intended to induce property changes consistent with the end use conditions, including the effects of the UV portion of sunlight, moisture, and heat. Typically, these exposures would include moisture in the form of condensing humidity. Exposures are not intended to simulate the deterioration caused by localized weather phenomena, such as atmospheric pollution, biological attack, and saltwater exposure. Alternatively, the exposure may simulate the effects of sunlight through window glass. (Warning—Refer to Practice G151 for full cautionary guidance applicable to all laboratory weathering devices.)  
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1.2 It is intended to be used in conjunction with a practice or method that defines specific exposure conditions for an application along with a means to evaluate changes in material properties. This practice is intended to reproduce the weathering effects that occur when materials are exposed to sunlight (either direct or through window glass) and moisture as rain or dew in actual usage. This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure.
Note 1: Practice G151 describes general procedures to be used when exposing nonmetallic materials in accelerated test devices that use laboratory light sources.
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1.3 Test specimens are exposed to fluorescent UV light under controlled environmental conditions. Different types of fluorescent UV lamp sources are described.
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1.4 Specimen preparation and evaluation of the results are covered in ASTM methods or specifications for specific materials. General guidance is given in Practice G151.
Note 3: General information about methods for determining the change in properties after exposure and reporting these results is described in Practice D5870.  
1.5 This practice is not intended for corrosion testing of bare metals.  
1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7 This practice is technically similar to the following ISO documents: ISO 4892-2, ISO 16474-2, ISO 105-B02, ISO 105-B04, ISO 105-B05, ISO 105-B06, and ISO 105-B10.  
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SIGNIFICANCE AND USE
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1.1 This guide covers elementary statistical methods for the analysis of data common to weathering experiments. The methods are for decision making, in which the experiments are designed to test a hypothesis on a single response variable. The methods work for either natural or laboratory weathering.  
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1.3 This guide is not intended to be a manual on statistics, and therefore some general knowledge of basic and intermediate statistics is necessary. The text books referenced at the end of this guide are useful for basic training.  
1.4 This guide does not provide a rigorous treatment of the material. It is intended to be a reference tool for the application of practical statistical methods to real-world problems that arise in the field of durability and weathering. The focus is on the interpretation of results. Many books have been written on introductory statistical concepts and statistical formulas and tables. The reader is referred to these for more detailed information. Examples of the various methods are included. The examples show typical weathering data for illustrative purposes, and are not intended to be representative of specific materials or exposures.  
1.5 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.

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Standard Practice for Natural Weathering of 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, relative humidity, time of wetness, temperature, wet-dry cycling, freeze-thaw cycling, 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 exposures, repeated over several years are needed to get a representative test result for a given location.  
4.3 Solar UV radiation varies considerably as a function of time of year. This can cause large differences in the apparent rate of degradation in many materials. 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 The duration of natural weathering tests is often based on time (24 months for example). The variability between different exposures can be reduced by using a duration based on total solar or solar UV radiant exposure. Solar UV measurements are typically made using instruments which record broadband UV (for example, 295 to 385 nm), as described in 7.2.4. An inherent limitation in timing a weathering test based solely on solar-radiation measurements is that temperature and moisture may also influence the rate or type of degradation.  
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SCOPE
1.1 This practice covers procedures to be followed for direct exposure of materials to the environment. Typically, this testing is performed on exposure racks tilted at a commonly-used tilt angle from the horizontal (such as 5 or 45 degrees) and facing the equator. Other exposure orientations can be used.  
1.2 This practice is not intended for the corrosion testing of bare metals, or for testing behind glass.  
1.2.1 For corrosion testing, refer to Practice G50  
1.2.2 For exposures behind glass, refer to Practice G24  
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.4 This practice is technically equivalent to the parts of ISO 877-1 and -2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

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ASTM G152-13(2021)(Practice)
Standard Practice for Operating Open Flame Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials

SIGNIFICANCE AND USE
5.1 The use of this apparatus is intended to induce property changes associated with the end use conditions, including the effects of sunlight, moisture, and heat. These exposures may include a means to introduce moisture to the test specimen. Exposures are not intended to simulate the deterioration caused by localized weather phenomena, such as atmospheric pollution, biological attack, and saltwater exposure. Alternatively, the exposure may simulate the effects of sunlight through window glass. Typically, these exposures would include moisture in the form of humidity.
Note 2: Caution: Refer to Practice G151 for full cautionary guidance applicable to all laboratory weathering devices.  
5.2 Variation in results may be expected when operating conditions are varied within the accepted limits of this practice. No reference, therefore, shall be made to results from the use of this practice unless accompanied by a report detailing the specific operating conditions in conformance with Section 10.  
5.2.1 It is recommended that a similar material of known performance, a control, be exposed simultaneously with the test specimen to provide a standard for comparative purposes. It is best practice to use control materials known to have relatively poor and good durability. It is recommended that at least three replicates of each material evaluated be exposed in each test to allow for statistical evaluation of results.
SCOPE
1.1 This practice covers the basic principles and operating procedures for using open flame carbon-arc light and water apparatus intended to reproduce the weathering effects that occur when materials are exposed to sunlight (either direct or through window glass) and moisture as rain or dew in actual use. This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure. A number of exposure procedures are listed in an appendix; however, this practice does not specify the exposure conditions best suited for the material to be tested.
Note 1: Practice G151 describes performance criteria for all exposure devices that use laboratory light sources. This practice replaces Practice G23, which describes very specific designs for devices used for carbon-arc exposures. The apparatus described in Practice G23 is covered by this practice.  
1.2 Test specimens are exposed to filtered open flame carbon arc light under controlled environmental conditions. Different filters are described.  
1.3 Specimen preparation and evaluation of the results are covered in methods or specifications for specific materials. General guidance is given in Practice G151 and ISO 4892-1. More specific information about methods for determining the change in properties after exposure and reporting these results is described in Practice D5870.  
1.4 The values stated in SI units are to be regarded as the standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5.1 Should any ozone be generated from the operation of the light source, it shall be carried away from the test specimens and operating personnel by an exhaust system.  
1.6 This practice is technically similar to ISO 4892-4.  
1.7 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.

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ASTM
ASTM G153-13(2021)(Practice)
Standard Practice for Operating Enclosed Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials

SIGNIFICANCE AND USE
5.1 The use of this apparatus is intended to induce property changes associated with the end use conditions, including the effects of sunlight, moisture, and heat. These exposures may include a means to introduce moisture to the test specimen. Exposures are not intended to simulate the deterioration caused by localized weather phenomena, such as atmospheric pollution, biological attack, and saltwater exposure. Alternatively, the exposure may simulate the effects of sunlight through window glass. Typically, these exposures would include moisture in the form of humidity.
Note 2: Caution: Refer to Practice G151 for full cautionary guidance applicable to all laboratory weathering devices.  
5.2 Variation in results may be expected when operating conditions are varied within the accepted limits of this practice. Therefore, no reference shall be made to results from the use of this practice unless accompanied by a report detailing the specific operating conditions in conformance with Section 10.  
5.2.1 It is recommended that a similar material of known performance, a control, be exposed simultaneously with the test specimen to provide a standard for comparative purposes. It is best practice to use control materials known to have relatively poor and good durability. It is recommended that at least three replicates of each material evaluated be exposed in each test to allow for statistical evaluation of results.
SCOPE
1.1 This practice covers the basic principles and operating procedures for using enclosed carbon-arc light and water apparatus intended to reproduce the weathering effects that occur when materials are exposed to sunlight (either direct or through window glass) and moisture as rain or dew in actual use. This practice is limited to the procedures for obtaining, measuring, and controlling conditions of exposure. A number of exposure procedures are listed in an appendix; however, this practice does not specify the exposure conditions best suited for the material to be tested.
Note 1: Practice G151 describes performance criteria for all exposure devices that use laboratory light sources. This practice replaces Practice G23, which describes very specific designs for devices used for carbon-arc exposures. The apparatus described in Practice G23 is covered by this practice.  
1.2 Test specimens are exposed to enclosed carbon arc light under controlled environmental conditions.  
1.3 Specimen preparation and evaluation of the results are covered in various methods or specifications for specific materials. General guidance is given in Practice G151 and ISO 4892-1. More specific information about methods for determining the change in properties after exposure and reporting these results is described in ISO 4582.  
1.4 The values stated in SI units are to be regarded as the standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5.1 Should any ozone be generated from the operation of the light source, it shall be carried away from the test specimens and operating personnel by an exhaust system.  
1.6 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.

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ASTM G160-12(2019)(Practice)
Standard Practice for Evaluating Microbial Susceptibility of Nonmetallic Materials By Laboratory Soil Burial

SIGNIFICANCE AND USE
3.1 These results may be used to compare the susceptibility of materials when exposed to this test procedure.  
3.2 Microbiological susceptibility may be reflected by a number of changes including staining, weight loss, or reduction in tensile or flexural strength.  
3.3 This practice may be considered an inoculation with a mixed culture of fungi and bacteria.
SCOPE
1.1 This practice is limited to the method of conducting an evaluation of a nonmetallic material's microbiological susceptibility when in contact with the natural environment of the soil under use conditions. This practice is intended for use on solid material test specimens that are no larger than approximately 2 cm (0.79 in.) thick and 100 cm 2  (15.5 in.2) or on film forming materials such as coatings which may be tested in the form of films at least 50 by 50 mm (2 by 2 in.) in size. This practice may be applied to articles that do not spend the majority of their service life in soil.  
1.2 A wide variety of properties may be affected by microbial attack depending on material or item characteristics. Standard methods (where available) should be used for each different property to be evaluated. This practice does not attempt to enumerate all of the possible properties of interest nor specify the most appropriate test for those properties. Test methods must, however, be appropriate to the material being tested.  
1.3 Materials intended for use in soil burial applications are often subjected to periods of exposure to solar radiation and other elements of weather for some time before they are buried. Because these exposures may alter the ability of a material to resist the effects of soil-borne microorganisms, it is recommended that this practice be combined with appropriate environmental exposures (for example, solar simulating weathering devices, the hydrolytic effects of extended aqueous contact, or extraneous nutrients) or fabrication into articles (for example, adhesive bonding of seams) which may promote microbiological susceptibility during the service life of the material.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information purposes only.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

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ASTM
ASTM G151-19(Practice)
Standard Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources

SIGNIFICANCE AND USE
4.1 Significance:  
4.1.1 When conducting exposures in devices that use laboratory light sources, it is important to consider how well the accelerated test conditions will reproduce property changes and failure modes associated with end-use environments for the materials being tested. In addition, it is essential to consider the effects of variability in both the accelerated test and outdoor exposures when setting up exposure experiments and when interpreting the results from accelerated exposure tests.  
4.1.2 No laboratory exposure test can be specified as a total simulation of actual use conditions in outdoor environments. Results obtained from these laboratory accelerated exposures can be considered as representative of actual use exposures only when the degree of rank correlation has been established for the specific materials being tested and when the type of degradation is the same. The relative durability of materials in actual use conditions can be very different in different locations because of differences in UV radiation, time of wetness, relative humidity, temperature, pollutants, and other factors. Therefore, even if results from a specific exposure test conducted according to this practice are found to be useful for comparing the relative durability of materials exposed in a particular exterior environment, it cannot be assumed that they will be useful for determining relative durability of the same materials for a different environment.  
4.1.3 Even though it is very tempting, calculation of an acceleration factor relating  x h or megajoules of radiant exposure in a laboratory accelerated test to y months or years of exterior exposure is not recommended. These acceleration factors are not valid for several reasons.  
4.1.3.1 Acceleration factors are material dependent and can be significantly different for each material and for different formulations of the same material.
4.1.3.2 Variability in the rate of degradation in both actual use and la...
SCOPE
1.1 This practice covers general procedures to be used when exposing nonmetallic materials in accelerated test devices that use laboratory light sources. Detailed information regarding procedures to be used for specific devices are found in standards describing the particular device being used. For example, detailed information covering exposures in devices that use open flame carbon arc, enclosed carbon arc, xenon arc, and fluorescent UV light source are found in Practices G152, G153, G154, and G155 respectively.
Note 1: Carbon-arc, xenon arc, and fluorescent UV exposures were also described in Practices G23, G26, and G53 which referred to very specific equipment designs. Practices G152, G153, and G154, and G155 are performance based standards that replace Practices G23, G26, and G53.  
1.2 This practice also describes general performance requirements for devices used for exposing nonmetallic materials to laboratory light sources. This information is intended primarily for producers of laboratory accelerated exposure devices.  
1.3 This practice provides information on the use and interpretation of data from accelerated exposure tests. Specific information about methods for determining the property of a nonmetallic material before and after exposure are found in standards describing the method used to measure each property. Information regarding the reporting of results from exposure testing of plastic materials is described in Practice D5870.
Note 2: Guide G141 provides information for addressing variability in exposure testing of nonmetallic materials. Guide G169 provides information for application of statistics to exposure test results.
Note 3: This standard is technically equivalent to ISO 4892, Part 1.  
1.4 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, an...

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    English language
    sale 15% off