ASTM G156-09
Standard Practice for Selecting and Characterizing Weathering Reference Materials

Standard No.

ASTM G156-09

Release Date

2009

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM G156-10

Latest

ASTM G156-17

Scope

Weathering reference materials are used in laboratory accelerated exposure tests to verify consistency among tests run at different times and in different laboratories, using the same exposure conditions. Specifications defining consistency of exposure conditions are based on the property change of a reference material after a defined period of time. Some weathering reference materials are used to define periods of exposure. Specifications calling for use of these materials require the material to be exposed until a defined change in the weathering reference material is achieved. Specifications are usually based on results for a single lot of the weathering reference material. When a new lot of the reference material is introduced, round-robin studies are necessary to compare the new and old lots and to establish appropriate limits for expected performance of the new lot.

Note 28212;An example of the use of a clear polystyrene reference standard for this purpose is given in SAE J1885 and SAE J1960.

Note 38212;Some weathering reference materials (for example blue wools) are also used to define periods of exposure. Although not specifically covered by this standard, the procedures described for characterizing a reference material used to monitor consistency of exposures are also generally applicable to characterizing reference materials used to define periods of exposure.

It is important to test the consistency of exposure in the laboratory accelerated device with a weathering reference material that responds to the test conditions similar to the way the test materials respond. Therefore, the weathering reference material should be sensitive to the spectral region of the light source mainly responsible for producing degradation in the test materials to provide the most meaningful evaluation of exposure test consistency. The weathering reference material should also provide information on consistency of temperature and humidity conditions if the latter are important factors in degradation of the test materials.

Note 48212;Material homogeneity can also be an important factor in selection of a weathering reference material, particularly if weathering is initiated by the radiation absorbed by impurities as is the case in aliphatic type polymers exposed to radiation longer than 300 nm.

The measurement of the characteristic property of a weathering reference material can be subject to error depending on the instrument and the procedure used to measure the property. It is important to develop measurement procedures that are clear and which minimize chances for operator misinterpretation. It is also important to determine the level of variability caused by measurement of the characteristic property.

When a reference material is used to monitor or specify the consistency of an exposure test, it is important that any specification limits defined by changes in the reference material be based on a sound statistical analysis of results from a properly designed round-robin experiment. This practice provides a procedure which can be followed to set up the round-robin, analyze results, and establish reasonable limits of change in the characteristic property of the reference material that can be used in specifications.

The results obtained according to this practice are valid only for the exposure cycle used for the round-robin and cannot be applied to the same weathering reference material used in a different exposure cycle.

The change in characteristic property of a reference material may be affected by the placement of the reference material in the exposure device. This is often due to variations in light intensity and temperature within the allowed exposure area. Random placement of replicate specim.........

ASTM G156-09 Referenced Document

• ASTM E1169 Standard Guide for Conducting Ruggedness Tests
• ASTM E177 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ASTM G113 Standard Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
• ASTM G152 Standard Practice for Operating Open Flame Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials*， 2024-04-19 Update
• ASTM G153 Standard Practice for Operating Enclosed Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials
• ASTM G154 Standard Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Materials
• ASTM G155 Standard Practice for Operating Xenon Arc Lamp Apparatus for Exposure of Materials*， 2024-04-19 Update
• ASTM G178 Standard Practice for Determining the Activation Spectrum of a Material (Wavelength Sensitivity to an Exposure Source) Using the Sharp Cut-On Filter or Spectrographic Technique
• ASTM G24 Standard Practice for Conducting Exposures to Daylight Filtered Through Glass
• ASTM G7 Standard Practice for Atmospheric Environmental Exposure Testing of Nonmetallic Materials
• ASTM G90 Standard Practice for Performing Accelerated Outdoor Weathering of Nonmetallic Materials Using Concentrated Natural Sunlight

ASTM G156-09 history

• 2017 ASTM G156-17 Standard Practice for Selecting and Characterizing Weathering Reference Materials
• 2010 ASTM G156-10 Standard Test Method for Abrasiveness of Ink-Impregnated Fabric Printer Ribbons and Other Web Materials
• 2009 ASTM G156-09 Standard Practice for Selecting and Characterizing Weathering Reference Materials
• 2002 ASTM G156-02 Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test
• 2002 ASTM G156-97 Standard Practice for Selecting and Characterizing Weathering Reference Materials Used to Monitor Consistency of Conditions in an Exposure Test