ASTM G151 Detection of Nonmetallic Materials in Accelerated Testing Devices Using Laboratory Light Sources

The ASTM G151 standard, “Standard Practice for Exposure of Nonmetallic Materials in Accelerated Testing Apparatus Using Laboratory Light Sources,” developed by the American Society for Testing and Materials (ASTM), describes general procedures to be used when exposing nonmetallic materials in accelerated testing apparatus using laboratory light sources. Detailed information regarding procedures to be used for specific apparatus is found in the standards that define the particular apparatus used. For example, detailed information covering exposures in apparatus using carbon arc, xenon arc, and fluorescent UV light sources is found in ASTM G152, ASTM G153, and ASTM G154 standards, respectively.

Carbon arc, xenon arc, and fluorescent UV exposures are also addressed in ASTM G23, ASTM G26, and ASTM G53, which define very specific equipment designs. These ASTM standards are performance-based.

This application also describes general performance requirements for devices used to expose nonmetallic materials to laboratory light sources. This information is primarily intended for manufacturers of laboratory accelerated exposure devices.

This application provides information on the use and interpretation of data obtained from accelerated exposure tests. Specific information on methods for determining the properties of a nonmetallic material before and after exposure is found in standards that describe the method used to measure each property. Information on reporting results from exposure tests on plastic materials is included in ASTM D5870.

ASTM G141 provides information for addressing variability in exposure tests of nonmetallic materials. The ASTM Committee is developing a standard guide for applying statistics to exposure test results.

This standard is technically equivalent to “ISO 4892-1 Plastics - Methods of exposure to laboratory light sources - Part 1: General guidance and requirements”.

When performing exposures on devices using laboratory light sources, it is important to consider how well validated test conditions will reproduce the property changes and failure modes associated with end-use environments for the devices under test. Additionally, it is essential to consider the effects of variability in both accelerated and outdoor exposures when setting up exposure tests and interpreting results from accelerated exposure tests.

No laboratory exposure test can be purported to be a complete simulation of actual use conditions in outdoor environments. The results from these laboratory accelerated exposures can be considered representative of actual use exposures only when the degree of rank correlation is established for the specific materials tested and the type of degradation is the same. The relative durability of materials under actual use conditions can vary significantly at different locations due to variations in UV radiation, exposure time, relative humidity, temperature, contaminants, and other factors. Therefore, even if the results from a particular exposure test conducted according to this practice are found to be useful for comparing the relative durability of materials exposed in a specific outdoor environment, they cannot be assumed to be useful for determining the relative durability of the same materials in a different environment.

Although very hot, it is not recommended to calculate an acceleration factor for radiant exposure relative to external exposure in a laboratory accelerated test. These acceleration factors are not valid for several reasons.

• Acceleration factors vary materially and can differ significantly for each material and for different formulations of the same material.
• Variability in the rate of deterioration, both in actual use and in laboratory accelerated exposure testing, can have a significant impact on the calculated acceleration factor.
• Acceleration factors calculated based on the irradiance ratio between a laboratory light source and daylight do not take into account the effects of differences in temperature, humidity, and spectral power distribution between the laboratory light source and daylight, even if the same bandpasses are used.

In short, ASTM G151 is a fundamental standard that provides a general framework for conducting accelerated light exposure testing of non-metallic materials. It plays a critical role in evaluating how materials such as plastics, coatings, textiles, and composites degrade when exposed to light, heat, and humidity (factors that mimic outdoor or indoor environments). This application is not a standalone test method, but rather a guide for conducting controlled exposure tests using laboratory light sources.

The primary purpose of this standard is to define general procedures and requirements for exposing materials in test chambers simulating environmental aging conditions. For example:

• Ultraviolet (UV) radiation
• Visible light
• Infrared (IR) radiation
• Humidity and moisture
• Thermal effects

This standard is intended to supplement more specific test methods such as ASTM G154 and ASTM G155 by providing general guidelines applicable to different types of laboratory light exposure devices.

The ASTM G151 standard is widely used across industries to simulate the effects of environmental exposure over time, helping to:

• Predicting product durability and lifespan
• Evaluating the weather resistance of the material
• Guiding material selection for outdoor or high-light environments
• Supporting quality control and product development

This standard is applicable to a variety of non-metallic materials such as:

• Plastics and polymers
• Paints and coatings
• Roof and construction materials
• Automotive components
• Textiles and fabrics

Some of the key issues addressed in the ASTM G151 standard include:

• Light source types: This standard addresses various laboratory light sources, such as fluorescent UV lamps, xenon arc lamps, and carbon arc lamps, and outlines their appropriate use cases.
• Specimen preparation and mounting: Provides guidelines on how specimens should be prepared and mounted to ensure consistent and meaningful test results.
• Test chamber operation: Covers operational requirements for light exposure devices, including irradiance, temperature, and humidity control.
• Test conditions: Offers guidance on selection of exposure cycles, including light/dark cycles, humidity levels, and spray cycles, but actual test conditions are often defined in other more specific standards (e.g., ASTM G154 or ASTM G155).
• Monitoring and documentation: Recommends procedures for monitoring irradiance, temperature, and other environmental parameters and documenting all relevant test conditions.

Our organization, which has been supporting businesses across all sectors for years with a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with ASTM G151 Standard Practice for the Detection of Non-Metallic Materials in Accelerated Testing Devices Using Laboratory Light Sources.