ISO 16474 Paints and Varnishes - Methods of Exposure to Laboratory Light Sources

The “ISO 16474 Paints and varnishes - Methods of exposure to laboratory light sources” standard, published by the International Organization for Standardization (ISO), consists of the following sub-sections published under the same title:

The standard “ISO 16474-1 Part 1: General guidance” provides information and general guidance on the selection and operation of exposure methods, which are detailed in subsequent sections. This standard also describes general performance requirements for devices used to expose paints and varnishes to laboratory light sources. Information on such performance requirements is provided for manufacturers of artificially accelerated weathering or artificially accelerated irradiation devices.

This standard also provides information on the interpretation of data obtained from artificially accelerated weathering or artificially accelerated irradiation exposures.

In principle, the samples to be tested are exposed to laboratory light sources under controlled environmental conditions. The described methods include the requirements that must be met for the measurement of radiation and radiation exposure in the sample plane, the temperature of the specified white and black sensors, the room air temperature, and the relative humidity.

When conducting exposure tests in devices using laboratory light sources, it is important to consider how well the accelerated test conditions simulate the actual use environment for the paint or varnish being tested. Furthermore, when setting up exposure tests and interpreting results from artificially accelerated weathering or artificially accelerated irradiation exposures, it is essential to consider the effects of variability in both accelerated testing and actual exposures.

The standard “ISO 16474-2 Part 2: Xenon arc lamps” describes methods for exposing samples to xenon arc light in the presence of moisture to reproduce the wear effects that occur when materials are exposed to daylight or daylight filtered through window glass in their actual end-use environments.

Samples are exposed to filtered xenon arc light under controlled conditions (temperature, humidity, or wetting). Various xenon arc lamps and filter combinations can be used to meet all requirements for testing different materials.

Sample preparation and evaluation of results are addressed in other international standards for specific materials. Xenon arc exposures for plastics are described in the ISO 4892-2 standard.

In principle, a xenon arc lamp equipped with suitable filters and properly maintained is used to simulate the spectral power distribution of daylight in the ultraviolet (UV) and visible regions of the spectrum.

Samples are exposed to various levels of radiation (radiation exposure), heat, relative humidity, and water under controlled environmental conditions. Exposure conditions can be modified by selecting the following:

Light filters.
Radiation level.
Temperature during light exposure.
When using test conditions requiring humidity control, the relative humidity of the room air during exposure to light and darkness.
Type of wetting.
Water temperature and soaking cycle.
Timing of the light/dark cycle.

Wetting is generally achieved by spraying test samples with demineralized/ionized water, immersing them in water, or by allowing water vapor to condense on the surface of the samples.

The procedure should involve measurements of radiation and radiation exposure in the plane of the samples.

To provide a standard for comparison, it is recommended that a similar material with known performance (control) be simultaneously exposed to the test samples. Unless a suitable statistical relationship has been established between the equipment for the specific material being tested, comparisons of results obtained from samples exposed on different equipment should not be made.

The standard “ISO 16474-3 Part 3: Fluorescent UV lamps” describes methods of exposing coatings to fluorescent UV lamps, heat, and water in devices designed to reproduce the wear effects that occur when coatings are exposed to daylight or sunlight passing through window glass in their actual end-use environments.

Coatings are exposed to different types of fluorescent UV lamps under controlled environmental conditions (temperature, humidity, or water). Different types of fluorescent UV lamps can be used to meet all requirements for testing different materials.

Sample preparation and evaluation of results are addressed in other ISO standards for specific materials. Fluorescent UV lamp exposures for plastics are described in ISO 4892-3.

In principle, when properly maintained, fluorescent UV lamps can be used to simulate the spectral radiation of daylight in the ultraviolet (UV) region of the spectrum.

Samples are exposed to varying levels of UV radiation, heat, and humidity under controlled environmental conditions. Exposure conditions can be modified by selecting the following:

Fluorescent lamp type (spectral power distribution).
Radiation level.
Temperature during UV exposure.
When using test conditions requiring humidity control, the relative humidity of the room air during light and dark exposures. Commercial fluorescent UV lamp devices generally do not provide relative humidity control.
Wetting type.
Soaking temperature and cycle.
Timing of the UV/dark cycle.

Wetting is usually achieved by the condensation of water vapor onto the exposed surface of the sample or by spraying the test samples with demineralized/ionized water.

The procedures may involve measuring the radiation intensity and radiation exposure in the sample plane.

To provide a standard for comparison, it is recommended that a similar material with known performance (control sample) be exposed simultaneously with the test samples.

Comparing results obtained from samples exposed to different devices or different types of lamps should not be done unless an appropriate statistical relationship has been established between the different types of equipment for the material being tested.

The standard “ISO 16474-4 Part 4: Open flame carbon arc lamps” describes methods for exposing samples to open flame carbon arc lamps in the presence of moisture to reproduce the wear effects that occur when materials are exposed to daylight or daylight filtered through window glass in their actual end-use environments.

Samples are exposed to filtered open-flame carbon arc light under controlled conditions (temperature, humidity, or wetting). Different filter types are used to simulate direct exposure to the environment or exposure through window glass.

Sample preparation and evaluation of results are addressed in other international standards for specific materials. Open flame carbon arc exposures for plastics are described in the ISO 4892-4 standard.

In principle, samples of the materials to be tested are exposed to open-flame carbon arc light with a glass filter, heat, relative humidity, and water under controlled environmental conditions. The exposure conditions can be modified by selecting the following:

Light filters.
Temperature during exposure to light.
When using test conditions requiring humidity control, the relative humidity of the room air during light and dark exposure.
Type of wetting.
Water temperature and soaking cycle.
Timing of the light/dark cycle.

Wetting is usually achieved by spraying test samples with demineralized/ionized water or by condensing water vapor onto the surface of the samples.

The procedure may involve measurements of radiation and radiation exposure in the plane of the samples.

To provide a standard for comparison, it is recommended that a similar material with known performance (control sample) be exposed simultaneously with the test samples.

Unless a suitable statistical relationship has been established between the devices for the material being tested, comparisons should not be made of results obtained from test samples exposed to different types of devices.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "ISO 16474 Paints and varnishes - Laboratory light source exposure methods" standard.