Testing Paints for Resistance to Weathering

Accelerated Weathering

Scope and Field of Application

These tests are designed to measure the effect of sunlight, moisture and temperature on surface coatings applied to a variety of substrates. If you are more concerned with the way that surface coatings protect substrates from corrosion, please refer to our Corrosion Resistance tests.

It is important to realise that the tests listed here provide comparative rather than absolute data. They will, for example, indicate whether Paint A has better weather resistance properties than Paint B. What is often required however is a report that states, for example, "The test results prove that Paint A will provide effective protection for at least 10 years when exposed in Southern Europe."

In order to obtain this type of absolute data, the client needs to supply a Reference Paint which, in the case of the above example, is known to provide effective protection for at least 10 years when exposed in Southern Europe. The Reference Paint should also be as close as possible in composition to Paint A. The procedure then is to run the test on both paints until one fails. If, for example, the Reference Paint fails first, our report would say " The test results indicate that Paint A will provide effective protection for at least 10 years when exposed in Southern Europe."

It must be emphasised that laboratory tests can (and do) provide misleading predictions regarding the weather resistance of paints in the real world. In practice manufacturers of exterior paints rely heavily on records of how their products perform in service. This information is supplemented by data obtained from test panels exposed at various locations throughout the world. This combination of service life and test panel exposure data then serves as a means of checking the reliability of laboratory test results.

In one respect exterior paint manufacturers become the victims of their own success, since the longer the service life of the products they develop, the longer it takes for them to obtain in-service performance data. It is for this reason that they place increasing reliance on the predictive ability of laboratory tests.

 

Test Methods

We can carry out the following tests:-

Test Standard
Artificial Weathering: Carbon Arc BS 3900-F3 (obsolete)
Artificial Weathering: Fluorescent Lamp ASTM G 154, BS EN ISO 11507, BS 3900-F16
Artificial Weathering: Plasma Erosion In-house method
Artificial Weathering: Xenon Arc BS EN ISO 11341, ISO 12040
Assessment of Lightfastness Numerous
Controlled Temperature and Humidity Exposure Numerous
Natural Weathering BS 3900-F6
Resistance to Temperature Change ASTM D 1211
Resistance to Water Immersion BS 3900-G 5, ISO 2812-1

BS 3900- G 8, ISO 2812-2

 

Please contact Peter Collins for further details.

Back to top of page