Resistance to Humidity

BS 3900-F2
BS EN ISO 6270-1: BS 3900-F9
ASTM D2247

Scope and Field of Application

These tests give an indication of how well a painted surface will resist specified humidity/condensation conditions in the absence of corrosive pollutants. The methods all involve exposure to high humidity combined with a limited choice of temperatures. If you require a test with a wider range of temperature/humidity conditions, please refer to our Controlled Temperature/Humidity Exposure page. Coatings intended to resist prolonged contact with water can be tested for Resistance to Immersion.

Like all laboratory tests they have their advantages and limitations and these are summarised on our Testing Paints for Anti-Corrosive Properties page.

There are no pass/fail criteria defined in the standards. This is a matter of agreement between the parties concerned.

The actual standards are copyright-protected documents and we are not able to provide you with copies. If required however, you can easily obtain copies from either the American Society for Testing and Materials or the British Standards Institution.

Summary of Methods

All the methods described here involve mounting test panels above a heated body of water. The height of the panels above the water is such that condensate forms on the test surface.

We offer three test methods:-

Test	Summary
BS 3900-F2	The water temperature is cycled continuously from 42°C up to 48°C then down to 42°C every hour.
BS EN ISO 6270-1 which is identical to BS 3900-F9	The water temperature is maintained at 40°C.
ASTM D2247	The water temperature is maintained at 38°C.

BS 3900-F2 is the most severe of the three methods and the one that is most commonly used for paint testing. This test is normally carried out for 500 hours and, in our opinion, a coating that shows no change in appearance after this time is judged to have good humidity resistance.

Sample Requirements

The requirement is the same for all three tests. We need 3 coated panels (150 x 100 mm). The substrate should be one that is appropriate to the type of paint being tested.

If you wish, we can prepare the test panels. The quantity of liquid paint we needs depends on the method of application. We will be pleased to advise you regarding our requirements.

Accreditation

PRA is accredited to ISO 17025 by the United Kingdom Accreditation Service (UKAS) to carry out all the tests listed on this page with the exception of ASTM D2247.

Please contact Peter Collins for further details.

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