Humid atmosphere adversely affects the condition of objects / structures / coatings. Verification of humidity resistance allows to determine the properties of coatings, paint systems or other protections applied to various substrates, both wooden, gypsum, plasterboard and metal. Continuous condensation of moisture occurs on the surfaces of the exposed objects, which affects its degradation. The damage caused during the tests may show blistering, discoloration, softening – reduced hardness, faster abrasion, wrinkling, brittleness, reduced adhesion, and also adversely affect the condition of the substrate.
The test is conducted at a specific temperature and humidity. It is essential to maintain the required parameters for the results to be representative. Objects are exposed at the right angle and subject to constant condensation. Assessment criteria are set individually, depending on the implemented project. During the test, periodic inspections are made to assess the changes taking place.
Both the protective system used, and the base material are subject to degradation. Thanks to the exhibition, it is possible to detect both the low quality of the products used, as well as production errors.
We conduct two types of moisture condensation tests:
- condensation, one-sided exposure (in accordance with PN EN ISO 6270-1)
Test specimens are exposed to continuous condensation of moisture on one side at elevated temperature, and the rear surface is cooled with air in room conditions. Lower ambient temperature causes an increase in water condensation on the exposed surface. This method often degrades faster than bilateral condensation.
- ondensation, two-sided exposure (in accordance with PN EN ISO 6270-2)
The test plates are placed in a chamber with constant (CH) or variable (ATH, AH) condensation conditions during exposure
The CH method consists in exposing the object in an insulated chamber with constant exposure conditions, i.e., 40 ° C and 100% humidity. The test reflects continuous condensation.
The AH and ATH methods consist in changing the exposure conditions during the tests. They are conducted in 24-hour cycles.
The test of resistance to humidity condensation can also be conducted thanks to the cataplasm tests. In this case, the assessment consists in determining the resistance to a moist compress. The test samples are wrapped in an absorbent material and placed in a foil. Depending on the type of test performed, they are flooded with acidic, alkaline or neutral buffer reflecting different exposure environments. A set of samples prepared in this way is exposed in the heating chamber for 7 or 14 days at the temperature of 70 ° C.
After the test, the samples are assessed in accordance with the PN-EN ISO 4628 standard. The test environment is so aggressive that very often, faster than in the case of other methods, the test shows corrosion changes.