ENGLISH
Enclosures used to protect and contain electrical and/or electronic equipment in harsh environments must be waterproof and robust. To achieve this, they are designed to be airtight. When subjected to temperature variations, this airtightness causes pressure changes and risks of condensation from the water vapor present in the air inside. This is precisely how condensation occurs.
To counter this, pressure stabilization and ventilation accessories available today are waterproof vent plugs, also called pressure compensator plugs. However, this type of solution does not always effectively control ambient humidity.In this context, we conducted a comparative test between our product Air Sponge and a pressure compensator plug to evaluate their performance in preventing water vapor condensation inside enclosures—a key issue to limit the effects of humidity on electronic components.
We carried out a test with three airtight IP66 boxes (IP rating for waterproofness):
These boxes were placed inside a foam insulating casing allowing thermal exchanges only through the glass surface, optimizing the visualization of fog formation. This phenomenon is a good indicator of the dew point, which can be found in dew point diagrams or relative humidity/temperature tables.
Before the test, an equal amount of water was introduced into each empty box. For this, water dishes were placed in the three empty boxes, with the pressure compensator plug sealed with adhesive putty (Patafix) to ensure the same initial conditions (see relative humidity calculation).
The three boxes inside the insulating casing were first placed in a chamber at 30°C for 30 minutes to evaporate the introduced water vapor, then transferred to a 0°C chamber for 30 minutes to allow condensation of water vapor on the glass surface and observe the resulting fog.
Once fog had formed in all three boxes, the water dishes were removed, the Air Sponge product was placed in box B, and the adhesive putty was removed from box C. The three boxes were placed again in the 30°C chamber for 30 minutes to evaporate the fog. This process simulates conditions where moisture absorption or dehumidification of a closed space is desired.
Finally, to study the performance of Air Sponge compared to the pressure compensator plug, the following test was conducted:
The three boxes inside the insulating casing, each containing humid air generated under the same conditions (Figure 1), were placed in a chamber with a temperature ramp from 30°C to 0°C over 1 hour 20 minutes. The experiment was recorded with a Nikon D5100 camera. The resulting video is below:[Time lapse video 29.04.25 _ accelerated]
The photos (start of test on the left and end on the right) in Figure 4 are extracted from the video.They show fog forming in box A (empty, reference) and in box C (with pressure compensator plug). Box B with the Air Sponge product shows no fog. This demonstrates that Air Sponge effectively absorbs moisture, preventing condensation formation.
The temperature change created a cold spot (glass surface). The dew point temperature was reached, causing condensation by relative humidity in boxes A and C. In box B, the water vapor was adsorbed by Air Sponge, reducing ambient humidity and preventing condensation.
