Carefully tested – all fine in the sunshine!
Usability tests on blinds sandwiched between vacuum-glazed panes are necessary to guarantee that such systems last long enough once installed. Frequent cases of damage show that even systems that have already been tested are often faulty. Such systems usually undergo certain tests: for example, samples with original dimensions go through endurance tests of 20,000 window-blind cycles (up/down) under laboratory conditions, and samples measuring approx. 1 to 1.5 m² are exposed to over 2000 hours of constant sunlight. In addition, there are tests for impermeability, the fogging effect and so on.
The systems currently penetrating the market – with triple glazing plus blinds between the outer two layers – are exposed to greater thermal stresses than conventional double-glazed systems, because they lose less heat to the interior.
These systems were subjected to tests that put greater demands on the triple glazing with between-glass blinds. During some 30,000 test cycles, the following were tested:
- Behavior in both summer and winter temperatures
- Rapid temperature changes
- Full and partial exposure to sunlight of the glazing featuring between-glass blinds
- Full and partial exposure to rain
- Behavior when exposed to alternating pressure/vacuum loads
All tests were performed under different conditions on the same test specimen, which has the same dimensions as the system used in the current construction project.
Test results indicate that most of the between-glass blinds tend to fail when temperatures dip below 0 °C, whereas they could generally withstand higher temperatures and direct sunlight without any problems.