Some detailed properties of insulating glass
The physical properties of the glass and the structure of the insulating glass determine certain specific properties of the insulating glass, which are not defects and are not subject to complaint:
Interference symptoms:
In the case of float glass insulating glass, interference may occur in the form of spectral colors. Optical interference is a characteristic symptom of two or more light waves overlapping at one point. They can be observed in the form of weaker or stronger colored zones (rainbow effect), which change their position when pressure is applied to the glass. This physical effect is enhanced by the parallelism of the glass surface. Interference symptoms occur randomly and cannot be influenced.
Concavity or convexity of glass
A sealed glazing unit contains a specific volume of gas in the space between the panes. The output parameters of the gas are determined largely by the barometric air pressure, the absolute height above sea level and the air temperature at the time and place of production. When installing insulating glass at different heights, changes in temperature and variations in atmospheric pressure inevitably result in concave and convex bending of the individual panes and thus optical distortions. The occurrence of this phenomenon indicates that the windows are well made - they are simply tight.
Water vapor condensation
Under certain conditions, condensation may also occur on insulating glass on external surfaces from the room side or from the outside.
On the room side, the appearance of condensate is determined by the U value, humidity, air circulation and external and internal temperature. It is worth adding that the basic issue in dealing with this type of problems is good and frequent ventilation of the rooms. This applies especially to rooms where, for obvious reasons, there is the most water vapor, i.e. kitchens, bathrooms and bedrooms. This problem occurs especially where old leaky windows have been replaced with new ones, much tighter than the previous ones.
If the set has particularly good thermal insulation, high air humidity and higher air temperature than the glass, condensate may form on the glass surface outside the room. This effect occurs especially on winter mornings and concerns glass with a very good U-value. Generally, it can be said that this phenomenon indicates the high quality of insulating glass .
Color deviations
The glass's own color (shade) depends on the thickness of the glass , the manufacturing process and the composition of the glass raw material mixture. Color deviations may occur, especially when ordering additional windows and glass, after some time has passed. Even when ordered from the same manufacturer, color deviations may occur and are a result of changes in the material itself, as well as constantly advancing glass production technology. Especially with glass with a thermal transmittance coefficient of U = 1.1, which is currently standard, there may be differences in the color of the low-emission coating (from different shades to even different colors). Therefore, when ordering windows, it is worth taking this fact into account and if we do not decide to replace all the windows in the building, at least all the windows on a given wall should be replaced as part of the same window order. This way we will avoid different colors of glass in adjacent windows. Unfortunately, if after some time one of these windows breaks or is replaced for other reasons, we will not be able to guarantee the same color.
"Cinging" of the mullions
This phenomenon is caused by the normal vibrations of this aluminum pole when opening, closing or even gusts of wind outside. The minimum width of the spacer frame when using mullions is 12mm. Failure to maintain this parameter means that in certain weather conditions (high air pressure) the glass may come into contact with the mullion, causing damage to the low-emission coating or even cracking the glass.
Glass crack
Glass , as a subcooled fluid, is a brittle body that is subject to some internal stress. They cannot be plastically deformed unnoticeably (like steel), but they crack immediately after exceeding the elastic limit. The residual stresses of float glass are characterized by high uniformity and a negligible initial value. If stresses occurred in the glass during processing, it could not be cut and machined. Glass breakage is therefore exclusively caused by external, mechanical or thermal influences.
Wettability of insulating glass due to moisture
The wettability of the glass surface on the outside of the insulating glass may vary depending on, for example, impressions of rollers, fingers, labels, vacuum suction cups... When the glass surfaces are wet due to the formation of tarnish, rain or water, different wettability may be visible in the form of distinct stains, theoretically with greater transparency.
Anisotropy in tempered glass
Anisotropies are created in glass that has undergone a thermal tempering process. Due to the different stress zones, double refraction of light rays is created. Polarized daylight waves cause these phenomena to be seen as spectral colors in the form of rings and clouds.