Thermopane or Dual Paned windows consist of two panes of glass, separated by a spacer bar and sealed together. Some windows were manufactured with argon gas injected into the cavity between the glass panels to increase energy efficiency. Argon was used because of its superior insulation properties on the ambient air. In some situations, the Argon gas dissipates out of the window cavity, causing a partial negative pressure or a vacuum under partial negative pressure.
Other causes of collapsed glass
There are other possible causes of a collapsed glass pane. When manufacturing large thermopane units, a glass panel is laid on the other panel, separated by the spacer bar, and then sealed together. The top panel of the larger thermopane units will naturally bend down to the center because of its weight, as it is sealed in the thermopane. The result is less pressure or gas inside the window cavity, which can lead to a collapsed glass condition after its installation and cooling. Ideally, after the large unit has been manufactured, it would be placed upright and briefly ventilated with a breather tube and re-closed to allow the cavity to level. The large thermopane that is not equalized will have a lower pressure in the window cavity after it is turned on.
Some smaller thermopane glass units are manufactured with a single (1/16 ") glass. This glass can, due to its weakness, bend inwardly under conditions
The lower pressure inside a glass cavity is an important problem in cold climates because the gas (air) In a collapsed window The cavity has a partial vacuum (low pressure) that contracts and causes both glass panels to flex inwardly.
Factors contributing to Glass collapsed
- If the argon placed inside the thermopane unit is dissipated through the seal.
- If the spacer bar (the visible, in most cases, the silver, the bar that runs around the perimeter of the thermopane unit) is a narrow type such as 39 , It was built and leaves very little room for the glass to flex before the glass touches.
- If the glass in the unit is a single resistance (1/16 ") that is weaker and easier to flex.
- If the temperature decreases, the air left inside the window cavity contracts further, pulling the two glass panels inward.
- If the thermopane consists of large glass panels where the glass top panel flexes down during construction and is sealed in this position, leaving less air in the window cavity.
How to tell if you have collapsed glass
The revealing sign of the collapsed glass is a false spot of arc In the center of the window (this is where the glass panels are touching) and, in some cases, an oval or round condensation point in the center of the window inside the window. House. The owner may think that because the oval condensation spot disappears during warmer temperatures, the problem may resolve, but this is not the case. The condition will probably recur and heat loss through the glass will resume.
Problems associated with collapsed glass
A Windows R value is mainly determined by the amount of space in the window Inside the window cavity. When the space between the glass is reduced, the insulating quality (R value) of the thermopane unit is reduced. The collapsed glass causes the two glass panels to bend, reducing the space inside the window cavity, reducing the insulating qualities of the window. This extreme flexing of the glass panels can also lead to a premature seal failure, which will then require a thermopane replacement. In some cases, the glass may be arrowed so that one or both panels will break.
Repairing the collapsed glass
The collapsed glass can be repaired. Using specialized tools, a technician can enter the glass, which relieves negative pressure and evenens the window cavity with the outside environment. A transparent seal is then placed over the hole to re-seal the window. This will restore the insulating qualities of the window less the original argon. If the collapsed glass occurs in a toughened glass pane (patio door or other large units where hardening is required), the glass can not be drilled as it is possible in a annealed unit (regular thermopane). These toughened glass units can be removed from the window frame, which allows the procedure to be carried out by penetrating the joint and the spacer, allowing the ambient air to equalize the window cavity , Then seal the unit.
Collapsed glass becomes more and more problematic when Windows ages and the original argon gas dissipates from the window cavities. As energy prices rise, it is more important than ever to restore the insulating characteristics of the windows and save the glass from the future replacement.
Source by Stephen J Bentley