This is a condo complex in
La Costa area. Notice the concave windows.
Such deformation is most visible on a narrow window of about 24 inches, and best seen curing a colorful sunset or sunrise. This is a common issue, only with larger windows the deflection is less noticeable, and rarely is the light just for
it to clearly show up in a photograph. The upper fixed sash is also concave, but it
was not photographically obviously.
Argon is an option used to
replace air in dual glazed windows. Being heavier than air, entails more energy
for to heat or cool the gas. This difference gives about a 1 to 2 degree improvement
in the surface of the inner pane of glass when compared to a similar windows without argon gas.
However, it will slowly leak out.
Holding the glass in place along its edges is a metal spacer bar covered with
an adhesive. A typical rating (the figures are for the Dual seal spacer bar and
adhesive system) is 0.09 grams of water/meter2 per 24 hours. The problem
occurs when argon travels faster through a sealant than does nitrogen and oxygen. In
areas where there is large changes in temperatures, the deflection is sufficient so that there are instances of the glass
imploding. In USGlass Magazine April 1999, wrote an article entitled Kaboom: There Goes Another Argon-Filled IG Unit. Door and Window Manufacturers Magazine also writes of the problem in their
The window industry is aware
of this problem and has ignored; except for in Europe where legislation requires testing and a better
Milgard has addressed
this issue by upgrading their spacer bar-adhesive found in their energy package, 3 D Max.