High-quality sheet of windowpane is transparent and colourless, with no “rainbow” or mat spots.
Durability of the glass depends on several parameters: method of workmanship and processing of surfaces and edges, homogeneity, fritting and tempering degree and size of the sheet. Microcracks on the surface and in the stratum reduce the durability of the glass in about 100 times. Even small splits on the edges become stress concentrators.
Usually windowpane has 2,5-4 mm in thickness, but for small sized windows. Windowpane of bigger size needs to be thicker, because it won’t withstand wind’s pressure, so they usually produced with 6 or even 10 mm thickness. And, besides, the higher windowpane is located, the thicker and lesser in size it must be.
