Shattered Glass

[JRF]

What would cause the inside portion of an approx. 4' x 8' sheet of glass on a sunroom to shatter.
A friend was at a house last night and watching t.v. around midnight when the inside portion of the glass just shattered. Outside portion looked fine, could not find any cracks or damaged. Does anybody have any ideas what might have caused this. Thanks in advance, JRF

[Stoneheartfarm]

Um, It wasn't one of those old memorex commericals with the lady busting wine glasses? [img]/forums/images/icons/laugh.gif[/img]

Steve

[Argee]

They call it a stress fracture. Probably when they put the panels together. The shatter comes from it being tempered glass.

Had a stress fracture on one of the house windows. Wife accused me of throwing a rock with the mower. Upon closer inspection it was the inside pane. Talked to the window manufacturer, they told me what it was and it's a common occurence.

It's not your house collapsing on itself. [img]/forums/images/icons/grin.gif[/img]

[Stoneheartfarm]

Argee,

Don't those usually show up fairly quickly after installation?

Steve

[Argee]

<font color="blue"> Don't those usually show up fairly quickly after installation? </font color>
Not really, my window was about a year old when it cracked.

[Stoneheartfarm]

I know that temperature change can set them off, you install when the weather is warm, and then when it gets cold, one pane cracks.

Steve

[8NTX]

We had a similar problem on a large, double insulated eyebrow (half-round) window in our bedroom. I installed a sunscreening film to the inside pane to cut down on glare, etc. The inside pane shattered after two months. The window technician who replaced it said the sunscreen caused the heat to reflect into the area between the two panes, causing the inside pane to shatter. He said it was common.

[Argee]

When you think about it, it is two pieces of glass separated by a 5/8" - 7/8" aluminum or stainless bar around the perimeter, then sealed air tight. When the sun hits the glass, the air inside has to heat and expand causing positive air pressure thus putting some stress on the individual panes, and going the other way on a really cold night to create a negative air pressure between the glass causing them to draw towards one another. I'm sure there are certain specifications on glasses ability to flex under these conditions. Just kind of interesting when you think about it. [img]/forums/images/icons/tongue.gif[/img] [img]/forums/images/icons/tongue.gif[/img]