Tempered Glass Window Breakage Diagnosis 4

[Structural_WIZ]

I am a structural engineer and I was recently asked to perform a preliminary structural condition assessment of a residential home. The owner was primarily concerned after a tempered glass window fractured. I did not find any evidence that the glass fractured due to a structural issue. However, I am not a glass expert and would like a second opinion as to the possible or likely causes of the glass breakage. Please include references to justify your opinions. My initial observation lead me to believe that the glass fracture was due to an inclusion or edge damage.

 

[dik]

Tempered glass sometimes breaks... could be from a stress point in the mounting. There appears to be a source on the LHS of the glazing unit... could be from a flaw in the glazing, or tempering. Maybe the glazing supplier can offer an explanation.

I remember as a kid, inserting a glazer's point into the frame and I guess it 'nicked' the regular glazing. Over a period of a month or so, a crack developed and slowly made its way across the window... my dad was less impressed that I used a crayon to date the progression of the crack. Tempered glass goes in a few milliseconds.

Dik

 

[klaus.]

since the source of the breakage is at the left boarder I would assume some stress concentration from whatever

another source is Nickle ...this can cause spontaneous breakage of fully tempered glass
Was the glass heat soak tested ?
Where is glass coming from ?
I cannot read the stamp on the top left corner

 

[IRstuff]

Ah, there's the problem, the window was installed upside down ;-)

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[glass99]

My guess would be there is a nail sticking out of the woodwork. Glass to metal contact is bad. Exactly this happened to me on a very expensive panel a few years ago. Wind load stress is low at the perimeter, nickel sulfide is unlikely at the edges, and thermal stresses in tempered glass rarely cause breakage.

 

[dik]

IRS: maybe inside out?

Dik

 

[IRstuff]

That, too...

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[klaus.]

hm...makes no difference...why ?

 

[dik]

klaus: An eng-tippers attempt at humour...

Dik

 

[klaus.]

lol

 

[Structural_WIZ]

Thanks for all of the feedback! In conclusion, we decided this breakage was not due to a structural issue.

 

[dik]

When the glazing is removed, it's a matter of examining the bedding area for 'hard points'.

Dik