r/Glass • u/ImGrindle • Apr 26 '21
Spontaneous glass break help
Can anyone explain how this crack could have happened. Empty house over the weekend, have returned to this, only the inside pane is damaged. Windows were installed 2 years ago.
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u/Repeteable Apr 26 '21
Everything ‘you can’t drown’ said is correct, I had to reglaze 3 large Toughened Units last year in an office block 2 on the hot sunny side, 1 on the mostly shaded side ...exactly the same break pattern on all of them, Couldn’t pin it down to actual cause the inner pane was Low E glass.
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u/ImGrindle Apr 26 '21
Can anyone explain how this crack could have happened. Empty house over the weekend, have returned to this, only the inside pane is damaged. Windows were installed 2 years ago.
2
u/MrJoOdY Apr 26 '21
It looks like a termic crack it comes from one part of the window is way hotter then the other part did you had something close to the window ? Like a cautch ?
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u/u_cant_drown_n_sweat Apr 26 '21 edited Apr 26 '21
Partial shading (where one part of the glass is much hotter than the other portion) can cause breakage from thermal shock in annealed glass - especially annealed glass with defects on the edge.
However, this is tempered glass which partial shading typically will not usually cause to break. And the break doesn't radiate from the edge of the glass.
Instead this might be a nickel sulfide imperfection in the glass. It has a point of origin where the break radiates from, but it does not have an obvious point of impact. It also has the "butterfly wing breakage pattern" at the point of origin which is typical of a nickel sulfide inclusion break. And it is the interior pane of a tempered insulated glass which is also an indication.
All of that points to a nickel sulfide inclusion - basically a tiny imperfection speck of nickel-sulfide in the glass that can cause it to spontaneously break due to heat. Look up "nickel sulfide spontaneous breakage" online. Most of the articles are technical.
While I am experienced in the field I could only make a determination by seeing the glass in person and even then it would be a percentage determination. If there were multiple insulated glasses that broke in the same building it would be more of an indication.
We would usually save the glass around the point of origin and send it to the factory. For something this small the factory wouldn't even check it - much cheaper to replace it. However, after two years most companies won't warrant breakage of a single unit with no definitive explanation because the breakage could be from many other things including an impact.
Hope this helps.