Double glazing exploded

The other day at 6pm when my house was nice and warm and it was very cold outside my double glazing exploded. It’s sounded like a brick had been thrown through it. When I looked there was a big hole on the inside pain. The onside pain was ok. It is now fixed but nobody can tell me why this was happened. The double glazing company who replaced it told me they had no idea why. There must be someone on this forum who knows

It can happen but it's quite rare. I went to a job once and exactly the same thing had happened. I did notice from the pane that was still intact that the glass unit was a tight fit in the frame. I can only presume that with expansion/contraction of window frames, that as they contract again they put pressure on the glass unit and shatter them, on toughened units the edges are the weak point.

Thanks for that. It make sense so we were just unlucky. Lets hope it do's not happen again

Happend to us too. A large hardwood window with cottage style panes. One evening there was an almighty bang but we could not discover the cause til next morning. one of the inner panes had a crack from top to bottom. Glass splinters everywhere. It did not seem that cold outside or hot inside so just accepted it was expansion problem.

Are your glass units Toughened? Sounds to me like it might be a nickel-sulphate inclusion.

IIRC Pilkington's used to estimate that 1m2 in every 10,000m2 of toughened glass has a nickel-sulphate inclusion which will eventually cause the toughened glass to "explode" for no apparent reason.

It's basically a flashy way of describing a microscopic (nickel) foreign body within the glass itself. Toughened glass in it's normal state is under a certain amount of stress and foreign bodies within the glass exaggerate this stress causing the glass to "pop" into a thousand little pieces. There is no way of knowing when the glass is going to break.

Glass with a nickel-suplhate inclusion may explode during the toughening process but some pieces do get through. The only way to test a piece of toughened glass for this prior to glazing is to put the sheet of glass through a process known as "heat-soaking". If nickel-sulphate is present then the heat-soaking will break the glass. If not, then you know the glass is okay and clear of foreign bodies. Not really a practical solution though unless the glass is to be used for overhead glazing like glass canopies and glazed roofs etc.

For the record, most (if not all) insurance companies refuse to accept this explaination for unexplainable exploding glass units because they think they know better so dont try to explain it to your insurer if you claim through them. Better to tell them you don't know what has caused it.
Believe me, I've come across about 3-4 cases over the last 10 years or so.

If the glass isn't toughened and cracks are appearing from the outside edges of the unit then it's a thermal fracture usually caused when the glass is too tight in the rebate or when dark window films are present.

Thats my understanding on the subject. Does this confuse you enough?

Same thing happened to us tonight, Sitting in the lounge when suddenly a loud bang, then noticed one of the panes of the french doors had shattered.
On closer inspection its the inside pane that has shattered, off to get a replacement in the morning.