"Jerry Built" ] wrote in message
...
Ziggur wrote:
Jerry Built wrote:
The only time I've heard of this happening it turned out that a plate
fell of a wall hanging and bounced down the stairs, hitting the pane
and breaking it. If it's a small pane, it's unlikely to be a thermal
effect - consider the temperature differential, it's tiny. Where in
the door is the glazing panel? What is the door made of?

Spontaneous disintegration of normal toughened glass is a well known and
accepted fact within the industry. Pilkington makes a special type of
toughened glass which "reduces the risk" (their words not mine) for
situations where the normal risk is unacceptable.

The OP's description did not suggest toughened glass was in use (it
"cracked quite badly (multiple cracks, almost on the point of being
smashed"). For panes below a certain size toughened/laminated is not
a requirement, as I should think you're aware.

If I had to guess (I'm guessing because I'm not at home right now)...I'd say
that the pane is 60cm by 30cm. The inner pane had no laminate on it, and was
textured...I don't know what constitutes toughened glass, but there were
shards of glass on the carpet where the postman normally posts letters

I've had another look at the outer pane, and there is strictly no damage, no
brick dust, no pellet marks, and I didn't hear any fireworks after I was
awoken....I'm gonna have to go with the 'Spontaneous disintegration' theory
on this one...