Tempered glass spontaneous breakage

Recently while inside our house my wife heard a loud "bang" in another room and upon investigating she found that one of our tempered sliding glass doors leading to our back yard had broken. The glass had completely "diced" at this point, but was still in place. The odd thing is that there was a hole (approx. 1/4" to 1/2") in the glass about one foot from the floor, and about three inches from the frame. The glass from this hole had shot 12 feet into our family room. I understand that tempered glass can spontaneously break, but under spontaneous breakage can a small piece get shot out this distance?

Guest User
Mon, 15/09/2003 - 19:06

Are you completely sure that it was spontaneous breakage? Is there any possibility of an object hitting the glass?

Norfolk & Wheypal
Wed, 17/09/2003 - 13:46

Reply to [B]Norfolk & Wheypal[/B]:

> Reply to Froi:
>
> >Breakage such as this is almost always caused by Nickel Sulphide inclusions in the glass, which are typically 80 to 350 microns in size and therefore invisible to the naked eye.
They are caused by metallic nickel contamination during the melting process. Contamination in raw materials, cullet, lack of metal detection on inputs to the furnace, poor housekeeping and lack of measures within the float line to stop this problem are the major causes. Small pieces of stainless steel are the most common contaminants.
The best suppliers of architectural glass would put the finished tempered pieces through a heat soak process before releasing them to the end user. This would cause the contaminated pieces to shatter in the heat soak process and prevent such occurrences in the glazed structure.
The excuse given that tempered glass pieces can break spontaneously in situe for apparent reason is rubbish. The nickel sulphide inclusion can burst the glass after one day or many years after installation depending on the temperature regime of its surroundings.

Guest User
Tue, 23/09/2003 - 00:38

Reply to [B]Norfolk & Wheypal[/B]:

> Reply to Norfolk & Wheypal:
>
> > Reply to Froi:
> >
> > >Breakage such as this is almost always caused by Nickel Sulphide inclusions in the glass, which are typically 80 to 350 microns in size and therefore invisible to the naked eye.
> They are caused by metallic nickel contamination during the melting process. Contamination in raw materials, cullet, lack of metal detection on inputs to the furnace, poor housekeeping and lack of measures within the float line to stop this problem are the major causes. Small pieces of stainless steel are the most common contaminants.
> The best suppliers of architectural glass would put the finished tempered pieces through a heat soak process before releasing them to the end user. This would cause the contaminated pieces to shatter in the heat soak process and prevent such occurrences in the glazed structure.
> The excuse given that tempered glass pieces can break spontaneously in situe for apparent reason is rubbish. The nickel sulphide inclusion can burst the glass after one day or many years after installation depending on the temperature regime of its surroundings.
>

Guest User
Tue, 23/09/2003 - 00:49

Reply to [B]Michalek[/B]:

> Are you completely sure that it was spontaneous breakage? Is there any possibility of an object hitting the glass?

No, I'm not sure it was spontaneous breakage. The possibility that it was an object hitting the glass is what I'm trying to determine. If during breakage a small hole was found in the glass, and the pieces from that hole were shot twelve feet into our house (which was what we found), then the question is, is this a characteristic of spontaneous breakage? If it is, then I'll assume it was spontaneous breakage. Otherwise, does anyone know if these indications are more indicative of a object striking the glass?

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