We were recently in the process of installing a toughened 10mm glass panel (2000x900mm)into a frameless shower channel when it exploded. The panel was in mid-air when it happened and had not been knocked at all up to the point of explosion. however there was a long scratch on the glass which the manufacturer had pointed out on its arrival. Because the glass had taken 6 weeks to arrive our client decided reluctantly to take it-could this have affected its strength and cause the glass to explode?The glass company denied this but could not provide us with any other explanation. the customer is now very concerned about the safety of installing a shower screen of this type as they have young children. We have set smaller pieces of toughened glass into our furniture in the past without any problems.
Hello Jon,
There are a couple obvious reasons for tempered glass can explode.
The most common is Nickel Sulphide inclusions.
Check out this article & the links.
Ive seen it a few times.. even had a piece explode on me one time when I was transporting a piece..I swear I didnt bump it either.
http://www.glassonweb.com/articles/article/96/
While NiS is a possiblity it is relatively rare. I think the clue is in your note and is the scratch. Toughened glass is very vulnerable to scratches. If the temper is light ie the stressed surface isn't very thick a fine scratch will almost penetrate it. Handling causing bending makes the crack extend a little and bang! The cause is therefore to do with a) how did the glass get scratched? and b) was the toughening adequate? - in a shower screen a high degree of strengthening is needed.
I agree that the scratch is the most likely cause; however, toughened safety glass should be measured for adequate surface stress (with instruments such as the GASP polarimeter) and test results should be on file for mechanical strength and fragmentation characteristics. These tests are a mandatory part of quality control procedures for CE marking requirements under EN-12150-2 and should be made available by the fabricator upon request. For more information, please E-mail me or visit our website at www.strainoptics.com.
The glass should go through a process called heatsoaking, this brings the nickle sulphide to the surface & if it is going to explode, it will do it in the heatsoak, this process is used for thick glass & glass that is going into high rised buildings,
Lynn
Hello Jon,
This is not a new topic at all..
In fact, if you do a search & check far enough back in the forums... you see the topic pop up several times. There are a few conditions that can cause this result.
One is the Issue of Nickel Sulphide inclusions.. Ill post an excellent article , as well check out the links on the page
http://www.glassonweb.com/articles/article/96/