Spontaneous glass breakage - what is the cause and what to do?
Has a glass panel or glass door suddenly shattered or exploded to pieces by itself in your office? It is not common, but due to the increasing amount of glass being used today, there are regular reports of spontaneous glass breakages. In this article, we look at the possible causes of glass panels to suddenly break and shatter by themselves, and what you should do if this happens.
What can cause spontaneous glass breakage?
Damaged glass edges
While glass is being handled, packaged, shipped, or installed onsite, a glass edge may be nicked or chipped. The damage may not be visible, maybe even hidden inside the glazing track. While no immediate breakage occurs, over time as the glass expands and contracts, stress concentration can build up around these points, and this may cause the glass panel to explode or pop.
Frame contact with the glass
Poor installation methods can cause the glass to come into contact with fixtures and fittings in the framing system. Especially in the case of external glass, glass often expands and contracts due to temperature changes. It can also be subjected to movement due to building movement or strong winds, for example. Failing to use glazing track inserts, gaskets, setting blocks, glazing packers correctly, all of which help "cushion" the glass and avoid glass to metal contact, may later result in a glass surface or edge becoming damaged. Add stresses to the glass and the glass may suddenly pop or fail.
Internal defects and Nickel Sulphide inclusions
There are many types of inclusions in float glass that can cause imperfections - also known as stones. One of the more commonly discussed inclusions is nickel sulphide - a known issue in toughened glass (also referred to tempered glass and sometimes safety glass). While glass is thermally toughened during production, small nickel contaminants react with sulphur. Initially, these remain in a smaller form and fixed in place during cooling. However, over time the Nickel Sulphide inclusion expands, creating internal stresses which result in glass breakage.
These breaks are often identified by the figure "8" shape or "butterfly wings pattern" (a pair of polygons next to one another, see below image). These are usually at the centre or the focal point of the breakage.
Other possible causes
When there is doubt or to be sure of the cause of the toughened panel breakage, the panel can be analysed by glass specialists. If you require this, the broken glass should be retained for investigation. Other possible causes for toughened glass panels to suddenly break could be due to:
Thermal stresses and changes especially with glass exposed to the elements
The glass is an inadequate thickness for its size and purpose
Poor production and toughening processes
What to do when spontaneous glass breakage occurs?
In our experience, it is not uncommon for a glass panel in an office that suddenly pops by itself to remain in-situ. However, the glass will not be stable. It is vital that it is not disturbed and only handled by professionals. Even though toughened glass is made to break into small pieces for safety reasons, large chunks can often still stay together and be dangerous. You should ensure anyone nearby is cleared away, barriers and warnings signs should also be placed around the area to ensure anyone does not access the area.
You should then contact an experienced glazing company, like Instrument Glasses, to clear the broken glass panel. Remember, if you want the glass panel to be analysed by glass specialists, inform the glazing company to retain the broken glass. Once the glass panel has been removed, measurements should be taken to order a new glass panel. While the panel is in production, the area should remain clear.
There are production options and alternatives that can help reduce the presence of impurities like Nickel Sulphide - for example, heat soaking glass panels. You should speak to your glazing company about the options available and costs.
We at Instrument Glasses have been able to help many customers with clearing glass panel breakages, replacing damaged glass panels, glass office door repairs and much more. For more information, see our services page.