Several Reports of Shower Glass Breakage in the Northland, Why Does This Happen?

Over the last week, I've had three reports of shower glass breakage in the Twin Ports and surrounding area. Luckily in all three cases, nobody was injured, but could have been seriously hurt.  So how does this happen in the first place, what's the cause?

Experts tell me a small manufacturing defects or minute damage caused during installation eventually spread until it reaches it's  failure point. The type of glass used is usually safety glass, which is manufactured so it is under tension. A small break releases the tension suddenly, causing the whole lot to shatter into small pieces.

The cause of the small defect expanding is known as thermal cycling. Temperatures rise during the day and fall at night, then rise again the next day in a repeating cycle. A difference of a few degrees is enough for the thermal expansion and contraction to put further stress on the defect, possibly causing slow expansion over several days until eventually it reaches it's breaking point.