Nickel Sulphide Inclusion is a naturally occurring phenomenon in glass. Impurities can still be contained in the glass pane after its manufacture and toughening processes. Small particles of Nickel Sulphide can still be present in the glass at point of installation.
Visually, you will not able to see these tiny particles of metal but they can still be present in the glass until they are aggravated.
Nickel Sulphide Inclusions have two main states: Stable at high temperatures and stable at lower temperatures. When the glass is heat soaked, the heat converts the Nickel Sulphide Inclusion to the high temperature state. When the glass is cooled quickly, the Nickel Sulphide Inclusion isn’t able to change to the lower temperature state. The transformation to the lower temperature state can occur over time, therefore a glass breakage caused by a Nickel Sulphide Inclusion can happen if the inclusion is large enough and if it is located within the central portion of the heat soaked glass.
A very simple way to determine whether a glass breakage has been caused by Nickel Sulphide Inclusion is to watch out for the ‘Butterfly Effect’ pattern on the glass. The implosion will centre around a singular point on the glass and will fan out in a butterfly wing formation.
What are the odds of a piece of glass having Nickel Sulphide Inclusion?