Heat Soaked Glass
Our heat soaked glass greatly reduces the possibility of unforced breakage and is perfect for applications where additional strength is required.
Glass is formed by combining sand, soda ash, limestone, dolomite, salt cake and various other ingredients into a furnace heated to a temperature around 1500°C. During this process extremely small quantities of nickel sulphide (not visible to the naked eye) can be left undissolved in the glass.
Due to the rapid cooling nature of glass toughening, the nickel sulphide in the glass does not have time to cooldown and is left in its high temperature state. Overtime the nickel will return to its low temperature state whilst increasing in volume. It is this volume increase that causes great stresses in the glass that can cause breakage.
Heat soaking is a process in which tempered glass is subjected to a temperature of 290°C for several hours in a heat-soaking oven. This will cause the panel to break if any nickel sulphide inclusions are found.
It is estimated that up to 95% of nickel sulphide-contaminated panes of glass are usually destroyed by this process, reducing the chance of on-site spontaneous breakage.
For architects and designers this provides added reassurance when specifying projects.