Introduction

Heat Soaked glass is toughened safety glass which is subjected to a further heat test to reduce the risk of spontaneous breakage which can occur at a later date, perhaps up to two years or more after the glass has been installed. Spontaneous breakage can occur for a host of reasons; edge damage, poor glazing, impact damage or foreign particles such as nickel sulphide.

Although this is rare, in some circumstances it may be sensible to reduce the risk of spontaneous breakage by using Heat Soaked Glass.

Heat Soaking is often used in applications like; roof or high glazing, balustrades, screens in public places such as shopping malls and schools, where there is a legal requirement to satisfy the safety aspect of local and/ or national building codes and where frameless bolted glazing is involved.

Fully tempered glass may break without warning due to the expansion of nickel sulfide inclusions present within float glass. To avoid the risk of spontaneous breakage in fully tempered glass, a common practice is to avoid the use of tempered glass whenever possible.

Although the incidence of tempered glass breakage due to these inclusions is rare, greater publicity of their occurrence has resulted in an increased awareness of this phenomenon. In fact, limiting the use of tempered glass in commercial building applications has become the recommendation of a number of glass suppliers, including Uniglass.

In some situations however, tempered glass is required to meet safety glazing requirements or for added strength. In these cases, Uniglass can perform a heat soak test to provide the added assurance that significant spontaneous breakage will not occur. For more information, refer to our technical document Heat Soak Testing.