Dual Seal Termal Stress in Glass
Thermal Stress in Glass
Thermal stress is the term used to describe the interal stresses created when glass is subjected to variations in temperature across its area.It particularly relates to solar control glass.
Glass in the vision and non-vision areas of a facade expands in response to the heat of the sun. The more absorbent the glass the greater and quicker its response to solar radiation.
The edges of the glass, however, can be encased within the rebate of the frame and are therefore protected from the direct heat of the sun, they heat up more slowly and expand less.
If the safe temperature difference between the main area of the glass and the edges is exceeded, the glass may crack. This is referred to as Thermal Breakage.
Thermal Breakage is generally recognised by the fact that it starts perpendicular to the edge of the glass and results in a 'lazy/meandering' crack.
Other factors which affect thermal safety, include the presence of blinds, internal heat sources, external shading, application of external films and profiles and geographic location.
Damaged edges may cause cracking at lower than expected temperature differentials.
Any glass that has a floor slab, or any other solid material/backup immediately behind it should be automatically toughened.
A Thermal Safety Risk Analysis can be undertaken by DUAL SEAL GLASS LTD, please contact Technical Sales for forms and details.
