Curved glass, also referred to as bent glass, is glass that has been heated past its softening point and formed into a curved shape, either by annealed gravity bending, or by heat-treated (tempered or heat-strengthened) bending. In case of gravity bending, the softened glass is placed over or into a mould and cooled down slowly after the required shape is achieved.
Although it allows many shapes, gravity bending is time consuming and the coating must withstand a longer heating period. With the heat-treated bending process, the glass is cooled down very quickly immediately after the desired curvature is reached to increase its strength. The main challenges here are how to avoid optical distortions caused by the production process and the limitation to cylindrical shapes and concave shapes when coatings are involved.
Curved glass gives architects and designers freedom to create aesthetically pleasing curved glazed facades where straightness, corners and edges can be enhanced with soft curves. These curves can be in the form of simple cylindrical shapes to the more complex 3D free form shapes.
The challenge is to choose a curved glass that still provides the required thermal and solar performance in its curved shape. A crucial factor here is the coating, which has to withstand the bending process without reducing the glass’ visual appeal.
For commercial curved façades, the Guardian SunGuard® range of coated solar control glass products are some of the highest performing bendable glass products available. Guardian SunGuard® glass coatings are designed to withstand the bending process, maintaining their high performance and aesthetic appeal. Using Guardian glass coated products allows to achieve uniform and homogeneous appearance of curved and flat parts of a façade.
This is backed up by technical support and SunGuard® glass coatings’ application advice from Guardian specialists. They work collaboratively with glass processors during the initial design phase to help them define key parameters such as the minimum bending radius, process tests and to produce mock-up samples, regardless of the type of bending process used. We also provide on-site support with the goal to minimise the visual disturbances in the glass such as roller wave, distortion or discolouration of the coating.