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Reduce the risk of potential breakage from nickel sulphide inclusions

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					Reduce the risk of
potential breakage from
nickel sulphide inclusions                                                                                             Core Products

Description                                             Technical outline
                                                                                                                       Heat Soaking
Heat Soaking treatment is a quality control             Toughened glass may potentially break from
process carried out on Viridian toughened safety        an impurity in the glass called nickel sulphide
glass. It is designed to reject glass panels that       (NiS). This type of breakage is very rare as most
may potentially break due to impurities such            breakages are the result of impact, incorrect
as nickel sulphide or defective edges that are          glazing or structural movement. The Heat Soaking
undetectable during manufacture.                        treatment process subjects toughened glass
                                                        to elevated temperatures for a specific time
Benefits
                                                        depending on glass thickness.
Heat Soaking treatment significantly reduces
the risk of breakage of installed toughened             The Viridian process is carefully controlled so that
glass from spontaneous fracture. For building           the toughened glass maintains its strength.
owners, developers and specifiers, Heat Soaking          NiS inclusions can occur in batches and therefore
treatment offers a number of benefits.                   may be more apparent in isolated projects.
                                                        Viridian policy is to Heat Soak all glass to detect
  Reduces potential public liability
                                                        this when specified. The Heat Soaking process
  Low cost compared to glass replacement costs                                                                         Applications
                                                        reduces the risk by eliminating over 95% of the
  Heat Soaking treated glass carries a                                                                                 Heat Soaking treatment should be used
                                                        potential breakages due to NiS inclusions.
  replacement warranty                                                                                                 when toughened glass is specified in
                                                                                                                       structural applications and in locations
Other considerations and alternative products                                                                          where safety is paramount. These
The breakage characteristics need to be                                                                                applications include:

assessed in the selection of toughened glass                                                                             Viridian Structural Glazed Systems
                                                                                                                         and suspended glass assemblies
(refer to page 11 – selecting the right glass).
                                                                                                                         Balustrading
  Laminated safety glass – the PVB or resin                                                                              Toughened glass used in spandrels
  interlayer will restrict glass granules falling.
                                                                                                                         Solar control glazing to high rise
  Heat strengthened glass – this provides                                                                                buildings
  resistance to thermal breakage and can resist                                                                          Overhead and sloped glazing
  greater loads than annealed glass.
                                                                                                                         Warranty requirement
  Its breakage characteristic means that if large
                                                                                                                       Maximum size
  pieces are broken, they often remain in place
                                                        Comparative potential breakage
  similar to annealed glass. It is not a safety glass                                                                    5500 x 2800mm
  but has reduced potential breakage from
  nickel sulphide inclusions due to lower stress
  than toughened glass.                                  Annealed
                                                         float glass1                                     0.8%

                                                         Toughened
                                                         glass2                          0.59%

                                                         Heat
                                                         Soaking      0.321%
                                                         treated
                                                         toughened
                                                         glass3    0%                      0.5%                 1.0%

                                                                           Probability of NiS breakage
                                                                           Potential of breakage at max load

                                                        1 Based on 6mm float glass. 2.0 kPa windload, max area.
                                                          Per Australian Standard AS1288 or New Zealand Standard
                                                          NZS4223
                                                        2 Toughened glass has 2.5 times resistance for equal
                                                          load and thickness
                                                        3 Heat Soaking treatment 95% NiS conversion

				
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Description: Reduce the risk of potential breakage from nickel sulphide inclusions