Silicone Spandrel Glass Coatings:Mitigating Glass Breakage Risk fromThermal and Other Stresses

Challenging Glass Conference Proceedings

Chris Barry¹  Lawrence Carbary²  Timothy Krytenberg³  Kris Vockler³  Chris Fronsoe³  John Swanson³  Stephane Hoffman⁴  George Torok⁴  Samir Blanchet⁵  Scott Norville⁵ 

[1] Chris Barry Glass Consultant;Dow Corning Corporation;ICD High Performance Coatings;Morrison Hershfield;Texas Tech University;

关键词: Glass Strength;    Silicone Coatings;    Insulating Glass Units;    Glass Weakness;    Ceramic Enamel Frit;    Architectural Glass;   

DOI  :  10.7480/cgc.6.2132

来源: DOAJ

【 摘 要 】

Curtain wall design commonly uses insulating glass units for vision and spandrel glazing to provide better visual harmonization of building façade glass. Risks with this design approach include higher thermal stresses, especially when low-emissivity coatings are used on insulating glass units in spandrel areas. Ceramic enamel frit – commonly used to opacify spandrel glass – is known to induce a bending strength reduction of up to 50%. The ability of ceramic enamel frit coated glass to resist thermal stress is similarly reduced. Multiple incidences of thermal stress related fracture have occurred with heat-strengthened, ceramic enamel frit opacified spandrel glass. An increased chance of spontaneous breakage, by nickel sulfide inclusions, may occur if ceramic enamel frit opacified spandrel glass is fully-tempered to withstand the thermal stresses that it is exposed to. Silicone spandrel glass coatings have been examined as a solution to prevent the strength reduction in heat-treated glass when ceramic enamel frit is applied as an opacifier. Four-point bending tests were used to investigate the flexural strength of coated heat-strengthened and fully-tempered glass.  Ball drop testing was used to investigate the impact resistance of coated fully-tempered glass. Test data shows silicone coatings have no adverse effect on the flexural strength or impact resistance of the substrate and, in some instances, improve it. Therefore, silicone opacifiers do not reduce the resistance to thermal stress of heat-treated glass. These coatings also provide fallout protection in accordance with ASTM C1048 (ASTM, 2012). This suggests using a silicone opacifier on heat-treated spandrel glass could greatly reduce the risk of fracture resulting from thermally induced tensile stress, flexural stress, and impact related glass breakage in addition to reducing risk of injury from fallout if breakage occurs.

【 授权许可】

Unknown