Insulating glass units: the effects of seal stresses and deformations on durability and service life

Adrian Panait, Michel Cossavella, Gérard Delsahut, Jean-Louis Galéa, Karine Morcant
Centre Scientifique et Technique du Bâtiment

Nowadays, new products with high thermal performances are widely used in Insulating Glass Units (IGU) in order to improve the thermal insulation of buildings and thus contribute to energy savings and environmental protection. Consequently, the primary and secondary seal of an IGU are undergoing more and more severe thermo-mechanical stresses as temperatures in the inter-pane cavity are higher. The seal integrity plays a key role in ensuring the IGU durability. Indeed, the humidity penetration into the inter-pane cavity of an IGU is a critical phenomenon that triggers the decrease of optical and thermal performance and finally leads to the end of the service life of the unit. That is, both service life and performance of an IGU depend on the diffusion of moisture and gasses through the primary seal and this phenomenon is directly related to the mechanical behaviour of the secondary seal.

As a contribution to the durability assessment of IGU, this work investigates the mechanical behaviour of secondary seal under different climatic actions. To achieve the objective, a numerical approach is developed in this work. The typical IGU defined in the EN 1279 for durability tests has been modelled using 3D finite element with the help of MSC MARC ® software in order to find out stress and deformation levels undergone by the secondary seal of an IGU passing the endurance cyclic tests imposed by this standard. Using a relevant material law for elastomers (Mooney-Rivlin), several numerical models have been realized in order to find out the influence of the seal geometry on the peak stresses undergone by the secondary seal.

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The Authors

	Mr. Adrian Panait Eng. CSTB Dr. Adrian Panait is a research engineer at the « Lightweight Constructions and Coverings » Division at the Centre Scientifique et Technique du Batiment-France. The PhD subject was : "Numerical and ex... Read more
	Mr. Michel Cossavella Enigneer CSTB Read more
	Karine Morcant Centre Scientifique et Technique du Batiment Ms. Karine Morcant is the head of the Lightweight Constructions Division at Centre Scientifique et Technique du Batiment, France. She has 12 years experience in facade and glazing field. She is respon... Read more