Structural Sealant Glazing

The state of the art for glued glass applications in Germany is currently struc­tural sealant glazing (SSG) [22]. In such systems, the glazing is connected to metal load bearing frames or adapter sections via linear adhesive joints. Stain­less steel or anodized or coated aluminum can be used as the material for the supporting members. Such glued glazing arrangements are classified as sup­ported or unsupported systems, depending on the way in which the load of the glass itself is carried. Supported SSG systems include setting blocks that ensure that the self-weight of the glazing is transferred directly to the supporting frame and from there to the load bearing structure. All other loads, which are gener­ally of only brief duration, e. g., wind, are carried by the adhesive joints. In con­trast to this, in an unsupported SSG system, all permanent loads are carried by the adhesive.

SSG systems can be further classified according to any retaining systems that may be necessary, which in the event of failure of the adhesive joints pre­vent the glass from slipping out of its frame. Metal brackets or clamps, undercut anchors, and wire retainers are examples of suitable retaining systems. This classification results in four types, the usage of which may be restricted depend­ing on national stipulations (Fig. 3). Building legislation restrictions in Ger­many mean that apart from a few exceptions, the only systems possible are those in which no permanent loads are carried via the adhesive joints (type I and II) and those above a mounting height of 8 m that include mechanical retainers as a backup, should the adhesive fail (type I).

European guideline ETAG 002 [23-25] describes the principles of the con­struction, the materials to be used, and the experimental testing required if

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FIG. 3—Classification of structural sealant glazing systems according to ETAG 002.

approval for a glued facade design is to be applied for. According to the guide­line, the choice of adhesives is restricted to silicones—adhesives for which test results and long-term experience are available and accepted by the building authorities. Silicone adhesives exhibit excellent adhesion on glass surfaces and are highly resistant to environmental influences. However, their low stiffness, low strength, and black coloring are regarded as disadvantages. Adhesive joints for SSG systems are normally produced under controlled ambient conditions during the further treatment of the glass or at the facade fabricator’s plant. In certain cases silicones are also used for in situ adhesive joints produced on site. However, the method then no longer complies with the stipulations of ETAG 002, which means that the work must be approved by the building author­ity responsible. Very careful workmanship and comprehensive quality control measures are essential for in situ adhesive joints produced on the building site.

Copyright by ASTM Int’l (all rights reserved); Tue May 6 12:07:08 EDT 2014

Downloaded/printed by

Rochester Institute Of Technology pursuant to License Agreement. No further reproductions authorized.