Page 38 - Glass-Technology International no. 4/2017

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The renovation of the UNO build- SEDAK
ing “United Nations Conference
on Trade and Development” in LARGE GLASS FOR UNO
Geneva shows how today’s pro-
duction technology makes monumental protection possible BUILDING IN GENEVA
also for buildings with glass façades. The 13m-high insulat-
ing glass units, which in 1971 had been fabricated manually Also the colour had to fulfil specific requirements: For the
and during an effortful process, had now to be replaced. UNO building, it was only allowed to use standard float glass
sedak delivered tempered double IGUs produced fully auto- (green glass) which cannot be procured as fast as low-iron
matically. The dimensions are still impressive. glass. “We were able to offset the longer delivery time of
It was a spectacular exchange: In 2016, parts of the glass the raw material with the quick production at sedak,” says
façade of the UNO building “United Nations Conference on Scheurer. The insulating glass units had been manufactured
Trade and Development” in Geneva (second headquarters within just a few weeks.
of the United Nations) were replaced. The about 45-year- sedak produced a total of nine double IGUs out of 12mm
old glazing had become foggy; some of the glass units had thick basic glass (dimensions: three units in 2.29m x 7.84m,
cracked; the bonding of the support structure of the glass fa- six units in 2.29m x 13.10m). The single glass panes had
çade had aged. Due to monumental protection, the new glass been produced as heat-strengthened safety glass to guarantee
units had to be true to the original, i.e. of the same oversize a higher break resistance.
dimensions. Additionally, the special supporting structure of The metal blocks of the old façade were replaced by glass
the building was supposed to be maintained. blocks that were attached to the IGUs with a special adhe-
The dimensions of the glass units were exceptional for sive. “Before replacing the metal blocks, the contracted metal
the year 1971. They were manufactured manually out of engineering company had run special material test series in
non-tempered glass and were said to be perhaps the largest Lausanne. In the end, glass turned out to be the best material
units that had been produced by then. Today, sedak provides for the bonding. That shows once again how versatile glass
tempered insulating glass up to 15m manufactured fully is,” explains Scheurer.
automatically. sedak packed the insulating glass units in specially fabricated
“To be able to install the glass in 1971, the building enve- boxes which were adjusted to the dimensions of the formats
lope was realized as a hanging façade. That principle had and corresponded to the safety requirements with a support-
to be kept in mind,“ says Ralf Scheurer, who was the sedak ing structure.
responsible for the project. It took the metal constructors A low-bed trailer transported the glass units to Geneva where
(Metallover SA, Carouge, Switzerland) about four months to they were installed with a truck crane and a glass vacuum
check whether the project is possible at all. lifter. In September 2016, the installation was completed.

36 Glass-Technology International 4/2017