Page 67 - Between light and shade

Light, transparency and reflection

Therefore, these thermal and acoustic issues
have a decisive influence on the architectural
composition and organisation of large complete
single glazed canopies (U=5.7 W/m² °K) in order
to help them retain their functional and environ-
mental legitimacy. Where it is necessary to create
a space that is climate-controlled in every way,
which should be avoided in principle, the use of
double glazing (U=1.1 W/m² °K) and, before long,
vacuum glazing (U=0.3 W/m² °K) will enable
thermal discomfort to be reduced, to a certain
extent, during the winter, at the expense of signi-
ficant energy costs, but still requires systems to
“cut out” cold draughts along vertical glass walls.

This is why, for the atria of the new headquar-
ters of KBC Verzekeringen 63 in Leuven [01/433,
Fig. 61], glass tanks at the foot of the vertical
glazing were included to re-heat the air from
draughts before it flows into the space, and for
the EUROPA building [01/494, Fig. 62], a finned
heating tube is arranged along the entire inside
of the double facade at a height of 5 m 64.

These are rare exceptions and complete glass
canopies are always designed, more logically,
with single glazing or a single skin.

63 Marc Dubois, Tussen binnenstad en spoor. Leuven 2003, Gent,
Ludion. 2005.

64 An inner facade with a steel frame and an outer facade with a
“patchwork” of oak frames.
67