Z E M C H 2 0 1 2 I n t e r n a t i o n a l C o n f e r e n c e
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Figure 4: Diagram of the walls of a building in the Sperone district
The roofs, however, were inclined. These roofs had a slight slope of 12%, made of a
layer of reinforced concrete hollow brick, placed above the r.c. slab, at the top of which
there were some sheets of polystyrene. These sheets were initially made of asbestos
cement and then replaced in 2001 by a roof covering of Portuguese tiles, placed on a
bituminous
slate.
For the technical elements constituting the envelope, in order to comply with the
standards of the Administration, the Gescal provided specific performance of thermal
insulation, both for the headed r.c. walls and the roof slabs. These technical elements,
having a thickness not ensuring enough insulation, were covered with polystyrene
sheets.
The worst aspect for energy consumption of these structures, made of fair faced r.c.
walls and slabs, was the presence of thermal bridges shown by thermographic analysis.
The heat loss due to thermal bridges in this type of structure is not negligible, since the
structures were made of fair faced concrete, the increase of transmission dispersions
through thermal bridges, which are usually 10-20%, in these cases were 30-40%.
As it is shown by the study carried out by ICITE on behalf of the Ravenna Consortium to
evaluate the problems of the thermo-hygrometric comfort in the joints between reinforced
concrete walls and slabs, it was measured an increase of the thermal flow due to the
joint shown by the ratio between the transmittance with the thermal bridge (0.95
Kcal/hm²°C) and without the effect of the joint (0.75 Kcal/hm²°C), equal to 1.27 (Fig.5).
Figure 5: (Left) Details of the technological solution of the joint between reinforced concrete wall and
slab. (Middle) The distribution of isothermal lines. (Right) The temperature distribution on the inner
and outer surfaces of the walls (ICITE analysis)
