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BB Centrum E BB Centrum E BB Centrum E BB Centrum E
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BB Centrum E
Prague
accomplishment 2006–2007
investor BBC Building E
general contractor Metrostav, divize 1
architect Studio A
type of construction complete external envelope, unitised facade, stick system facade, external cladding, shading systems, access systems
type of building administrative
project volume of the facade 2–3,9 mil. EUR

Seven-storey administrative “E” building is one of objects of so called BB Center and encloses a planned protection shield against negative effects of transport for residential buildings that are planned. Position of the building in the immediate vicinity of a large scale thoroughfare also requires a solution enabling to eliminate traffic noise reflection from its envelope to the houses on the opposite side of the road.
Sipral took a part in this project with a complex supply of facade frame constructions of windows and doors, main entrance doors and complex supply of external glazed wall along the whole perimeter of the building. Also facade cladding with full and perforated aluminum sheets, composite boards and other materials, cladding of spandrels and heads and other relating interior structures including glazed facade of atrium were supplied by our company. Sipral also delivered all shading of the building and Rostek system for the building maintenance.
During development, design and realization of the supply Sipral had to cope with plenty of small constructions as well as atypical complex constructions.
Project specifics lay in the solution of noise reflection that became its principal architectonic motive, reacting to physical principles of noise reflection. The building geometry enables the envelope areas to reflect noise either to a grassy slope between highway and a ramp where it is naturally absorbed, or upwards under high angle and it gets diffused at height. So the facade system treats mainly those parts of the envelope that cannot be attenuated – glazed ribbons of windows and the rest of full areas, that are not able to absorb noise. The prevailing main full area of the facade is designed with perforation as sound absorbing.
Perforated facade is done as spatial made of reinforced concrete with window openings with bearing columns in between them copying their geometry. Panels in facade openings are designed as fixed areas of facade grid construction. For this particular aim there were special trapezoidal profiles made corresponding with the designed slopes of the facade.  Glazing and connection to the rough construction is made to ensure acoustic comfort in the interior – in individual offices the supposed maximum level of acoustic pressure Laeq is 45 dB. Choice of a particular glass material was made with regards to the facade loading with solar radiation, there are used glass units preventing increase of heat load, glazed areas are equipped with exterior louvers. These can be controlled individually for each office module or centrally.
Full parts of the envelope are designed as warmed-up facade with a set-off cladding made of perforated sheet boards, metallic powder coated. Sheet perforations were again chosen in cooperation with an acoustic professional. The sheets are anchored to the bearing grid with bolts. The grid also drains water off the envelope area. With respect to the perforation the mineral acoustic and thermal insulation are protected with waterproofing foil on the whole area. Jambs with window spandrels and niches for exterior louvers are made with exact surrounds made of Larson composite aluminum panels. Parapets are made in similar way and faces of the set-off wall on both ends of the building. To clean and maintain the facade there is a system of eyes on the cladding to anchor service staff.
Acoustic facade forms a hypothenuse of the building triangular concept, two remaining facades facing inwards the area are designed as all-glazed envelopes with irregular horizontal rasterization. The envelope is made in the element facade system additional, areas in the parterre and oriel facade above the entrance are made as a standard stick system facade where full areas are clad with varnished aluminum sheet and Larson composite panels.