A new concept of courthouse completely enveloped in high-transparency glass skin

To further increase its low level of energy consumption the iconic building’s curtain wall incorporates cutting-edge technological features such as natural ventilation, high thermal insulation and extensive use of integrated photovoltaic panels which also bring the façade to life with special reflection. The sustainable façade along with additional eco-friendly features - such as rainwater harvesting, heat recovery and automatic control - guarantees the outstanding energy performance of the building whose energy consumption has been reduced to 75 kWh per square metre per year. Tribunal de Paris has HQE (Haute Qualité Environnementale) certification and is also BBC (Bâtiment Basse Consommation) labelled.
Permasteelisa France and Permasteelisa Italy - both member of the Permasteelisa Group - worked in synergy and with a consolidated approach able to combine local expertise with global resources meeting the tight execution schedule for completing the project. Besides timing, the variety of customized façades had to face each a particular challenge.
The podium, which is open to the public, features five different types of Blast Protective Façade, the avant-garde technology developed by the Permasteelisa Group’s Innovation & Solutions Department. With a combination of unitized curtain wall systems and stick systems this explosion-proof envelope had to be resistant but, at the same time, thin and transparent, very well lighted and flooded with natural light. Blast enhancement has been integrated preserving the architectural scope and the major façade requirements for energy efficiency, comfort and safety. The façade of the entrance hall consists of 13.5 m tall slender mullion featuring extra-large in size elements glazed at the base with bright silver double-layer, insulated and acoustic glass which offers special reflections and a coating with high thermal insulation.
The skyscraper’s west and east side, from their most important surfaces, look at Montmartre and the Eiffel Tower respectively, while the narrow south and north façades, with a smaller surface, look at the center of the city and at Clichy and Mont-Valérien. A bespoke double-skin façade, incorporating photovoltaic modules - designed as sun protection - wraps the tower’s east and west sides for an overall area of 24,500 sqm (263,700 sq ft). The individual façade elements are 1,350 mm wide and between 3,250 mm and 4,467 mm high while weights range from 250 kg to 507 kg. The outer panes are made of laminated low-iron glass with a silver coating, the inner panes - operable for natural ventilation - are made of insulating glass with a special coating for solar control. The efforts of all the parties involved were mustered to meet a wide range of technological challenges such as combining the values of the thermal transmittance with the specific fire protection regulations reflecting, at the same time, the aesthetic intent of the architect. The integration of the photovoltaic, sun-shading modules had to guarantee high transparency and wind resistance and required applying for a statutory Demande d’Appréciation Technique d’Expérimentation (ATEx) pursuant to French law - a form of certification for the development of innovative processes and products.
The north and south sides are covered with 4,500 sqm (48,400 sq ft) of single-skin façade with aluminum fins for sun protection. Facing the Boulevard Périphérique busy ring road, the envelope’s challenge of the north side lied in the engineering of operable panels meeting the high sound insulations requirements of 42 dB+ctr.