North Triangle, the first of the Challenger buildings to be renovated, has obtained each of these distinctions at the very highest level: “platinum” for LEED, “outstanding” for BREEAM and “exceptional” for the Passeport HQE. These three ratings are the highest certification standards reflecting the environmental performance of buildings in respectively, US, UK and France.
Bouygues Construction has been renovating buildings at Challenger to make the 67,000 square metre complex into a showcase of the firm’s know-how. SRA Architecture is overseeing the renovation of the 1988-built Challenger estate, originally designed by Kevin Roche. North Triangle building was the first building to be renovated and handed over in February 2012.
Unique renovations which are being carried out at the entire estate are the construction of a cockpit (the control centre and showcase), the installation of 21,500 square metre of photovoltaic panels and 420 square metre of thermal solar panels, the installation of 75 geothermal sensors, and the creation of a phyto-purification installation. The aim is to make Challenger into a showcase of Bouygues Construction’s know-how, using the latest cutting-edge 21st century technologies. As a result, primary energy consumption on the site will be a tenth of what it was for the original development while annual water consumption will be reduced by 60%. The maintenance and operation of the site will be managed by Exprimm, another Bouygues Construction subsidiary, which became involved in the project at the design stage in order to optimise costs over the entire lifecycle of the buildings.
For HQE certification, it is essential to determine the environmental impact of all the materials used on the site. A life-cycle assessment of the building was carried out using the Elodie software tool, jointly developed by the Scientific and Technical Centre for Building (CSTB) and Bouygues Construction.
BREEAM certification specifically called for special care to be given to preserving biodiversity. A phyto-purification installation that enables grey water and rainwater to be purified through the action of plants was employed.
LEED certification focuses on interior air quality, entailing the use of materials with low volatile organic compound and formaldehyde content, construction processes that limit dust and air quality tests carried out on handover of the building. It calls for meticulous research into all the materials used, 20% of which must be sourced within a radius of 800 kilometres and have high recycled content. It often refers to standards rarely employed in France, particularly ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), which stipulates analysis of all the building’s energy consumption, including that relating to its users. The renovation took care of all these aspects.
The Challenger renovation works began in 2010 and they are scheduled for completion in the third quarter of 2014. Following the North Triangle, a second building, the South Triangle, was handed over in August 2012. When the renovation is complete, all the buildings on the site will have triple certification.
