Back in 2010, Bouygues Construction launched a vast programme to renovate its head office, Challenger, which is situated in Guyancourt, in the western suburbs of Paris, and was built 25 years ago. The aim is to turn the complex into a showcase for the Group's sustainable construction know-how, using the latest cutting-edge 21st-century technologies. In this context, Challenger has been awarded a trophy as the building with the best score in 2012 on the BREEAM^® International Design Stage¹ rating system, one of the world's most stringent and widely recognised levels of environmental certification. The presentation was made by the BRE (Building Research Establishment) at Ecobuild, the world's premier event in the field of environmentally friendly construction.

"2012 was a record year for BREEAM registrations and certifications," commented Richard Hardy, managing director of BRE Global. "Since 1998 BREEAM has certified more than 16,000 projects, equating to over 45 million m² of floor area."

The trophies are awarded to projects that implement a fully-integrated approach to environmental aspects, from the design phase through to construction and the operation.

This prize underlines the excellent environmental performance of the Challenger renovation project. Challenger recorded an overall score that has never been equalled, 87.83%, and the best possible classification, "outstanding".

Among the solutions adopted by Bouygues Construction teams that have resulted in this level of environmental performance were the installation of 21,500 m² of photovoltaic panels (equipped with an innovative technology that enables them to operate independently of one another), 420 m² of thermal solar panels and 75 geothermal sensors at a depth of 10 metres, along with the creation of a phyto-purification installation capable of treating all the site's wastewater and stormwater. Primary energy consumption on the site will be divided by 10 and the annual water consumption will be reduced by 60% by comparison with the original data. The maintenance and operation of the site will be managed by Bouygues Energies & Services, a Bouygues Construction subsidiary, which was involved in the project at the design stage in order to optimise costs over the entire lifecycle of the buildings. A cockpit, which is to be the control centre of the complex, has also been created.

A number of innovations have been developed for this project by Bouygues Construction Research and Development teams in conjunction with industrial partners, among them a new variable water flow air-conditioning system, a system of individual LED lighting and a system enabling photovoltaic panels to operate individually.

Yves Gabriel, Chairman and Chief Executive of Bouygues Construction, said: "When the renovation is complete, Challenger will be a physical demonstration of Bouygues Construction's ambition of being a leader in sustainable construction for both new build and renovation projects."

North Triangle, the first of the Challenger buildings to be renovated, is also the world's first building to achieve triple certification: LEED^®, BREEAM^® and HQE^®.

The Challenger renovation works began in 2010, and they are now halfway through. The project is scheduled for completion in the third quarter of 2014.

¹ BREEAM^® Europe Commercial 2009 rating system