Marking the first Rwanda-based development to achieve the highest certification in green building standards, the proposed 19-storey Nobelia Office Tower, in Kigali, has been awarded a 6-Star Green Star building rating by the Green Building Council of Rwanda.

This followed the completion of the final design of the planned 11 469 m2  building by project designer, multidisciplinary engineering firm WSP Parsons Brinckerhoff’s Green by Design unit in October.

The project owner was currently lobbying for funding to proceed with construction.

“We are extremely proud of this 6-Star rating achievement. At the onset of the project, the owner’s brief was to produce a design that would set the bar for green buildings in the country and we have certainly [done this],” Green by Design sustainability consultant Eloshan Naicker said in a statement.

Green Building Council of Rwanda’s Eudes Kayumba added that the building would set a precedent for future sustainable development.

“We are so impressed with the 6-Star Green Star rating of this project that we are aiming to use the design of the Nobelia Office Tower as the benchmark for all future green buildings in Rwanda and the wider Central East African region,” he commented.

As the Green Building Council of Rwanda was in its infancy at the start of the project’s design phase, a local context report had to be developed so as to establish the groundwork for the Green Star and set the appropriate standards for the climate and environment in Rwanda, as this was to be the standard to which all building projects will be rated.

This process required a significant amount of research and assessment, all undertaken by WSP Green by Design, and submitted for assessment by the Green Building Council governing body, the company noted.

Naicker added that this process provided the Green by Design team with “invaluable” insights into the local environment, which was influential to key innovations within this project.

Among the innovative and sustainable features of the building, including those implemented during the construction phase, the project designers were able to offset the carbon emissions that would have been related to the import of cement from South Africa by substituting cement with volcanic ash, which was a natural substance and widely available within Rwanda.

In addition, the façade of the building contained no glass and was rather made of a polycarbonate material mesh structure that allowed plants to grow beneath it.

“The objective is to ensure vegetation could grow all over the mesh, thus creating natural shading. In addition, the entire façade is manufactured for full disassembly – for reuse or recycling,” Naicker explained.

The Green by Design team also incorporated a sophisticated heating, ventilation and air-conditioning system to dehumidify the fresh air, which would be distributed through hollow-core floor slabs, where the air was fed at floor level, displacing the air in the room and extracting it higher up at ceiling level.

An on-site waste management system would, meanwhile, be used to create compost on site – adding ecological value by improving soil, plant growth and biodiversity.

An on-site water treatment system would result in a 90% total reduction of water discharge by treating black and grey water for reuse on site, while a 430-panel photovoltaic installation generating 198 804 kWh a year, which would reduce the peak energy demand of the building by 53.4%.

All usable areas would feature light-emitting-diode fittings, with intuitive daylight sensors, which could detect how much natural light was available and compensate for the difference, as well as occupancy sensors.

Further recommendations were made that no formaldehyde products, or ozone depleting products, be used in the construction of this building, improving the quality of the indoor environment.

“Overall, during the design assessment the building achieved a high score for its energy performance potential.  This score can be attributed to the reduced carbon footprint and carbon dioxide emissions that the design was able to achieve.”

“To achieve a 6-Star rating you need to be prepared to push previously conceived boundaries. And, through the collective and dedicated efforts of the project team, not only were we able to achieve the best possible outcome on this project, but we have certainly set the benchmark high for future green building projects in Rwanda,” concluded Naicker.