Sustainable architecture

Call it sustainable architecture, where we ask architects to design buildings that are sustainable and still beautiful. What is the thinking behind sustainable architecture?

You probably know this: The International Energy Agency says our industry is responsible for about 40 percent of global CO2 emissions through the construction, heating, cooling and demolition of existing buildings. This may be why more architects are working toward climate-friendly buildings and seeing the business opportunities in this.

In the past, the focus on the environmental impact of buildings has largely been on energy consumption alone. In climate-focused construction, we look at the total greenhouse gas emissions throughout the life of the building. This accounting also includes the emissions and carbon footprint of the building materials.

Integrating sustainability as a defining part of your project will lead to new, architectural solutions. Sustainable architecture involves cost-effective construction, with the least possible greenhouse gas emissions seen in light of the entire life cycle, and buildings that provide good health, where people thrive and where they achieve good productivity.

Architect’s place in a circular economy

In a circular economy, we utilize resources to the maximum. This means that materials and products are used again, so that waste is not created and then sent to a landfill. In this way, we minimize raw material consumption, waste, emissions and energy consumption. It also leads to environmental benefits related to pollution, biodiversity and water consumption. We are architects and builders. Our jobs are to design and construct. But instead of constructing new buildings with new materials and products, we can transform and renovate existing buildings, re-using products and increasing our use of recycled materials. And sure, we can also do this with new buildings.

Building materials can reduce greenhouse gas emissions significantly
Our basic competence as an architect is to analyze and deal with functional and spatial-aesthetic issues. With conscious thinking about energy efficiency and product life cycle when it comes to material selection, for example, you can use your knowledge creatively and solve problems that are also tied to sustainability. Using old building parts and recycled materials will allow your refurbishment or new building project to reduce its greenhouse gas emissions considerably. Waste is also reduced.

It is important for us that suppliers manufacture products that help us create good architectural quality while at the same time leave us feeling confident that these products deliver as little negative impact on the environment as possible in terms of climate effects, resource utilization and biodiversity.

Aluminum contributes to lower carbon footprint

Aluminum has a life cycle that few other materials can match. Foremost is the fact that the metal can be recycled over and over again, and it requires only a fraction of the energy that is used to produce virgin, or primary, metal.

Hydro CIRCAL is an aluminium alloy that contains minimum 75 percent recycled aluminum – metal that has been used in actual products before. It has a footprint of 2.3 kg CO2 per 1 kg of aluminum, compared to the industry average of 16.7 kg CO2 per kg aluminium. By using used and recycled scrap as a raw material, aluminium that would otherwise be at the end of its life cycle is used again, without compromising the quality of the product. The conscious use of materials and resources combined with good design pretty much sums up the foundation of sustainable architecture.

Project | Økern Portal

Oslo’s newest business hub will meet high sustainability standards, with aluminium facades.

One of the largest development projects in Norway, the Økern Portal will be covered in low-carbon aluminium that is both eye-catching and highly sustainable.

Oslo is about to get a new urban business hub at Økern, just 15 minutes outside the city center. The building will set an environmental footprint in the area, and the goal for lead architect agency DARK Arkitekter is to keep this footprint as small as possible. 

Sustainability is key in the large project Økern Portal. Recycled Hydro CIRCAL aluminium helped reach the ambitious BREEAM Excellent certification. (Photo: 3D Estate/DARK Arkitekter)

“We work in an industry that emits a large carbon footprint, both in the city and in nature. We want Økern Portal to become a positive footprint, through sustainability,” says Tor Christian Møglebust, partner and architect in Norway-based DARK Arkitekter. 

One factor that will contribute to the sustainability of the building is embedding nature itself, both around the building and atop it. The spacious rooftop garden will have large trees, plants, space dedicated for local crops, beehives and a running track. The park surrounding the building will include social areas and facilities able to host events like small festivals and concerts. The building’s spatial frame structure spanning over some 30 meters across across what is referred to as “the portal square” makes it possible to increase the amount of public space, so that the entire park flows through it.

The open and friendly shape of the building will create a strong identity within the vast surrounding urban landscape, and, in turn, the architectural details serve to humanize it. 

Tor Christian Møglebust, partner and architect in DARK Arkitekter, Oslo

75% recycled aluminium

The building itself has an area of approximately 80,000 square meters. This includes office spaces, a business hotel, communal areas and a food court. 

During the planning and building phase of the project, the development team targeted meeting the highest energy efficiency standards. Energy consumption, emissions and the supply of materials were audited to ensure sustainable construction and an extended life cycle while complying with the standards needed to achieve BREEAM Excellent classification.

Hydro’s aluminium building systems brand WICONA is the system supplier for Økern Portal, providing the facades in Hydro CIRCAL aluminium. The aluminium was used for the entire outer layer, a solution that supports the building’s sustainability goals. 

“In this building, there is a large facade to cover, and fenestration (windows and doors) plays an important part. There were a lot of discussions throughout the project about how we should design the facade to meet the requirements of the BREEAM certification. And we were very excited to learn that we could have a facade made of recycled material with Hydro CIRCAL and thus be able to incorporate sustainability even on the facades,” says Arne Reisegg Myklestad of DARK Arkitekter. 

Advanced scrap sorting

Hydro is the first aluminium producer supplying prime-quality aluminium with certified content of more than 75% recycled post-consumer scrap – scrap from discarded products. This is made possible by Hydro’s advanced scrap sorting technology. The production process is fully traceable, and the product is certified by an independent third party (DNV GL).

“Our customers in the building and construction sector are focusing on sustainability. They want material and solutions that can help them meet their sustainability targets. Hydro CIRCAL has a low carbon footprint that fits well with the most demanding sustainability requirements,” says Egil Hogna, Head of Hydro’s Extruded Solutions business.

The engineering contractor Staticus has produced and assembled Økern Portal’s eye-catching facades, which will cover 14,600 square meters in total.

“Staticus strives to reduce, reuse and recycle wherever possible. With this facade, we will reduce the total carbon footprint of the building project by using recycled aluminium. I believe we have only seen the start of sustainability in the building and construction sector,” says CEO Aušra Vankevičiūtė in the Staticus Group.

Økern Portal is owned by Oslo Pensjonsforsikring, with Stema responsible for project management. Vedal Entreprenør is serving as project lead and main contractor in a design-and-build contract. The project is scheduled for completion in 2021.

An example of the facade element at metal builder Staticus’ production site in Lithuania

About Hydro CIRCAL in buildings

The construction sector in Europe represents 40% of the continent’s total energy consumption, producing 35% of greenhouse gas emissions. Starting in January 2021, European legislation will require all new buildings to operate at zero-energy, meaning that most of the energy used by the building will have to come from renewable energy. Furthermore, the EU has the overall ambition to be climate-neutral by 2050 – i.e. an economy with net-zero greenhouse gas emissions.

The carbon footprint of primary aluminium varies considerably. The global average is 16.7 kg of CO2 equivalents per kg of aluminium. The European average is 6.7 kg of CO2e per kg aluminium. The footprint of Hydro CIRCAL is 2.3 kg of CO2e per kg aluminium.

Make a difference

Definitions of pre- and post-consumer scrap aluminium

Aluminium can be used again and again, without loss in quality. It is one of few materials that keeps its properties after recycling. But aluminium is not just aluminium. The same goes for recycled content. 

WICONA uses process scrap aluminium and post-consumer scrap material as sources in secondary metal production. Both are considered recycled content by the aluminium industry. Yet they are quite different. 

Process scrap, or pre-consumer scrap, is production waste from manufacturing processes, such as extrusion. Such scrap also comes from handling damages that occur during transport, as well as clippings, stampings and various trims in the production of the final product. It is metal that has not been applied in a consumer product – it has never been used. It is collected from the shop floor, and later melted and used in the production of new billets. 

Post-consumer scrap is metal that has been used in a product that has gone through its full lifecycle. The post-consumer stage starts when a used aluminium product is ready for disposal, recycling or reuse. An aluminium window frame in a building is considered post-consumer scrap when the building is demolished and the aluminium is obtained and re-melted, then applied in a new product. Recycling post-consumer scrap reduces the carbon footprint of the new product. Process scrap does not. This is because post-consumer scrap has already been used for a product lifetime. 

Of course, the metal is recycled in both cases, and this is positive, considering that when we recycle aluminium, we save about 95% of the energy used in the production of primary aluminium. 

Definitions according to ISO 14021

WICONA also endorses the definitions for recycled content according to ISO 14021, which specifies the requirements for self-declared environmental claims regarding products. These definitions are more technical than the industry definitions, but with no meaningful differences.

Advanced technology needed 

Another significant difference between the two types of scrap is that it is more difficult to produce high-quality metal that has a high content of post-consumer scrap, than with pre-consumer scrap. The latter is basically virgin metal, while post-consumer scrap is not.  

Example: An aluminium window frame is normally anodized and painted. It may contain thermal break. Recycling the aluminium from a window frame is a complex process with many steps, which include inspection, separation, shredding and de-coating. After shredding in small chips, the metal is x-rayed to determine its mass characteristics, then segregated.  WICONA’s parent company, Norsk Hydro, has the advanced technology that is needed to carry out these steps, which is important, because this is real recycling. The higher the recycled post-consumer content in aluminium, the lower the carbon footprint. Hydro CIRCAL, which contains a minimum of 75% post-consumer aluminium, delivers the lowest carbon footprint in WICONA’s product offering.