Reach climate targets through smart use of construction materials

It is no longer enough to build energy-efficiently. We need to work hard to minimize emissions from the construction materials we use, including those that are generated when buildings are demolished. The construction sector has made great strides when it comes to building more efficiently in order to lower the energy consumption of buildings themselves. However, we still need to cut down on emissions associated with construction materials.  

“There is significant waste associated with construction materials. Buildings are often demolished rather than re-purposed and essentially recyclable materials are used as filler or burned. If we were talking about energy optimization, this would result in a poor rating. The thing is, though, that if you waste material, there’s no way of measuring the wastage. This is happening invisibly,” says Per Klevnäs, partner at Material Economics, a management consultancy firm dealing with sustainability and resource strategy that has researched value-retaining materials systems. 

Emissions from Swedish use of aluminium, steel, plastic and cement alone are estimated to account for 13 million tonnes of CO2 per year by 2040, if current production processes and systems for recycling remain unchanged.  

“We need to consider what happens to the materials once products and buildings, have served their purpose. We can achieve this by making changes to production and to the way that we use and handle various materials. Doing so would also result in a significant reduction in Sweden’s CO2 emissions,” explains Klevnäs.  

Traceability and materials bank 

 What is special about the construction sector is that there is a long lead time between materials being used and those same materials becoming available for recycling. During these lead times, the materials develop further, making it difficult to know exactly what their composition is and what additives they contain.  

A more holistic approach would make it possible to turn buildings into predictable sources of recyclable materials — so-called materials banks. 

“In order for this to be possible, there needs to be a high degree of traceability. This would allow a demolition contractor to know in advance what materials streams a building will generate. What we are missing today is a comprehensive system for this, but we’re moving closer to one,” says Klevnäs. 

Sweden currently applies a system whereby all materials involved in a building must be documented. If this system is updated continuously, it can serve as a record of materials, which is useful when it is time to demolish the building. The system is pioneering because it contains detailed information about chemical compositions. What remains to be done is to digitalizse the records and establish guidelines to ensure that updates are made continuously during ownership and management. 

aluminium scraps
What happens to the materials? “We need to consider what happens to the materials once products and buildings, have served their purpose,” says Per Klevnäs.

As beneficial for the economy as it is for the environment 

 Securing the circular materials system has as many economic benefits as it has environmental benefits. Sweden consumes steel, plastic, aluminium, paper and cement worth SEK 55 billion each year. Only 24 per cent of the material’s original value is retained following one usage cycle. This represents a loss in value of SEK 42 billion each year, according to Material Economics’ research report “Retaining Value in the Swedish Materials System.

“Consider how much freedom you have when it comes to choosing or applying the circular economy principles to your project. Reuse local materials, cut down on waste in the construction process and build in a way that makes it possible to recycle the materials,” says Klevnäs.  

aluminium scraps melting
THINK RECYCLING: Securing the circular materials system has as many economic benefits as it has environmental benefits.

Low-carbon aluminium

In order to preserve greater values in the future, we not only need to recycle more. It must also be possible to repeatedly reuse that which is recycled. 

“We can achieve this by making changes to production and to the way that we use and handle various materials,” explains Klevnäs. 

The good news is that this is entirely possible.

In response to consumer demand for climate-smart products, Hydro has developed two new aluminium products. One consists of at least 75% recycled materials and the other is produced using hydropower, resulting in CO2 emissions of a maximum of four kilos per kilo of aluminium. The aluminium manufacturer is now experiencing growing demand for CIRCAL 75R and REDUXA 4.0 for use in BREEAM-certified construction projects.  

“We want the use of our metal to generate fewer carbon emissions. These new low-carbon certificates mean that we are able to help our clients fulfill their ambitious climate strategies. Together, we can work toward a future where emissions from the industry as a whole are low,” says Eivind Kallevik, Hydro’s executive vice president responsible for the Primary Metal business.

At Hydro, we believe passionately in a sustainable future. In this article series, we will be talking to industry leaders and professionals and exploring the topic of “a sustainable construction sector”. Here we discuss how we can create a future for building and construction through technical innovation.

Future trends in B&C

Prefab building in the “Smashing Twenties” 

In many ways, he believes the 2020s to become a reprise of the 1920s.
So, here are the trends having an impact on B&C industry:

  • In that era garden cities emerged, where people could live in green environments, with gardens, large terraces, parks etc.  The same is expected in the post-corona era. 
  • Re-urbanisation will be major, large cities will shrink, many citizens migrate to rural regions where they can live, work from home part-time or full-time and where they anticipate living from lockdown to lockdown in a century of pandemics and social unrest.
  • Small electric planes will enhance re-urbanisation.
  • Factories return from China: reshoring.
  • And multi-generational homes will become trendy. Also, communities of friends (= family, families of friends) can live together in order to beat loneliness.
(c) Adjiedj Bakas

Trendwatcher Adjiedj Bakas (1963 ) will speech about the post-corona world,he sold 1 million books worldwide, here a video about his vision. He is author of the book ‘The New Renaissance’.

Project | Mercator One

‘I hope the industry discovers the untapped potential of recycled aluminium’

Germany’s first building with a facade made of recycled end-of-life aluminium is about to see the light of day. Mercator One is a shining example of sustainability, created by Hamburg-based Hadi Teherani Architects.

“With Mercator One we’ll show that it’s possible to make an office building with a facade made entirely of recycled aluminium. It is the first of its kind in Germany and I hope this project can help lead the way and inspire other architects to use this sustainable material,” says Bernd Muley of Hadi Teherani Architects.

The material they chose for the facade of Mercator One is Hydro CIRCAL 75R, which consists of a minimum of 75% recycled end-of-life aluminium. This could be aluminium from demolished building projects, food and drink containers or even cars. Material that has been a product used by a consumer before and put back into the cycle.

Muley is a Senior Architect at Hadi Teherani Architects, whose work is characterized by a holistic urban approach and top class design. Their projects carry sustainability evaluation standards such as “Green Building” and green building certifications such as DGNB, LEED and BREAAM.

A consideration for longevity is the foundation upon which their buildings are designed. They are especially known for landmark buildings such as the office buildings The Dancing Towers, the Dockland Building and the Berliner Bogen in Hamburg, the Zayed University and the hotel and residential building The Oyster in Abu Dhabi, the Twin Towers in Dubai and the luxury residential tower Lodha Altamount in India.

Cradle to Cradle

“I have always cared a lot about the environmental aspect,” says Muley, who has worked at Hadi Teherani Architects for 20 years.

“I have the Cradle to Cradle (C2C) principle in mind when I work, which means that when I choose materials for a building I think of – in addition to the architectural aspects – where the material comes from, how efficiently it is produced and what happens to the material after the lifetime of that specific building. Recycled aluminium is great in this regard. It is one of the best solutions at the moment when building a facade, as it is highly recyclable and can be used again and again,” says Muley.

The Cradle to Cradle principle can be defined as a design and production process that is sustainable, where nothing goes to waste. Towards the end of the product’s life span, it can be recycled or returned to the earth completely safe, nontoxic and biodegradable. C2C methodology builds on the concept that “waste = food,” meaning that the materials can be used again in a new product cycle.

“At Hadi Teherani Architects, we always try to fit those ideas into our buildings, and as more people in the industry do, buildings will eventually improve their sustainable performance. Creating aluminium requires a lot of energy, but its lifespan can be long, if recycled several times,” Muley says.  

“I also try to find materials that can be used in their purest form, so that we know what they consist of. Materials such as wood, stone, concrete, steel, glass and aluminium are great, and when choosing a pure mix of them for a complete concept it gives a more radical appearance. The exclusion of composite materials also helps when separating materials at the end of the life cycle of a building,” says Muley.

“Recycled aluminium has the same strength as new, is easy to maintain and highly sustainable, and requires only 5% of the energy which is used for the production of new aluminium.”

On site during building process Mercator One.jpg
ON SITE: During the building process at Mercator One in Duisburg, Germany, with Hadi Teherani.

Discovering new solutions

The decision to use recycled aluminium came about after Muley had a chance meeting with Peter Hemmert and Thomas Staiger from Hydro during the Bau Fair in Munich, the world’s leading trade fair for architecture and building industries, in January 2019. They started talking and shared ideas about buildings and facades. Muley was in the process of developing the construction plans for Mercator One at that time, and Hemmert explained the qualities of their new material Hydro CIRCAL 75R.

“This is why it is important to meet others in the industry – we discover new solutions. This material is both sustainable and easy to maintain,” says Muley.

He based his decision on several aspects: Does the recycled material have the same quality as the newly produced one? Could they deliver the material in time? Does it have a competitive price point? Would the facade builder approve? And would he get his client onboard?

“When all these criteria were met and the client and the builders were onboard, I was ready to go for it. Now the building is nearly finished, and it looks just the same as if we had used brand new aluminium. The process and support from Hydro has been great. There is an unused potential for using recycled aluminium, especially in office buildings or high-rises.”

Building with Aluminium systems.jpg
LEADING THE WAY: Aluminum is strong, flexible and lightweight. It can be shaped in endless ways, and was chosen for this façade. “We work on big projects for important clients, and we receive a lot of interest in our projects., Therefore, it’s our responsibility to always do things better,” says Senior Architect Bernd Muley.

Great responsibility

“Our office has existed for almost 30 years, and from the beginning we have been interested in improving the way we build and always look for sustainable and green solutions. We work on big projects for important clients, and we receive a lot of interest in our projects. Therefore, it’s our responsibility to always do things better,” says Muley, who is a certified auditor through the German Sustainable Building Council (DGNB). DGNB is one of Europe’s biggest networks for sustainable building, with an aim to promote climate friendly change in the building and property market.

“Every day we should ask ourselves: What can we do better? In our case, we can improve the way we build!”

Trustworthy information

How can you find trustworthy information on a product’s environmental impact?

It is challenging to find trustworthy and accurate information on the environmental impact of a material or a product, but it is not impossible. Here are some ideas to help you find what you need, quickly.

Like you, other architects and construction engineers and industrial designers want to find solutions that reduce the environmental impact of their products or buildings. As an example, the building industry uses a tremendous amount of raw materials that also involve high energy consumption to produce. How do you come up with a more sustainable building? Finding a better way to construct the building is one thing – your thing – but how do you find the best building materials, based upon data that you can trust?

An increasing number of green building rating systems like BREEAM, LEED and DGNB are evolving to integrate measures to reduce GHG emissions during the full life cycle, to evaluate and understand the emissions of materials and the construction phase, to reduce waste and to value recyclable materials. This is also why most of these systems are now making use of Life Cycle Assessments (LCAs) to assess the footprint of buildings during their full life cycle. I see these rating systems evolving to increase verification and rigor in those aspects.

Life Cycle Assessments take into account all emissions and energy consumptions for each and every step in the life cycle of a building or a product. An LCA gives you the total environmental impact. Now you could calculate this by using average data assembled for a certain raw material or product in a certain region of the world. But you would still not be any closer in finding the best choice, because the data would be too inexact and too general to really make a difference.

There is another easier way that is better.

Independently verified and registered EPDs

An Environmental Product Declaration (EPD) is an independently verified and registered document that communicates transparent and comparable information about the life-cycle environmental impact of products. An EPD is a so-called Type III environmental declaration in accordance with ISO 14025, and it was developed out of an increasingly widespread demand from customer to supplier to have a standard of comparison between different products.

EPDs show the most significant environmental aspects of a particular type of product, without going into value which is more or less sustainable, but showing an objective and verifiable information about the environmental problems of the product/service it provides.

EPDs give you the environmental impact of the material from these perspectives:

  • GWP – Global warming potential
  • ODP – Depletion potential of the stratospheric ozone layer
  • POCP – Formation potential of tropospheric photochemical oxidants
  • AP – Acidification potential of land and water
  • EP – Eutrophication potential
  • ADPM – Abiotic depletion potential for non-fossil resources
  • ADPE – Abiotic depletion potential for fossil resources

The first one, GWP, is expressed in kg CO2 equivalents per kg of the product – or selected “functional unit.” This is the one most in focus today, but looking forward, the other values could become more important.

You can also find out what happens with the product at the end of its useful life, for example when the building is torn down and you sort all the materials. An EPD shows you how much can be sorted and recycled and subsequently and turned into new products.

Reducing the environmental footprint with the right aluminium

One way of reducing the footprint is using renewable energy for material production and another is using as much recycled end-of-life materials as possible. In both cases, aluminium offers a positive story.

Aluminium is used in buildings because its properties, such as low weight, formability and corrosion resistance, are well-suited for doors and windows and facades. And it is fully recyclable. Already today, the vast majority of aluminium in use is recovered and turned back into new products.

But producing virgin aluminium is energy-intensive, right? Big footprint? This is particularly important when it comes to buildings, as they are made to last for decades and hence it takes a long time before the material can be recycled and sent back into the loop.

Stop for a second.

There are always better options if you know where to find them. In this case, the footprint depends on how and where aluminium is produced, and there are vast differences out there. If you really want to find them.

metal shavings

Low-carbon CIRCAL and REDUXA aluminium

I will name just two of the innovative aluminium products out in the market that can help you reach your sustainability goals.

One is Hydro REDUXA, which is low-carbon primary aluminium based on renewable energy. It has a maximum of 4.0 kg CO2-equivalent per kg aluminium. This is less than one-fourth of the global average.

The other is Hydro CIRCAL, which is based on a high amount of post-consumer scrap – aluminium that has already been used in other products and scrapped, like a window frame.

Both of the aluminium products are verified by EPDs.

How do you find EPDs?

Let me finish what I started: How do you find what you need, quickly, in terms of trustworthy data?

If you do want to look for comparisons of products, using independently verified EPDs as your tool, then you can find them easily in common databases such as Ökobaudat, GABI, EPD Norge, InData Network and Environdec. The EPD is normally valid for three years, or five years for construction products.

And don’t forget that using products with EPDs will also allow building owners to help harvesting extra points in the BREEAM environmental certification systems.

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.