The Role of Steel in the Sustainability of Insulated Metal Panels
By AIA Partner Kingspan
When it comes to reducing carbon emissions in the manufacture of insulated metal panels (IMPs), steel plays a critical role. That’s because steel is a key component of IMPs, which are made by sandwiching high performance insulation between steel panels. The properties of steel, as well as how steel is manufactured, are two key factors that can help reduce embodied carbon in IMPs.
The inherent properties of steel make it the most recycled material on the planet, according to the World Steel Association. Steel is 100% recyclable, which makes it an important material choice for creating sustainable building products. Steel can also be recycled endlessly into new steel products such as steel beams or refrigerators or insulated metal wall and roof panels.
In the U.S. alone, there are typically 60 to 80 million tons of steel scrap recycled per year into new steel products. In fact, the U.S. recycles enough steel scrap to build 25 Eiffel Towers every day of the year, and annually recycles enough steel scrap to build more than 650 Golden Gate Bridges. In fact, United States steel producers are 75-320% more carbon efficient when comparing CO2 emissions from global producers, according to the Climate Leadership Council.
Durable and recyclable, steel aligns with the push toward a more circular economy. Once produced, steel becomes a permanent resource that can be continuously recycled into new steel. When it comes to insulated metal panels (IMPs), which are a composite of steel facings and a foam core, according to Kingspan waste panels from the manufacturing process are deconstructed in order to recycle the steel facings. The small amount of adhesive and foam that remain on the steel do not present a problem for the scrap companies who collect the steel sheets once separated from the foam core. At Kingspan 100% of the steel from its five North American plants is collected and melted down for re-use in other forms.
Once installed, IMPs may still contribute to circularity – with care, they can be uninstalled from the original buildings and re-used in other projects.
Greener production methods are also being embraced by the steel industry with this sector’s commitment to further reduce steel’s carbon footprint and make the transition to CO2-neutral steel production. Progress is being made on this front by companies using lower carbon technologies such as electric arc furnaces (EAFs) to manufacture steel. Accounting for approximately 2/3 of steel production in the U.S., the EAF process uses an electrical current to melt scrap steel to produce molten steel. EAF steelmaking technology emits a fraction of the CO2 of blast furnaces. Through Traditional blast furnace technology that makes steel from iron ore using coal, produces roughly two metric tons of carbon for each ton of steel produced. More recently, there are more EAFs powered by renewable energy sources. Steel production from scrap, rather than raw materials, further reduces emissions, per the International Energy Agency.
Industry innovations on the horizon will continue to reduce the CO2 intensity of steel produced. Green hydrogen technology is being developed to achieve an almost completely CO2-free steel product. Using this process, green hydrogen gas is produced by electrolysis using electricity generated from hydro and wind power. One ton of H2 Green Steel will emit less than 0.1 ton of CO2, cutting about 95% of the CO2 emissions associated with the traditional blast furnace production process.
The recyclability of steel, coupled with green production methods, suggests that building materials, such as IMPs, are often a sustainable choice. According to the American Iron and Steel Institute, as a building material, steel also meets sustainability requirements in standards such as the International Green Construction Code and in green building rating systems like U.S. Green Building Council’s (USGBC) Leadership in Energy and Environmental Design (LEED). Industry-wide environmental product declarations (EPDs) are now moving toward supplier specific LCA data, “allowing designers to select steel and fully understand its environmental impacts and benefits.”
To reduce embodied carbon in insulated metal panels, IMP manufacturers need to work closely with steel manufacturer supply chain partners that have a strong commitment to sustainability including the use sustainable production methods and a focus on innovation for developing CO2-neutral technologies and processes.
To further explore how insulated metal panels reduce embodied carbon, download Kingspan’s white paper on Reducing the Embodied Carbon of Walls in Industrial Buildings.