Why Steel


Structural Steel: The Premier Green Construction Material

Structural steel is the premier green construction material. Its high recycled content and recycling rate exceed those of any other construction material. Over the past three decades, the steel industry has reduced greenhouse gas and overall emissions by 36% and increased the water recycling rate of steel production to 95%. Today, the American steel industry is the least carbon-intensive of all major steel-producing countries, and its footprint will continue to decrease as the U.S. power grid becomes more and more fossil-free.

As the green building movement grows, more and more building owners, architects, engineers, and contractors are selecting structural steel framing systems to meet sustainable design and construction goals. 

The LEED Green Building Rating System, developed by the U.S. Green Building Council, has been crucial to this movement. And under LEED 2009 and V4 criteria, structural steel receives maximum credit for its contribution to the overall rating for a structure, due in large part to its recycled content, recycling rate, and transparency.

Structural steel produced in the United States contains 93% recycled steel scrap, on average. At the end of a building's life, 98% of all structural steel is recycled back into new steel products, with no loss of its physical properties. As such, structural steel isn't just recycled but "multi-cycled," as it can be recycled over and over and over again. It is truly a cradle-to-cradle material.

We encourage you to explore the below resources to learn more about steel and sustainability and access information on providing required LEED documentation. You can also contact an advisor in AISC's Steel Solutions Center to discuss how steel can contribute to the sustainability of your project: 866.ASK.AISC, solutions@aisc.org.

Steel's Sustainability and Commitment to a Greener Industry

On the 50th Anniversary of Earth Day, the American Institute of Steel Construction and the National Steel Bridge Alliance celebrated structural steel's commitment to sustainability as the most environmentally friendly construction material. Check out our 2020 Earth Day video now!


Cradle-to-Cradle Life Cycle of Structural Steel


Structural Steel Mill
Overall carbon emissions have been reduced by 36% since 1990 and steel production has a water recycling rate of 95%, resulting in a net consumption of only 70 gallons per ton.

More than 1,700 steel fabricators in the United States supply fabricated structural steel for building and bridge projects; these fabricators purchase structural steel shapes and plates and fabricate the steel to meet the unique requirements of each project.

Construction and Erection
Steel is fabricated off site to strict tolerances and can be erected quickly in the field, meaning fewer workers on the job site, safer working conditions, shorter construction schedules and reduced emissions from construction equipment.

Building Operation
Long-span beams with open, column-free spaces attract potential occupants. In addition, steel framing can more easily be adapted for future changes in loading conditions, vertical expansion and changes in occupancy when compared to other framing systems.

Beams, columns and other structural steel elements removed from a building can be re-fabricated for use in new structures without having to be melted and rolled; remaining steel elements are captured as scrap and used to create new steel products!

Scrap Collection 
By weight, 81% of all steel products are recovered for recycling at the end of their life. This includes 85% of automobiles, 82% of appliances, 70% of containers, 72% of reinforcing bar and 98% of structural steel.

Scrap Processing
Steel is the most recycled material in the world, with domestic mills recycling more than 70 million tons of scrap each year. Currently, structural steel includes 93% recycled content!


Sustainable Characteristics of Structural Steel

Sustainable Structural Steel Material Attributes

  • Recycled content of 93%, the highest of any building framing material
  • Recycling rate of 98%, also the highest of any building framing material
  • High strength-to-weight ratio coupled with a low carbon footprint (1.16 tons of CO2 per ton of fabricated hot-rolled steel) results in an overall reduction of the embodied carbon of a typical structure as compared to buildings constructed with other framing materials
  • Significant potential for material reuse
  • While other products can only be recycled into a lower-quality product (down-cycled), steel can be recycled over and over again and remade into new members without any loss of quality (multi-cycled). This makes it the first and only true cradle-to-cradle building framing material
  • Superior water resource management: The structural steel making process boasts 95% water recycling rate with no external discharges, resulting in a net consumption of only 70 gallons per ton

Sustainable Manufacturing Process

  • Increased productivity by a factor of 24 since 1980 (reduced labor hours per ton from 12 to 0.5)
  • Increased material strength by 40% since 1990 (36 ksi to 50 ksi)
  • Decreased carbon footprint (per ton) by 36% since 1990
  • Decreased energy intensity (per ton) by 31% since 1990
  • Decreased greenhouse gas emissions (per ton) by 45% since 1975
  • Earned an EPA best industry performance designation

Sustainable Fabrication and Construction

  • Structural steel is fabricated regionally in off-site facilities to stringent tolerances, then erected on-site
  • Minimal waste is generated at fabrication facilities and construction sites
  • Any waste generated is fully recyclable
  • Centralized, off-site fabrication minimizes employee travel
  • Modern fabrication technology provides greater precision, productivity, and safety
  • Steel members are efficiently transported by truck, rail, or barge

Sustainable Projects

  • Steel buildings are easily deconstructed, enabling reuse of the steel members
  • Minimal, if any, ongoing maintenance is required
  • Steel-framed buildings are highly durable and have a long life-span and are easily modified or expanded
  • Steel framing allows easy integration of mechanical systems, resulting in low floor-to-floor heights, less building volume, and lower energy consumption
  • Steel framing systems allow for large window areas, resulting in plentiful natural lighting, higher occupant comfort, and reduced electrical consumption
  • A well-established, high demand for steel scrap ensures future reuse/recycling of a steel building frame

Sustainable Future

  • As the electric utility grid becomes more renewable, the embodied carbon in structural steel will  continue to decrease as the majority of steel's carbon footprint is due to electrical consumption in the steel-making process
  • Research is underway on new production processes, with the goal of carbon-neutral steel
  • The global steel industry is working together as a global manufacturing community to address sustainability issues, including environmental emissions
  • The structural steel industry is committed to a sustainable future, and structural steel will remain the sustainable building material for generations to come

Environmental Documentation

  1. Environmental Product Declarations (EPDs)
  2. Buy Clean Laws
  3. LEED 2009 - Documenting Recycled and Regional Content


  1. The Sustainable Steel Supply Chain
  2. More than Recycled Content: The Sustainable Characteristics of Structural Steel
  3. China, Global Warming and Hot-Rolled Structural Steel Sections
  4. The Global Warming Potential of Hot-Rolled Structural Steel
  5. Whole Building LCAs: More than Meets the Eye 
  6. Thermal Bridging Solutions: Minimizing Structural Steel's Impact on Building Envelope Energy Transfer
  7. And the Winner is... (August 2010)
  8. National Environmental Report
  9. Sustainable Project Case Studies:
    1. Greening Steel Construction - Low-impact facility sets high standard for future sustainable construction.
    2. An Inside Job - Converting a nearly abandoned vintage power station into prime office space relied on a detailed erection plan and flawless execution.
    3. Ecologically Sound - Planned and constructed for sustainability, new music facilities earn LEED certification as well as acclaim.
    4. A Green Building for a Green Company - Committed to practicing what they preach, this manufacturer's new facility is built to achieve LEED certification.
    5. Built to Last - The Kirsch Center at DeAnza Community College stands as an eco-friendly example of how sustainability and structural steel go hand-in-hand.
    6. Heifer International Headquarters (an IDEAS2 Award Winner)
    7. Seattle City Hall (an IDEAS2 Award Winner)

Steel Solutions Center 

The Steel Solutions Center is for people who need technical assistance, innovative solutions, or tools to make structural steel design even easier.

Visit the Steel Solutions Center