Steel is the most sustainable construction material available for a world interested in maintaining ecological health. Beyond the material itself, the processes of producing, transporting and recycling steel also provide benefits in the form of lower energy use and better air and water quality, in comparison to many other manufactured materials.

Building with steel is the epitome of sustainable construction with a host of advantages and few—if any—disadvantages.

Sustainable Production

Developments over the past few decades have significantly reduced the amount of energy and raw materials required to produce steel. For example, in the past 60 years:

• the amount of energy required to produce a single ton of crude steel has decreased by more than 60 percent;
• water loss has been reduced to 10 percent or less; and
• wastewater from steel production is treated and returned to the source cleaner than when it was taken.

Steel production also makes use of 100 percent of scrap created during production by recycling it back into the system to be added to the next steel run. Nothing is wasted and very little is lost.

Sustainable Transportation

Steel, for all its strength, is a light material for its size. More steel can be transported using a single volume of fuel than any other construction material. Rock, concrete and wood are all strong substances, but their strength-to-weight ratios do not come close to matching that of steel.

Since steel production is spread throughout the country, it also saves on fuel use and energy costs because of shorter transportation distances, enhancing the savings from the lighter weight.

Sustainable Construction

Steel contributes substantially to sustainable construction.

• Steel buildings can be pre-manufactured off-site to reduce scrap and noise abatement at the construction site.
• The need to haul away scrap is eliminated, reducing vehicle emissions.
• Fewer pieces of construction equipment are required to erect a steel frame, further reducing fuel use and emissions.
• A pre-manufactured steel building takes less time to assemble, also reducing noise abatement efforts and equipment emissions.

By using steel, there is less disruption to the surrounding community, the construction site has a smaller footprint and construction is safer with less time at the site, resulting in lower numbers of injuries and accidents.

Also, since steel has the highest strength-to-weight ratio of any construction material, much less is needed to erect a structure than concrete or wood.

Reuse and Recycling

Steel is the ultimate recyclable material. It is 100 percent recyclable, with almost all steel scraps being recycled or reused. There is no loss of strength no matter how often steel is recycled.

Nearly 650 metric tons of steel are recycled annually around the world, reducing the need to mine iron ore, which in turn reduces carbon emissions and alleviates mining accidents and injuries. Less need for coal and limestone reduces the need to mine those materials as well with the same benefits to the environment and safety.

Steel recycling takes less effort than mining raw materials because it is easily separated from other materials by taking advantage of its magnetic properties. Pre- and post-consumer waste gives up steel quickly and easily, allowing it to be diverted back into production.

While steel itself is easily recycled and reused, steel buildings are also sustainable. A well-designed steel building can be used for a wide variety of activities. A building that was originally a warehouse can be converted to a theater or a sports arena. Rooms in an office building can be resized and reconfigured without the need to demolish and rebuild.

Less demolition and rebuilding reduces material use, emissions and noise while maintaining better air quality.

The Case Against Trees in Construction

A common argument for using wood frame construction is that it is a sustainable material. While technically true, it takes many long years for a sapling to grow large enough to harvest. There are more steps and more chemicals used in the process of converting a harvested tree to boards and other construction material than in producing steel. Often, trees are clear-cut, leaving large swathes of unproductive land.

Few forests in the United States are certified for lumber. Forests certified as sustainable have yet to reach the threshold required for true sustainability. Any wood taken from these areas must be transported great distances; during construction, much scrap is produced that must be hauled away as unusable scrap.

Unfortunately, trees can be used only once. When a structure built of wood is demolished, the wood can be incinerated or sent to the landfill.

On the other hand, steel manufacturing, transportation, and construction reduce hazardous air quality conditions and scrap. At each stage, steel provides substantial cost savings through shorter construction times, less clean up and lower maintenance and repair requirements.