Steel is widely recognized as one of the leading materials in sustainable construction. By default, steel is a highly recycled material. The common practice of converting scrap metal back to new steel saves the steel mill time and money versus starting with virgin steel. Typically the recycled content produced in the U.S. is between 90-99% total recycled content (70-95% Post Consumer, 5-20% Pre Consumer), but can vary from mill to mill. The amount of recycled content is largely dependent on the type of process which the mill uses to produce its steel (EAF-Electric Arc vs. BOF-Basic Oxygen), this will be discussed in greater detail below. Reinforcing steel, used with Concrete Design, also contains a high content of recycled material, but usually somewhat less then wide flange sections. With careful detailing, steel can also lend itself to future adaptive re-use. One way it does this is in giving a building which has lived out its useful life a chance to be repurposed through deconstruction and reuse. In addition, through the use of millwork and prefabrication, work on-site can be minimized, thus saving on energy, material waste, and site space. As with any building material, designers should make themselves aware of the embodied energy costs of producing steel and delivering it to a job site. It is not recommended to specify that a minimum recycled content for steel be met. This could result in a requirement that the steel would come from a mill a farther distance away from the site than a more local mill with less recycled content, thus adding unintended transportation impacts.

Refer to the links provided below for more information on sustainable steel design:

Overview of Steel Recycled Content

Typical recycled content levels in Steel