Structural Steel Simplifies Satisfying Green Codes, Standards and Rating System Requirements

Structural steel is a green, sustainable material with the highest recycled content and recycling rate of any construction material.  Building code officials are often charged with verifying the compliance of a new building to the requirements of a jurisdictional requirement for sustainable construction, such as the International Green Construction Code, ASHRAE 189.a or local code ordinances or rating systems such as LEED.

Each of these programs has unique requirements for the materials used in a project.  These requirements typically fall into 5 categories:

• Documentation of recycled content

• Documentation of regional content

• Documentation of bio-based content

• Submission of Environmental Product Declarations

• Performance of a whole building life cycle analysis

 

Recycled Content

All domestic structural steel is produced using recycled material as its primary feedstock.  The recycle content of domestically produced structural steel is typically between 90% and 100%.  Documentation of the recycled content of the structural steel on a project is provided by the structural steel fabricator to the general contractor. Each of the steel mills producing structural steel in the United States provides individual fabricators with letters stating the average recycled content for the material they produce.  

The formulas used by each green program vary regarding how the overall recycled content of materials on the project are calculated. Some use the actual recycled content while others factor the recycled content based on the combination of pre- and post- consumer material making up the scrap stream.

In every case, the ultimate contribution is calculated based on the cost of the material as a percentage of the total project cost. The material cost is defined as the its cost  as delivered to the project site. For structural steel, this would include material, detailing and fabrication costs but exclude erection costs.

Regional Content

Regional content is defined differently in every program. The distance from the project site considered to be “regional” varies from 100 to 500 miles. The definition of regional material may include that the material needs to be harvested/extracted/recovered and manufactured within the specified distance or be harvested/extracted/recovered or manufactured within that distance. Some programs allow adjustments based on the mode of transportation (truck, train, barge or ship).

In most programs the credit is earned if the fabrication shop is within 500 miles of the project site.  The amount of credit is proportional to percentage of scrap used to produce the structural steel originating from within 500 miles of the project site. The steel fabricator can obtain this information from the producing mill and pass it to the general contractor.  

The ultimate contribution to the required percentage is calculated on the same basis as for recycled content.

Bio-based Content

Structural steel does not contain any bio-based material.

Environmental Product Declarations

Several programs require either industry average or producer-specific Environmental Product Declarations (EPDs) to submitted for a specified number of materials or products used in the project.  

Industry-average EPDs for fabricated hot-rolled structural steel, fabricated steel plate and fabricated hollow structural steel sections (HSS) are available at www.aisc.org/epd

Whole Building Life Cycle Analysis

A whole building life cycle analysis (WBLCA) is a detailed look at all of the components of a building through all of the life cycle stages of a building in order to estimate the total of all of the environmental impacts generated by the building. Often, the WBLCA is performed on two designs (or the actual design and a reference design) for the same building in order to determine which design has the lowest level of environmental impact. In order to perform a WBLCA, design professionals including a structural engineer (to verify the accuracy of the material quantities) and a LCA professional are required.

The role of the building code official is not to verify the accuracy of the WBLCA but rather to verify that the WBLCA has been peer-reviewed by an independent third-party expert.

Resources:

• A Green Road Map 

• Whole Building LCAs: More than Meets the Eye  

• What’s New with Steel and Sustainability?