Design & Construction Guidance
Use shapes that come from electric arc furnaces
North American manufacturers typically use electric arc furnaces to manufacture steel for hot rolled shapes like wide-flange members, angles, channel shapes, and rebar. Be cautious of hollow structural sections (HSS) and metal decks because they require a second process to roll the steel into its form, tend to use more primary steel, and come from BOF mills that have greater emissions. Plates can be produced on either an EAF or BOF mill, so if these shapes are needed, seek products that come from EAFs and not BOFs.
Utilize salvaged or reclaimed structural steel
There are used pipe dealers that offer pipe decommissioned from oil and gas facilities and distribution systems. Use these pipes for pipe piles or columns, where possible, to eliminate the emissions associated with creating new materials5. The best way to source salvageable structural steel is to identify upcoming demolition projects in your region, and then contact the demolition companies. It may be necessary to hire your own professionals to help with careful deconstruction. Also, check your area for salvage yards and inquire about their building materials.
Use braced frames instead of moment-resisting frames
For the building’s lateral-load-resisting system, a recent study found that using braced frames instead of moment frames in a 3-story building reduced the embodied carbon impact of the building structure by 12%6,7. This is because moment-resisting frames and beams tend to be significantly heavier and require more material than braced frames in order to transfer forces and resist lateral loads. Additionally, a greater number of moment-resisting frames are often needed, compared to braced frames, to support the same load8.
Use joists or trussed members instead of rolled shapes
Joists and trussed members are often lighter and can support the same weight compared to heavier rolled shapes. Using joists and trussed members may reduce the overall quantity of steel required thus reducing the embodied carbon impact of the structure (for example, see resources).
Rightsize: one size does not fit all
Right-sizing steel members reduces excess material and thus reduces the embodied carbon impact of a project. Plan ahead and size each member precisely, instead of using set sizes for the whole project.
Utilize higher grade steel
Use higher grade steel, which can accomplish the same structural task using less material. However, ensure that the increased strength of the material does not result in additional CO2 emissions.
Design for adaptability and deconstruction
Due to its metal fasteners and standardization, structural steel framing is well suited for deconstruction and reuse. Make a plan to have structural steel members recycled or reused at the end of the building’s life.
Use reinforcement only when needed
Some applications of concrete (e.g. some slabs on grade) can be used without steel reinforcement as long as alternate crack control measures are taken. Whenever possible eliminate steel reinforcement from concrete to reduce the project’s overall embodied carbon footprint. Be sure to verify that this does not increase the amount of concrete required to ensure that the emissions associated with removing steel reinforcement are offset.
Work with fabricators to increase the efficiency of your design
Work with steel fabricators, explaining your objective for low carbon emissions by reducing steel quantities, using higher grade steel, and/or increasing the use of recycled steel4.
Contact steel producers directly
Designers should contact producers directly to inquire about the specific production methods used to produce the structural steel for their project.