Sensitivity Analysis highlights options for impacting carbon footprint

The Aluminum Extruders Council (AEC) has released its updated Environmental Product Declarations (EPDs) for Aluminum Extrusions and the corresponding Life Cycle Analysis (LCA). In conjunction, the Council has released a sensitivity analysis which shows product specifiers how they can impact the carbon footprint of the products that they specify.

These aluminum extrusion industry EPDs document the environmental performance of aluminum extrusions produced in the U.S. and Canada. Certified by UL Environmental, they are based on a detailed study of the process inputs and outputs of eight AEC member extruders. Thirty separate facilities, located across the U.S. and Canada, with nearly 100 extrusion presses and a variety of finishing and thermal improvement facilities, were included in the study. In aggregate, extrusion production of 1.75 billion pounds, or about 38% of the North American total for 2020, was covered in the study; this coverage is an improvement on the estimated 33% of the market covered in the initial AEC EPDs produced in 2016.

The EPDs quantify the "cradle-to-gate" lifecycle environmental impacts of aluminum extrusions. One EPD is for thermally-improved extrusions – of particular interest for fenestration applications – and one covers extrusions that have not been thermally improved. Both provide data for mill finish, painted and anodized products, so architects, engineers and product developers can assess the environmental impacts of finishing and thermal improvement decisions.

The corresponding LCA, or EPD Background Report, presents the conclusions shown in the EPD. The LCA provides additional detail about items such as: inputs at each process step, secondary data sources employed, key assumptions and allocations, assessment of alternative scenarios regarding key inputs, data quality and completeness assessment.

“One of the highlights of this work is the accompanying sensitivity analysis, which details what designers and specifiers should be aware of as they utilize aluminum extrusions” notes Guy Charpentier, Chair of the AEC Industry Promotion Steering Committee. “The EPDs show that the predominant determination of extrusion’s Global Warming Potential, or GWP (expressed in carbon dioxide equivalent (CO2e), ) is the feedstock, i.e., the aluminum billet that is the raw material for the extrusion process.”

The deeper analysis of the AEC EPDs demonstrates how the decisions purchasers make can have an impact on the embodied carbon for their products containing extruded aluminum components. “The sensitivity analysis shows how – by adjusting certain ‘levers’ in the sourcing of the raw material – specifiers, designers and architects can reduce the embodied carbon of their products. They should contact their aluminum extruder early in the process to ensure their environmental impact goals can be met.”

For extrusions that require the least intensive processing, such as standard extrusions in mill finish, the CO2e contribution to the module A1-A3 total from the extrusion process is less than 25%. The A1-A3 modules of the EPDs represent the raw material supply, transportation and manufacturing and finishing of the aluminum extrusion products up to the point where they leave the manufacturing facility.

For the product form that has most intensive processing, i.e. painted extrusion that is thermally enhanced, the contribution from the extrusion/paint/thermal process is less than 33% of the A1-A3 total. These assessments are based on the average aluminum billet composition documented in the new Life Cycle Assessment (LCA) – a 47% prime, 53% recycled aluminum mix with the prime assumed to be the North American average as reported by the Aluminum Association.

It is important to note that achieving significant reductions in the embodied carbon is most practically achieved by adjusting the billet mix – increasing the recycled content and/or shifting the prime content towards prime aluminum produced from less carbon-intense energy sources.

For more information, download the AEC EPDs on the UL Spot Sustainable Product Database website at The EPDs and corresponding LCA are also available for download from the AEC website at

Aluminum extrusions help make vehicles and buildings more energy efficient and recycling is an important factor in the aluminum extrusion story. Low-carbon primary aluminum is increasingly available as a raw material component for extrusion. With 170 locations in 40 U.S. states and Canadian provinces, there is an aluminum extruder nearby; many are operating their own remelt facilities, producing aluminum billet from scrap. That convenience and vertical integration minimizes carbon emissions from transport. In addition, there is a robust recycling network in North America. Studies show more than 90% of aluminum from buildings and vehicles is recycled at end of life.