CarbonStar®

An essential tool for decarbonizing the built environment.

What is CarbonStar®?

CarbonStar® is a quantification & specification method for calculating the embodied carbon of concrete.

The CarbonStar® Standard (CSA/ANSI R118:24) and associated CarbonStar Calculator were developed by a broad range of industry, government, academic, and NGO experts to enable the decarbonization of concrete.

Who benefits from CarbonStar®?

There are many participants in the design and construction process and each participant plays a role in specifying, purchasing, manufacturing, and using decarbonized building products. CarbonStar® can help building owners (public and private), architects, engineers, contractors, sub-contractors, and concrete manufacturers make informed decisions and select lower carbon-intensity cement or concrete to reduce the environmental impact of their projects. These professionals can use the CarbonStar® Standard and Calculator to facilitate procurement of environmentally preferable concrete using a standardized approach to carbon accounting, creating efficiencies during the building process.

Contractors

Manufacturers

Architects

How to use the Standard with the Calculator

The CarbonStar® Calculator is based on CSA/ANSI R118:24, and the Standard should be used in conjunction with the Calculator. When used together, they help remove a major obstacle to decarbonizing concrete by providing a quick, rigorous, and standardized way to quantify and specify low-carbon or carbon-sequestering concrete. CarbonStar® can be used on its own or to enable more rapid and accurate environmental product declarations (EPDs).

The CarbonStar® Rating, as measured by the Calculator, represents the net embodied carbon in a unit of concrete, presented as either a negative (net sequestered), zero (net neutral), or positive (net emitted) value. This calculation accounts for both emitted and sequestered carbon per unit of concrete:

CO2CarbonStar = CO2Emitted - CO2Sequestered

CO2CarbonStar = CO2Emitted - CO2Sequestered

CO2CarbonStar = CO2Emitted - CO2Sequestered

Why CarbonStar® is essential…

Health groups, airports, and other organizations now recognize CarbonStar® as a critical step to enable cities and institutions to decarbonize.

Georges C. Benjamin, MD, Executive Director of the American Public Health Association

“CarbonStar® is already enabling innovation that addresses not just global warming, but other health-damaging pollution as well. As the leading voice for public health in the United States, the American Public Health Association is keenly aware of the enormous health costs of climate change, which disproportionately burden the most climate-sensitive populations.”

Ian Riley, CEO of the World Cement Association

“A central lesson from COP28 is that we must do more to reduce global warming. This must include the decarbonization of concrete, which is responsible for about 8% of the world’s CO2 emissions. The publication of CarbonStar®, a major government, academic, industry, and NGO-supported standard, provides us with a valuable tool to measure and specify the carbon intensity of concrete. Improving the measurement of embodied carbon is something we will need to work on for many years and is essential to managing and reducing concrete’s global warming impact.”

Greg Kats, CEO/Founder of the Smart Surfaces Coalition & Chair of the Technical Committee on Concrete Carbon Intensity Quantification and Verification

“CarbonStar® is the only binational standard for the quantification and verification of the carbon intensity in concrete. We are working with cities that make up more than 10 percent of the US population, and our city partners all want to cut pollution and become more resilient. CarbonStar® is essential because it is the first user-friendly standard enabling cities to effectively quantify and decarbonize their concrete.”

Sarah Saltzer, Managing Director of the Stanford Center for Carbon Storage & Technical Committee on Concrete Carbon Intensity Quantification and Verification member

“Successful climate-change mitigation and carbon sequestration requires rigorous consensus standards. CarbonStar® provides this for the essential effort of decarbonizing concrete.”

Anthony Bernheim, Healthy and Resilient Buildings Program Manager of the San Francisco International Airport & Technical Committee on Concrete Carbon Intensity Quantification and Verification member

“CarbonStar® provides design, construction, and concrete manufacturing professionals with the ability to specify low embodied carbon concrete mixes as they address their building projects’ approach to reducing impacts on climate change. SFO is using CarbonStar for its new construction and major renovation projects because it is a rigorous and relatively simple method to measure the carbon intensity of concrete.”