The BEAM tool: An Easy Way to Know Your Building’s Carbon Footprint

If you’re new to BEAM, we hope this article will explain the basics and give you a little background on why you should use it. The information here is from the presentation Chris Magwood (one of the driving forces of the BCA and natural building) gave at the Ontario Natural Building Coalition 2022 Conference and the Building Sustainability podcast Episode #082 with Chris Magwood. 

In 2017 there was 241 million square meters of new low-rise residential construction. If built with conventional materials, this construction emitted as much carbon as 15 coal burning plants. If built with carbon sequestering materials, this construction would instead remove the carbon emissions of 10 coal burning plants. This is what motivates the Builders for Climate Action (BCA) to study and encourage low carbon building.

There’s nothing quite like the BEAM estimator when it comes to designing low carbon buildings. BEAM, which stands for Building Emissions Accounting for Materials, is a user-friendly tool produced by the BCA that allows you to estimate the embodied carbon of your building. Making low carbon buildings, or even buildings that store more carbon than was used to build them, is a major tactic to fight climate crisis. Until a few months ago, upfront carbon emission data for the materials you’d use in low-rise construction was scattered and hard to find. Now with BEAM, it’s easy to compare the UEC of different materials as you pick them. Back in 2014 Chris Magwood was working on another project to compare the impacts of different materials. This was his book titled Making Better Buildings, an encyclopedia that allowed you to compare all kinds of sustainable building materials across consistent ratings for qualities like energy efficiency, durability, labor input, and more. During the research for that book, Magwood first heard about the importance of embodied carbon, and started telling everyone he could about “the Embodied Carbon Elephant in the Room” (the title of a talk he gave at the 2015 ONBC conference). Back then there wasn’t too much public discussion of UEC, despite it being a much larger share of a building’s total embodied carbon than OEC usually is. Magwood decided to go back to school to learn about embodied carbon, and completed a few studies and a white paper called “Low-rise Buildings as a Climate Change Solution”. To do these studies, he made his own increasingly bulky spreadsheet comparing materials. Eventually he realized that further studies required something more robust, so he gathered a team to make the BEAM estimator.

These first few studies that BEAM was used for have made big ripples in Canadian public policy. The results showed just how much carbon emissions are produced by the Canadian construction industry (greater than the annual car tailpipe emissions in Canada!), and have spurred cities and the national government to revise building codes. The effects of these studies will be covered in more detail in an upcoming issue of The Last Straw. BEAM does not calculate the total carbon footprint of a building. The materials included form a substantial portion of any building and were chosen based on the data available, largely from materials’ environmental product declaration sheets (EPD’s). The carbon emissions from material transportation are also not included in the estimate, because these vary widely depending on the particular supply chain and your project location. When the BCA did calculate the carbon emissions from material transportation, the numbers were smaller than you might think at 65% to 85% of the total UEC. BEAM instead calculates a portion of what’s called the material construction emissions (MCE). After getting your project’s MCE you can then divide that number by your project’s floor area to get the material construction intensity (MCI). With this result you can compare your project’s carbon impact to others regardless of size. The steps to using BEAM are pretty straightforward: input your basic project information like the address, floor area, region, etc.; input the various assembly and overall dimensions and material takeoffs; select materials for each component while seeing their MCE in real time; get your results, and then save and iterate to get your best options! One of the main motivations for creating BEAM was to affect decisions in the next couple decades, when action is crucial for mitigating the worst effects of climate change. Because of this carbon sequestration that takes place over very long periods of time, like that of lime plasters and even concrete, is not factored in. This might surprise you: BEAM does not count using virgin lumber as carbon sequestration. According to the BCA, there isn’t reliable and conclusive evidence that commercial virgin lumber used for construction stores more carbon than was emitted in its production. Life cycle assessment conducted by the forestry industry doesn’t account for large amounts of the tree lost during processing and drying, and the impact on the massive carbon sequestration in a living forest. As Magwood says, “You can’t shrink the carbon sink of a forest and move some of that carbon into buildings and say we helped the climate” (Buliding Sustainability podcast episode #082). The answer would be to harvest wood while continuing to grow the forest, which is not happening  today in the North American forestry industry.

Now that BEAM has been released to the public, you can go to the Builders for Climate Action website and download it for your own projects on a pay-what-you-can basis (with suggested contribution amounts to help keep the project going). The BCA hopes to continue developing BEAM further, so that it can integrate with other software and expand its product selections. We’re excited about this tool, so go ahead and try it out and tell a friend!