For each material, it specifies the carbon dioxide footprint, embodied energy and water used to obtain, purify, process, transport and shape it for a project. The guide also lists potential alternative material options, and includes environmental best practices for design, storage, use and disposal of the materials. 

Northwestern will soon have a digital tool with an algorithm that can provide material recommendations based on project specifications. The tool, which the BMEG team is building with a machine learning model, will suggest environmentally responsible, yet cost-effective options. 

“Selecting the right materials for building reconstruction is a complex process that can involve dozens of competing considerations and tradeoffs,” Northwestern engineering professor Andreas Waechter said in a statement. “This includes sustainability and climate impacts as well as material costs. We’re developing a versatile computational tool that uses mathematical optimization and detailed building models and allows for rapid comparisons of options in the decision-making process.”

World Wildlife Fund created the first version of what is now BMEG after the 2015 Nepal earthquake, and the guide was intended to lessen the chances of future disasters associated with floods, deforestation and erosion landslides, the group says. The Institute for Sustainability and Energy at Northwestern joined the project in 2017 to expand BMEG. 

BMEG differs from other environmentally focused material guides because it also lists mechanical properties, thermal properties and durability for each material in the database. Stacy Smedley is the executive director of Building Transparency, the nonprofit behind the Embodied Carbon in Construction Calculator (EC3), which allows users to search for materials with specific characteristics or input project details to compare embodied carbon levels. She says BMEG could give people in the industry a better understanding of the environmental impacts of different stages of a material's use thanks to the high level of detail it provides. However, all that information may appeal more to people doing research than someone on the construction side, she adds.

“Some of the tables and the level of detail it goes into might overwhelm certain folks that are just trying to go in and find the easy answer,” Smedley says.

Ren DeCherney, business development manager for manufacturers and interiors at the International Living Future Institute (ILFI),  calls BMEG a valuable reference. She says there are other factors outside BMEG's scope to consider, especially around toxic chemicals used in manufacturing, and that it would best be used alongside other tools like ILFI's Declare product database and its Red List of materials it says should be phased out of production because of their risks to health or the environment.

BMEG is available for free online. Anyone interested can find it on Northwestern’s website.