This course is part of the Mass Timber Academy

Photo courtesy of Jeffrey Roscoe

LCA tools and carbon calculators.

The complex process of building design and construction must meet many criteria – aesthetics, safety, budget, code compliance, occupant comfort, durability, and more. Architects and other design professionals are increasingly recognizing the value of adding green building to the list.

This course will help you understand that sustainable design begins with sustainable building materials. Because there are many factors to consider in assessing a building’s sustainability, it can be challenging to fully understand the long-term impacts of choosing one building material over another. However, material choice greatly affects the environmental impact of buildings, both during construction and over the building’s life cycle.

Because 80 percent of a building’s embodied carbon comes from the structural materials used to build it, building material specification is impactful. “Upfront” embodied carbon is the total amount of greenhouse gas emissions associated with the harvesting/extraction, transportation, and manufacturing of materials used in building construction. The effects of sustainable building design extend well beyond the construction phase to the way a building performs over its lifetime─through lower energy use (operational carbon) and occupant health and well-being, for example.

Architects can incorporate sustainable features into their designs through their choice of building materials. Wood building products and components fit well within many sustainable building scenarios, while also adding other benefits such as natural warmth and beauty. Wood is a versatile, durable building material that can be used in almost any building application. It is renewable and sustainable, and wood products typically require less energy to produce than other building materials. Green building standards also recognize wood’s contribution to improved energy performance over time.

The Basics Of Green Building

The world’s ability to meet climate goals depends on reducing carbon emissions, and the building industry accounts for nearly 40 percent of annual global CO₂ emissions. Architects and designers are showing that buildings can be constructed sustainably, with a reduced carbon footprint, while still meeting critical design goals including functionality, cost, comfort, and more.

While there are many ways to approach it, the goal of green building is to design projects and use construction processes that are environmentally responsible and resource-efficient and to reduce carbon emissions both during construction and throughout a building's life cycle. This can be accomplished a number of ways, from smart site selection and construction material choice to how the design and building materials impact energy use over the life of the building.

A 2018 study from the World Green Building Council found that additional costs of green building can be outweighed by the life cycle benefits of creating a better building, which include lower energy consumption, improved occupant satisfaction and well-being, and better financial performance in terms of improved lease rates and developer return on investment. The 71 global companies that participated in the study found that staff turnover and absenteeism decreased while productivity and job satisfaction increased–all of which translate to measurable economic benefits.

Tools Used To Assess Green Building Certification

There are as many reasons to pursue green building certification as there are certification programs from which to choose. Certification can be used to comply with client, civic, or jurisdictional requirements; it can also serve as a marketing tool for the building owner to help attract tenants.

To understand green building certification, it is important to become familiar with the primary methods that are used to assess certification requirements.

Life Cycle Assessment (LCA)

An LCA is a performance-based methodology that measures the environmental impact of a product, assembly, or structure over its life span; it’s a way to assess the sustainability of a building and its constituent parts. LCA measures the energy required to both construct and operate a product or building over its lifetime, beginning with the extraction or harvest of the material through to its manufacture, distribution, installation, use, and end-of-life disposal.

LCA analysis is required for many green building certification programs; results allow project teams to understand the overall impact of choosing one building product or construction system over another. LCA studies consistently show that wood products have a lower environmental impact than alternative materials. The Consortium for Research on Renewable Industrial Materials (CORRIM) has done numerous LCA studies comparing wood products to other building materials, and has found that wood has lower carbon emissions and uses less overall energy to produce than other products.

There are numerous LCA options available to help guide design decisions by evaluating the environmental impact of everything from individual building products to entire buildings, known as WBLCA (Whole Building Life Cycle Assessment).

LCAs provide varying levels of detail and complexity:

• Athena EcoCalculator is a free tool that measures the LCA of common building assemblies. Data is pulled from a library of predefined options for quick and simple assessments. Separate calculators are available for commercial and residential assemblies, and calculations are based on an assumed building service life of 60 years.
• Athena Environmental Impact Estimator is a more robust tool that evaluates whole building LCAs; it also measures the environmental impacts of the building’s ongoing operation, allowing for easy comparison of design options. This tool can be used for new construction, renovations, and additions on all building types.
• The Embodied Carbon in Construction Calculator (EC3) is a database populated with product EPDs. It is useful after a building has been designed. SimaPro and GaBi Solutions are life cycle inventory databases that also have tools to conduct an LCA and measure the environmental impact of individual building products.
• Tally, a Revit software plug-in, uses the GaBi database to evaluate WBLCA.
• One-Click is another LCA tool that can be used for early design optimization, life-cycle costing, and benchmarking against similar projects and other metrics.

Table courtesy of ThinkWood

LCA tools and carbon calculators.