SLB’s 2021 Annual Report Now Available; SLB and Program Partners Lead Crucial Conversations at Mass Timber Conference | SLB May 2022 Newsletter

Now in its fifth year, the Timber-Strong Design Build (TSDB) competition—often a university student’s first experience designing and building with wood—expanded this year to reach more than 125 students from over 20 universities across five regions.

The competition, which since 2018 has been hosted annually by the American Society of Engineers (ASCE) in partnership with the AWC, APA – The Engineered Wood Association, and Simpson Strong-Tie, challenges student teams to design and build sustainable, two-story wood light-framed buildings. The Timber-Strong competition emphasizes building with wood as a completely renewable, carbon-friendly material and is one of several unique design and building challenges ASCE hosts as part of its annual multiday Student Symposia.

For this year’s Timber-Strong competition, participating teams created a building design and accompanying computer model in advance, then built their structures during the symposia. Entrants were judged on a host of design and construction criteria, including the structure’s estimated carbon benefit, which was calculated using WoodWorks’ Carbon Calculator tool.

Timber-Strong was developed in part as a counter program to the Concrete Canoe Competition, which is also hosted by ASCE as part of the Study Symposia. In this competition, student teams build and race canoes built with concrete. In recent years, the competition was sponsored in part by the National Precast Concrete Association (NPCA).

The International Code Council (ICC) recently held its Group B Code Development Hearings in Rochester, New York, during which committees considered proposals affecting the International Residential Code, International Existing Building Code, ICC Performance Code, and the structural provisions of the International Building Code. AWC staff held several influential committee positions at the hearings, including two chairships, and were active across committees in creating and protecting opportunities for wood.

The AWC successfully testified against changes before the Administrative Code Development Committee that would have added criteria for how manufacturers should label products to conform with standards. The proposed language—which was disapproved—was not compatible with the quality assurance process currently used by the wood products industry. The Administrative Code Committee also considered updates to the AWC reference standards, including the National Design Specification^® for Wood Construction and the Wood Frame Construction Manual, both of which were recommended for approval.

Under the Residential Building Code Development Committee, which was chaired by an AWC staff member, an AWC-proposed change to add ASTM D8391 for determining the equivalency of wood-based floor assembly fire protection was recommended for approval with a floor modification. The new standard will provide a valuable point of reference for code officials when evaluating alternative products for use on I-joists and trusses. Several changes related to snow- and wind-load maps were also recommended for approval, which will affect the development of future AWC design aids, including the Wood Frame Construction Manual.

The AWC opposition contributed to the nixing of a proposed change that would have required homes being rebuilt outside of wildland-urban interface (WUI) zones, which were destroyed in a WUI event, to be constructed to meet WUI requirements. Local jurisdictions have the authority to designate WUI zones, and thus this change was beyond the building code’s scope.

The ICC will hold additional public hearings on recommended changes in September, followed by final online voting.

The AWC’s Fire Service Relations Manager, Ray O’Brocki, recently provided construction fire safety education to 25 students in the Fire Engineering program at Eastern Kentucky University as part of their capstone requirement to graduate. This was the AWC’s first—of hopefully many—foray into graduate-level education and represents another important step in helping to ensure that fire safe practices are well known and followed at all levels of the building industry, from designers to fire officials.

Higher-education students entering design and construction disciplines have been identified by the SLB as an area deserving greater effort. The SLB has previously reported on engagements with architecture and engineering students through Think Wood and WoodWorks. Taking advantage of this opportunity was a way for the AWC to be a compelling influencer of emerging design and construction professionals.

Although commercial and multifamily buildings have focused on reduced carbon footprints in recent years, the concept is relatively new for homebuilders—especially measuring embodied carbon. Still, low carbon construction ranked at the top in Think Wood’s 2022 Timber Trends survey of more than 500 architecture, engineering, and construction professionals, some of whom design and build single-family homes.

Most homebuilders are familiar with operational carbon, which refers to greenhouse gasses emitted from a home’s energy use after it is built. However, fewer are versed in embodied carbon, which is all the energy that went into manufacturing and transporting a home’s building materials as well as emissions associated with physical construction. Right now, a home’s embodied carbon is likely higher than most green-focused homebuilders realize.

The average U.S. home produces 45 kg of CO₂ per square meter annually from an operational perspective, according to a 2020 University of Michigan study. But a recent Canadian report found embodied carbon accounted for 250 kg of CO₂ per square meter in residential buildings, or more than five times as much. This means that even the most energy-efficient new homes built today have already contributed five years’ worth of greenhouse gas emissions to the environment before their first owner moves in.

The good news is that framing homes with wood—which, fortunately, is the dominant method of framing today—offers a lower carbon footprint than other structural materials. Of the three primary structural materials used in construction, manufacturing lumber is the least energy intensive, accounting for comparatively low embodied carbon.

To better understand how residential builders are approaching carbon reductions, Think Wood interviewed Aaron Smith, CEO of Energy & Environmental Building Alliance (EEBA) and GreenSmith Builders; Bill Rectanus, COO of Thrive Home Builders; and Corey Donahue, Co-Founder of Bettr Homes. Read what they had to say about this emerging trend: https://www.thinkwood.com/blog/making-zero-carbon-homes-a-reality.

In 2021, WoodWorks undertook a project to better understand how Whole Building Life Cycle Assessments (WBLCAs) are being used by design and construction professionals to make sustainable design decisions and to survey the tools. In Phase 1, they learned that the most significant elements of WBLCA tools driving favorable or unfavorable results for wood are biogenic carbon accounting approaches and end-of-life scenarios and assumptions. Most users do not have the information or knowledge to make educated decisions related to these topics, which can result in sub-optimal results for wood. Some firms are also creating their own internal databases of WBLCA results to establish benchmarks. Without consistent, accurate data going into these analyses, firms may not realize the superior environmental benefits of wood.

There is clearly confusion in this space, and WoodWorks is working collaboratively with other SLB-funded groups to support developers and building designers with relevant and transparent information. With input from Think Wood and AWC, WoodWorks recently published the first two in a series of Expert Tips on this topic—Introduction to Whole Building Life Cycle Assessment (WBLCA) and When to Include Biogenic Carbon in an LCA—and several others will be released this quarter.