Building Life-Cycle Impact Reduction

LEED recognizes the value of extending the life of buildings and minimizing material impacts with up to 5 credits available. Constructing an addition onto an existing metal building or dismantling and reusing parts of the building helps achieve the Building and Material Reuse option. For new construction, the Whole Building Life-Cycle Assessment (LCA) option is ideal for metal buildings when using Whole Building LCA software like the Athena Impact Estimator software. MBMA contributed industry-wide life-cycle data with metal building specific capabilities to help design professionals achieve this credit.

The embodied carbon content of building materials has received a lot of appropriate attention recently. That’s because the majority of construction-related CO₂ emissions —about 11 percent of the global total—are associated with manufacturing building materials, transporting materials to construction sites, and the actual construction process, according to a U.N. Environment Global Status report. In that light, the most obvious perceived environmental attribute of metal buildings comes from its primary material—steel. According to the American Iron and Steel Institute (AISI) and the Canadian Sheet Steel Building Institute (CSSBI), steel is the most recycled material in North America. By specifying recycled steel, which is often processed in an electric arc furnace, the emissions and embodied carbon content of the steel is greatly reduced.

To understand the relative significance of using recycled steel metal buildings, a life- cycle assessment comparison of buildings with different structural and envelope materials was produced independently by the engineering firm of Walter P. Moore & Associates. The resulting report concluded that “Metal buildings showed lower environmental impacts in all six metrics when comparing structural and envelope materials to load bearing masonry walls, concrete tilt-up, and steel framed construction of the same building footprint and functional equivalence.” Further, with all metal building components typically delivered simultaneously from the manufacturing plant to the construction site, emissions related to material delivery are vastly reduced over other forms of construction.

RENEWABLE ENERGY RETROFIT PROJECT

Photo courtesy of MBMA

Project: Word of Life Christian Center
Location: Honolulu, Hawaii

Energy Retrofit Strategy: Utility costs in Hawaii are higher than those in other states in the U.S., so it’s wise to install solar panels on large facilities to take advantage of the state’s plentiful sunshine. After making minor repairs to their existing 30-year-old standing- seam metal roof, the Word of Life Christian Center installed an 82-kW solar photovoltaic array. Metal roofs typically last over 60 years, so there was plenty of reason to reuse the existing roof since photovoltaic panels have a typical life expectancy of 30 years. The panels were attached with approximately 450 clips that didn’t require penetration of the roofing material since metal roofs are manufactured to be solar-ready. The addition of the solar panels required no money down and allowed the congregation to save money by using their own solar power and by selling unused electricity back to their local power provider.

MATERIALS AND RESOURCES PROJECT

Photo courtesy of MBMA

Project: Plano Recycling Facility and Learning Center
Location: Plano, Texas
Architect: Anchor Construction

The Project: This 77,000-square-foot, state-of-the-art building serves the recycling needs of more than 510,000 residents and 2,500 commercial customers in North Texas.

Sustainable Strategies: This project achieved a LEED Silver designation from the U.S. Green Building Council. Constructed of steel and other metal, its high percentage of recycled content reduced the environmental impact and the resulting fossil fuels and carbon emissions. From an operations standpoint, it houses advanced sorting equipment and technologies, allowing the facility to process approximately 350 tons of recyclable material per day. The building incorporates optical sorters, next-generation anti-wrap fiber screens, and other leading processing tools. An automated touchscreen control system and tablet-based technologies aid the processes inherent in real-time systems management, monitoring, and data acquisition. The facility also includes a 5,000-square-foot interactive learning center with an observation deck.

Building Product Disclosure and Optimization—Environmental Product Declarations (EPDs)

Environmental Product Declarations (EPDs) are widely recognized as the best way to communicate the environmental impacts of building products. LEED recognizes and encourages their use, with up to 2 credits available in this category. In support of the creation of these documents, the MBMA funds extensive research related to the environmental impacts of metal building systems. Through collaboration with the Athena Sustainable Materials Institute and UL Environment, MBMA developed an industry-wide LCA report and three industry-wide environmental product declarations (EPDs) for designers to use when specifying MBMA-member products. These are available to architects and others for download at mbma.com.

MBMA also recently released revised environmental product declarations (EPDs) for three specific metal building product categories: primary rigid framing, secondary framing, and metal cladding for roofs and walls. These provide architects, specifiers, designers, and other industry professionals with transparent, third-party documentation of the environmental impacts of products used in metal building systems. MBMA partnered with UL Environment to develop and certify these EPDs which summarize the cradle-to-gate environmental impacts of a metal building system. The EPDs are based on Product Category Rules (PCRs) used to develop a life-cycle analysis (LCA) final report, which is summarized in the EPDs. Significant improvements were noted in the most recent EPDs over the previous ones developed using the same process. For example, the use of recycled steel has improved by 20 percent and the scrap produced has dropped 15 percent. The MBMA industry-wide LCA Final Report and the three MBMA industry-wide EPDs conform to ISO 14044 and ISO 21930, with the cradle-to-gate scope to help earn credits.

Building Product Disclosure and Optimization—Sourcing of Raw Materials

The sourcing of raw materials is a significant concern with up to 2 credits available in LEED to address this. Toward that end, metal building manufacturers' lists may provide the information to meet the Raw Material Source and Extraction Reporting option. The Leadership Extraction Practices option includes the list of traditional single-source attributes, such as recycled content, materials reuse, etc. The recycled content is a strong point for metal building construction. Steel is the only material with the approved default recycled content of 25 percent. Many steel producers and metal building manufacturers publish their true recycled content to increase the percentage for calculation purposes.

Some related points here, include the following:

• Metal buildings are generally manufactured from at least 65% recycled steel, substantially reducing the need for virgin materials excavated from the earth. Then, at the end of a building’s life, the raw steel can be 100% recycled to be used in various products, such as cars, appliances, buildings, and bridges.
• Steel’s recyclability exceeds other comparable construction materials and its contribution to a circular economy is increasing. Steel products are becoming more lightweight and designed for diverse applications and extended useful life. In particular, metal buildings are more lightweight (use less material) than other forms of steel construction and as a result have less embodied carbon than many competing forms of construction.
• New steel, made with recycled material, uses as little as 26% of the amount of energy required to manufacture steel from iron and other naturally extracted materials.
• Steel can be continually recycled into new steel products without any deterioration in product quality.
• Net-zero carbon steel, manufactured in the US, provides emissions-free steel products to help architects meet their sustainability goals. It is also important to note that, today, the United States is the cleanest place in the world to make steel, accounting for less than 2 percent of the GHG emissions from the global steel industry. The AISI points out that steel source energy is increasingly from electricity, with more of that electricity coming from renewables than previously.

INDOOR ENVIRONMENTAL QUALITY PROJECT

Photo courtesy of MBMA

Project: Full Goods
Location: San Antonio, Texas
Architect: Lake|Flato

The Project: Lake|Flato was commissioned to develop an innovative master plan to redesign the Full Goods Warehouse at the historic Pearl Brewery complex in San Antonio, Texas.

The Design Approach: Because the original nature of the building was metal, the design team believe it made sense to use steel structures that lend themselves to the philosophy of the project. It was an industrial brewery site and so they wanted to bring a certain level of grit to it so that it felt authentic. To accomplish this, the original structure of the warehouse was preserved, but it was made more efficient with the addition of a mezzanine level constructed from steel structural systems and metal panels in an effort to blend the old and the new into an extensive, flexible space.

The Sustainability Strategies: Besides the authentic aesthetic, the other benefit of using a metal building system for this project was that the use of steel incorporated the commitment to sustainability. Inside, the building is naturally lit and cooled by large fans and breezeways that take advantage of San Antonio’s temperate climate. The total commitment led the project to be LEED Gold certified for its sustainable site development, water conservation, energy efficiency, materials selections, and indoor environmental quality.

The Results: The designer says that there is an array of benefits to using metal buildings, but from an architect’s perspective, he sees unique beauty in the structures beyond their utilitarian characteristics. “I just love being able to use metal buildings because they’re so beautiful,” he says. “I’ve done a number of designs with them because they provide that grit that is cool and they relate well to so many different types of uses and environments.”