Construction and Demolition Waste Management

Building construction and demolition generally produces a lot of on-site waste, which is why LEED offers up to 2 credits to reduce and manage it. It is advantageous, then, that all the components of a metal building system are custom designed and efficiently fabricated in an off-site, controlled environment. They are then delivered to the site according to a pre-determined construction schedule. That means there is no extra material sent to the construction site with very little, if any, field cutting required. In fact, metal buildings typically generate more than 50 percent less job-site waste than other construction approaches. In most cases, they have readily achieved the LEED credit for Option 2—Reduction of Total Waste Material—generating no more than 2.5 pounds of waste per square foot of a building’s floor area.

Indoor Environmental Quality

People spend most of their time inside buildings, including metal buildings. The quality of their indoor experience, including impacts on their health and well-being, is directly related to the quality of the indoor environment. In that regard, sustainability and green building have always included a focus on this critical part of building design, including the following aspects.

INNOVATION PROJECT

Photo courtesy of MBMA

Project: Costco Stores
Location: Nationwide
Architect: MG2

The Context: According to Ali Moayeri, senior vice president of construction for Costco Wholesale Corporation, the technology used for fabricating and constructing metal buildings has improved so substantially over the past few decades that this multinational retail corporation now uses metal building systems to construct 90 percent of its new warehouse stores.

The Metal Building System Attributes: “Costco first tested using a metal building system 32 years ago in California,” Moayeri says. “Since then, the technology and process for completing metal building projects have improved considerably. For example, metal building manufacturers can now achieve 60-foot spans between rafters. That has enabled us to eliminate three bays, 200 joists, and 33 columns. These changes result in a cost savings of about $150,000 per warehouse store and increase our flexibility for merchandising.” Speed of construction, durable and attractive exterior finishes, innovative coating processes, and the ability to achieve a lightweight, strong structure are also key benefits described by Moayeri and others involved in the design and construction of Costco stores.

Low-Emitting Materials

Emissions of volatile organic compounds (VOCs) inside buildings has been documented to be detrimental to human health, both in the short term and long term. Therefore, LEED offers up to 3 credits to reduce or eliminate VOCs and other substances from buildings, particularly as found in painting, adhesives, coatings, etc. Metal building components typically have coatings and paint applied to the steel off-site in a controlled fabrication facility. Therefore, they do not affect the VOC calculations within this credit. More importantly, VOC emissions from painted or primed metal building components are very limited, thus helping to avoid human exposure to these compounds.

Daylight

Daylight has been found to provide significant health benefits, both physical and mental health. Because of the compelling nature of this aspect of green buildings, LEED offers up to 3 credits for buildings that provide natural daylight to occupied areas of buildings. Designing metal buildings to incorporate daylight to help achieve this credit is readily possible with a variety of design approaches using windows, sidelights, and skylights. A common metal building product also includes light-transmitting, translucent panels installed on the metal roof or wall area. Any of these strategies may also include diffusers to enhance the light distribution and light quality.

Looking a little further into this topic, customizable fenestration is an important attribute in the design of metal buildings just as it is for any occupied structure. All buildings need fenestration openings for egress, light, and ventilation. However, providing those openings in a manner that is sustainable is a function of controlling the things that pass through them. While it is important for windows, doors, and skylights to admit light, it is equally important to restrict solar heat gain when air-conditioning is in use. Conversely, heat loss and air infiltration through fenestration are energy concerns when the building is being heated. Proactively, the fenestration industry has developed products with performance characteristics related to overall thermal U-factors, solar heat gain coefficient (SHGC), visible light transmission (VT), and air infiltration. These commercial products can be readily incorporated into metal buildings, and, in some cases, the metal building manufacturers offer their own customizable products in the form of windows, skylights, and translucent wall and roof panels.

Innovation in Design

Sustainability usually involves innovation—thinking beyond the customary or the norm to achieve the desired outcome or results. LEED can seem rather prescriptive to some, but its intent was never to limit creativity or innovation. As such, there are multiple credits available for innovation and creative ways to achieve more sustainable and well-designed buildings. Some LEED innovation credits rely on showing how a particular design exceeds the minimum requirements to earn a credit. It should be clear by now that metal building systems have advantages that can certainly help in that regard. There are also other ways to incorporate innovation, and the design flexibility, customization, and affordability of metal building systems certainly help in that regard as well. Even if a particular innovation doesn’t fit into a category to achieve an additional credit, the net result for the building can still be quite positive to benefit the owner, the users, and the environment.

Conclusion

Metal buildings have been shown to be a preferred way to design and construct green and sustainable buildings in all parts of the country. The design is fully flexible, customizable, and economical with metal building systems proving to be applicable to any type of commercial, industrial, or institutional low-rise building. They have also been shown to contribute very significantly to earning credits under the LEED green building rating system. For more information or to see any of the resources described in this course, you can refer to the MBMA website at https://MBMA.com.

Peter J. Arsenault, FAIA, NCARB, LEED-AP is a nationally known architect and a prolific author advancing sustainable buildings through better design. www.pjaarch.com, www.linkedin.com/in/pjaarch