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Long-spans amplify the collaborative relationship between architects and engineers

By: Richard C. Master, AIA, CSI
Chair Emeritus, Specifications and Building Technology, Professional Interest Area (PIA), AIA
Manager, Architectural Systems
USG Corporation

Given these benefits, the use of recaptured gypsum in drywall would seem to be a win/win scenario. And in most cases, it is. However, when the embodied energy required to transport the panels over a longer distance is factored in, the green value of recaptured gypsum can be significantly diminished. When a recaptured gypsum panel is shipped more than about 200 miles by truck or 400 miles by rail, the environmental benefits of the recaptured content in the board are offset by the increased energy required for long-distance transportation. In other words, it doesn’t make environmental sense to ship recaptured gypsum panels made in Alabama to a job site in California.

The same premise holds true with other recycled and renewable products, making transportation a key factor to be aware of when creating sustainable specifications.

With that said, let’s take a closer look at how gypsum board, acoustical ceiling panels, cement board panels and gypsum fiber panels rate in terms of the reduce, recycle and renew principles.

Gypsum Board Panels

	Cement board panels are made from approximately 20 percent recycled materials, including fly ash, a by-product of power plant emission control processes.
	To minimize construction waste, conduct a pre-construction meeting with contractors to discuss waste and disposal strategies and to explore alternative reuse options.

Gypsum board scores extremely high on nearly all sustainable design criteria. Gypsum, the primary raw material used to make wallboard, forms naturally like salt or limestone, and is one of the most abundant minerals on the planet. It is neither rare nor endangered.

The bulk of the remaining materials in gypsum board consist of paper (recycled, from newspapers, phone books, old corrugated cartons and cardboard cuttings) and corn or wheat starch binders. The corn and wheat starch binders are renewable agricultural resources and are environmentally superior choices compared to using polymers derived from petroleum.

The embodied energy of gypsum board is extremely low. Drywall has less embodied energy than a wide variety of building products, including brickwork, concrete, particleboard, insulation, glass, vinyl flooring, plastics, steel and aluminum.

It is also important to note that manufacturing gypsum board is a low-waste production process. Approximately 95 percent of the raw materials entering a board plant leave as finished product. And most of the remaining 5 percent is recycled into small strips used to support stacks of finished gypsum panels. Overall, high-efficiency board plants can produce less than 1 percent material waste.

Manufacturers are now using hundreds of thousands of tons of recaptured gypsum to produce wallboard, reducing power plant landfill needs. Both mined and recaptured gypsum can also be reused to manufacture new gypsum panels. Other reuses include soil amendment (using gypsum as a high-calcium fertilizer or as a method for treating high soil pH), neutralizing the high pH levels caused by road salt applications, odor treatment and concrete set.