Drywall (FGD)

Drywall is ubiquitously used in building construction as interior wall enclosures, ceilings, and partitions in both load-bearing and non-load-bearing cases. There are many types of drywall including but not limited to acoustical, fire-resistant, moisture-resistant, and mold-resistant varieties. Recently, lightweight drywall that is approximately 0.3 lbs/ft² lighter than standard drywall has also become common. This Common Product profile represents a standard drywall product. Drywall is composed of gypsum plaster pressed between a paper lining. The key material is gypsum (calcium sulfate), which is available in different hydration levels, and in anhydrous form. Natural gypsum stone is calcium sulfate-dihydrate (CaSO4*2H2O). The anhydrous calcium sulfate can be found in nature as anhydrite (CaSO4). Gypsum also occurs in large quantities as the industry by-product, otherwise known as flue-gas desulphurization (FGD) gypsum. There are not significant differences in the composition of finished drywall products made using these different source materials, but natural gypsum is preferred over FGD gypsum because the FGD drywall production process can release mercury into the environment. The amount of FGD and natural gypsum used in drywall varies regionally. Products tend to be composed primarily of one type or the other. Boards can also contain around 1% recycled scraps from the drywall manufacturing process and less commonly, scraps from drywall installation or demolition. This common product profile characterizes a drywall product made with FGD gypsum.

Historical versions of standard drywall CPs for products containing various levels of natural and FGD gypsum can be found here:
Historical Common Product: Drywall (Natural Gypsum) - 2015
Historical Common Product: Drywall (FGD) - 2015
Historical Common Product: Drywall (Mixed Gypsum) - 2015