By Jack Maxwell

Jul 26, 2016

For a century, one ASTM technical committee has helped steer the modern evolution of the ancient construction material known as gypsum.

One hundred years.

That's how long ASTM Committee C11 on Gypsum and Related Building Materials and Systems has been active, helping to shape the evolution of one of the most ubiquitous materials in the inventory of modern construction products - gypsum.

As ASTM marks the centennial of C11's formation, let's pause for a moment to look back at the history of this important committee, assess its many accomplishments and look ahead to a future where gypsum drywall and other gypsum-related products are key components of ever more sophisticated wall, ceiling and floor systems - offering performance undreamed of in 1915.

A (Very) Abbreviated History of Gypsum

The use of gypsum as a construction material dates back thousands of years. It was mixed with sand and utilized as construction mortar and plaster in the Egyptian pyramids¹ and has been found in ancient structures from South America (the Incas) to Mesopotamia (Babylon) to the Indian subcontinent.

Fire resistance is one of the key attributes of gypsum, and was recognized as far back as the Roman Empire. After the Great Fire of London in 1666, France's Louis XIV ordered that all wooden buildings in Paris be protected with gypsum plaster because of its fire-resistant properties.² Benjamin Franklin became interested in gypsum during his years as America's first ambassador to France and introduced the use of the mineral to the United States.³

Formation of gypsum plaster into boards began in England in the late 1800s, pioneered by the Sackett Plaster Board Company. This firm was purchased in 1909 by USG, then known as United States Gypsum Company, which was formed in 1901 by the merger of some 17 independent gypsum mining and plaster companies. (See the Business Case article, "Safety and Quality: Assured," for more.)

Sackett board consisted of multiple layers of gypsum plaster and wool felt paper, with untaped edges. It was very heavy and difficult to handle. In 1917, an improved version made with just a single layer of plaster encased in paper facing and taped edges was introduced. This new product evolved into today's modern gypsum board, also known as drywall. Through the 1940s, using wet plaster remained the dominant practice for finishing walls and ceilings, but beginning with the post-World War II construction boom, innovations in gypsum products and technologies led to drywall becoming the predominant means of finishing building interiors and providing fire and acoustic control in buildings today.

A Committee Is Formed

ASTM Committee C11 was formed in 1915 to address the need for consistent standards in the nascent gypsum products industry. According to an article written by Gene Erwin (longtime ASTM member and former C11 chairman) for SN on the occasion of C11's 75th anniversary in 1990, one of the committee's first actions was to develop standard C11, which comprised definitions of terms for gypsum and related products and helped create a common language for the discussion of issues related to gypsum products.⁴

Erwin's article goes on to list some of C11's other early accomplishments: "From 1919 to 1930 the committee promulgated specifications for gypsum, gypsum plaster, aggregates, molding plaster, Keene's cement, dental and pottery plasters, gypsum plaster board (later gypsum wallboard and gypsum lath), gypsum block or tile, and gypsum sheathing board." The 1960s and 1970s saw the committee's scope widen to include a number of products related to the installation of drywall, such as joint tape, adhesives and bonding compounds, steel framing and fasteners, as well as gypsum-based products like backing board. During this era the committee also expanded its purview to encompass application and installation standards for these products.

Not Your Grandfather's Drywall

One of the challenges faced by C11 - and indeed almost every ASTM committee - is the phenomenon of the "moving target." Even as standards and test methods for the current iteration of a particular product work their way through the committee, advances in material science and manufacturing technologies result in new products to complement or supersede existing products. Depending on the nature of the new products, these may require new test methods and standards.

Keith Poerschke is chairman of Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products and director of external services at National Gypsum Company, Charlotte, North Carolina. "Gypsum board is basically a commodity product that didn't change much during the first 80 years or so," he says. "But in the last 20 years, fiberglass mat facing was introduced as a replacement for traditional paper facing. The committee had to develop new standards because a lot of the strength of the board derives from the mat."

Other examples of the inexorable march of product innovation in the drywall market are impact- and mold-resistant board, sound-attenuating board and lightweight board. "Back in the 1970s, C11.01 eliminated minimum weight requirements for board and replaced them with performance requirements; they were removed because they stymied the development of new products," Poerschke says. "More recently, changes in technology and manufacturing processes have ramped up the move to lighter weight alternatives, which still must meet those performance requirements developed in the '70s."

Subcommittee C11.01 focuses on products themselves, working closely with gypsum board manufacturers. Robert Wessel, a longtime member of C11 who is senior director of technical services at the Gypsum Association, Hyattsville, Maryland, says, "This committee gets things done."

The Quest for Consensus

Subcommittee C11.02 on Specifications and Test Methods for Accessories and Related Products is responsible for a wide range of products used in gypsum board wall systems, including metal studs and lath, nails, screws, joint compound and tape. There are different trade groups for each product category, each with their own perspectives. The standards for these products must work with standards like C1396/C1396M, Specification for Gypsum Drywall.

Fortunately, the collaborative structure of ASTM helps smooth the way. The chairman of Subcommittee C11.02, Michael Kerner, code development manager at ClarkDietrich Building Systems, Westerville, Ohio, says that, "During the standards development process, members of the various subcommittees often seek or contribute input to each other. Part of this development process sometimes results in contrary points of view ... but that is part of the consensus process itself, and the resolution of these conflicts follows the rules of ASTM."

Subcommittee C11.03 on Specifications for the Application of Gypsum and Other Products in Assemblies sorts through the many regional approaches to application and installation of exterior Portland cement-based plaster. "They do things differently in different parts of the country because of variations in weather and other environmental conditions," says Lee Jones, C11.03 chairman and director, technical services, for the Association of the Wall and Ceiling Industry, Falls Church, Virginia.

Jones points out that key ASTM installation and application standards may not necessarily be the best or only way to do the work. "In fact, our group has an ongoing discussion of whether regional standards would be better." This issue is serious enough to warrant a task group called the Stucco Work Group, which conducts virtual monthly meetings to discuss and resolve issues concerning stucco standards and will host a workshop on stucco control joint installation requirements in May.

Members of Subcommittee C11.05 on Application of Exterior Insulating and Finish Systems and Related Products have developed three standards for the application of three different EIFS classes. This group works closely with Subcommittee E06.58 on EIFS, part of ASTM Committee E06 on Performance of Buildings, on the development of test methods and specifications.

A Century of Impact

The work of ASTM Committee C11 has been integral to the development of safer, better performing wall systems. Following are just a few examples of the impact of this legacy committee.

The committee's drywall performance and installation standards are referenced in the International Building Code, providing guidance to architects, specifiers and contractors.

In response to problems with substandard drywall produced outside the United States, the Drywall Safety Act of 2012 charged the U.S. Consumer Product Safety Commission with developing rules concerning the sulfur content of gypsum board. Committee C11 provided a mechanism by which the industry could develop parameters and provide input to the CPSC. "The ASTM process gave us a way to work through this situation in a relatively short period of time, about a year to a year and a half," says Poerschke. The result was the adoption of the newest edition of ASTM C1396. (For more detail, see the article, "ASTM International Standards Used for U.S. Drywall Act.")

Committee C11 has developed standards for fiber-reinforced gypsum panel, glass mat used as sheathing and coated glass mat gypsum backing panel. All have helped pave the way for the increased use of high performance drywall that improves the safety and durability of buildings around the world.

Pamela Shinkoda, who is manager, technical solutions and quality at CGC, Mississauga, Ontario, Canada, is the current chairman of C11. "The work of this committee helps manufacturers improve efficiency, makes it easier for installers to apply and fasten drywall, and ensures that, as products change, the performance is still up to the standards the public is expecting. Members of the committee put in a lot of effort and time - on a volunteer basis - to make this all happen."

A lot can happen in 100 years. The original members of ASTM Committee C11 would probably be amazed at how the gypsum industry has changed. But they would undoubtedly recognize the kindred spirits who continue the work they began, and offer a tip of the cap and a "job well done" to current and future members of this committee.

References

1. Gypsum Association, "Gypsum Through the Ages."

2. USG, "Fire Performance."

3. Gypsum Association, "Gypsum Through the Ages."

4. Erwin, A.E., "The Evolution of Space Enclosure from Mud and Reeds to Modern Walls and Ceilings," ASTM Standardization News, Vol. 18, No. 12, Dec. 1990, pp. 44-48.

Jack Maxell is a freelance writer based in Westmont, New Jersey.