Brick and Structural Clay

SPECIAL SECTION/BRICK & CLAY RECORD: Pushing for Green

October 31, 2008
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Industry can help make the case that clay brick is the most sustainable green building material available.



Green building design and sustainability are becoming more and more integrated in today’s culture and vernacular. Articles on this topic are appearing in news outlets more than ever before. More than 100 cities have requirements for green buildings, and standards for green building design and sustainability are gaining a stronger foothold in residential construction as well.

The whole idea of green is here to stay. Brick manufacturers and distributors have a great opportunity to promote brick because its innate attributes frequently represent the same goals emphasized by the advocates of green building design and sustainability.

Versatile Green Cladding

Environmentally preferred products are those that have a lesser or reduced effect on human health and the environment when compared to competing products that serve the same purpose.1 In “Evaluating and Selecting Green Products from the Whole Building Design Guide,” John Amatruda, RA of Steven Winter Associates, states that green products available today offer one or more of 13 health and/or environmental attributes, most of which brick qualifies for.

Brick is durable and requires little maintenance. While brick’s service life is projected at more than 100 years, brick structures have surpassed this benchmark in numerous instances. Brick can also be salvaged from existing or demolished buildings for reuse. Most reclaimed brick is salvaged from buildings constructed 50 to 60 years ago and laid with lime and sand mortar (not mortar made with Portland cement).

It should be kept in mind that older brick manufacturing and construction processes differ from those of today. Brick from this era were primarily made in periodic and scove kilns. Unlike contemporary tunnel kilns, greater temperature variations were present in the kiln during firing. These variations resulted in brick with a wide range of properties, from over-burned brick (commonly referred to as “clinkers”) to hard-burned brick to under-burned brick (known as “salmons” due to their usual pinkish-orange color).

Typical design and construction practices at that time used brick through the full thickness of the wall, whereas today it is used primarily as a veneer. Most exterior brick walls were loadbearing and at least 12 in. thick with three wythes of brick. The hardest, most durable units were placed in the exterior wythes; the salmons (and others) were used for wythes inside the wall and were not exposed to the weather. As a result, when brick are salvaged from buildings of this era, they can be used in different settings depending on their type. For example, salmon brick and other interior wythes should not be exposed to weather but can be used in interior settings.

Since brick masonry avoids the release of volatile organic compounds (VOCs), it promotes good indoor air quality (typically through reduced emissions of VOCs and/or formaldehyde). VOCs are often found in paints and coatings applied to interior surfaces, but brick does not require the painting or other maintenance typically associated with other interior finishes. In addition, brick does not support mold growth, which can be another concern when it comes to indoor air quality.

Brick incorporates recycled content (post-consumer and/or post-industrial), and non-hazardous waste products like petroleum-contaminated soil or sludge can be used. Recycled waste from other industries, such as fly ash from coal-fired generators, glass, stone dust and ceramic tile, can also be incorporated in limited amounts. In addition, reclaimed industrial metallic oxides can be used as colorants in brick.

Because fired brick is inert, brick can safely encapsulate many materials. When brick are fired, the individual clay particles are fused together through vitrification. Some brick manufacturers have used clay or soil that would have otherwise been considered waste, such as mine tailings, clay from gravel and sand washing operations, fireclay overburden from coal mining, and excavated soil from swimming pool and road construction. In addition, brick itself can be recycled in the production process.

Unlike with other cladding materials, many local communities prefer to retain the original brick in renovated buildings rather than replace it. When old brick factories, warehouses or other structures are renovated, product resources are conserved, demolition waste is diverted and the life of the building stock is extended. Brick can also be re-used on the ground. Clay pavers set in sand can easily be reused in the future. When underground utilities must be accessed in pavements with sand-set clay pavers, the pavers can be removed, stockpiled and reused.

Brick is made using natural and/or renewable resources. Oxygen, silica, aluminum and iron-the elements that make up the clay and shale used to make brick-are the four most abundant elements in the Earth’s crust. Soils made of these elements are not viable for agriculture without the addition of fertilizers and supplements. Most brick plants use material from the same pit extracted through multiple soil layers for a minimum of 50 years, thus minimizing the impact to the surface area.

Once a pit’s material production has subsided, mined areas are reclaimed for future use by replacing overburden and topsoil. The resulting property can be used for a variety of functions, including farmland, residential and commercial sites, and even wetlands. In this way, valuable clay and shale resources are obtained while still enabling the land to be reused for different purposes.

Brick has low embodied energy, which is the energy required to produce and transport the product. The average amount of energy required to extract raw materials and manufacture and deliver brick has decreased significantly from just a few decades ago. Circa 1970, around 4000 Btu per pound of brick was required, while the current industry average is approximately just 1239 Btu per pound.

In addition, almost all of the mined raw materials are used in the finished brick product. Nearly 95% of all the mined clay and shale goes to the plant, and an average of only 3½% of the manufactured product ends up as scrap, most of which is returned to the manufacturing process or recycled for secondary uses like structural fill.

Brick does not contain chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) or other ozone-depleting substances. With today’s environmental concerns, the brick industry recognizes the need for compliance with state and federal regulations for clean air and the environment. Air emissions are minimized with controls like scrubbers installed on kiln exhausts. Lime waste that accumulates in scrubbers is often recycled as a beneficial additive to soil. In addition, dust in brick plants is controlled through the use of filtering and containment systems, vacuums, additives, and water mists. Even vehicular emissions are being addressed, with brick manufacturers monitoring truck emissions; recycling waste oil, antifreeze and hydraulic oil; and regulating truck speeds for improved fuel efficiency.

Brick does not contain highly toxic compounds, and its production does not result in highly toxic byproducts. For that matter, except for the 5% of mined raw material that does not make it to the plant, and the 3½% of scrap loss in the plant, there are no solid by-products either. Brick is a 100%  non-organic, inert material.

Most brick is manufactured with materials obtained from within a few miles of the manufacturing plant. The average distance that raw materials travel to a plant is 15 miles. In addition, brick manufacturing facilities are located in 38 states across the country and in close proximity to urban areas. More than 25 plants on average are located within 500 miles of the 50 largest metropolitan statistical areas (MSAs) in the U.S. At least two brick plants fall within 500 miles of 49 MSAs, and more than 70% of these MSAs have at least one plant within 200 miles.

Unlike other cladding materials that need several other components to make a sufficient wall system, brick masonry walls perform multiple functions by themselves, thus reducing a building’s environmental impact. In fact, a single brick wythe can:
  • Serve as a load-bearing structural element.
  • Provide an interior or exterior finish without the need for paints or coatings.
  • Provide acoustic comfort with a sound transmission class (STC) rating of 45 or greater.
  • Regulate indoor temperatures as a result of thermal mass.
  • Provide fire resistance (a nominal 4 in. brick wall has a one-hour fire rating).
  • Provide impact resistance from wind-borne debris or projectiles.
  • Improve indoor air quality by eliminating the need for paint and coatings (no VOCs).
  • Provide a non-combustible material that does not emit toxic fumes in fires.
  • Provide an inorganic wall that is not a food source for mold.
  • Serve as a heat-storing element in a passive solar design.
  • Last for generations or even centuries.


Educating the Industry

Members of the brick industry can and should learn more about brick’s role in the green building movement. As noted in the August 2008 Brick & Clay Record (“Building Green,” and available online at www.ceramicindustry.com), the Brick Industry Association (BIA) recently launched a new website at www.greenbrick.com that focuses on brick’s role in green building design and sustainability. The site offers the BIA’s latest green building design and sustainability technical information, as well as links to the prevailing residential and non-residential rating systems.

The site also features Brick Gallery, an interactive feature that allows users to search and download projects from the BIA’s awards competitions for the past several years. Searches can be narrowed to include sustainable and/or green building projects, a category that will surely grow in the near future.

Many of the BIA’s publications can be seen and/or downloaded from the site as well. For example, Builder Note 5: Green Building Design and Sustainability shows how brick can attain ratings points from both NAHB and LEED, and Technical Note 48: Sustainability and Brick is in its second edition. The site also hosts the BIA’s new online Sustainability/Green Building Design course, which is available to BIA manufacturer and distributor members at no charge.

From historic landmarks to contemporary architecture, brick masonry provides superior performance and durability in green building and sustainable design. The BIA has assembled the materials necessary to help the industry make a strong case for brick and is continuing to develop methods to best position this timely-and timeless-building material.

For more information regarding brick’s role in green and sustainable building, contact the BIA at 1850 Centennial Park Dr., Suite 301, Reston, VA 20191; (703) 620-0010; fax (703) 620-3928; e-mail brickinfo@bia.org. Technical Notes and other information on many of the topics discussed in this article can be found online at www.gobrick.com.

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