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