Green Attributes of Products and Materials

by Nadav Malin
excerpted from The Architects Handbook of Professional Practice, Fourteenth Edition

Ed. note: The article below is a sampling of new content, which makes up a third of the recently released The Architects Handbook of Professional Practice, Fourteenth Edition, edited by the AIA and published by John Wiley & Sons Inc. It is drawn from Section 12.8, “Environmentally Preferable Product Selection,” and was written with the intention of helping building professionals make more informed choices about products by understanding the standards that currently govern and guide their classification as ”green.”

For a range of social and cultural reasons, certain characteristics of building materials have been widely adopted as indicators of environmental preferability. These “green attributes” include recycled content, low indoor chemical emissions, and the possibility of using a product in its natural state; in other words, with minimal manufacturing. Because of a general familiarity with these attributes, products with any one of them are often selected for use in a building in place of other products, even though the others may, in some cases, have a lower overall environmental impact.

“Green attributes” include recycled content, low indoor chemical emissions, and the possibility of using a product in its natural state; in other words, with minimal manufacturing

Most existing EPP [Environmentally Preferable Product] programs, including purchasing mandates from government agencies and voluntary programs such as the U.S. Green Building Council LEED Green Building Rating System®, are based on specific green characteristics of products. Sometimes these green attributes are targeted as part of explicit social agendas. In such cases, the term “EPP” is applied as a way of broadening the appeal of what is fundamentally a narrowly focused initiative. In other instances, an agency or organization may actually intend to promote the use of products that are environmentally preferable in a broader sense, but for practical purposes uses a single green attribute as a preferable environmental indicator.

Recycled content
Promoting recycled content, as an overall preferable environmental indicator, is an example of using a specific societal agenda to make particular products attractive. The recycled content prerogative is a response to the problem that emerged when recycling first became popular—the accumulation of collected material that did not have a viable end use. The federal EPA, many state agencies, and other organizations all have programs that promote or mandate the use of materials with recycled content under the mantra of “closing the loop.”

Nearly all recycled-content programs distinguish between post-consumer recycled materials, which have been discarded after fulfilling their intended use, and pre-consumer (or “post-industrial”) recycled materials

Nearly all recycled-content programs distinguish between post-consumer recycled materials, which have been discarded after fulfilling their intended use, and pre-consumer (or “post-industrial”) recycled materials. Pre-consumer materials are those that have entered a waste stream before reaching their intended end use, such as paper trimmings at a printing plant. Most definitions of pre-consumer recycled materials specifically exclude those that are reused within a single manufacturing facility or operation, since those materials have never become “waste” at all. For example, glass manufacturers routinely break off-spec glass at the end of the processing line and melt it again to make new glass.

Further confusing matters, the EPA uses the term “recovered material” to include both post-consumer and pre-consumer recycled material, but other organizations use the term more broadly to include materials that would not qualify as recycled under most definitions. For example, the Composite Panel Association’s EPP specification includes logging slash—tree tops and limbs not useable as lumber—and logs from forest thinning operations in its definition of the “recovered fiber” used in making particle-board and medium-density fiberboard.

Bio-based sources
In theory, building materials derived directly from plants are renewable indefinitely and, as such, represent a solution to the problem of products whose manufacture adds to the depletion of finite mineral resources. Plant-based materials tend to be less manufacturing-intensive than materials produced from petrochemicals as well. Their structural qualities are typically provided by the cellular structures of the plants from which they are made. Some agricultural products, however, are grown with extensive use of pesticides and herbicides and in a manner that contributes to the loss of topsoil.

The U.S. government has long promoted the use of agricultural materials as a way of supporting farms, most recently in the 2002 Farm Bill, which mandates that federal agencies establish preferential purchasing programs for certain types of bio-based materials

The U.S. government has long promoted the use of agricultural materials as a way of supporting farms, most recently in the 2002 Farm Bill, which mandates that federal agencies establish preferential purchasing programs for certain types of bio-based materials. The Department of Agriculture initiative for implementing this mandate includes a program to label bio-based materials and promote new markets for them. Wood, although obviously bio-based, is excluded from the draft regulation because it is deemed to have a mature market. To address concerns about ecological problems with bio-based materials, the Farm Bill includes a screening process based on environmental life cycle assessments.

Other incentives to promote bio-based materials, such as a credit for using rapidly renewable materials within the LEED rating system, also exclude wood products on the basis of their relatively long rotation time. This exclusion of wood is at least partly driven by concerns among environmentalists about the impact of logging on sensitive and threatened ecosystems. These concerns are further addressed through the introduction of certification programs for good forestry practices.

Low chemical emissions
In response to concerns about indoor air quality in buildings, the off-gassing of chemicals from building materials and furnishings is increasingly being scrutinized. Many of the substances under investigation fall into the category of volatile organic compounds (VOCs), a term that describes carbon-based compounds that occur as gases under ambient temperature and pressure conditions. Some VOCs are known to cause adverse health effects and discomfort, and many contribute to smog. Not all VOCs are harmful, however, and some (both harmful and benign) occur naturally in the environment.

Some VOCs are known to cause adverse health effects and discomfort, and many contribute to smog. Not all VOCs are harmful, however, and some (both harmful and benign) occur naturally in the environment.

The off-gassing of VOCs and other substances is measured by placing a sample of the product or material in a stainless steel testing chamber and collecting then analyzing the gases emitted into that chamber. The Carpet and Rug Institute began using this process in the early 1990s as the basis of its Green Label program, which certifies that emissions of total VOCs and certain specific compounds from carpets do not exceed specific thresholds. Beginning in 2004, the Green Label program was replaced with the more robust and stringent Green Label Plus program.

The lab that developed and still implements Green Label Plus for the carpet industry, Atlanta-based Air Quality Sciences Inc., expanded the program to other industries via the nonprofit Greenguard Environmental Quality Institute. Greenguard establishes allowable chemical emission thresholds for a wide range of materials used indoors and certifies products that do not exceed those thresholds. Greenguard is referenced in the LEED for Commercial Interiors program as an approved certification program for furniture systems. More recently, the furniture manufacturers’ trade association, BIFMA International, introduced its own similar standards for testing indoor emissions from furniture.

Greenguard emphasizes compounds that have been shown to affect building occupants right away (acute effects), while California is more focused on chemicals associated with long-term health problems

In California, a specification was developed for state office buildings using a similar type of chamber testing for products, but with a different list of chemicals and allowable concentrations to determine compliance. This specification is codified in Standard Practice for the Testing of Volatile Organic Emissions from Various Sources Using Small-Scale Environmental Chambers. The California protocol has become the basis of the FloorScore certification program for resilient and hard surface flooring and the Indoor Advantage Gold product certification from the Scientific Certification Systems (SCS). SCS also provides the LEED-compliant certification program Indoor Advantage™.

Although both Greenguard and the State of California rely on testing methods using stainless steel chambers, their programs differ in other ways. Greenguard requires samples to be collected directly from the manufacturing line and tested immediately to capture the worst-case emissions. California calls for a two week conditioning period before samples are tested to get a more accurate reflection of conditions when a space is occupied. One explanation for this difference in protocol is that Greenguard emphasizes compounds that have been shown to affect building occupants right away (acute effects), while California is more focused on chemicals associated with long-term health problems and has much stricter limits on those chemicals than Greenguard. However, a new standard from Greenguard—targeted specifically at products for children and schools—incorporates the California thresholds based on long-term health concerns.

Naturally and minimally processed materials
Although there are few formal ways to reference or certify natural materials, designers and their clients generally consider natural or minimally processed products to be environmentally preferable. Included in this category are natural fiber carpets and fabrics, natural stone floors, cork, linoleum, and bamboo. The use of wood is omitted from this category, at least in North America. In the U.S., concerns about the destruction of domestic old-growth forests and deforestation in the Amazon and other tropical rainforests have discouraged some designers from embracing wood as a green material. In Europe, however, wood is generally considered to be a sound ecological choice.

To assuage concerns about the sustainability of wood, several certification and labeling systems have been developed to provide some assurance that wood from certain sources is a good ecological choice.

To assuage concerns about the sustainability of wood, several certification and labeling systems have been developed to provide some assurance that wood from certain sources is a good ecological choice. The most widely accepted system is the Forest Stewardship Council (FSC). This international organization establishes regional forest management plans based on its “Principles and Criteria for Forest Stewardship” and then accredits third-party organizations to certify forest operations for conformance with these plans. The FSC also requires certification of every organization in the chain of custody for the wood to ensure that wood from certified well-managed forests is not inadvertently mixed with uncertified wood.

A number of countries, including Malaysia and Indonesia, have developed their own forest certification programs, but these programs have failed to establish credibility among wood buyers, primarily in Europe. In response, these programs have merged with the FSC system to meet FSC requirements. In North America, the Canadian Standards Association (CSA) and the American Forest & Paper Association (AF&PA) have created other certification programs, which are preferred by most of the forest products industry. Over time, both the CSA National Standard for Sustainable Forest Management and the AF&PA Sustainable Forest Initiative® have evolved to a level of rigor that seeks to match that of the FSC program. Proponents of the industry-supported system argue that their programs are now equivalent to those of FSC, but many environmentalists are unconvinced. Given the complexity of the systems and the ecological and business environments in which they are used, comparing them is not easy.

Low embodied energy
Another indicator used to measure environmental impact is the amount of energy used to create a product. This metric is sometimes called “embodied energy,” “embedded energy,” or the “energy intensity” of a product. Measures of embodied energy include the quantity of fuels and electricity used to mine or harvest raw materials, transport them, and process them into a product ready for delivery to a construction site. The embodied energy of a product is not something that can be readily found on a label or manufacturer’s Web site, but some international researchers have estimated embodied energy figures for certain product groups.

Measures of embodied energy include the quantity of fuels and electricity used to mine or harvest raw materials, transport them, and process them into a product ready for delivery to a construction site

Embodied energy is often reported in units of BTUs per pound, or gigajoules per tonne. For these figures to be useful in comparing products, it is necessary to also consider the weight of the material in question and how much of it is needed to perform a given function. For example, concrete may have a lower embodied energy than kiln-dried lumber on a per-pound basis, but if it takes many more pounds of concrete to perform the same job, the lumber needed to support a structure will likely have lower embodied energy. The comparison is complicated even further by the question of durability or longevity. If the concrete structure will last significantly longer than the wood structure, the additional longevity should also be factored into the comparison.

Reprinted with permission of John Wiley & Sons, Inc.