Natural Stone Fact Versus Myth: Addressing Common Misconceptions Educational-Advertisement

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Photo courtesy of Gallegos Corporation CONTINUING EDUCATION

The columns and cladding for the Ralph Carr Colorado Judicial Center in Denver are composed of granite.

Natural Stone Fact versus CONTINUING EDUCATION

1 AIA LU/ELECTIVE

Myth: Addressing Common Learning Objectives After reading this article, you should be able to: Misconceptions 1. Compare and contrast the performance of natural stone to artificial materials used in Sponsored by Natural Stone Institute similar applications. 2. Counter myths around natural stone regarding its cost, maintenance atural stone is a beautiful, Natural stones are stones that have been requirements, and sustainability. durable, and sustainable mate- harvested from their in-situ positions in 3. Describe the resources and applicable test standards relevant to natural stone. rial that can be used for a broad the earth, then cut and machined into final N 4. Explain how natural stone can satisfy range of interior and exterior applications. products without alteration to the natural green building goals and support overall Unfortunately, some design profession- fabric of the materials. They may be cut sustainability of building projects. als are hesitant to specify natural stone, into shapes, including slabs and tiles. either because they are unfamiliar with Though a resin or sealer may be applied to To receive AIA credit, you are required to the product or have questions regarding its the face, the internal fabric of the stone is read the entire article and pass the quiz. maintenance requirements. In fact, when unchanged. By contrast, engineered prod- Visit ce.architecturalrecord.com for the the natural right stone is selected for the ucts that are made from aggregates bound complete text and to take the quiz for free. right application and installed properly, it together with cementitious or resin binders AIA COURSE #K2104M can perform for decades. do not meet the definition of natural stone.

1 NATURAL STONE FACT VERSUS MYTH: ADDRESSING COMMON MISCONCEPTIONS EDUCATIONAL-ADVERTISEMENT

This abundant and variable material of the earth’s crust. They include such ASTM Test Standards defines many of the world’s iconic build- common minerals as quartz, feldspar, and ASTM Test Standards relevant to natu- ings, both ancient and contemporary. mica. Siliceous stones tend to be strong and ral stone can be divided into two broad The fact that some of these buildings have resistant to acids. categories: those that pertain to the stone’s endured for centuries is a testament to the Natural stone also can be categorized physical performance, and those that tell material’s strength and resistance to wear. by how it is formed. Sedimentary stones us something about how the stone will per- Dimension stone is cut or sawn into specific are formed from preexisting rocks or the form under certain circumstances. shapes. It can be finished by honing, polish- bodies of once-living marine organisms. ASTM C97: Absorption and Bulk ing, or sandblasting, all of which affects the Metamorphic stones are created through Specific Gravity of Dimension Stone is stone’s appearance. Many types of natural a combination of heat, pressure, and time. the test method used to determine the stone, including granite, marble, and Igneous stones have their start as molten absorption of water, expressed as a percent limestone, can be fabricated into thin panels material that originates from deep with the by weight, and the bulk specific gravity, CONTINUING EDUCATION CONTINUING and used on the exterior of buildings. earth near active plate boundaries. which is the means by which density is Versatile, beautiful, and durable, determined. natural stone has long been mankind’s Specifying Natural Stone ASTM C170: Standard Test Method for preferred building material. The applica- The Natural Stone Institute recommends Compressive Strength of Dimension Stone tions for natural stone are nearly limitless. proper testing, specification, and installation is used for all dimension stone types, using Historically, stone served as the structure of natural stone. To meet these require- a specimen that is a rectangular prism, for many buildings; today, it is more ments, design professionals should work cube, or cylinder. The compressive strength typically used as nonstructural cladding. closely with a quarry or distributor during is reported as the failure stress in either Natural stone is used extensively in land- the specification process. Also consider us- lbs/in² or MPa. scaping, serving as pavers, walkways, walls, ing fabricators and installers that have been ASTM C99: Standard Test Method for and other outdoor structures. accredited by the Natural Stone Institute, as Modulus of Rupture measures the bending Inside, stone can be installed as flooring they have been tested and audited on their or flexural strength of a stone material and countertops, as well as in vertical craftsmanship abilities. under a single-point load. applications, such as wall cladding. Other One of the most important resources for ASTM C880: Standard Test Method options include mantels, fireplace sur- design professionals is the set of standards for Flexural Strength of Dimension Stone rounds, bath surrounds, and furniture. and testing procedures developed by evaluates bending strength using two points ASTM International and the American of loading and a sample that is the actual How Natural Stone Is Classified National Standards Institute (ANSI). These thickness of the stone to be installed. When specifying natural stone, it is impor- standards guide the natural stone industry ASTM C1353: Standard Test Method for tant to have basic knowledge about the ma- and help protect end users. In fact, most Abrasion Resistance of Dimension Stone terial’s inherent characteristics; this way, architectural specifications require that Subjected to Foot Traffic Using a Rotary you can choose the appropriate stone for stone meet certain specified ASTM or other Platform, Double-Head Abraser determines the given application. The stone’s mineral testing standards before it will be accepted the degree to which a stone material can composition and how it was formed can for use. withstand scratching or abrasion using an tell you much about how it will perform. Design professionals can seek test instrument called the Taber Abraser. Natural stone can be divided into two data from a quarry, material supplier, or ANSI DCOF (dynamic coefficient of broad categories based on its chemistry, or fabricator. In addition, these experts will friction) measures slip resistance of an mineral composition. Calcareous stones such be able to provide anecdotal and histori- object in motion and is relevant for flooring as marble, limestone, and onyx are made of cal information about the performance applications. calcium carbonate and tend to be affected of a given material. They may refer you ASTM C1354: Strength of Individual by acids, even common ones like lemon to projects that used the same stone in a Stone Anchorages in Dimension Stone juice. Siliceous stones are made of silica or similar application. For more information, evaluates the performance of individual silicates and make up close to 95 percent visit bit.ly/2Q9gsBR. anchors with a specific stone product.

Which Tests for Which Application? The test data you seek will largely depend on the application. If the stone is going to be installed outside, it must be resistant to weathering and decay, as it could be exposed to temperature extremes, freeze- thaw cycles, pollutants, and chemicals such as deicers. Because stones in interior applications are sheltered from the elements, the range of choices is much wider. However, there are special considerations for interior stones that are to be used in flooring applications or installed where

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they could be exposed to chemicals, Let us look at an example comparing test Comparing Granite and grease, or prolonged moisture. data of different countertop materials, first Engineered Quartz CONTINUING EDUCATION If the stone is being used in a struc- considering the material’s hardness as mea- Granite and engineered quartz are both tural capacity, you should seek test data sured by the Moh’s scale. Glazed porcelain popular choices for countertops. To under- for compressive strength and flexural tile and engineered quartz are around 7, stand how they perform, let us look at how strength. If the stone is to be exposed to while granite ranges between 6 and 8. each material is made. the elements, study the stone’s absorption, Next let us consider absorption rate. Granite is composed of igneous rock porosity, and permeability. In addition, Porcelain tile is classified as impervious that once flowed as molten magma. As the you may want to seek test data for how it and has an absorption rate of less than 0.05 magma cools it forms crystals. This process reacts to freeze/thaw cycles. If the stone percent. Engineered quartz has an absorp- takes place deep within the earth over a is to be installed in a vertical application, tion rate of 0.05 percent, which is also great period of time. Variations in the com- study the anchorage system and specify considered very low. The absorption rate position of magma and the rate of cooling ASTM C1354. If the stone is to be used of granite ranges from 0.05 percent to 0.40 account for granite’s wide range of colors in a floor areas that receive foot traffic, it percent; the application of a quality sealer and patterns, resulting in a dense, durable should be tested for abrasive hardness and can further reduce the absorption rate. stone with many practical applications. slip resistance. Absorption and density are As these data show, the differences in Manufactured quartz is composed of also important considerations. hardness and absorption rate among these mineral quartz, pigments, and polyester three materials are quite small, and each is resins, which bind the material together. Comparing Natural Stone to likely to perform equally well. In this case, These ingredients are mixed together and Other Materials the decision of which material to specifiy poured into a mold, where a combination ASTM test data allows specifiers to objec- should be made by considering other factors, of heat, compaction, and vibration are tively compare one product with another such as aesthetics and sustainability. used to cure the slurry into slabs. The resin based on certain attributes, such as abra- helps create a low-porosity surface. sion resistance and absorption rate. Testing Products Most granites are composed of two Let us consider countertops, which If you are not sure how a product will per- minerals, mineral quartz and feldspar, lend themselves to an almost overwhelm- form, you always have the option of testing with smaller amounts of hornblende, ing range of options, from natural granite it yourself. biotite, and other minerals. Mineral quartz and marble to engineered quartz, solid For example, a geologist tested several has a hardness of 7, while feldspar has a surface, and laminates. materials side by side: two samples of hardness of 6 to 6.5. Engineered quartz There are several considerations when granite, both sealed with an impregna- has a hardness of around 7, although the specifying countertops. The material tor; two samples of engineered quartz; pockets of resin will be much softer than should be scratch resistant, and you one sample of sintered surface (a heated the mineral particles they surround. should also understand how the material and highly compressed blend of clays, Both granite and engineered quartz reacts with acids so you can properly care feldspars, silica, and other minerals); and have low absorption rates, although the for and maintain it. Countertops used one sample of poured concrete with gravel percentages for granite varies depending on for food preparation should be easily aggregate that had been sealed with an its source and crystal structure. Both are sanitized. As always, choose the correct acrylic polymer sealer. nonreactive to household acids; however, material for the proper application. These samples were tested for hardness, some granites should be sealed periodically With this in mind, key characteristics acid resistance, thermal resistance, stain- to protect them from staining. The resins to study include hardness and absorption ing, and cleaning with an abrasive pad. in engineered quartz make it susceptible to rate. A quick way to evaluate a material’s The tests were performed using common permanent damage by heat. hardness is its Mohs Hardness Scale household items; for example, she used rating. This scale rates the relative hard- vinegar to test for acid resistance, turmeric Photo courtesy of Natural Stone Institute ness of a material between 1 and 10; the paste and food dye to test for staining, and higher the number, the more resistant to a hot skillet (both dry and oiled) to test scratching. for heat resistance. A series of “hardness ASTM C97 test data will inform you of picks” was used to determine the material’s the material’s absorption rate. However, the hardness according to the Moh’s scale. stone’s mineral makeup is the key determi- The results showed that both the granite nant of how resistant it is to chemicals and samples and sintered surface held up very acids. Therefore, it is important to research well to all of the tests. One of the samples the individual stone. Again, the fabricator, of engineered quartz suffered heat damage quarrier, or distributor will be an excellent from the hot skillet, and one showed stain- resource. ing from food coloring, turmeric, and hot Though it is by no means the only oil. Both engineered quartz samples became The Universal Testing Machine is used to choice, granite is an extremely popular dulled when scrubbed with an abrasive perform many physical properties tests, building material, in part because it is pad. The concrete sample fared the worst in including flexural strength (ASTM C880), hard, stable, and has a low absorption rate terms of stains and scratches, as it is a soft modulus of rupture (ASTM C99), and anchor while also being beautiful. and porous material. pull tests.

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Image courtesy of Natural Stone Institute CONTINUING EDUCATION CONTINUING

As this chart illustrates, many commonly specified countertop materials are highly stain and scratch resistant, but they differ when it comes to the environmental impact of manufacturing.

Aesthetically, both granite and engineered end natural stone products out there, the large 50 years. In that same time span, vinyl may quartz come in a variety of colors and patterns. spectrum of natural stone options on the mar- have to be replaced up to three times; in addi- Note, however, that engineered quartz tends to ket ensures that there is a stone for nearly every tion, the maintenance costs may be higher. be uniform, whereas granite will have natural budget, application, and aesthetic preference. In another example, tile has a comparable variation, even if subtle. In addition, many natural stone products are in lifespan to natural stone, but it requires more Of course, there are additional criteria to a similar price range as other popular options, maintenance, especially of the grout, which consider other than performance and aesthetics. such as quartz, large-format porcelain, sintered requires regular cleaning and periodic restora- In the next section, we will see how to evaluate surface, concrete, and glass. tion. A life-cycle cost analysis can help you materials for their sustainability by looking at The price of a given natural stone product compare the total life-cycle costs of different their entire life-cycle impacts, including the will depend on many factors, including options—including maintenance, replace- opportunities for recycling and reuse. demand, availability, and distance from the ment, and disposal—and will ultimately save quarry or fabricator. Incidentally, working the client money in the long run. COMMON MYTHS ABOUT directly with a quarry or fabricator can NATURAL STONE save the client money and gives you a direct Myth: It Is Hard to Maintain While there is little disagreement over the line to information about the stone and the Many natural materials require some degree beauty and timelessness of natural stone, company’s practices. of maintenance. Wood floors, for example, there is considerable confusion around its In addition, when you consider the full must be swept, cleaned, and oiled to protect cost, care and maintenance, and sustainabil- life-cycle cost of the product, natural stone is them from scratches and stains. Similarly, ity. Let us look at some of the common myths not only competitive but also a sound invest- natural stone requires routine cleaning surrounding natural stone. ment because of its durability and longevity. and maintenance to ensure that it stays as Consider the service life of various flooring beautiful as the day it was installed. These Myth: It Is Too Expensive products—including ceramic tile, vinyl, and procedures are not difficult or time consum- Many specifiers and customers shy away from laminates—over a 50-year time span. Natural ing; often it is a matter of understanding the natural stone because they assume that it is too stone flooring will not have to be replaced in products and regimes that are appropriate for expensive. While it is true that there are high- that time and in fact should last at least another that particular stone.

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In addition, natural stone can often be stone products, as the trace levels of hydro- location, and how it is maintained all need repaired, restored, and refinished should a fluoric acid in these products will attack to be considered when determining how to CONTINUING EDUCATION stain, scratch, or etching occur. Most man- silicates and other minerals. protect the stone. made imitations cannot be returned to their Cleaning procedures for natural stone, Impregnators are water- or solvent-based original state. engineered quartz, sintered surface, and tile solutions that penetrate below the surface are similar. A clean rag mop should be used on of the stone, where they become repellents. Myth: It Is Not Sustainable floors and a soft cloth should be used on other Impregnators are typically hydrophobic Unfortunately, some people have precon- surfaces, such as countertops. The area should (water repelling) and oliophobic (oil repel- ceived notions about the natural stone be rinsed thoroughly after washing with the ling). They keep contaminants out without industry’s practices, with images of vast soap solution and dried with a soft cloth. The preventing moisture from inside the stone mining operations that harm workers and rinse water should be changed frequently. from escaping. Hence, these products are the environment and leave gaping holes in One notable difference between natural stone, considered “breathable” since they allow the landscape afterward. In fact, quarrying engineered quartz, and tile compared with the transmission of vapor. Impregnators are is a well-regulated operation; what is more, laminates is that laminates should not be recommended for surfaces that frequently the natural stone industry holds a Sustain- flooded with water, as moisture can penetrate contact water and oils—for example, vanity ability Standard for quarriers and fabrica- the seams and possibly cause delamination. tops and food preparation areas. Make sure tors. This along with stone’s naturally low Tiled surfaces also require periodic mainte- the impregnator product is nontoxic and carbon footprint help make it an excellent nance of the grout to prevent or remove the safe for use around food preparation. choice for green building projects. buildup of dirt and other mateirals. Finally, it is important to understand that We will take a deeper dive into the Wet areas have special considerations. sealing is not a cure-all for stains. Sealers sustainability of natural stone later in Using a squeegee after each use can slow the absorption rate of porous materials; this course. Now, let us consider the best minimize the buildup of soap scum. To they do not make stone stain proof. Regular practices for the care and maintenance of remove soap scum, use a nonacidic soap use of coasters and trivets and jumping on natural stone. scum remover or a solution of ammonia and spills right away will complement the protec- water (about ½ cup ammonia to 1 gallon of tion provided by the sealing product. THE CARE AND MAINTENANCE OF water). Frequent or overuse of an ammonia For guidance on sealing and the care of NATURAL STONE solution may eventually dull the surface of natural stone, visit bit.ly/3eHo48Y. You would not use citrus-based or acidic some stone types. cleaners to clean a marble vanity. In fact, the Special Considerations: Marble most critical factor in properly caring and To Seal or Not to Seal Marble is softer than granite and may be maintaining natural stone is understand- The porosity of stone products varies; some susceptible to scratches and etching. The ing the stone's geological classification and will require more frequent sealing; others hardness of marble is comparable to other composition. This information is vital for may not need to be sealed at all. For some household materials, including solid surface, selecting the best cleaning products and stone products, periodic sealing can help hardwoods, and resins in engineered quartz. regimes for the particular stone. protect the surface from dirt and reduce the Because it is a calcareous stone, marble is That said, there are some general recom- incidence of staining; however, there are softer and more vulnerable to stains, scratch- mendations for cleaning most natural stone several factors to consider before breaking es, and etching, especially when the surface products, many of which are applicable to out the sealer. The type of stone, its finish, its comes into contact with an acidic substance. most other materials as well. First, choose a neutral cleaner, stone soap, or mild liquid dishwashing detergent to clean stone STAIN AND SCRATCH PREVENTION surfaces, and avoid abrasiove pads. This is a good rule of thumb for all surfaces, not Sharing these general guidelines with your clients will help prevent stains and scratches just natural stone, as harsher cleaners and in most flooring and countertop materials, including natural stone products. abrasive pads may dull or scratch the finish. Coasters: Use coasters under all glasses, particularly those containing alcohol or Acidic or abrasive cleaners can also damage citrus juices. grout in tille surfaces. In addition, many Trivets: While many stones can withstand heat, the use of trivets or mats is suppliers offer products specifically formu- recommended. lated for cleaning stone. The manufacturer’s Dust mopping: Sand, dirt, and grit are abrasive and can damage natural stone. Dust directions should be followed. Use warm mop interior floors frequently using a clean, nontreated dry dust mop. water to dilute the product if necessary, as Mats/rugs: Mats or area rugs inside and outside an entrance will help contain the a concentrated solution may leave a film or sand, dirt, and grit that can scratch a stone floor. The underside of the mat or rug should streaks. be a slip-resistant surface. Products that contain lemon, vinegar, or Vacuum cleaners: Be aware the metal or plastic attachments and/or wheels of a other acids should be avoided, as they may vacuum cleaner can scratch the surface of some stones, if worn. dull or etch calcareous stones. Similarly, Spills: Blot the spill with a paper towel immediately. Do not wipe the area, as wiping scouring powders or creams often contain spreads the spill. Flush the area with water and mild soap, and rinse several times. Dry abrasives that may scratch certain stones. the area thoroughly with a soft cloth. Repeat as necessary. Rust removers should never be used on

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Such common kitchen items as tomatoes, citrus fruits and juices, vinegar, and sodas are STONE AND RADIATION acidic. Wine and oils can also cause stains if not wiped up in a timely manner. All natural stone products, especially stone, minerals, and sand, contain trace amounts Etching and stains can be prevented by of some radioactive elements called NORMs (naturally occurring radioactive minerals) the diligent use of cutting boards, trivets, and that can produce measurable amounts of radiation and sometimes radon gas. coasters. Marble countertops should be cleaned According to the U.S. Environmental Protection Agency, radon originating from regularly, but the product must be appropriate the soil beneath homes is a more common problem and a far larger public health risk for the material. Mild soaps and stone cleaners than radon from granite building materials. The stone industry has conducted research are safe choices. showing that the amount of radon found occasionally in a slab of granite is not harmful Some varieties of marble may benefit from to humans who are exposed to it. This research mirrors independent studies that an impregnating sealer; however, application produced the same results. According to Air Chek Inc., if a stone surface emits a small CONTINUING EDUCATION CONTINUING and maintenance frequency may depend on amount of radon, it will generally be insignificant when diluted with the quantity of air in stone variety and use. It is best to consult the the entire space. Still, if radon is a concern, it is recommended that the space be tested sealer manufacture for specific product recom- using a professional accredited radon testing kit. mendations, which can range from every year to every 10 years or more. The surface treatment makes a difference. Polished marble may show is durable, will not need replacing, and Embodied energy tallies the energy etching, while honed surfaces may make etching requires little maintenance. The material consumed by all the processes associated with less noticeable. Refinishing can restore the sur- does not emit harmful chemicals and is the production of a building, including mining face of marble countertops to its original luster; 100 percent recyclable. and processing of natural resources, manufac- a honed surface can be refinished less frequently. Because of these characteristics, natural turing, transport, and product delivery. The One way to test whether the stone needs reseal- stone has a favorable life-cycle environmental embodied energy of a building material can be ing is to drop a small amount of water onto the impact when compared with other building equivalent to many years of operational energy. countertop. If it leaves a dark spot after a couple materials, especially when sourced locally. Natural stone is nearly complete as a of minutes, the marble needs to be treated. In addition, a sustainability standard building material in its natural state; it has one developed for the natural stone industry of the lowest embodied energy values of any Special Considerations: Granite ensures the sustainability of certified stone comparable building material. Granite requires regular cleaning. Daily wiping products, from cradle to gate. By working Once extracted, natural stone requires with a mild, neutral cleaner should be adequate. with a quarry that has implemented socially minimal processing or fabrication. As with any stone surface, the use of and environmentally responsible practices, Consequently, the energy associated with cutting boards, trivets, and cooling racks can including a plan for reclamation, you can feel quarrying and preparing stone for market is protect the material from stains. Paying atten- confident that you are specifying a product quite low compared to many other materials tion to areas that are frequently exposed to with a good environmental pedigree. Natural used in similar applications—for example, water can help prevent the buildup of calcium stone products can also contribute to green ceramic tile, carpet, and vinyl flooring. and magnesium, which can leave a dull, whit- building certification. A German study that compared the life- ish film on any surface. cycle impacts of several floor coverings showed Some varieties of granite may benefit from An Enduring Life Cycle that natural stone has the lowest global-warm- an impregnating sealer. However, application The best evidence for the durability of nat- ing potential (GWP) of all of them. According and maintenance frequency may depend on ural stone lies in the many iconic buildings to the study, which used environmental stone variety and use, so it is important to that still stand centuries after they were product declarations (EPDs) provided by consult the sealer manufacturer for specific built. In contemporary architecture, there manufacturers to compare impacts, the GWP product recommendations. Some may not is a trend to “build for the future,” with an of carpet was more than 20 times higher than need sealing at all or will only require one understanding that a “green” building is that of natural stone tile. application. Others may require several appli- one that will stand the test of time. Materi- Because stone is so durable, it does not need cations to properly seal them. Penetrating als and products with a longer life cycle can refurbishing or replacement. A stone floor, for sealers should be used for surfaces that see help contribute to the longevity of these example, will easily last 50 years or more and heavy use or are exposed to water on a daily buildings and reduce the embodied energy require little maintenance other than routine basis, such as bathroom and kitchen counters. and energy associated with replacing them. cleaning. In that same period, carpeting may A sealer can last up to 10 years; however, inap- Whether the application is a stone floor, need replacing up to four times. propriate cleaning products can compromise countertop, or wall cladding, natural stone It should be noted that transportation the sealer. should last for at least 100 years or longer. energy can be quite high for natural stone, When the building is finally demolished as it is a dense (heavy) material. However, NATURAL STONE AND SUSTAINABILITY and/or the stone product removed, it is natural stone is a single-ingredient mate- Natural stone is naturally sustainable. It easily recyclable. In fact, nearly 100 percent rial. Other competing materials contain has been used for millennia, often requir- of stone from deconstructed projects is multiple ingredients, each of which require ing minimal processing. Natural stone is recyclable and may be recovered for use transportation to the manufacturing not bonded together with petroleum-based in new buildings, or crushed for use in facility and contribute to the total environ- resins, nor is it created in a factory. Stone roadbeds and other infrastructure. mental impact.

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Photos courtesy of Polycor Consequently, sourcing stone products regionally can go a long way toward reduc- CONTINUING EDUCATION ing the material’s environmental footprint. In addition, most green building rating systems incentivize the support of products and businesses that are close to the project site. Regionally manufactured and extracted materials reduce environmental impacts by reducing emissions of green- house gasses during transportation while supporting local economies. Fortunately, there are stone quarry sites within 500 miles of nearly every building site in the United States and Canada. Selecting reclaimed material is another good option that will extend the stone’s operational life and reduce the embodied energy of your project.

HEALTH AND INDOOR AIR QUALITY Natural stone can support good indoor air quality. Because it is a natural material with few if any additives, it is easy to “vet” and unlikely to contain any harmful materials or chemicals, such as those included on the Liv- These photos from an active quarry show how much stone has been harvested over a ing Building Challenge’s Red List. Be aware, 10-year period. however, that processing may add resin or cementitious fillers, fiberglass mesh backing, is based on point totals and includes four Site Management: site-specific measure- topical or penetrating sealers, or other chemi- tiers of certification: Bronze, Silver, Gold, and ment plans to ensure responsible management cals; be sure to seek material transparency Platinum. Operations must be monitored and of environmental impacts documents for these products. reevaluated periodically to maintain their Land Reclamation: responsible and Research conducted by the University of certification. The chain-of-custody (COC) sustainable reclamation of quarry sites once Tennessee's Center for Clean Products found standard complements the sustainability operations have ceased that natural stone does not directly emit standard. Its aim is to drive sustainability Human Health & Safety: plans to ensure any volatile organic compounds (VOCs). throughout the supply chain, ensuring that that workers are provided with a safe and Low- and no-VOC setting materials may be natural stone products that are produced with healthy work environment specified to ensure indoor air quality is not best practices are also handled throughout Corporate Governance: social respon- compromised. Natural stone also does not the supply chain in a manner that ensures and sibility through workplace regulations and release harmful substances when exposed to upholds their sustainability. employee/community programs fire, and the material is itself noncombustible. The 10 categories in ANSI 373-2019 are: Water: minimal freshwater use in pro- Green Building Programs The Sustainability Standard cessing and ensuring good quality of water ANSI 373 was updated in 2019 to align with In 2014, the natural stone industry estab- being released back to the environment evolving green building programs, such as the lished the sustainable stone certification Energy: energy-efficient operations with U.S. Green Building Council’s Leadership in standard. ANSI 373: Sustainable Produc- low carbon impacts Energy and Environmental Design (LEED) tion of Natural Dimension Stone provides Custody & Transportation: efficiency of and the International Living Future Institute's natural stone quarriers and fabricators with the transportation and handling of stone Living Building Challenge. third-party verification of their sustainable Chain of Custody: an unbroken chain of These changes are helping designers practices. The standard also allows builders certified organizations from quarry to the end and project teams meet their sustainability and designers to confidently specify stone as user goals. Let us examine how certified natural a sustainable material. Finally, the standard Chemicals & Materials: safe management stone products can contribute to these will help drive continual improvement in of chemicals within operations and avoidance goals. the industry as preference is shown to prod- of Red List chemicals ucts that have been certified as sustainable. Excess Materials: low amounts of excess LEED v4 ANSI 373-2019 applies to all processors processed material and solid waste that goes In LEED v4, certified natural stone can of natural stone, from quarry operations to into landfills contribute to Option 1 under the credit final stone fabricators. The standard utilizes Innovation: promoting continuous Building Product Disclosure and Optimiza- a point-based system with both required and improvement and transformation of the tion: Sourcing of Raw Materials, provided optional criteria in 10 categories. Certification industry that the facility and/or quarry operation

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In addition to its sustainability COMPARING MATERIALS: QUESTIONS TO CONSIDER standard, the Natural Stone Council publishes best practices for transporta- In a previous section, we looked at how to compare the performance of different tion, solid waste management, water materials with natural stone. Here are some questions to ask when comparing the management, and quarry site manage- sustainability of different products. ment. Unfortunately, many people equate Embodied energy: How much energy is required to extract the raw materials, quarrying with mining and are unaware process them, manufacture, transport, and distribute the final product? Is the material of the best practices that are employed by available regionally and/or can a salvaged/recycled product be used? many quarries and fabricators. Health: What are the health impacts to workers during all phases of manufacture and Most natural stone quarries have a transportation? Once installed, does the material emit chemicals that can compromise small footprint and operate in the same indoor air quality? What about if the product is exposed to fire? location for decades. In most modern CONTINUING EDUCATION CONTINUING Transparency: Does the product have associated transparency documents or quarries, the stone is meticulously certifications that make it easy to understand its environmental and health impacts? extracted with little to no blasting, as this These include environmental product declarations (EPDs), health product declarations can fracture the stone. Quarries strive to (HPDs), and labels such as GREENGUARD, Declare, and others. minimize waste and utilize most if not Durability: How many times will the product have to be replaced over the life of the all of the extracted stone, often finding building? creative ways to divert “waste” into new Maintenance: What is the required cleaning and maintenance regime for the income streams. In some cases, donating product? Maintenance can comprise a significant portion of the total life-cycle cost of or recycling scrap is possible. certain products. As noted earlier, transportation energy Recycling/end of Life: Are there established programs for recycling or repurposing can be significant, as stone is incred- the material, or is it destined for the landfill? ibly dense, or “heavy.” Industry best practices range from centralizing freight management to choosing carriers that use has earned certification, including either Living Building Challenge fuel-efficient vehicles, and even switch- optional credit 7.2.1: Ecosystem Boundaries The Living Building Challenge has been ing to reusable and non-plastic packing or 7.2.2: Environmental Impact Assessment. instrumental in pushing the building in- materials. All of these strategies not only This option, found under the Material Re- dustry toward a more holistic approach to help reduce the environmental impact of sources category, requires the use of at least green building. It consists of seven catego- transportation but also save the operation 20 different permanently installed products ries, called Petals, which address various money. from at least five different manufacturers aspects of a healthy, sustainable building. ANSI 373 encourages quarry operators “that have publicly released a report from The Materials Petal strives to “help create a and fabricators to minimize freshwater their raw material suppliers that includes materials economy that is nontoxic, ecologi- consumption and ensure the quality of raw material supplier extraction locations, cally restorative, transparent, and socially water released back to the environment. a commitment to long-term ecologically equitable.” Under the Materials Petal, the Re- Operators must develop and maintain an responsible land use, a commitment to sponsible Industry Imperative requires that annual water inventory, and recapture reducing environmental harms from extrac- project teams advocate for the creation and and recycle a minimum of 25 percent of tion and/or manufacturing processes, and adoption of third-party-certified standards the total water used. In fact, some opera- a commitment to meeting applicable stan- for sustainable resource extraction and fair tions recycle far more than that. dards or programs voluntarily that address labor practices. For stone, project teams must Most quarries will have plans in place responsible sourcing criteria.” advocate to quarries and/or manufacturers of that seek to limit habitat loss, waterway In addition, natural stone that has earned all dimension stone products used within the damage, erosion, pollution, noise, and an approved label such as Declare may project for certification under ANSI 373. vibrations. In addition, they will have a contribute to Option 1: Material Ingredient In addition, natural stone is supportive reclamation plan to guide rehabilitation Reporting under the credit Building Product of several other Imperatives, including the of the site once the operation is closed. Disclosure and Optimization: Material Biophilic Environment and Healthy Indoor ANSI 373 requires that certified quar- Ingredients. This option requires that the Environment, which both fall under the ries develop such plans; many states project use at least 20 different permanently Health & Happiness Petal. also require them. According to ANSI installed products from at least five different 373, plans should include proposals for manufacturers that use a USGBC-approved The Scoop on Quarries and site cleanup, infrastructure renewal, site program to demonstrate the chemical inven- Fabricators safety, and ecosystem restoration. It is also tory of the product to at least 0.1 percent The natural stone industry has long been recommended that stone companies work (1,000 ppm). Material ingredient reporting committed to sustainable practices. That said, with the original landowners or the local uses a wide range of programs, includ- quarrying and processing operations are not community when developing their plans. ing Cradle to Cradle and health product without impacts. Choosing certified stone can Even before the sustainability declarations (HPDs). Since natural stone is help ensure that you are rewarding sustainable standard was developed, many shuttered composed of a single (and natural) ingredi- operations while meeting the “green” goals of quarries have been converted into parks ent, it is an easy product to document. your project. and reservoirs.

8 ARCHITECTURAL RECORD APRIL 2021 EDUCATIONAL-ADVERTISEMENT NATURAL STONE FACT VERSUS MYTH: ADDRESSING COMMON MISCONCEPTIONS

Image courtesy of Natural Stone Institute CONTINUING EDUCATION

Engineered quartz has greater embodied energy than natural stone because there are many more steps in the manufacturing process.

The 684-acre Quarry Park and Nature CONCLUSION stone products that are appropriate for Preserve located just outside of St. Cloud, Natural stone is a beautiful, versatile the application—and that with the proper Minnesota, provides a compelling example material with many possible applications, care will last for decades. In addition, you of how a once-productive quarry has both inside and out. In addition to lend- can show them how natural stone can been reclaimed as an attractive recreation ing a timeless quality to building projects, help them attain their sustainability goals destination. In summer, people flock to the natural stone is a key component in bio- while lowering the overall environmental quarry to swim, picnic, hike, fish, and rock philic design. Natural stone elements can impacts of the construction and operation climb; in winter, cross-country skiing and help create a serene, warm environment of their buildings. snowshoeing are popular. From the 1880s to that promotes well-being and supports the 1960s, several stone companies operated health. Unfortunately, some clients are quarries in present-day Quarry Park, which reluctant to specify natural stone out of opened to the public in 1992. concern for its cost, maintenance require- Take the quiz at ce.architecturalrecord.com Other creative uses for old quarries ments, and sustainability. As design include golf courses, amusement parks, professionals, you can help clear up these housing developments, and shooting ranges. misconceptions, guiding clients to select

The Natural Stone Institute offers a wide array of technical and training resources, professional development, regulatory advocacy, and networking events for the natural stone industry. Learn more at www.naturalstoneinstitute.org/stoneacademy.