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Limestone: The Natural Choice for Sustainable Performance Flooring

March 11, 2022
SPC flooring in a bedroom with a chairs, table and open closet.

Earn CEU Credits:

i+s’ Continuing Education Series articles allow design practitioners to earn continuing education unit credits through an article.

Use the following learning objectives to focus your study while reading this article. To receive one hour of continuing education credit (0.1 CEU) as approved by IDCEC or 1 Learning Unit as approved by AIA, read the article, then log on to take the associated exam

After reading this article, you should be able to:

  • Gain an understanding of the formation and natural history of limestone

  • Describe how limestone is quarried and processed

  • Discover the benefits of locally sourced limestone and supply chain disruption

  • Gain an understanding of limestone uses for industrial products

  • Learn resilient flooring options and applications

  • Discover the sustainable attributes and life cycle cost analysis of resilient flooring

  • Learn the felt-backed sheet vinyl manufacturing process

  • Understand the resilient flooring benefits in a post COVID world

*This CEU opportunity is sponsored by Congoleum.

 


 

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Limestone 101: Formation and Natural History

Limestone is a sedimentary rock that comprises about 15% of the Earth’s sedimentary crust. Limestone is composed largely of the mineral calcite (calcium carbonate, CaCO3) with this amount typically 95%. The calcite in limestone is produced by marine organisms that secrete shells or whose calcium carbonate skeletons build coral reefs.

As these organisms die, their shells and bones are broken down by waves and settle on the ocean floor where they are compacted over millions of years, creating limestone from the sediments and the pressure of the ocean water. Limestone is a naturally occurring material; however, it is considered to be a nonrenewable resource because the amount of time taken to form the limestone is much longer than the rate at which humans use it.

Limestone most commonly forms in shallow, calm and warm marine waters. Buildups of limestone can be found between 30 degrees North Latitude and 30 degrees South Latitude of the globe. Such deposits are found in the Caribbean Sea, the Indian Ocean, the Persian Gulf and the Gulf of Mexico. 

Limestone also forms around the world through evaporation in caves where water pours through the floor. The calcium carbonate dissolves and forms deposits throughout the ceiling and wall of the cave. These deposits grow larger as the years go by, and they can reach into the deepest parts of the cave. 

Limestone is also associated with hills and occurs in regions with other sedimentary rocks typical-ly clays. Bands of limestone emerge from the Earth's surface in often spectacular rocky outcrops (a rock formation that is visible on the surface) and islands.
 
Examples include the Niagara Escarpment bordering Canada and the United States; Notch Peak in Utah; the Burren in County Clare, Ireland; the Verdon Gorge in France; Malham Cove in North Yorkshire, England; Fårö, near the Swedish island of Gotland and the Ha Long Bay National Park in Vietnam.

Characteristics and Varieties of Limestone

Limestone can be found in many varieties with different textures and porosity depending on its mineral composition and physical structure. When composed of calcium carbonate alone, it is white or nearly white. Limestone may also contain magnesium, iron or manganese which will affect its whiteness. Other colors like gray, yellow and brown are produced by the presence of chert, clay, flint, sand, organic remains and iron oxide. Limestone is easily scratched. It is a soft rock with a hardness of 3-4 Mohs and a density of 2.5 to 2.7 grams per cubic centimeter.

Travertine is a type of limestone that is formed by mineral deposits along streams, hot or cold springs and near waterfalls. This sedimentary stone is created by a rapid precipitation of calcite. Other minerals mix together with the calcite to create unique swirls and movement that give travertine its distinctive character.

Chalk is a soft, white, porous form of limestone. Chalk is formed in shallow waters by the gradual accumulation of the calcite mineral remains of microorganisms, over millions of years. Chalk has been quarried from prehistory, providing building material and soil conditioner for fields. The famous white cliffs of Dover in Kent, England are formed entirely of chalk deposits. The Champagne region of France is mostly located on chalk formations, with caves being carved out beneath the hills.

Coquina is a form of limestone composed of the shell fragments of ancient mollusks and other marine invertebrates that over time are glued together by dissolved calcium carbonate in the shells. When first quarried, coquina is extremely soft. This softness makes it very easy to remove from the quarry and cut into shapes. To be used as a building material; however, the stone must be left out to dry for approximately one to three years.

Mining and Extraction

Limestone is extracted from quarries and underground mines either by blasting or mechanical excavation depending on the hardness of the rock. 

When mined from a quarry—also known as open pit mining or surface mining—limestone is being extracted from the surface of the Earth. First, the top soil is removed and then the overburden (the material below the top soil that covers the mineral) is removed. Drilling is performed to break the rocks. Large rocks that are difficult to break during the drilling process are removed by explosives in order to extract the limestone. 

Limestone can also be mined underground. Underground mining is done when the limestone is present more than 100 meters deep or when the topsoil covering the mineral is rock hard. Unlike the open pit mining process, horizontal drills produce much smaller blast holes. Explosives are sent down the holes producing a volume of rock with each blast. After blasting, the loose rocks are removed from the mine with scaling rig equipment.

Processing: Crushing, Screening and Grinding

Limestone is one of the most widely available and versatile rocks for many uses. Extraction for slabs is made by separating the rock in quarry ledges and dividing it into blocks. Most of the lime-stone that is mined is processed for aggregate. Limestone can be processed into crushed lime-stone, pulverized limestone, concentrated calcite and lime (quicklime and slaked lime). 

After quarrying or mining, the limestone is transported to the processing plant by truck and dumped into a bin for coarse crushing. Crushers are used for initial size reduction. Crushed stone pieces are conveyed to a vibrating, inclined screen that separates oversized rock from the smaller stone. The undersized material is transported to a storage pile and sold as base material. The stone that is too large to pass through the top deck of the screen is processed in the secondary crusher which typically reduces material to about 1 to 4 inches in size. 

The material (“throughs”) from the second level of the screen bypasses the secondary crusher because it is sufficiently small for the last crushing step. The output from the secondary crusher and the “throughs” from the secondary screen are transported by conveyor to the tertiary circuit, which includes a sizing screen and a tertiary crusher.

The next step in the processing is grinding the limestone into a fine powder. After that comes calcination. This is when the limestone is heated in a rotary or shaft kiln and broken down into calcium oxide, i.e. quicklime and carbon dioxide. The quicklime is then crushed again to reduce it into different sizes. Following that, the crushed quicklime is ground into a fine powder. At that point, slaked lime can be formed by mixing quicklime with water.

Locally Sourced: Avoiding Supply Chain Delays

Egypt is home to some of the largest limestone quarries in the world, as well as some of the most recognizable and identifiable limestone structures. The world’s other largest limestone producers include China, the U.S., Russia, Japan, India, Brazil, Germany, Mexico and Italy. France exports its collection of limestone to the U.S. The UK is another exporter of limestone that can’t be found anywhere else in the world.

Covid has caused many disruptions in the supply chain; however, there is no need to specify limestone from abroad. In most regions of the U.S. it is possible to obtain locally sourced lime-stone. The State of Michigan boasts large limestone quarries near the coastlines of the Great Lakes. Another prolific source of limestone is Bedford limestone, also known as Indiana lime-stone, a geological formation primarily quarried in south central Indiana between the cities of Bloomington and Bedford. Its limestone has been used for projects like The Pentagon, The Lincoln Memorial, The Empire State building and Millennium Park in Chicago.

Natural Stone Industry Embraces Sustainability

Even before COVID supply chain issues, locally sourced limestone was a popular option. Reducing the amount of transportation is environmentally responsible and it offers the incentive of being less expensive in many cases due to the reduction in transportation costs. Also, increasingly architects and designers are opting for sustainably sourced materials produced to meet US Green Building Council (USGBC) LEED standards as well as other green building standards. 

According to USGBC guidelines, locally sourced stone is defined as having been quarried or harvested within 500 miles of the build site. There are numerous natural stone quarries offering consumers a wide variety of locally sourced stone including limestone. 

At the same time, the natural stone industry is striving toward more sustainable environmental, social and human health practices for facilities where limestone is processed. The ANSI/NSC 373 Standard was created by the National Stone Council to recognize sustainable environmental, social and human health practices in the natural stone industry. Guidelines include the conversion of otherwise unusable stone into various grades of crushed stone, the reduction of energy consumption and improved stormwater containment and management systems to protect local watersheds and the ecosystem.

Popular in Architecture and Manufacturing

Limestone is one of the most commonly used natural rocks on the planet. It is readily available and relatively easy to cut into blocks or carve elaborately. Limestone is used in the manufacture of cement, mortar, quicklime (calcium oxide) and slaked lime (calcium hydroxide). Crushed lime-stone is useful in constructing the solid base for roads. 

Lime is produced when limestone is subjected to extreme heat and calcium carbonate is changed to calcium oxide. Lime is used in hot-mix asphalt as an anti-stripping additive and as a mineral filler. Incorporating hydrated lime into hot-mix asphalt can add years to the life of a highway. Pulverized limestone is used as a soil conditioner to neutralize acidic soil conditions. 

Very high-grade limestone deposits with a calcium carbonate content over 95% are quarried and ground to a variety of sizes with diameters ranging from a fraction of a micron to several microns. These fine powders have many uses as fillers in manufactured goods like paints, plastics, ceramics, cleansers, paper and carpets. Coquina is quarried or mined as a source of paving material. 

Limestone is also long-lasting and it stands up well to exposure from the elements. For these reasons it is popular in architecture and has been used to make many landmarks around the world—from ancient landmarks in Egypt to the medieval churches and castles of Europe and many significant structures in North America as well. Kingston in Ontario, Canada, has so many buildings constructed from limestone that it was nicknamed "Limestone City.”

Lutetian limestone (also known as “Paris stone”) is a variety of limestone particular to the Paris, France, area. It has been used there as a building material since ancient Roman times and con-tributes to the unique appeal of the “City of Light.”

In recent years, thin limestone plates have been used as a facade on some skyscrapers. However, limestone is a heavy material, making it impractical for tall buildings. Also, limestone is reactive to acidic solutions. Many limestone statues and building surfaces have suffered severe damage from acid rain.

In residential spaces, limestone is used for countertops and flooring. It is also crushed and screened for cement and other construction materials. Between making concrete, road base, pipe bedding, under slab filler, flux stone, driveways, railroad ballast and agricultural lime, the modern uses for limestone are nearly endless.

In the glassmaking process, limestone helps the liquid glass be easier to handle and form into the required shape. Also limestone helps to avoid devitrification, a process of crystallization around small impurities in the mix that causes clouding and other defects.

The calcium carbonate found in limestone is also used as a dietary supplement and as an antacid. When used as a food additive, calcium carbonate acts as an anti-caking agent, an 
added source of calcium and a white food color.

Waterproof Flooring: A Brief History

Humans discovered long ago that a hard, relatively waterproof surface makes a good floorcovering. In primitive homes, compressed earth was mixed with ox blood because it dried into an easily-swept surface. Later, painted wood floors were relatively easy to maintain but they did have to be refurbished periodically. In earlier times it was also difficult to keep carpeting clean in eating areas. In the early 18th century, people placed large squares of fabric under dining tables to catch crumbs and other debris. After the meal they were taken outside to be shaken free of crumbs and then returned to their spot under the table.

In the 1700s, a new concept emerged. The floor cloth was produced from a sturdy fabric like can-vas, hemp or linen. It was transformed into a waterproof surface with a coating of evaporating oil and paint. Easy to scrub and sweep, these floor oilcloths were an improvement over the fabric floor cloths. They were hand made at home or, later in the 19th century they were mass produced and easily purchased. This innovation perhaps inspired the invention, in the 1800s, of linoleum which was manufactured from linseed oil, cork gums and pigment.

Linoleum was popular from 1900 until after World War II when floorcovering manufacturers sought to replace it with other long-wearing, fashionable and easily maintained floorcoverings. By the late 1950s, resilient floor coverings/vinyl arrived on the scene. Vinyl quickly dominated the market because it was brighter and more colorful than linoleum.

Resilient Flooring Options and Applications

Today, resilient flooring is a popular choice for both residential and commercial spaces, and it is ideal for high-traffic areas. Defined as a generally hard flooring that still has some “give” and flex, resilient flooring today is mostly man-made vinyl-containing flooring, although specialty categories of resilient exist such as cork or vinyl-free flooring. Resilient flooring comes in sheets or  planks/tiles. As with many building materials, resilient sheet and tile flooring is available in residential grade and commercial grade. Residential vinyl flooring varies in thickness. Commercial vinyl flooring conforms to specifications that require superior durability and stain resistance. Some commercial-grade vinyl floorcovering has added non-slip attributes for high-traffic public areas.

Made from selected natural and synthetic materials including limestone, resilient flooring is extremely durable. It is available in the marketplace as the following general types of products: 

1.    Solid Polymer Core (SPC) Vinyl Plank Flooring

Standing for both solid polymer core and stone plastic composite, SPC vinyl flooring often simulates the look of real wood or stone, with a traditional PVC cap or wearlayer. SPC is engineered through the use of limestone, PVC plastic and stabilizers that combine to form a rigid and durable mostly PVC product. The most popular form of SPC is sometimes referred to as click-float flooring, which refers to the rigid planks/tiles clicking together and “floating” over the subfloor, with no adhesive required. This means the subfloor does not have to be perfectly smooth or 100% prepped. 

SPC is waterproof and popular for primarily residential spaces and for select non-residential ap-plications that do not involve heavy rolling or pivoting loads. These types of loads can cause flexing and possible damage to the locking mechanism of the flooring, as the flooring is not glued to the subfloor. For spaces with just foot traffic—even high foot traffic—SPC is ideal. If needed, the surface can be treated with anti-bacterial technology. 

SPC is fast becoming one of the most popular flooring types in the world. It is the second generation of click-float flooring, following first-generation WPC which is similar to SPC but with more air in the PVC/limestone core and thus less indent resistance. With proper care, SPC’s lifespan can be 20 years or more in a home. The non-residential lifespan is around 15 years.

2.    Luxury Vinyl Tile (LVT) Flooring

Luxury vinyl tile (LVT) flooring is similar to SPC. Both are composed of a durable and scratch-resistant PVC wearlayer on top, a decorative/image layer, a waterproof indent-resistant PVC/limestone core, and a backing layer. SPC is rigid and generally 3.5 mm in gauge or thicker to allow for the tongue and groove click install, while LVT is flexible and generally 3.2 mm in gauge or thinner. LVT is almost always glued to a properly prepared subfloor with no clicking together; many in the industry refer to LVT as “dryback” flooring.

LVT flooring in a kids playroom
LVT Flooring

Both SPC and LVT are waterproof and highly durable, and both use the same high-quality PVC print films as their decorative/image layer. These print films are often scanned images of wood or other stone that are manipulated on a computer.

LVT requires adhesives and is glued down to the subfloor, so the subfloor needs to be fully smooth and properly prepared. Installers need to pay attention to using the right glue in the right amount. As the flooring is adhered to the subfloor, it will resist flexing and pivoting under heavy loads and is thus preferred over SPC for commercial spaces. It will last for decades in a home. Commercial applications include multifamily buildings, corporate offices, healthcare, education, retail, government building, recreation/fitness and hospitality.

3.    Luxury Vinyl Sheet Flooring

Luxury vinyl sheet flooring has been around for decades and is still a popular flooring in a variety of market segments including healthcare and assisted living, corporate/workplace, classrooms, multifamily housing, hospitality, grocery stores and other retail spaces.

Luxury vinyl sheet flooring contains some limestone, but not as much as SPC or LVT. This flooring is made using a printing process known as “rotogravure” which prints a pattern on the flooring via an engraved cylinder and ink. Sheet vinyl is generally glued down to the subfloor, but perimeter (glue just the outer edges) and loose lay (no glue) installations are also possible with select types of sheet vinyl. 

Sheet vinyl at a home center store
Sheet vinyl at a home center store

As this flooring comes in 6', 12' or 16' sheets, the flooring must be cut to fit the room exactly, with no room for error. For larger rooms, exact-fit seams must also be created. Trained installers for sheet vinyl are harder to come by each year, with the ease of no-glue SPC accelerating the demand for SPC in many residential homes. 

Healthcare facilities are still a stronghold for sheet vinyl flooring, as a patient or examining room can often be one continuous flooring surface, without the cracks and crevices created when SPC or LVT planks or tiles are installed next to each other. This can make for easier cleaning, with fewer spots for dirt or contaminants to gather.

4.    Vinyl Composition Tile (VCT) Flooring

Vinyl composition tile (VCT) is a flooring product used primarily in institutional, educational and commercial applications. VCT is primarily composed of limestone (more than 65%) and PVC. Durable and inexpensive, VCT is used for high-traffic commercial applications including retail businesses, public buildings, schools and large office complexes. 

VCT is a popular choice due to its low cost and durability. Unlike LVT and SPC tile options in the resilient flooring marketplace, VCT is not manufactured with a decorative layer of film. The color and design are created as part of the manufacturing process from colored PVC. Accordingly, stone and wood visuals are not possible. The standard size for VCT tiles is 12" x 12.”

As part of the manufacturing process, a thin layer of wax is applied to the surface of VCT tiles to protect them during transport and installation. After the tiles are installed to a properly prepared subfloor by use of an adhesive, this factory-applied wax is stripped, and one or two coats of a more durable sealant is applied to provide protection and a finished sheen.

As the color and design are built into the product through colored PVC, VCT tiles can withstand decades of wear with little change in appearance, requiring only stripping and polishing as needed.

5.    Specialty Products: PVC-Free Resilient Flooring

In recent years, resilient flooring manufacturers have been rolling out a new breed of PVC-free flooring products with performance that rivals that of vinyl flooring. The chlorine used to make PVC raw material is a human and environmental concern for some people, as are the plasticizers that often ride along with the PVC.

Most PVC-free flooring contains limestone blended with plastic that is not PVC, such as polypropylene, ethylene vinyl acetate or polyethylene. Challenges arise with these types of non-PVC plastics, as they may not stick to the other components of the flooring, or to the subfloor, as well as PVC. Special manufacturing techniques may be needed to produce the flooring, which can sometimes raise the price. Of the small number of PVC-free resilient flooring products that exist, an even smaller number are made in the U.S.

The Felt-Backed Sheet Vinyl Manufacturing Process

The manufacturing process for resilient flooring varies according to the specific product type being produced. The felt-backed sheet vinyl process is one example that demonstrates how materials received at the plant are transformed into products for residential and commercial applications. 

Step 1: Receiving Materials

The felt-backed sheet vinyl manufacturing process is powered by the gel line, the coating lines and printing lines.

First, felt rolls are received from the felt plant to form the carrier at the gel line. 

Meanwhile, vinyl resins, fillers and liquids are unloaded into silos. Vinyl resins, plasticizers, limestone, stabilizers and other minor additives are mixed into a plastisol in a fully computer-controlled, automated system. Components are blended together based on formulas for given product lines. These formulas have been previously loaded into the computer system; the particulars of any given batch of plastisol are electronically retained. Once blended, the coatings are sent to the coating lines.

In a separate process, the latex, pigment inhibitors and water are mixed into inks and sent to the print lines.

Step 2: The Gelling Operation

The previously mixed gel, from the fully automated plastisol mix room, is applied to a felt roll at the coater as a white liquid and are then cured to a smooth finish for printing. Fumes from the curing station (primarily plasticizer) are incinerated for environmental compliance. The amount of gel applied is dependent on the product and the performance characteristics. This gel will later be expanded to provide the foam layer of the product.

During the production process, physical properties of the gel plastisol, primarily related to flow, are evaluated. Additionally, the gelled felt is continuously visually examined for defects and physical properties on a routine basis to ensure curing is completed. All of these tests are documented and retained for potential investigative purposes. Test results are associated with a felt roll number established in the felt plant. Product in the field can be associated back to a particular felt roll, and thus the gelling operation, using a computer database.

Step 3: The Printing Operation

The gelled roll is sent to the print operation. Here the pattern is created in separate print stations. Each print station has a print cylinder engraved with part of the image and a different color water based ink. The ink is dried between each print station before reaching the next print station. All stations are kept in register to achieve the overall image clarity. The inks are mixed prior to the print run and after each print run the inks and cylinders are changed and cleaned ready for the next pattern.

Production records for a given gel roll are associated with the felt roll number, as in the gelling process. The primary quality considerations in the printing operation are visual defects such as misregistration or misprint and the how well the print shade corresponds to a design standard.    

Step 4: The Wear Layer and UV Coating Operation

The printed material is sent to the final operation where a clear vinyl wear layer is applied. This coating protects the printed image and gives the product its wearing properties. After applying the wear layer the product is cured and the previously applied gel is expanded and texture is created. In some products a final urethane coating is applied and cured, for extra scuff resistance and dirt prevention. Some manufacturers also apply a special stain-repellent coating at this stage. The finished product rolls numbers are associated with the original felt roll number. These “parent” rolls are further visually examined and split into smaller rolls for shipment.

During this production, the wear layer plastisol is inspected for flow characteristics. The product is also continuously inspected for visual defects. As specified in the Finished Material Requirements, the physical properties of the finished product (such as thickness and gloss) are routinely inspected. The results from these inspections are logged for historical and investigative purposes. These data are logged in an electronic database. Finally, samples of the finished product are retained for trailing finished goods testing as outlined in the Finished Material Requirements. These results are also logged in an electronic database.

Step 5: The Backcoating Operation

For some vinyl sheet good products, the manufacturing process is completed at Step 4. With other brands, an additional layer is applied to the unprinted side of the product coming out of Step 4. This “backcoating” balances the sheet’s dimensional properties such that it can be installed without an adhesive and still lay flat with time. The backing coating is a highly limestone filled vinyl coating. It is applied with a roll coater in an operation similar to the gelling operation.

During this operation, the flow properties of the coating are closely monitored. The strength, thickness and visual characteristics are monitored continuously and logged for historical purposes. 

Staying Creative with Pattern and Color 

The design departments of resilient floorcovering companies are constantly seeking new inspiration for successful patterns and colors that will work in sheet and tile form. The designers work with marketing groups to determine what colors and styles will capture the public's interest as much as five years from production. The designs are scanned from natural materials or created directly on a computer, and mock-ups of the different patterns are produced in an array of colors. The designs are then printed on full-size paper and in full color.

Sheet vinyl flooring in a home. Zig zag pattern accented with a rug, white coaches and coffee table.
Sheet vinyl flooring

If a full-scale paper pattern is approved for use, printing plates or cylinders are created by engravers. These plates and cylinders are used to create the color and pattern as the flooring is manu-factured. A recent alternative to engraved metal cylinders and plates is digital printing. 

The protective wear layer is applied over the printed pattern, so the designers have a close approximation of the finished product. The prototype is either approved as is, edited or discarded. The time it takes from design to market typically can range from three to twelve months.

Resilient Floor Covering Institute

In recent years, residential consumers as well as commercial property owners are thinking much more about the lifecycle of the products they purchase. They want to know what ingredients go into the manufacturing process, whether recycling is an option or whether the products will wind up in the landfill at some point in the future.

The Resilient Floor Covering Institute (RFCI) is an industry trade association of resilient flooring manufacturers and suppliers of raw materials, additives and other flooring products for the North American market. In 2021, the Resilient Floor Covering Institute and its manufacturing members took their “Beautifully Responsible” message to flooring consumers, sharing their views that “Resilient Flooring is all about Mindful Manufacturing” and their commitment to sustainable sourcing, designing and manufacturing.

Members of the Resilient Floor Covering Institute are committed to sustainably manufacturing flooring products that reduce waste over time and promote healthy indoor air quality through third-party certification programs. The organization serves as a resource for designers and consumers who want to stay abreast of new developments in limestone resilient flooring manufacturing. Resilient flooring products offer many benefits.

Benefits of Resilient Flooring: Cleaning and Disinfection

Limestone is a naturally occurring material that enhances every product to which it contributes. It is a nonrenewable resource because the amount of time taken to form the limestone is much longer than the rate at which humans use it. At present, limestone continues to be widely available all over the world. Nearly anywhere on the globe, there are opportunities to purchase domestically sourced limestone. This is good news for resilient flooring manufacturers seeking to increase their limestone content as new processes for creating environmentally friendly specialty products are rolled out.

Even before the pandemic resilient flooring (along with modular carpet tiles) was one of the two most popular choices for workplace remodels and new construction. Resilient flooring offers a reasonable initial cost, high performance, durability, styling and aesthetics that can help further corporate branding.

As we transition from the COVID pandemic to an endemic, employers and workforce will be looking for products that promote confidence in the safety of the work environment. Proper maintenance of workplace flooring surfaces helps limit the spread of infection. Resilient flooring products are easy to clean and disinfect.

Compared to the soft quality of modular carpet, resilient flooring possesses a hard surface that can be easily and thoroughly cleaned and disinfected. 

The EPA List N is the reference document for registered cleaning products that are anticipated to be effective against SARS-CoV-2 inactivation. All surfaces within a workplace that are to be cleaned and disinfected need to be reviewed for compliance with the material, surface or product manufacturer recommendations and the cleaner or disinfectant chemical manufacturer to verify that the chemistries are compatible and will not degrade the material, surface or product.

However, advanced wear layers found on most resilient flooring products eliminate the need for harsh chemical solutions during regular cleaning. Resilient floors usually only require sweeping and damp mopping with a pH neutral cleaner. This maintenance advantage reduces the chemicals (and related volatile organic compound emissions) that workers are exposed to and also saves time and money for the business. 

Benefits of Resilient Flooring: Indoor Air Quality

In addition to ease of cleaning and disinfecting, resilient flooring can positively contribute to indoor air quality and wellness in the workplace and residential settings. Today’s resilient flooring, and even many of the adhesives used to install some resilient flooring products, is designed to emit little to almost no VOCs into the air. 

VOCs may cause a variety of adverse health effects in some people, from eye, nose and throat irritation to fatigue and dizziness; therefore, the resilient flooring industry supported the creation of a standard and subsequent certification, FloorScore® that addresses indoor air quality. The FloorScore certification is one of the most well-known and frequently searched for and referenced by the design community. FloorScore is a voluntary, independent certification program that tests and certifies hard surface flooring and associated products for compliance with criteria adopted in California for indoor air emissions of VOCs with potential health effects. The program uses a small-scale chamber test protocol and incorporates VOC emissions criteria developed by the California Department of Health Services.

When specifying resilient flooring, some specifiers look for the FloorScore designation, which is one assurance that the specified floor has been third-party tested to contribute to good air quality due to greatly reduced VOCs.

Ortho-phthalates have been used as plasticizers to make vinyl products flexible. However, there have been some concerns raised regarding the potential of ortho-phthalates being endocrine disruptors. As a result, in 2010, the resilient flooring industry began replacing ortho-phthalates with terra-phthalate plasticizers that have no known impact on the endocrine system. Terra-phthalates can be made from renewable or bio-resources such as soybeans, palm oils or castor oils. Today, all Resilient Floor Covering Institute (RFCI) member manufacturers use only terra-phthalate plasticizers in their vinyl flooring (has this sentence been verified ? maybe replace the word “all” with “many”). 

Another concern that has been addressed is the usage of heavy metals for stabilizers in flooring formulations. Heavy metals (lead, hexavalent chromium, cadmium and mercury) testing can be completed per test method EPA SW 846 Method 3052 and should not exceed the limits of 100 PPM by combined weight. No intentionally added heavy metals are utilized by RFCI members and almost all companies that manufacture vinyl flooring. 

Health & Wellness Building Certifications

In addition to product certifications, the pandemic has created a need to address occupant health within buildings in the context of COVID-19 and community acquired infections, resulting in the development of several standards and sets of guidelines. Fitwel’s Viral Response Module (VRM) is one. It sets standards for safeguarding occupant health and wellness including a third-party certification to mitigate viral transmission in buildings.

The WELL Health-Safety Rating certification system has existed for several years before the pandemic, focusing on operational policies and procedures, maintenance processes and the development of emergency preparedness plans to address a post-COVID-19 world.  

Resilient flooring can also help contribute to healthier environments in new construction and major renovation by meeting requirements for lower VOC emissions set forth in LEED EQ 4.3. 

Looking at Life-Cycle Cost Analysis

When facility managers and building owners begin to look at the purchase of resilient flooring as an investment, they should also quantify the costs associated with cleaning and maintenance over the life of the product in addition to performance characteristics. This comprehensive evaluation determines the return on investment (ROI) and is referred to as life-cycle cost analysis (LCCA). 

LCCA creates a bridge between operations and purchasing, so that decision-making is not based solely on initial cost, but on the long-term cost of ownership over the lifetime of the product. Facility managers and commercial building owners who require a minimum of 15 years and up to 30+ years from their flooring investment may find the shift to life-cycle cost analysis to be an economic advantage.

Several factors beyond aesthetics can impact the purchase decision. Performance characteristics like ease of maintenance; slip, wear and stain resistance; durability, acoustics, underfoot comfort, infection control, health and wellness and indoor air quality (IAQ) are all key considerations. These features, along with appearance, shape the perception of a space and contribute to a floor’s life-cycle cost. 

Every floor looks great when it is first installed. But how it’s cleaned and maintained determines its visual appeal after one year or five years; and a minimum of 15 years determines whether the initial investment was a good one. The level of cleaning and maintenance a floor requires is often overlooked, but it must be considered during the selection process to support long-term operational optimization and efficiency.

The economics of flooring decisions comprise many factors. Operational optimization, sustainable cost of maintenance and IAQ rise to the top. LCCA provides a method for evaluating the economic impact of alternative materials with similar functional performance criteria but varying cost over the service life of a building or a building system. It includes the cost to purchase, install the floor (labor, material, adhesive and preparation) and to clean and maintain it (including man-hours, la-bor rate, material, equipment size, cleaning frequency and cost of chemicals). 

A healthcare facility, for example, requires flooring that supports the patient experience and hygienic properties, while educational spaces are more concerned with flooring that lessens absenteeism by reducing the amount of harsh chemicals needed for cleaning and enhancing learning with exceptional acoustic qualities. LCCA requires calculating the life-cycle cost for all flooring products under consideration, enabling the project team to generate a side-by-side comparison in the areas of first-cost, aesthetics, acoustics, cleanliness, comfort, maintenance, durability, installation and useful service life. 

Taking total cost of ownership and dividing it by the number of years the flooring is expected to last results in the total cost per square foot/per year. Service life data from RFCI, manufacturer warranties and past performance metrics help determine the functional integrity and lifespan of various resilient products, dependent on the owner’s requirements, size of the project, function of the space and traffic.
 
Resilient floors generally do not require the application and removal of finishes and they offer additional savings because large areas of a facility do not need to be closed for extended periods of time. Also, IAQ is not compromised. This is especially important in a 24/7 environment such as healthcare facilities, where efficiency improves and room turnover can be accomplished quickly. It also positively impacts educational sites, where allergy and asthma are the leading cause of absenteeism, responsible for more than 14.4 million missed school days in the United States per year.

Diverting Waste from the Landfill

Residential and commercial designers have never been more aware of environmental issues than they are today. The interest in understanding manufacturing processes has increased with each new generation of designers many of whom are doing everything they can to support the vision of a circular economy with closed loop manufacturing processes.

Diverting construction waste from the landfill continues to be a high priority. Many materials that wind up in the landfill take up precious space and never actually decompose. Vinyl has been diverted from landfills and trash sites since before the turn of the century, and post-industrial recycling helps to put even the cut-offs back into other finished vinyl products. In the resilient flooring category, the tile or plank format utilizing click-float installation that requires no glue is the easiest to recycle.

In general vinyl products can be chipped and melted down and used to make a variety of products including plastic wrap, PVC pipe for houses and plastic bottles. Recycling vinyl is more involved than standard plastics, but fillers, lubricants, impact modifiers, resins and pigments are other items that use recycled vinyl material in their production.

Some luxury vinyl flooring products include recycled material in their manufacturing process. If the floors were made in the last decade, it is usually possible to reuse whole pieces; however, this depends on the glues used in the original vinyl. Tiles and shorter boards can be made from re-used vinyl plank flooring, which can also be used whole as carpet backing. 

Vinyl plank flooring can therefore often be recycled if they are kept as whole as possible (has this sentence been verified?). Recycling vinyl products helps protect the environment by diverting the material from the landfill. It also helps conserve energy resources. It is estimated that if products were made from at least 50% recycled material, there would be a 30% reduction in greenhouse gasses produced.

Comparing Resilient Flooring to Other Options

When compared to other flooring options in the marketplace for residential and commercial applications, resilient flooring offers distinct advantages. Resilient boasts high durability against im-pacts, scratches and wear resistance. Laminate flooring is also extremely resistant to scratching due to its strong melamine finish on the top layer. However, hardwood, by comparison, offers only medium scratch resistance. Wood is softer than vinyl or the new PVC-free resilient options, so it shows impacts and scratches more.

It’s hard to beat resilient flooring in terms of water resistance. Submersion for days or weeks might cause a problem, but vinyl and PVC-free resilient are essentially waterproof. Ceramic and porcelain tiles also do well in terms of water resistance. Of all the flooring options, carpet is the least water resistant. When comparing ease of installation between the various resilient flooring products and other flooring such as carpet or hardwood, SPC is the easiest to install. Simply score and snap. No glue is required, so there is minimal subfloor prep. LVT and sheet vinyl re-quire the additional step of applying adhesive and laying the flooring in the adhesive.

SPC flooring install
SPC flooring install.

Compared to carpet and natural stone which need to be vacuumed to pick up dirt particles (unless the natural stone is a smooth surface), resilient flooring is easiest to maintain with just a damp mop. Hardwood flooring can also be mopped, but grit and other dirt particles can scratch wood.

Ancient Material in a Modern World

Resilient flooring is a steadily growing market. According to a study by The Freedonia Group, global demand for resilient flooring will grow to 3.9 billion square feet in 2022. Currently, it can be seen everywhere: main street stores, big box megastores, hotels, restaurants, healthcare facilities, single-family homes, multifamily buildings and more. And the visuals become more and more lifelike and natural looking each year, as scanning and computer-aided-design software continues to become cheaper, better and more accessible.

As the building industry moves forward with new technology to create more sustainable products with improved manufacturing techniques, the ancient material limestone will continue to dominate the conversation.

 

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Sources

1-National Ocean Service 
https://oceanservice.noaa.gov/facts/coquina-tabby.html

2-Limestone Facts: Geology of the World. World Atlas 
https://www.worldatlas.com/articles/limestone-facts-geology-of-the-world.html

3- Minerals Database: Limestone. Minerals Education Coalition
https://mineralseducationcoalition.org/minerals-database/limestone/

4-Great Mining
https://www.greatmining.com/limestone.html

5-Global Outlook: Limestone Around the World. Miami-Dade Limestone Products Association
https://mdlpa.org/limestone-around-the-world/

6-Sciencing
www.sciencing.com

7-LVT Update-Focus on Rigid Core: An Overview of the Evolving Rigid Core Market. Floor Daily
https://www.floordaily.net/floorfocus/lvt-update-focus-on-rigid-core-an-overview-of-the-evolving-rigid-core-market-feb-2020

8-What is Resilient Flooring and its Types. CivicConcepts
https://civiconcepts.com/blog/resilient-flooring

9-When Planning for Sustainability, Remember the Flooring. Cleaning and Maintenance Management
https://www.cmmonline.com/articles/when-planning-for-sustainability-remember-the-flooring

10- Can Vinyl Flooring be Recycled? Home Steady
https://homesteady.com/can-vinyl-flooring-recycled-23444.html

11-US Green Building Council
https://www.usgbc.org/credits/new-construction-core-and-shell-schools-new-construction-retail-new-construction-data-38

12-Resilient Floor Covering Institute
https://rfci.com/about-the-institute/

13-The Role of Resilient Flooring in Supporting Wellness in the Workplace. The Resilient Floor Covering Institute for Interiors & Sources
https://iands.design/articles/45116/resilient-flooring-wellness-workplace?fbclid=IwAR0bcLqa13r3i3vRRgZ5q4XuIdWpR76jv76PzKXho9dftwn1IqPpMdE9u0c

14-How Life-Cycle Cost Analysis Impacts Flooring Procurement. FMJ the magazine of IFMA
http://fmj.ifma.org/publication/?i=496688&article_id=3087652&view=articleBrowser&ver=html5

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