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Resilient Flooring and Materiality: Transparency, Product Service Life and Performance
Earn CEU Credits:
interiors+sources’ 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:
1. Provide a process for developing Owner’s Project Requirements for flooring products.
2. Understand the project conditions for successful flooring installations.
3. Understand the material ingredients in resilient flooring products.
4. Understand product manufacturing processes and installation methods for resilient flooring products.
*This CEU opportunity is sponsored by Resilient Floor Covering Institute (RFCI).
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When specifying products for the built environment, it is important to transparently understand the origin of material ingredients, how materials are used to produce finished products, and have background on the installation process and related priorities for a successful installation.
In the planning project phase, the Owner’s Project Requirements (OPR) are identified with the client, design team, and other stakeholders.
For each installed product, the OPR process identifies desired product service life, application of products for a specific use, and the performance characteristics required.
A process for identifying the criteria for inclusion within the OPR is part of the program as it relates to the resilient flooring product category and each type will be reviewed to better understand the materiality and construction of each flooring type, including vinyl tile and sheet; luxury vinyl tile, plank, and rigid core product; linoleum tile and sheet; rubber tile and sheet; and cork tile.
Owner’s Project Requirements
Establishing the goals of the project from the onset is crucial for the development of a successful project. As part of the process, asking the right questions is imperative to glean operational data and information that is used as a basis for the design of the physical environment.
Regardless of the type or project, the questions are based upon understanding each operation or function that takes place within a setting.
For example, for a healthcare outpatient space, the multi-disciplinary team would want to understand:
- The entry/check-in process for patients, including drop-off and pick-up sequence
- The timeclock or check-in process for staff and employees
- The waiting process (if applicable) for patients with a focus on reduced/eliminated wait times
- The charting process and communication on availability of charts to patients/family members
- Infection prevention protocols, i.e. location of handwashing sink, types of surfaces used within the examination room, and existing rates of healthcare acquired infections
- Educational materials and other health and wellness activities available for the care population and staff
- The process for patients to go to examination room
- The process to have labs completed (inhouse or outside lab)
- The follow-up process for communication of results and information—in-person or telemedicine opportunities to reduce risk and save time
- The prescription process for having medications filled and delivered to the patient
- The exit process for the patient including payment options and scheduling of follow-up appointments
- The cleaning and disinfection process for examination rooms and shared space between patients and at the end of the day
- Identification of the cleaning and disinfecting responsibilities for not only care areas, but also waiting space, registration/triage, staff spaces, toilet rooms, meeting or conference rooms, security areas, and any other types of spaces that are part of the outpatient clinic spaces
- Operational policies and procedures that impact the supportive design
In terms of OPR from a product selection process, there needs to be an evaluation of criteria and sharing of experience, anticipated outcomes, and understanding cleaning and disinfection protocols. This was important prior to the pandemic but is now even more of a priority as surfaces can be an indirect means of transmission of infection by touching a contaminated surface and subsequent touching one’s eyes, nose, or mouth.
For killing SARS-CoV-2, the virus that causes the disease COVID-19, it is essential to understand three parts of the cleaning and disinfection performance requirements:
1. Provide the least caustic disinfecting chemical that eradicates the virus and poses the lowest exposure to the environmental services technicians
2. The disinfecting chemical needs to be effective in killing the virus
3. Determine if the chemicals used to clean and disinfect a surface will not cause harm or degrade the surface
The regulatory authority for disinfectant efficacy is found in the U.S. Environmental Protection Agency’s (EPA) List “N”. The Centers for Disease Control and Prevention (CDC) provides guidance on cleaning and disinfecting of not only surfaces, but also provides recommendations for healthcare and other community spaces, such as workplace, hospitality, schools and homes.
Ultimately for all interior products it is recommended to contact not only the product manufacturer for cleaning and disinfecting recommendations, but also the cleaning and disinfecting chemical product manufacturer to verify efficacy and potential impact to surface degradation if a chemical manufacturer has tested their product on the flooring type. When a surface becomes damaged, it can become a reservoir for pathogens and create an infection transmission risk.
When selecting interior products, there needs to be a balancing of criteria as part of the functional and physical space programming process completed with the owner/client and the interdisciplinary team that includes:
- Product performance characteristics required for the specific product application and space
- Identification of sustainability goals including the anticipated product life cycle for a product (e.g. 5 years, 10 years, 15 years, etc.)
- The type of installation that is suitable for the setting (e.g. healthcare, workplace, hospitality, retail, etc.)
- Maintenance considerations for cleaning and disinfection including identification of in-house or contract environmental services team
- Product type and building budget
In selection of interior resilient flooring products, the programming process to establish the OPR includes additional information that requires review. These may include:
- What flooring product considerations are available from owner through specification or customer request?
- What is the application for the flooring product, including traffic level?
- What is the product service life required for the application?
- What is the wear layer required based on the traffic level?
- Is a sheet product or tile product most conducive to the application?
- What is the budget for the flooring portions of the finishes for the project?
- What are the desired aesthetics for the project?
- Do you have a standard specification for flooring products?
- How frequently do you replace flooring product?
- How much attic stock do you typically maintain for the project and where is the attic stock typically inventoried and stored?
- What technical and maintenance information do you need for the flooring specified?
- Do you require sustainable product certifications for flooring products as part of the specification?
- Has COVID-19 created additional considerations for flooring specifications?
- Have you had any transition issues between different types of flooring products visually or physically?
OPR & Performance Testing
Tied to the OPR is the overall performance testing that is utilized for resilient flooring products. The ASTM Resilient Floor Coverings Committee (F06) develops and publishes test methods for resilient flooring products. Of particular mention is ASTM F925-13 Standard Test Method for Resistance to Chemicals of Resilient Flooring which is used as a minimum performance test method for evaluation of cleaning and disinfecting chemicals on resilient flooring.
It is anticipated that because of additional types of disinfection methods being used because of novel coronavirus (SARS-CoV-2 virus), performance testing will continue to evolve to include the impact of UV-C (ultraviolet light for disinfection), which has been a strategy used in healthcare settings and with some mechanical systems to reduce potential spread of infection, and is now being evaluated in all types of settings.
Hydrogen peroxide mist is another technology that is utilized in healthcare and being evaluated in other verticals. These strategies and other additional products and additives are currently being researched for not only efficacy but also the impact to surfaces and potential degradation, particularly if chemical cleaning and disinfection occurs prior to an additional treatment (creating an additive impact to a surface or material).
The application methods of chemicals may also impact surfaces, as electrostatic sprayers have become a popular delivery method in the course of responding to the pandemic. This is a constantly growing body of research being completed by universities as well as manufacturers, all trying to better understand the impacts to resilient flooring products.
Resilient Flooring Types & Related Performance Standards
There are minimum performance standards for the various resilient floor covering types, which include:
- Vinyl composition tile (VCT) - ASTM F1066
- Homogeneous sheet vinyl - ASTM F1913
- Heterogeneous sheet vinyl - ASTM F1303
- Solid vinyl tile - ASTM F1700, Class I
- Luxury vinyl tile or plank (LVT/LVP) - ASTM F1700, Class III
- Rigid core LVT (SPC and WPC) - ASTM F3261
- Rubber tile or sheet - ASTM F1344 or ASTM F1859 or ASTM F1860
- Linoleum tile or sheet - ASTM F2195 or ASTM F2034
- Cork tile - ASTM F3008
- Various types of other polymers - ASTM F2982 or ASTM F3009
No matter what type of resilient flooring product is installed, the subfloor preparation is key to a successful installation. Preparation involves measuring the moisture content in concrete slabs and selecting a condition appropriate adhesive for the installation. There are two types of moisture content tests:
1. Anhydrous Calcium Chloride (ACC), which measures moisture movement through the slab (MVER: Moisture Vapor Emission Rate).
2. Relative Humidity (RH) Test, which includes drilling into the subfloor and utilizing an electronic probe to determine the percentage of moisture. The second method, which is based on ASTM F2170 Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes is used for the Relative Humidity (RH) Test.
Calculating relative humidity levels allows for the identification of the most appropriate adhesives to be used based upon site conditions. For example, many standard flooring adhesives are rated to withstand up to 80% relative humidity, but if resilient flooring products were to be installed in a more humid environment, a different flooring product or moisture mitigation solution would need to be specified that could withstand conditions including higher relative humidity.
The recommendation is to always reference a specific product manufacturer’s recommendations for the recommended adhesives based upon the site conditions.
Another component for a successful installation includes working with the General Contractor (GC) to verify qualifications and training of finish Subcontractors. This is important, as the final installation reflects on not only the installer, but the designer/specifier and the manufacturer of the product. Specifications that include subfloor preparation, installation information, and inclusions of qualifications can mitigate installation issues.
The organization INSTALL can assist the design community with specifications that reinforce the need for recommended qualifications for resilient flooring installation. It is recommended that pre-construction meetings with the General Contractor (GC) and finish Subcontractors be held prior to installation of any finishes.
During these meetings, the OPR should be reviewed with the GC and Subcontractors to reinforce the understanding of why the design is supportive of the users and confirm various installation methods and expectations for the completed project. Additionally, a communication system for detail and material questions should be set up with the GC and relevant Subcontractors.
For vinyl, rubber, and linoleum sheet products, there is an opportunity to cold or hot weld seams and to create coved integral base solutions that are effective in healthcare and other institutional settings. Any space that requires a continuous flooring solution can use a sheet product with a coved base that protects the floor and base of the wall; while supporting cleaning and disinfection requirements of the surfaces.
Solid vinyl tile flooring can also be welded and coved to the wall. Some carpet manufacturers have vinyl backed carpet that can also be cold or hot welded to a vinyl sheet product to create a continuous flooring solution for appropriate applications, such as senior living settings. This creates a continuous moisture barrier across the subfloor without needing a transition strip that could impact mobility.
In addition to preparation of the subfloor and testing for moisture in the subfloor, there is also the need to understand the importance of a continuous flooring solution between materials that supports a smooth transition between surfaces as a project condition.
This example shows a successful installation of carpet and LVT. There is also a rubber underlayment utilized for acoustical benefit and underfoot comfort. Because the product thicknesses differ, the underlayment thickness used was 5mm under the LVT and 2mm under the carpet between a work area and a conference room in an office setting.
In senior living and multifamily housing communities, smooth transitions are a very important detail from a Universal Design perspective, because they support mobility within the space. Smooth transitions and supportively designed environments aid those utilizing various types of assistive devices and the general public, such as accommodating mothers with strollers, shoppers with carts, materials management, laundry services, etc.
Transition strips may be required to provide a smooth transition when floor materials of different thicknesses abut. Strips can be installed under the thinner flooring material and flash patched to accommodate the height changes to create a continuous, even transition between one material and another.
In the past the concept of Universal Design has been solely equated with accessibility. However, the University of Buffalo’s definition emphasizes how Universal Design actually supports building all-inclusive community, defining Universal Design as “A process that enables and empowers a diverse population by improving human performance, health and wellness, and social participation”.
The process includes a supportive environment plus access to services and amenities as the definition of an overall successfully designed community.
Resilient Flooring Types: Materiality
Vinyl Resilient Flooring
There are various types of vinyl resilient flooring, with luxury vinyl tile or plank (LVT or LVP) being the most widely specified in the commercial marketplace. The merging of advancements in digital technology, which has provided all types of aesthetics to choose from, including wood, stone, tile, linens/textiles, and abstract patterns, with the durability of a resilient flooring product are both contributing factors to the popularity of LVT and LVP.
Per Diagram 1, salt is coupled with ethylene from natural gas results in chlorine, which is used to create vinyl chloride monomer, a building block for polyvinyl chloride. The salt is usually mined by using hot water extraction of salt from large naturally forming, underground mounds.
A polymerization process transforms vinyl chloride monomer into PVC resin. When compounded into vinyl resilient flooring, the resin is combined with fillers, additives, modifiers, stabilizers, and plasticizers.
Fillers include calcium carbonate, also known as limestone, which is used for not only thermoplastic flooring types like vinyl, but also thermosets such as rubber flooring. Vinyl is a thermoplastic, which means that it can be reheated, remolded, and cooled without causing any chemical changes and scrap generated in the process of manufacturing vinyl flooring can be added directly back into the mix.
Vinyl resilient flooring types include the following with various advantages depending upon the product:
1. Vinyl composition tile (VCT) has modular flexibility including large format shapes, sizes, and colors. The product has a through-pattern and withstands heavy foot and rolling load traffic. Many VCT products include a factory finish, but because of the high content of limestone in VCT, it needs to be waxed or polished, requiring periodic stripping and reapplication of wax or polish. VCT is often chosen because of its reasonable first cost.
2. Homogeneous and heterogeneous commercial sheet vinyl floorings are constructed differently but have several similar advantages and installation methods. They are both durable under heavy rolling loads, their seams can be heat welded, and the products can be flash coved to create an integral base with the flooring.
Homogeneous sheet vinyl has a through-color construction, which provides even wear and a consistent appearance over time. Homogeneous vinyl may have a slightly lower tolerance for error in subfloor preparation because it does not have any patterns or embossing, as heterogeneous sheet vinyl products do.
As a result, it is much easier for imperfections in the subfloor to be telegraphed through and evident under a homogeneous product. The smoother and more monochrome the vinyl is, the more it shows imperfections in the subfloor.
Both homogeneous and heterogeneous sheet products can be produced using a calendering method as shown in the production Diagram 4 below. Calendering is a process that uses rollers to smooth, coat, or thin a material, and can be used in the manufacturing of wallcovering, coated textiles, and flooring.
In additional to calendering, the heterogenous sheet vinyl production process also utilizes a plastisol method, which uses a liquid mixture of PVC resin, plasticizer, fillers (with the exception of the wear layer) and additives that is the consistency of a paste.
This paste (or plastisol) is applied by a coating process and transformed in the solid state by heating (termed “Gelification” in the diagram below), which is in contact with a hot drum and subsequently hardened on cooling rollers.
3. Solid vinyl tile can be made in two ways, either by cutting homogeneous vinyl sheet into tiles or by placing ingredients into molds that go into a heated static press. An advantage of solid vinyl tiles is that they are modular, and easier to transport throughout the supply chain and during installation compared to rolled goods that are more than 270 pounds per roll.
They can also be made in various sizes, including 12-by-12, 24-by-24, and 36-by-36 feet, allowing ease in creating flooring patterns as well as wayfinding options. The larger format is mostly used in healthcare applications, as hallways are wider and the products can be welded and coved to the wall providing the same advantages as homogeneous sheet products.
4. Flexible luxury vinyl tile (LVT) or plank (LVP) is a layered product that includes a wide range of aesthetics. LVT and LVP have design versatility with sizing and durable finishes suitable for many types of verticals across residential and commercial settings.
For commercial applications, there are two types of installation methods for LVT/LVP—glue down (including peel and stick) and loose lay (including “click” product). The glue down installation method involves the use of an adhesive to adhere the dryback luxury vinyl flooring to the subfloor. Using an adhesive creates dimensional stability and ensures the flooring maintains its natural characteristics.
There are three glue down methods that use two distinct types of adhesives:
3. Self-sticking pressure-sensitive
Hard set and releasable adhesives are spread along the floor and the flooring is laid on top. Self-sticking pressure-sensitive adhesive is on the flooring product itself and is bond to the substrate with pressure. These types of products are often called peel and stick.
Loose lay installation can be used over existing floor coverings. The LVT/LVP is adhered to the edges or the perimeter of the subfloor typically with a takifying adhesive, then additional planks and/or tiles are typically laid in place without an adhesive. This makes loose lay LVT/LVP an ideal option for areas where flooring may be temporary or have a short lifespan, particularly because removal and replacement will not damage the substrate, or the flooring material, which can then be reused.
Loose lay LVT can be used over most raised access floors and would be an advantage when a raised floor needs frequent access. Loose lay is thicker than dryback LVT and as a result offers improved sound testing results between floors (Impact Insulation Class (IIC)) that can be helpful in the design of corporate, multi-family, hospitality, and senior living settings. Because of the thickness, loose lay can match up to other products’ thicknesses creating a ‘smooth transition’ without using a transition strip.
Because the product is not fully adhered but rather “loose laid”, the substrate has to be solid as well as clean, level, and flat. Soft substrates, such as recycled rubber, carpet, or cushioned sheet vinyl may have too much deflection and cause issues for a loose lay installation. In such situations it may be necessary to remove the existing flooring for a successful installation.
5. The newest product introduction in the vinyl category is rigid core luxury vinyl tile and plank. There are two types of rigid core flooring products:
1. Stone Plastic (or Polymer) Composite (SPC)
2. Wood Plastic (or Polymer) Composite (WPC)
SPC features a core that is typically comprised of around 60% calcium carbonate (limestone), polyvinyl chloride and plasticizer. WPC’s core typically consists of polyvinyl chloride, calcium carbonate, plasticizers, a foaming agent, and wood-like or wood materials such as wood flour.
Manufacturers of WPC, which was originally named for the wood materials it was comprised of, are increasingly replacing the various wood materials with wood-like plastics and very few contain wood materials today. Both are durable and stable and offer superior impact noise reduction between floors. However, SPC is more durable and denser overall due to its higher limestone content. WPC is softer and quieter underfoot while SPC offers better resistance from scratches and dents.
There are not any substantial differences in installation for SPC and WPC LVT, as rigid core is intended to be a floating floor. There is a “click” together installation and some adhesive may be used similar to flexible LVT/LVP floating floor but should not be fully adhered. If full adherence is required, the product specification should be changed to use a fully adhered installation.
Rigid core advantages include a locking or “click” system to enable a floating floor installation for predominantly residential and light-commercial applications. There is no telegraphing of minor subfloor irregularities or imperfections and the rigid structure provides resistance to humidity and temperature variations. Rigid core can be installed over most existing hard surfaces, including ceramic tile.
Rubber Tile and Sheet Resilient Flooring
Rubber flooring has been a flooring of choice in healthcare applications as it is durable and can be seamed and coved to the wall providing a continuous flooring solution.
Compared to other resilient products it offers excellent noise management and lower sound transmission properties, as well as comfort underfoot for staff standing for long hours. Rubber flooring is available in sheet format as well as in tiles with a multitude of profiles for different types of applications. For example, a smooth finish will be preferred in healthcare application, but elevated round profiles that provides slip-resistance properties will be preferred in staircases.
Rubber flooring can be made from multiple sources and its composition will vary from manufacturer to manufacturer as well as across different product lines. Most rubber flooring is made of a mix of natural rubber from plantations and synthetic rubber that is made from oil or natural gas to create ethylene styrene butadiene. It includes fillers and some may also use sulfur with other additives for compounding and curing the rubber flooring.
Some manufacturers also add an optional polyurethane coating layer. Rubber is a thermoset versus a thermoplastic. A thermoset is a material that strengthens when heated but cannot ever be remolded or heated like it was during the initial forming. When recycling rubber, it is usually shredded or chopped to then be pressed or added back into the mixture for new rubber flooring.
The production process for rubber flooring includes mixing the ingredients and using a calendering process to make the rubber flooring into sheets. Rubber flooring can remain in sheets or be cut into various sizes to create tiles. Rubber tiles and stair treads can also be produced by molding the rubber compound in a heated stack press.
As with installations of other types of resilient flooring, installations of rubber flooring require the proper job site conditions and sub-floor preparation to be successful. Preparation of a smooth subfloor reduces the possibility of imperfections telegraphing through from the subfloor to the finished floor surface.
Cork Tile Resilient Flooring
Cork comes from the bark of the cork oak tree (Quercus suber), which is grown near and around the Mediterranean Sea. Every nine years the bark is hand-harvested, leaving a protective inner layer of bark that allows the tree to continue to grow and regenerate new bark.
The majority of cork used for flooring uses the scraps left over from punching out wine bottle corks, but some may come directly from dried bark, which is boiled as the next step in the production process.
For cork sheet, which is used as an underlayment under flooring or for cork bulletin boards, the granulated cork is combined with a polyurethane binder under pressure in large cylinders and “peeled” to create the desired sheet thickness.
For cork tiles, the beginning processes are similar but instead of being placed in the large cylinder under pressure, the mixture of granulated cork is placed in molds to create blocks, which are then cut into tiles and packaged.
Similar to other types of resilient flooring, homogeneous cork can be directly glued down to the substrate and consists of a cork tile that is pre-finished with polyurethane. Some installations require additional polyurethane finish to be added onto the installed flooring. Heterogeneous cork can also be directly glued down and consists of a cork tile, cork veneer, and polyurethane finish.
Cork tile has a floating floor option with a click system. This product includes a cork backing, an intermediate layer, cork tile, and a polyurethane finish.
Advantages of cork tile include that it is a natural material and harvesting does not harm the trees, it is a good acoustic and thermal insulator, it promotes underfoot comfort, and it is resistant to fire, stain, mold and mildew. An installation example of a floating cork flooring installation is shown below.
Linoleum Tile and Sheet Resilient Flooring
Linoleum is produced by oxidizing linseed oil, rosin, and a drying agent to make a linoleum cement, which is a tough sticky material. It is stored in containers for a few days for further reaction and then is mixed with cork flour, wood floor, filler and pigments. The filler is typically limestone (calcium carbonate).
These ingredients are mixed together and are calendered onto a jute backing and stored in drying rooms until cured to the required hardness. After approximately 14 days, the material is taken out of the drying room to the trimming department where the factory finish is applied on the product. The edges are trimmed, and linoleum is cut into sheet lengths or cut into tiles. The trimmings and reject product are reused.
Linoleum installation requires more advanced skills for installation in some cases, and the material has a propensity to expand in width and shrink in length when rehydrated in adhesive. There are techniques to mitigate this type of movement. And there is also the possibility of end curl memory.
Due to drying the material and rolling it in its packaging, the ends of each cut must be worked out prior to installation to “break the memory” and allow the material to lay flat. This reinforces, the importance of the designer to work with the General Contractor and finish subcontractors to verify that they have the skills required to provide a successful installation of linoleum sheet or tile flooring products.
Advantages of linoleum flooring include that it is a bio-based product and includes renewable ingredients, it is a through-pattern material, and, similar to sheet vinyl and rubber, can be heat welded with an integral coved base.
Other Polymers used for Resilient Flooring
Innovation in the resilient flooring market is ongoing. Polyolefin and polyester are two additional polymers that have been developed into resilient flooring products. There are also many types of composite products that combine different types of materials together, such as rubber and cork, sheet vinyl and fiberglass stabilization layers, etc.
Resilient flooring product manufacturers and researchers are continually evaluating alternative polymers and additives and composites to combine or improve upon the strengths of other materials to create products that address key applications, such as added underfoot comfort or acoustic performance.
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For more information on resilient flooring products, please go to the Resilient Floor Covering Institute (RFCI) website. For product specific questions, please reach out to your product manufacturer. Any additional questions can be directed to Jane Rohde at JSR Associates, Inc. at firstname.lastname@example.org.