Flooring Forensics: How disinfectant sprays can impact flooring and furnishings over time - Aug/Sept 2020

By Lew Migliore

Since the start of the coronavirus outbreak, cleaning has taken on a renewed importance. Nationwide, there’s been an increase in demand for sanitization and disinfection services within office buildings and spaces in which large numbers of people gather. And while the treatments being used aren’t new, they are being applied more frequently and in greater quantities. As a result, we have had several inquiries from clients whose customers have been asking about the long-term effects of treating soft and hard surfaces.

HOW ARE PUBLIC SPACES BEING DISINFECTED?
Whether the space is a corporate office, healthcare facility, public space or hospitality setting, when disinfection services are needed, a professional should be enlisted to do the work. In-house staff or building maintenance can take care of the simpler things, such as wiping down doorknobs, faucet handles or surfaces that are touched by occupants regularly and repeatedly.

The processes being used to disinfect are many and varied and include things like fogging or electrostatic spraying and use chemicals like bleach, oxidizers and quaternary ammonium compounds.

The products should be hospital-grade disinfectants listed on the Environmental Protection Agency’s “N” list, which meet the EPA and Centers for Disease Control and Prevention’s efficacy requirements against the novel coronavirus-that is, they kill 99.999% of bacteria and viruses on contact and are safe in all environments and on all surfaces.

When it comes to the coronavirus, all companies producing and applying any disinfectants are only allowed to claim that these products disinfect on nonporous surfaces. The EPA will not allow claims that a product can disinfect a porous substrate such as carpet or textile furnishing because there is the risk that not all areas are covered with the product when it is applied. However, there can be a statement that the disinfectant product can be used on porous surfaces to “clean” them, but it may not make the statement that it will disinfect them.

Does this mean that carpet should not be disinfected? Certainly not. The disinfection method here would essentially be a normal cleaning. In this case, that would be hot water extraction. Detergent and water will kill the virus, and the cleaning agent in hot water extraction should be effective. However, there is currently only one EPA-registered and Carpet and Rug Institute-listed carpet cleaning agent-Vital Oxide-that kills bacteria and would be effective on viruses.

RISK OF DAMAGE TO MATERIALS AND SURFACES
Prolonged use of chemical cleaners can impact the integrity of the furnishings in a space. In hotel rooms, for example, there is flooring (both soft and hard), bedding, draperies, hard furniture and upholstered furniture. High-end hotel properties most often have woven Axminster carpets that are an 80/20 wool/nylon blend, which is particularly susceptible to oxidizing agents.

Many of the disinfectants being used contain oxidizers or bleaching agents. Oxidizers can destroy color in soft flooring materials, decompose wool and embrittle synthetic fibers. Disinfectants that are chlorinated products could turn into hydrochloric acid, which can discolor and even destroy nylon and wool. It can also affect and degrade cotton sheeting and various wool products. The hydrochloric acid can also impact coatings on wood and other fixtures. Synthetics will be affected at a slower rate than organics like wool and cotton.

Under current conditions, the expected extremely high frequency of the applications-daily in some cases-is going to build up heavy residues, which may not only impact the carpet but other textile materials and hard surfaces, as well. Hotels have been particularly concerned because they feel compelled to treat the rooms after each guest stay. Not only will the repeated use of disinfectants compromise the furnishings, but because the application is with foggers spraying a light mist, it’s not going to dry for an extended period of time. In the process of being diligent about safety and health, the repeated applications of the disinfectants may also tighten up the replacement cycles due to impacts on furnishings.

But there are other things to consider, as well. Will there be residue buildup from repeated applications? Are there harmful effects of the chemicals themselves? If everything gets wet or damp, will there be microbial growth and odor?

THE DISINFECTANTS
There has been talk about the use of ozone generators. Ozone is a disinfectant and powerful oxidizer that can kill microorganisms. Since it is a gas, it will go everywhere in a space. Research indicates exposure times in the space of ten to 30 minutes are effective, depending on the size of the space. It is a much stronger oxidizer than other common disinfectants such as chlorine and hypochlorite, and it dissipates quickly. However, with uncontrolled exposure, it may have an adverse effect on the respiratory system, so its use for air disinfection is generally not recommended if people are around. And over time, it will progressively damage rubber, plastic, fabrics, paint and metals.

In addition, though the Centers for Disease Control says bleach can be safely used to disinfect surfaces, it can’t be used on all surfaces. Bleach is sodium hypochlorite. If bleach is sprayed on textiles and allowed to sit without being wiped off, colors will fade over time. It will also deteriorate cotton, linen, wool and other natural fibers, and pinholes may begin to appear. Synthetic materials like nylon and polyester will typically just show some color fade and not much yarn/fiber deterioration. Solution-dyed synthetic yarns and fabrics will be impacted the least if sprayed with bleach.

Quaternary ammonium compounds (quats) have been recognized as being effective against the coronavirus. These positively charged (cationic) cleaners, if sprayed on resilient surfaces and not rinsed off, can damage topical finishes and cause yellowing, especially in high temperature environments. They also reduce lightfastness properties of some dyestuffs. Stain-resistant treatments on residential nylon carpets can also be diminished, and their use invalidates stain resistance warranties. Cationic materials are also known to attract soil particles, which is why cationic detergents are not used in carpet cleaning agents.

If the quat also contains a surfactant (if it is used for cleaning) and is not rinsed from the floor, the surfactant will attract dirt from shoes and could be redeposited to other areas in the building. If quats are sprayed on office chairs made from synthetic fibers, the cationic quats can “stick to” anionic fabrics (cotton pants, jeans or shirts for example) and, eventually, yellow those fabrics. Opposites attract. Cotton is anionic (negatively charged), and the positively charged quats will be attracted to them.

In addition, peroxide or chlorine-based agents can impact textile colors. They can also have an effect on the polyurethane wear coatings on vinyl tile and planks. These reactions may take months to manifest, or they may take only hours. In areas that are repeatedly treated, the effects would be compounded. If sunlight floods a space, the UV light can accelerate the effects of oxidizing agents and speed color changes or loss. If the furnishings in a hotel room are washed repeatedly, the washing can speed the deterioration of the fabric. Another possible side effect is that moisture on fiber surfaces-natural or synthetic-can increase if the peroxide decomposes to oxygen and water. If the HVAC system does not remove this moisture, it could lead to other problems like mold and mildew.

UV light is also being applied to fight the virus. The UVc wavelength is the only one that is highly effective; UVa and UVb wavelengths are not. Unlike foggers, UV is only effective where it shines. It does not permeate the space and won’t reach everywhere, so it is not an adequate means to disinfect. And, at the level of intensity necessary to act as a disinfectant, it can cause physical and chemical changes. If exposed long-term or repeatedly, it can fade colors and affect many natural and synthetic polymers, including some rubbers, neoprene and polyvinyl chloride (PVC). This means any synthetic flooring-soft or hard-can be damaged by UV light that has sufficient intensity to disinfect a surface, so exposure time is critical.

NO EASY SOLUTION
So what’s the answer? There is no definitive solution, as carpet varies from the type of nylon, wool, blends and dyes used, and treatments applied will have varying effects.

Of concern also should be the time these wet agents have to spend on the surface of carpet or furnishings and other sensitive equipment, like computer keyboards, and the effects this will have on them.

Therefore, every fabric and chemical will have to be tested to determine the effects. These tests can be conducted by the Professional Testing Laboratory here in Dalton, Georgia. The catch, however, is that the existing standard lab test for disinfectants’ effects on flooring is a one-hour test. The test would have to be modified for extended periods of time and multiple applications to emulate real-life conditions.

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