Selecting Coatings for Hospitals by Service Area

Coatings used in hospitals and healthcare facilities must be kept clean, which typically requires frequent scrubbing and disinfecting. These coatings must therefore be resistant to abrasion and to the chemicals used in cleaning products. Meeting these requirements typically indicates the need for high performance coatings.

But there are often other requirements for coatings used in these settings, such as low odor and low VOC (volatile organic compound) content, particularly when work occurs in a facility that remains in operation. These further restrictions limit choices in many cases to water-based coatings. Another mechanism used in some coatings to keep surfaces clean is the addition of biocides in the formulation. Antimicrobial or microbicidal coatings inhibit growth on a surface and in some coatings can actually kill harmful infectious agents. One major manufacturer recently introduced a microbicidal coating with the claim that it kills 99.9 percent of certain infectious bacteria. For a manufacturer to make this claim for a coating, the coating must be tested and registered by the EPA.

Interestingly, at the same time antimicrobial coatings are promoted by manufacturers, Kaiser Permanente, a health-care provider and insurer, recently announced that its hospital facilities would no longer use antimicrobial coatings due to questions about their effectiveness.

The selection of suitable coatings largely comes down to the cleaning requirements of particular hospital areas and the need for a coating that provides adequate performance. Typical areas include common areas, corridors, rest rooms, kitchen/food service areas, patient rooms and surgery rooms. Candidate coating systems include various water-based acrylics, water-based epoxies and water-based polyurethanes.

COATINGS FOR WALLS AND CEILINGS

An acrylic latex system may be suitable in areas with less stringent cleaning requirements, such as common areas. An acrylic latex system should include a primer specific to the substrate (e.g., wallboard or concrete block) and two finish coats. Better performing acrylic finishes include 100% acrylics and acrylic epoxies. These systems can typically withstand more frequent cleaning than typical acrylic latex paints. Acrylic epoxies may be promoted by manufacturers as single-component or pre-catalyzed epoxy coatings, but cannot compare to the performance of two-component epoxies. An acrylic latex finish that also functions as a microbicidal coating may offer enhanced performance by keeping surfaces cleaner than coatings without biocides.

Areas with the most stringent cleaning requirements, such as operating or surgical rooms, will require high-performance, two-component epoxy systems. These systems are most often water-based and should include an appropriate primer and two finish coats. In addition to having a hard and relatively impermeable surface with excellent chemical resistance, water-based epoxies will be low-odor and low-VOC materials. It’s possible that a water-based polyurethane finish coat will be used together with an epoxy primer or epoxy primer and intermediate coat. Polyurethanes have excellent performance and chemical resistance similar to epoxies, with the added benefit of withstanding UV (i.e., sunlight) exposure, should this be required.For areas with more stringent cleaning requirements, like restrooms and some patient rooms, 100 percent acrylic or acrylic epoxy systems should be used at a minimum. These areas may also require the best performing systems as described below.

Examples of generic coating systems for specific hospital areas are provided below. These systems are most applicable to walls within a specific area. Although the same coatings can be used on ceilings, lesser performing coatings are often used on ceilings since they are not as easily contaminated or require as frequent cleaning. It should be noted that for acrylic latex systems, the use of a microbicidal coating can offer enhanced performance as previously discussed. Coatings for floors are addressed separately below.

Table 1 – Examples of Generic Coating Systems for Hospital Areas

COATINGS FOR FLOORS

Floors in hospitals, which are often concrete slabs, can be covered with a variety of materials. Coatings are a good choice because they offer a seamless surface that can be more easily cleaned and kept clean than other types of flooring. Floor coatings may include acrylics, epoxies, polyurethanes, polyureas, polyaspartics and hybrid coatings. Again, when available, water-based formulations are preferred for minimizing odor and VOCs. Additionally, an important aspect for applying any floor coating is proper surface preparation. Surface preparation details are not discussed here except for noting that the concrete surface must be roughened sufficiently to achieve good adhesion of the coating.

Water-based acrylic floor coatings are single-component materials normally applied at 2 to 3 mils per coat in two- or three-coat systems, including a primer and one or two finish coats. Acrylics provide moderate performance but may not be the best choice where heavy wear is expected.

Epoxy coatings may be the most widely used coatings for concrete floors. A variety of epoxy coatings are available, including solvent- and water-based formulations. Two-component epoxies have good abrasion resistance and moderate to excellent chemical resistance.

Polyurea coatings most often refer to thick-film coatings that require specialized application equipment, cure very quickly and offer excellent chemical resistance. They’re often found in industrial settings or locations where chemical exposures are expected.Polyurethanes are multi-component materials with good abrasion resistance and moderate chemical resistance. They’re also used in a broad variety of settings. Typical polyurethanes are applied in one or two coats at just a few mils per coat. A polyurethane coating may be applied as a topcoat over an epoxy coating where sunlight or weathering is an issue. Thicker-film polyurethanes, which are high- or 100-percent solids, multi-component materials, are available for specialized applications where increased chemical resistance is required. Similar to the thicker-film epoxies, these coatings cure quickly and may require specialized application equipment.

Polyureas are similar to 100 percent solids polyurethanes but cure faster. Application is less affected by ambient conditions such as moisture, but the faster cure can also make it a challenge to achieve adequate adhesion to the substrate.

Polyaspartic ester-based polyureas are a newer technology and may be referred to as simply “polyaspartics.” These coatings are analogous to conventional polyurethanes and offer many of the same properties. Polyaspartics cure more slowly than polyureas (within several hours) and are typically applied in one or two coats at several mils per coat.

Hybrid coatings generally refer to polyurethane/polyurea coatings, formed by combining the two resin types, producing a coating with the best features of each. The properties, application and surface-preparation requirements will generally be the same as for the thick-film, 100-percent solids polyurethane and polyurea coatings.

SUMMARY

In summary, there are multiple coating options for various areas in hospitals or health-care facilities. Coating systems, which are most often water-based, should be selected based on the cleaning requirements for an area. The “better” systems may cost more initially but would be expected to require less maintenance over time. Increased offerings by manufacturers of water-based systems and the use of microbicidal coatings should increase future coating options.

As seen Durability & Design, March 2016

 ABOUT THE AUTHOR: Jayson Helsel is a senior consultant with KTA-Tator Inc. He holds a master’s degree in chemical engineering from the University of Michigan, is a licensed professional engineer in several states, an SSPC Protective Coatings Specialist, SSPC Certified Concrete Coatings Inspector, and a NACE Certified Coatings Inspector. At KTA, Helsel manages coating projects, performs failure investigations and coating surveys, writes coating specifications, and is a regular instructor for KTA coating inspection courses. He previously served as a Lieutenant Commander in the U.S. Coast Guard with experience in marine vessel inspection.