What is DCOF?

DCOF (Dynamic Coefficient of Friction) is a numerical value that describes the amount of friction between a floor surface and something moving across it—typically a person walking. In simple terms, it indicates how much grip a tile provides once movement has started.

There are two basic types of friction values:

• Static Coefficient of Friction (SCOF) – measures the force needed to start movement.

• Dynamic Coefficient of Friction (DCOF) – measures the force needed to keep movement going.

Modern tile slip-resistance testing for floors focuses on DCOF because it better reflects what happens as people walk across a floor.

A higher DCOF value generally indicates a more slip-resistant surface under the test conditions. However, no single number can guarantee a slip-free floor. Real performance always depends on the specific environment: contaminants, footwear, slope, cleaning and maintenance.

How DCOF is Tested

In North America, DCOF for hard surface flooring is most commonly measured according to ANSI A326.3, the standard test method for dynamic coefficient of friction of hard surface flooring materials.

During testing, a specialized instrument moves a standard test slider across the tile surface under controlled conditions. The test is performed using a slightly soapy solution to simulate wet conditions, which generally produce lower friction values than dry testing. The result is reported as a DCOF value, for example: 0.42 wet.

The product standard ANSI A137.1 references a minimum wet DCOF of 0.42 for level interior spaces that are expected to be walked on when wet. This gives specifiers a benchmark when comparing products.

It is important to remember that these are laboratory conditions; they provide a comparative reference, not an absolute guarantee of slip resistance in every situation.

Where to Find DCOF in Our Product Information

For floor-rated mosaic lines, DCOF information is included in the technical section of the product documentation or specification sheet. You will typically see one of the following:

• A specific value or range, for example “≥ 0.42 wet”, indicating the product has been tested and is suitable for certain wet interior flooring applications when installed and maintained correctly.

• A higher wet value, commonly used as a guideline for more demanding environments such as pool decks or exterior wet areas.

• “N/A – wall only” for decorative mosaics that are not designed, tested or warranted for any floor use and must be installed on walls or other non-walking surfaces.

Always check both the recommended use (floor vs wall) and the DCOF information together. Make sure the selection aligns with local regulations and with the level of risk that is acceptable for the specific project.

Recommended DCOF Ranges by Application

The following ranges are general industry guidelines and a starting point for specification. They do not replace local codes or a detailed risk assessment for each project.

Dry interior, level floors

Typical spaces: residential living areas, dry corridors, office spaces, retail sales floors.

Suggested DCOF: a value equal to or greater than 0.42 in dry conditions is generally considered appropriate, combined with good housekeeping and cleaning practices.

Wet interior, level floors

Typical spaces: building entrances, interior transition zones, commercial restrooms, locker rooms outside shower areas.

Guideline: a minimum wet DCOF of 0.42 is commonly used for level interior spaces expected to be walked on when wet. In high-traffic or high-risk spaces, specifiers may prefer higher values and additional safety measures such as mats.

Exterior wet areas

Typical spaces: exterior walkways, terraces, patios, covered outdoor paths where water may be present.

Guideline: higher wet DCOF values (often around or above 0.60) are recommended to help manage slip risk in outdoor environments where rain, debris and seasonal changes add variability.

Barefoot and pool-adjacent areas

Typical spaces: pool decks, spa surrounds, public showers, wet locker room zones.

Guideline: products with higher wet DCOF values combined with small formats and many grout joints are typically preferred. The extra grout and surface texture help maintain traction under constant moisture.

Areas exposed to oils, grease or food contaminants

Typical spaces: commercial kitchens, food prep areas, dishwashing zones.

Guideline: these are among the highest-risk environments. Even with high DCOF values, specialized commercial flooring systems are often recommended. Decorative mosaics may be more appropriate for walls and surrounding areas rather than for primary working floors in these spaces.

Why Mosaics Often Perform Well for Slip Resistance

Mosaics offer several natural advantages in slip-sensitive applications, especially compared to large-format tiles:

• More grout joints: small pieces mean more joints per square foot. Grout lines can help break up surface water and reduce the chance of hydroplaning on wet floors.

• Better conformance to slope: mosaics follow complex slopes more easily, making it simpler to create the drainage and pitch required in showers and around drains.

• Texture options: many mosaic collections are offered in matte or textured finishes that are designed to enhance foot traction.

At the same time, certain factors can reduce effective slip resistance, even on mosaics:

• Highly polished or glossy finishes in wet or greasy environments.

• Build-up of residues such as soap scum, body oils, grease or cleaning products that leave a film on the surface.

• Inadequate or incorrect cleaning routines.

For high-risk areas, it is generally best to choose matte or structured surfaces, small formats and a maintenance program tailored to the expected contaminants.

Maintenance, Cleaning and Long-Term Performance

A laboratory DCOF test result is a snapshot under controlled conditions. Over time, the practical level of slip resistance can change depending on how the floor is maintained.

Good practices include:

• Using manufacturer-recommended cleaners that do not leave a slippery film on the tile.

• Rinsing thoroughly after cleaning, especially in showers and wet zones, to avoid residue.

• Keeping grout joints clean and in good condition, since they contribute to traction and drainage.

• Paying special attention to high-risk areas where water, oils, food or other contaminants are common, and adjusting cleaning frequency and methods accordingly.

In critical commercial installations, some specifiers choose to carry out periodic field slip-resistance testing through qualified third parties. This can help verify long-term performance and support a documented safety program.

No floor surface is completely “slip-proof”. Choosing an appropriate DCOF level, designing for drainage and slope, installing correctly and maintaining the floor carefully all work together to help manage slip risk.

DCOF FAQs