Tile Slip Resistance Standard: ANSI A326.3

ANSI A326.3 provides a standardized method for measuring the Dynamic Coefficient of Friction (DCOF) of hard surface flooring materials in laboratory and field conditions. It also establishes product-use classifications that manufacturers use to communicate where a flooring product may be appropriate.

Standard

ANSI A326.3, formally titled the American National Standard Test Method for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials

Minimum requirement

Minimum wet DCOF of 0.42 for the Interior, Wet classification

Earlier Method

Earlier tile specifications used Static Coefficient of Friction (SCOF) testing, while ANSI A326.3 uses a dynamic measurement taken while the sensor is moving

Test method

The DCOF AcuTest, performed with a tribometer that drags a sensor across the tile surface to simulate motion

Published by: TCNA, on behalf of the ANSI Accredited Standards Committee A108

The document is available as a free download directly from tcnatile.com. The underlying test method, known as the DCOF AcuTest, originally appeared as Section 9.6 within ANSI A137.1, the broader specification for ceramic tile. In 2017, the ANSI Accredited Standards Committee A108 formalized the test into its own dedicated standard, ANSI A326.3, published by TCNA, giving slip resistance testing a clearer and more consistent framework across the industry.

DCOF measures the friction encountered while a standardized sensor moves across the flooring surface under specified test conditions. This distinguishes it from SCOF, which measures the force required to initiate movement between two surfaces.

Static Coefficient of Friction, or SCOF, testing measures the force required to initiate movement between two surfaces. DCOF testing measures friction while a standardized sensor is already moving across the flooring surface.

This dynamic measurement provides a standardized method for comparing surfaces tested under the same conditions. However, ANSI A326.3 states that the result does not predict whether a person will or will not slip. Maintenance, contaminants, drainage, surface structure, footwear, and intended use must also be considered.

ANSI A326.3 Product-Use Classifications

Product-Use Classification	General Condition
Interior, Dry (ID)	Interior areas expected to remain dry
Interior, Wet (IW)	Interior areas exposed to water; minimum wet DCOF of 0.42
Interior, Wet Plus (IW+)	More demanding interior wet conditions
Exterior, Wet (EW)	Maintained exterior areas exposed to water
Oils/Greases (O/G)	Areas where oil or grease contamination is expected

A minimum wet DCOF value of 0.42 applies to the Interior, Wet classification. This value is not a universal safety threshold for every area exposed to moisture, and it does not establish that a product is suitable for shower floors, pool decks, ramps, exterior surfaces, or other specialized applications.

The 2021 edition of ANSI A326.3 introduced five product-use classifications: Interior, Dry; Interior, Wet; Interior, Wet Plus; Exterior, Wet; and Oils/Greases. Manufacturers classify products for one or more of these categories using relevant testing, quality-control criteria, manufacturing parameters, and experience with similar surfaces. The appropriate classification should be confirmed in the manufacturer’s technical documentation.

How the AcuTest Works

The DCOF AcuTest uses a tribometer that moves a standardized sensor across the flooring surface at a controlled speed and records the friction encountered. The resulting value allows surfaces tested under the same specified conditions to be compared. However, ANSI A326.3 states that the measurement does not predict whether a person will or will not slip.

Why This Matters When Selecting Tile

When our team helps customers select flooring for a bathroom, mudroom, entryway, or exterior-adjacent space, the manufacturer’s ANSI A326.3 product-use classification is one of the specifications we review. A wet DCOF value of 0.42 applies to the Interior, Wet classification, but it should not be used as a universal requirement for shower floors or every moisture-exposed application. The intended use, contaminants, drainage, maintenance, surface structure, footwear conditions, and manufacturer’s recommendations must also be considered.

Conclusion
ANSI A326.3 provides a standardized method for measuring DCOF and a classification system for communicating the intended uses of hard surface flooring products. The measured value allows surfaces to be compared under specified test conditions, but it does not predict whether a slip will occur. Before selecting a tile, verify that the manufacturer’s product-use classification and approved applications correspond to the conditions of the project.

Frequently Asked Questions

What is ANSI A326.3?

ANSI A326.3 is the current industry standard for testing slip resistance on hard surface flooring, published by TCNA. It measures Dynamic Coefficient of Friction, or DCOF.

What does the 0.42 DCOF value mean under ANSI A326.3?

A minimum wet DCOF value of 0.42 applies to the Interior, Wet classification. It is not a universal safety threshold for every wet or moisture-exposed application. The manufacturer’s product-use classification and approved applications must also be checked.

How does DCOF differ from SCOF?

SCOF measures the force required to initiate movement between two surfaces, while DCOF measures friction while a standardized sensor is already moving across the flooring surface. DCOF provides a consistent basis for comparing surfaces under specified test conditions, but it does not predict whether a person will slip.

Where can I find the official DCOF testing standard?

ANSI A326.3, the American National Standard Test Method for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials, is published by TCNA and available as a free download at tcnatile.com.

Does a higher DCOF rating mean a tile is better overall?

Not necessarily. A higher DCOF value indicates more available traction under the specified test conditions, but it does not make a tile better for every application or predict whether a slip will occur. The product-use classification, intended environment, maintenance requirements, and manufacturer’s recommendations must also be considered.

About Nova Tile and Stone

Nova Tile and Stone is a direct natural stone importer and tile retailer serving Northern Nevada and Northern California. We carry natural stone slabs, tile, countertops, hardwood and LVP flooring, pavers and exterior stone, and carpet across four showroom locations. Our commission-free team offers free design consultations to help you find the right material for your project, whether you are selecting tile for a single bathroom or sourcing stone for a full home renovation.