Epoxy Floor Slip Resistance
DCOF Explained

Slip-and-fall accidents on hard floor surfaces result in thousands of serious injuries annually. Floor coating specifications for commercial and institutional applications routinely include slip resistance requirements. Even residential garage floors benefit from understanding how slip resistance is measured and how to specify a level appropriate for the use conditions.

COF vs. DCOF: The Measurement Difference

Coefficient of Friction (COF) is the ratio of the friction force to the normal force between two surfaces. Static COF (SCOF) measures the force required to initiate sliding from rest; Dynamic COF (DCOF) measures the force during sustained sliding motion. DCOF is considered more relevant to slip-and-fall incidents because most falls occur during walking, where the foot is sliding relative to the floor rather than stationary. Modern slip resistance standards have largely moved from SCOF to DCOF measurement.

ANSI A326.3 and the BOT-3000E

ANSI A326.3 (American National Standard for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials) defines the test protocol using the BOT-3000E tribometer — a device that slides a standardized sensor foot across the wet floor surface and measures the resistance force. The DCOF value is calculated from the friction force at steady sliding. ANSI A326.3 recommends DCOF ≥ 0.42 for level interior floors in wet conditions — this is the widely cited threshold. However, ANSI explicitly notes that values above 0.42 are required for ramps, areas with specific hazard levels, or applications where the risk of slip is elevated.

The Wet vs. Dry Distinction

Dry COF values are typically 30–60% higher than wet COF for the same surface. Most slip-and-fall incidents occur on wet surfaces, making wet DCOF the critical measurement. For a residential garage where the floor may be wet from rain, car washing, or spills, specifying anti-slip additive is advisable even though the floor is technically "indoor" — the risk conditions are those of a wet exterior surface for much of its use. Residential floor coating contracts rarely specify DCOF requirements, but asking your contractor about wet DCOF capability of the proposed system is a reasonable quality question.