Friction is the force that resists the sliding motion of one surface against another, such as the motion of a foot against a tile floor. Contaminants, such as liquids, oil, dirt and debris, can alter the innate friction of a surface.
There are two types of friction: static (SCOF) and dynamic (DCOF). SCOF is the ratio of forces necessary to start two surfaces sliding. This is what the former ASTM C1028 static test measured. DCOF is the ratio of forces necessary to keep two surfaces sliding. The new DCOF AcuTest measures this ratio, which many manufacturers now believe better relates to the friction coefficient at work when a person slips on tile flooring.
The new 0.42 DCOF wet rating replaces the old 0.60 SCOF wet rating as the benchmark for friction in flooring applications.
The new, more stringent DCOF AcuTest uses a portable robot (the BOT 3000), an SBR rubber sensor and slightly soapy water (0.05% sodium lauryl sulfate solution) to measure dynamic friction. It’s a repeatable, reproducible method for measuring DCOF and, according to the TCNA, it is a major improvement over the old test method. It also offers a standardized minimum threshold, which is new to the industry.