Tile and stone terminology can be confusing at times. Below, we've described the Coefficient of Friction (COF) term you might find on our website or product sheets to help you better understand our products.
Slip Resistance of a Tile (Coefficient Of Friction)
There are two international tests recognized to give the slip resistance of tile:
North American Standard - DCOF (Dynamic Coefficient of Friction)
This test measures the amount of force required to keep an object in motion as it slides over a tile and reflects real life situations where a person might slip on wet tiles.
The measurements require that for level interior floors tiles, wet with water, the minimum slip resistance is 0.42 DCOF and for level exposed exterior floors that are wet with water, the minimum slip resistance is 0.60 DCOF. Other situations, such as slope, standing water, oil, grease, or other slippery substances, may require higher DCOF numbers.
The European (ISO) Standard - R rating (ramp test)
This test requires an operator who is protected by a fall restraint harness, and wearing standard footwear, walk backwards and forwards over a sample of a flooring material that has been evenly coated with oil. Beginning with the ramp in a horizontal position, they gradually increases the angle of inclination until the limit of safe walking is reached and the test person slips. The acceptance angle obtained is used to express the degree of slip resistance. The ratings scale goes low to high, R9 – R13.