Static Friction - The resistance opposing the force required to START the movement of one surface on or over another.
Dynamic Friction - the resistance opposing the force required to CONTINUE the movement of one surface on or over another.
For years, the most standard way to measure a floor’s slip resistance was through measuring its static coefficient of friction - the amount of force required to move an object over a surface. The test methods being used, ASTM D-2047 James Machine and ASTM C1028 Pull Method, performed reliably under dry conditions, but when exposed to contaminants like water and grease their results were varied and unreliable. For that reason the ASTM C-1028 method was withdrawn in 2014.
Dynamic Coefficient of Friction or DCoF is gaining popularity. Unlike static, the dynamic test measures the amount of force required to keep an object in motion as it slides. It is believed that dynamic testing may represent more life-like, real world scenarios, as a slip and fall generally starts from a state of motion - not standing still.
There are a few test methods that now measure DCoF. More and more tile manufacturers are moving towards testing for DCoF, but the industry has not settled on one standard moving forward. Getting all the manufacturers and the different committees to agree on one test method is very difficult and at this time there is no clear successor for testing in North America.
One dynamic test method that Altro endorses is the British Pendulum Test, which was adopted by ASTM as the standard ASTM E-303. This test method allows for reliable testing on a variety of surfaces and contaminants. It is the preferred method in the United Kingdom and is portable, allowing for tests to be performed in the field, a unique advantage that this test has over many others.
Altro prefers this test as the best for our slip resistant testing and conducts it on all of our safety and slip resistant floors.