Floor slip resistance testing

There have been numerous floor slip resistance testing tribometers and lab devices produced around the world to measure both the static (stationary) and dynamic (in motion) coefficient of friction, but presently there are only a few that have been proven to be reliable for obtaining useful safety results and that have current official test methods.

Static coefficient of friction (SCOF) testing has always been unreliable for assessing safety in the wet condition, so any reliable slip resistance test will be measuring the available slip resistance to someone who is moving (dynamic) across the floor, and therefore will be assessing dynamic coefficient of friction (DCOF).

[8] It was validated for pedestrian traction in 1971, together with its safety standards, in the UK over a period of 25 years by 3500 real-world public walking area tests and site accident records.

One of the many disclaimers added to the latest version of the test method states that "the measured DCOF value shall not be the only factor in determining the appropriateness of a hard surface flooring material for a particular application.” This means that A326.3 should not be used to assess real-world slip risk, but is rather a useful test method to assess changes in slip resistance due to wear, maintenance practices, and other factors.

The disclaimers in this test method also state that this test, “can provide a useful comparison of surfaces, but does not predict the likelihood a person will or will not slip on a hard surface flooring material.” The Variable-Angle Ramp is a German-developed method for obtaining pedestrian slip resistance values.

Over 150 safety criteria have been adopted in Germany and Australia for specific situations — swimming pool decks, commercial kitchens, restrooms, etc.

[4][15] Many ASTM and ANSI standards have expired or been withdrawn over the years and should not be used to assess the slip resistance of floors.

Also included in In-Ju Kim's book "Pedestrian Fall Safety" (see page 47 of his book), he notes that not only did F1677 and F1679 get withdrawn “for failure to include an approved precision statement,” he goes on to state that, “Using these two instruments, different labs showed very different answers on identical tiles amongst interlaboratory studies.

These findings suggested that both test methods [for the Brungraber Mark II and English XL] were unreliable and unable to provide ‘reasonable precision statements’ for slip resistance evaluations.”[18] ANSI/NFSI B101.1-2009 was allowed to expire because it's a static coefficient of friction test, which measures how slippery a floor is to someone standing still on it.