All You Need to Know About the Latest ANSI A326.3 and ANSI A137.1 Tile Slip Tests

If you specify or buy flooring based on a minimum wet dynamic coefficient of friction (DCOF) of 0.42 referred to in the 2012 International Building Code (IBC), you may be vulnerable to charges of negligence if a slipping injury occurs on that floor. Here we tell you why, and how to avoid the situation.

The ANSI A326.3 hard flooring slip test standard (which is what the old ANSI A137.1 tile slip test has now become) now applies to all hard flooring materials. But the amount of disclaimers, warnings and asterisks in this test standard are not something you should ignore. In fact, the disclaimers state that the numbers given for minimum dynamic coefficient of friction (DCOF) for various types of areas (0.42 for indoor level floors, 0.50 for Interior Wet Plus areas, 0.55 for clean and maintained outdoor areas, etc.) are not actually what you’re shooting for. Once you’ve achieved that minimum, there are a ton of “other factors” to consider. How do you consider them? That’s up to you, and no guidance is given.

We recommend considering the use of a test based on 50 years of international research in at least 50 nations instead, such as the pendulum DCOF slip resistance test. It gives recommendations and safety criteria based on extensive research and accident investigations all over the planet. This is the test used all over Europe, the UK, Australia, New Zealand, Singapore, Israel, and basically every country that tests floors for slip resistance to help put a stop to needless slip and fall accidents. In the USA, the pendulum test is ASTM E303, and it was just updated in 2022 to more closely mirror the pendulum test methods recently published in Europe, the United Kingdom and Australia. The most knowledgeable and reliable source of pendulum slip resistance testing in the USA is Safety Direct America. They have decades of experience and are certified by the City of Los Angeles as an official floor and road slip resistance testing lab.

The ANSI A326.3 Tile Slip Test has not been based on reliable slip and fall research, and you should not rely on it as a test to determine slip risk on a particular type of flooring. The latest version of the ANSI A326.3 floor “DCOF Rating” test, in fact states “The coefficient of friction (COF) measurement provided in this standard is an evaluation of hard surface flooring materials under known conditions using a standardized sensor material prepared according to a specific protocol. As such it 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.” So to use the results of this test as an assessment of slip risk would be to ignore what the standard plainly states in black and white on page one. It cannot be used to assess slip risk. For that, you need a pendulum DCOF test, which is what the world outside the ultra-litigious USA has been using for decades to assess the real-world slip resistance of a floor based on international research.

American National Standards Institute (ANSI) published their previous A137.1, “Specifications for Ceramic Tile,” in 2017. In 2021, the Tile Council of North America (TCNA), who works to help flooring manufacturers sell flooring, not to help building owners or architects concerned about safety, updated it with a ton of disclaimers and changed the name to ANSI A326.3, which now gives some rather confusing guidance for areas other than interior level floors. The test specified in A326.3, sometimes referred to as the DCOF AcuTest, is used within the United States and a few smaller countries. But anyone using this test to assess slip risk is ignoring that the test method plainly states that this test method “…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 “DCOF Rating” test is conducted using the BOT-3000E digital tribometer. The photo below shows the BOT-3000E’s top.

BOT-3000 tribometer - slip test

BOT-3000E Tribometer

The ANSI A326.3 coefficient of friction test requires a minimum wet dynamic coefficient of friction (DCOF) of 0.42 “for tiles in level interior spaces expected to be walked upon wet.” A DCOF rating of 0.38 using this test method, according to the TCNA research mentioned below, has been found to closely correlate with the old 0.60 SCOF number from the now-withdrawn ASTM C1028 static coefficient of friction (SCOF) test. That test was not based on scientific slip and fall research either, and the ASTM finally withdrew that test method in 2014. It is no longer a current test method and there are, thankfully, no plans to ever resurrect that very poor test method that has been causing slip and fall accidents and billions in ill-advised flooring purchases all over the USA for many years. More information on that horrible test is at c1028.info.

The Tile Council of North America (TCNA) states that through their own extensive research, the results from ANSI A137.1 and ASTM C 1028 have to been shown to correlate closely. That means that like the (now-withdrawn) ASTM C1028 test results, the ANSI A326.3 test results should never be trusted as a reliable indicator of slip resistance. Achieving a 0.60 SCOF using C1028 never meant that you had a safe floor when wet, and achieving a 0.42 (or 0.50 or 0.55) using this newer test method is just as unreliable as an indication of safety.

So does a wet DCOF rating of 0.42 mean the tile is safe for use in a wet area? Absolutely not. If the DCOF were a “passing grade” in school, 0.42 would be equal to a D minus. ANSI A326.3 sets a very low bar: a minimum DCOF (0.42) that most tiles exceed no matter how slippery they are in real world situations. It does not ensure safety. That’s the buyer’s job. There are much more reliable slip resistance test methods available to ascertain what your real-world slip risk will be. Click on reliable tile slip testing or head over to SafetyDirectAmerica/Floor-Friction-Testing to get more information on what tests you can do to minimize your negligence and chances of a slip and fall on your tile or property. Safety Direct America also performs the ANSI A137.1/A326.3 tile slip tests (DCOF rating) for ill-informed code compliance purposes.

Click on ANSI A326.3/A137.1 Disclaimers to read the numerous and confusing disclaimers ANSI and TCNA have written into this test method.