Slip accident prevention in the USA and Canada finally emerged from the Stone Age when dynamic coefficient of friction testing with a specific test method and safety standard became a verified part of the current International Building Code (IBC) in February 2013. The IBC is used in more than a dozen countries, such as the USA, Canada, Saudi Arabia, and Chile. The new dynamic friction test is conducted using the BOT-3000 digital tribometer and is sometimes called the AcuTestSM.
This is the first time any U.S. national building code or regulation has had specific instructions regarding wet or dry slip resistance. In the past, property owners spent many billions on floors that were unsuitable for their intended use because they were slippery when wet (lobbies, commercial kitchens, pool decks, showers, etc). Use of static coefficient of friction often gave misleading results, causing buyers to think that the flooring they were buying was safe when it in fact was very hazardous. Years ago, the Access Board of the U.S. Department of Justice, which administers the Americans with Disabilities Act, denied any support or responsibility for using static friction tests.
The current (2012; the Code is published every three years) IBC states on p. 435, “2103.6 Ceramic Tile. Ceramic tile shall be as defined in, and shall conform to the requirements of, ANSI A137.1.” Up until recently, this meant using static coefficient of friction (SCOF). The minimum SCOF, ANSI said, “shall be as agreed upon by manufacturer and purchaser.” In other words, the flooring retailer wasn’t involved, and a mistake leading to an accident was the customer’s fault. Now that has changed. According to Tile Council of North America, “any party involved in the chain of sales will be responsible for knowing what the [ANSI A137.1 DCOF] requirement is and what it means.”
The new version of ANSI A137.1 (American National Standard Specifications for Ceramic Tile), published in 2012 with the DCOF test method re-verified in February 2013, specifies (Table 6 on p. 10) a minimum DCOF of 0.42 “for level interior spaces expected to be walked upon when wet.” For a ramp an unspecified higher value is required. We believe this should include consideration of the angle of the ramp and whether the pedestrian is controlling a separate load (wheelchair, shopping cart, gurney, heavy suitcase, etc.). See “Safe Friction Values for Inclined Surfaces (Ramps)” farther down in this blog.
The ANSI tile standard correctly points out “the COF of installed tiles can change over time.” This speaks to the value of periodic monitoring of COF so that action can be taken to solve any problems before an injury occurs. This helps establish that the property owner has used due diligence, best possible practice, and has done everything reasonable and practicable to prevent slipping accidents.
The testing procedure is specified by ANSI in Section 9.6 and names the BOT 3000 automatic testing device. The flooring is wetted with water containing a trace of the wetting agent SLS (sodium lauryl sulfate) to reduce surface tension so that the water doesn’t bead up on the surface. The SBR hard rubber test foot is roughly an inch wide, and curved cylindrically so that only a line of the rubber touches the flooring surface.
Though ANSI A137.1 is specific to ceramic tile, it seems likely that the test method will also be applied to other flooring such as marble, granite, terrazzo, vinyl, etc.
For exterior surfaces, where people are more likely to be running (especially if it’s raining!) we recommend a minimum wet Pendulum Test Value of 36 using the test method specified since 2001 by Ceramic Tile Institute of America. The pendulum is a higher-speed device than the BOT-3000. It is a national standard for pedestrian slip resistance in 49 nations, and it’s been in continuous use for floor friction testing since 1971. It is also specified for the Sustainable Slip Resistance test procedure developed by McDonalds Restaurants and adopted by major cruise ship companies and major property owners to ensure that their new floors will have durable wet slip resistance.
The new IBC specification was developed by a committee representing 58 organizations and was spearheaded by Tile Council of North America (TCNA). Ceramic Tile Institute of America and TCNA deserve credit for resolving what was an unfortunate situation in which a bad test method (static friction) caused life-changing accidents, inappropriate flooring investments, and countless lawsuits. It also led to ceramic tile having a reputation, with many people, of being unsafe. (Time will tell whether the new safety criterion of 0.42 is high enough.) In fact the right ceramic tile, produced in a quality-controlled factory and designed to give good, sustainable wet slip resistance, can be the safest and most versatile type of attractive flooring available.
A new model of the BOT-3000, the BOT-3000E, has begun the verification process to be ruled acceptable for ANSI A137.1 testing. Another test method using the BOT-3000, namely ANSI B101.1 (static friction) now appears to be mostly obsolete. The old static friction method ASTM C 1028 is expected to die a natural death when it comes up for periodic renewal by ASTM.
Another dynamic test method using the BOT-3000, ANSI B101.3, has some small but important details that are different from the ANSI A137.1 test method. The B101.3 method usually results in lower DCOF data, yet has the same basic safety criterion: 0.42 for a level floor. This method might be a better choice for property owners looking for safe new flooring, but it’s unlikely to be used by tile vendors because it’s less favorable to products that are marginal in terms of wet slip resistance.
Safety Direct America offers laboratory and field slip resistance testing using the new ANSI A137.1 AcuTestSM method, as well as the other methods mentioned above. A laboratory AcuTestSM costs only $200.00, and turnaround is normally less than three business days. Field tests are conducted on a time and expenses basis (nationwide, but from a southern California base). We also offer periodic monitoring (e.g. quarterly or annually) for commercial/industrial premises, and slip-fall expert witness service.