This blog has previously praised Dal-Tile for recognizing that “one size fits all” does not work when it comes to slip resistance standards (or bikinis, for that matter). For instance, Dal-Tile has recommended a minimum ANSI A137.1 DCOF AcuTest wet dynamic coefficient of friction of 0.60 for swimming pool decks, public showers, and locker rooms.

Unfortunately we can’t agree with Dal-Tile on that suggestion. As an example, the white honed marble in the photo (with a penny for scale) has a DCOF rating of 0.65 using ANSI A137.1, yet is quite slippery, when wet, to bare feet. With a peak-to-valley total mean surface roughness (by Surtronic 10 profilometer) Rtm of 12.7 microns (about 0.0005 inch) it is fairly smooth; many floors with good wet slip resistance have an Rtm exceeding 20 microns.

The marble has a wet Pendulum Test Value (PTV) of 24, far below the minimum of 40 recommended for swimming pool decks and communal shower rooms. A minimum PTV of 35 is recommended for locker rooms. Soft rubber (IRHD hardness of 55) is used for these tests to substitute for bare skin.

We therefore warn that Dal-Tile’s recommendations must not be used. A better idea is to use the Standards Australia recommendations, which have been in continuous use since 1999 and have been reaffirmed since then.

Many people are confused by the fact that ANSI A137.1 recommends a minimum wet DCOF rating of 0.42 for indoor areas that may get wet in use. However, that same standard goes on to mention a multitude of other factors that must also be considered; obviously for many situations a minimum DCOF of 0.42 is not sufficient for accident prevention.

If you love the white marble, could you use it on a pool deck, shower or locker room? Yes, if you coat it with SparkleTuff™ transparent anti-slip floor coating exclusively from Safety Direct America. This shows the beauty of the floor underneath and has excellent wet slip resistance. It also passes the McDonalds Restaurants test for Sustainable Slip Resistance, meaning it maintains good wet slip resistance after hundreds of thousands of people have walked across it.