It is amazing how often both large and small swimming pool decks are installed with no thought to wet slip resistance until falls, sometimes catastrophic, begin to happen. By the time the first serious slip injury happens, the flooring vendor has usually cashed his check and is unconcerned about the problem.
Wet bare feet have no tread and in addition are flexible, so that the skin can deform without penetrating the thin water layer and can hydroplane even at very low speed. Think skimboarding at the beach (see two photos), which is hydroplaning on a flexible board with larger weight-bearing area but over a very slip-resistant surface — wet sand.
When the heel of a shoe touches down on a pool deck, the weight on it can be less than a quarter of a pound and hydroplaning can occur — the heel touches little of the solid floor; it touches mainly the thin water film, which might still be deeper than the microscopic peaks on the floor can penetrate.
The slippery pool deck problem happens frequently not only in the USA, but in other countries as well. The German slip resistance barefoot walking test method DIN 51097:1992 on a variable-angle ramp (see CSIRO photo) was intended to provide a very realistic laboratory test of wet barefoot traction. However, even when this DCOF slip rating test is used things often go wrong.
What problems occur? The same ones that happen in areas where shoes are worn, discussed earlier in this blog. However, the risks are even higher in barefoot areas: small children and inebriated adults running, with a disastrous slip and fall accident being far from their minds.
Richard Bowman of Australia, in a paper at Qualicer in Spain 12-13 February 2018, summarized pool deck slip resistance requirements in Spain. The building code (known as CTE) starting in 2014 called for Class B tiles (as classified by the German DIN 51097 barefoot walking test) to be used for level pool decks. A disadvantage of the test is that it can’t be used on tiles already installed. This puts an extra risk on the property owner, who has no way of knowing whether the floor is in compliance once installed until the falls start to mount up. Without an in situ test, the new Spanish requirement led to slip and fall accidents. In case of claims, owners have no legal defense.
Since 2006, Spain had required British pendulum DCOF slip resistance testing to select the pool deck material. Using a soft CEN rubber slider to model bare feet, the wet Pendulum test value (PTV) had to be greater than 45. (Safety Direct America can conduct this test.) For barefoot bathrooms, Spain required a PTV between 35 and 45. Slip resistance was to be maintained for the life of the pavement/floor. A general certificate from the flooring manufacturer is not accepted as valid.
In 2011 Spain required that shipments of flooring for pools be tested in situ with the pendulum skid tester before the pool could be opened. This worked well until the 2014 requirement mentioned above was allowed and the in situ test requirement was dropped.
If you have wet pendulum data for your flooring using a TRL soft rubber slider, it is expected to be very close to the PTV value used in the Spanish requirement. However, Safety Direct America conducts pendulum tests using either the TRL or the CEN slider as required.
If you have an existing pool deck that is slippery, a quick and easy way to make it safe is to coat it with durable SparkleTuff™ Anti-Slip Floor Coating from Safety Direct America. Its wet slip resistance is excellent using all the valid portable DCOF rating tests. We should note that the ANSI A137.1 and A326.3 tests are for indoor, level floors, and are not valid tests for predicting slip risk on a pool deck area. SprakleTuff easily passes both tests, but those tests were developed for comparing surfaces, not for assessing real-world slip resistance, and they set a very low bar in a slip coefficient of 0.42 using a hard rubber slider that is not at all representative of bare feet. A video of a SparkleTuff™ installation on a pool deck and a shower room is on the left-hand side near the bottom of the page at https://safetydirectamerica.com/diyabrasivefloorcoating/.
This report was prepared with the kind assistance of Juan Iriate, Technical Director, Wessex Laboratorio de Resbaladicidad, Tajonar, Navarra, Spain.