In Europe, a slip resistance test for flooring is prescribed by German Institute for Normalization (DIN) standard DIN 51130. A person wearing industrial-type treaded shoes walks, facing down slope, on a variable-angle ramp which has the flooring to be tested on it. The flooring is coated with motor oil. The walker (without holding the handrails) adjusts the ramp angle, several times, to the highest value he or she can walk without slipping. The test is repeated with a second walker and the results are averaged.
As in the case of tires, treads are very helpful in slippery (e.g. wet road or track) situations. Because of the heavy treads on the specified standard test shoes, the test tends to favor flooring with a raised-relief profile or otherwise very rough surface, and it is not applicable to shoes without strong treads.
The test results are classified as R9 thru R13, with R13 being the highest slip resistance (steepest ramp angle without slipping). The R9 category has minimal slip resistance, and the R13 is suitable mostly for tough industrial situations such as fish processing, mayonnaise manufacture, and (remember, it’s a German test) production of sauerkraut.
Some flooring buyers use the results of this oily slip test to infer slip resistance of water-wet flooring walked on with non-treaded or lightly-treaded shoes, which most pedestrians wear outside of the industrial workplace. However, because of the difference of this situation from the DIN test procedure, the results of DIN 51130 can be deceptive. This unfortunately can result in a slippery floor being specified for large commercial areas, resulting in bad investments, serious accidents, and personal injury lawsuits.
In most cases, a better alternative to DIN 51130 is the pendulum DCOF test, in use since 1971 and a national standard in at least 50 nations. The pendulum test uses a non-treaded rubber slider (either hard or soft rubber or both) and water as a lubricant. This is much more representative of everyday situations than is DIN 51130. Also, the pendulum test can be conducted on-site on either installed or uninstalled flooring for quality control. The DIN test can only be done in a laboratory.
Can we convert the test results from one test to the other? Not really. The graph below (from Richard Bowman of SlipBusters, Australia) shows a comparison between the tests on various glazed, porcelain, and terra cotta tiles using a hard rubber slider on the pendulum.
The graph shows that the R10 category alone covers all the pendulum classifications V thru Z (shown on the graph), and can give pendulum results anywhere between 20 and 60 British Pendulum Number (BPN, also called Pendulum Test Value, or PTV). Flooring shown to have an R-Rating of R11 can also have far too wide of a range of slip resistance test values. The DIN ramp test is unfortunately largely useless for predicting pendulum test results, and shouldn’t be relied upon on its own.
The variable-angle-ramp test is expensive, time-consuming, and misleading, and resources are better spent on pendulum testing to assess real-world slip resistance of floors.
In addition, the German ramp test DIN 51130 tells us nothing about the durability of a flooring’s slip resistance. Some flooring can lose its wet slip resistance in a matter of weeks after heavy use. Some floors become slippery after the flooring installer or maintenance crew has inadvertently or purposefully polished the floor down to increase the shine (thereby accidentally decreasing the available slip resistance.) This is why McDonald’s Restaurants developed the Sustainable Slip Resistance test and made it part of its flooring specification for customer areas.
Some research suggests that you can make “general comparisons” from the German Ramp DIN 51130 test results to Pendulum Test Values. That can be very dangerous and misleading, as noted above, but here is what some sources use as a “general comparison”:
The United Kingdom Slip Resistance Group (UKSRG) warns that:
- The Pendulum and DIN 51130 are not measuring the same thing, and therefore a value from one test method should not be converted in to another test method’s slip potential category
- One should not rely on the DIN 51130 “R rating” alone. It’s measuring a floor with motor oil and work boots. That’s mostly irrelevant for most flooring situations where water, dust, drinks, or soap residue will likely be the more likely contaminants, and
- A pendulum test may evaluate slip potential much more accurately than a DIN 51130 test.
Here’s a chart of values the UKSRG found in one study comparing the two test methods:
As you can see above, the DIN 51130 test does a poor job of predicting pendulum test value. The British Pendulum Test is based on 50 years of international research both in the lab, but also critical research in the field where countless slip and fall accidents have been investigated (and continue to be investigated) around the world, and the pendulum has also tested countless floors that have had none such slip incidents reported. The pendulum is clearly the most useful test for assessing real-world slip resistance for pedestrian surfaces.
Safety Direct America can conduct the pendulum test (as well as other floor slip resistance test methods) and the Sustainable Slip Resistance test. Normal turnaround is three business days and the cost is much less than a German Ramp test, and a WHOLE lot cheaper than a serious slip and fall lawsuit. Pendulum testing using a soft rubber slider is also useful for wet barefoot areas.
If a floor is slippery when wet, it can be remedied by coating it with our durable SparkleTuff™ anti-slip floor coating. This works well on both shod and barefoot areas. Cost for large areas is about $1 per square foot — cheaper than a broken hip. Looks great — no slips!