Hospital Floor Slip Resistance: One Lobby, Two Tests, Two Different Answers
By Walkway Management South Florida
A hospital lobby in the Tampa area had sealed terrazzo floors, the kind of polished stone finish that shows up in medical center entrances because it looks clean, reads as high-end, and holds up to decades of wheelchairs and gurneys. We tested three spots along the main entrance path, wet, using two different methods on the same visit. One method said the floor was mostly fine. The other said every single spot was a high slip risk. Both readings came from the same square feet of stone, taken within minutes of each other.
That’s not a contradiction. It’s what happens when two test methods measure slip resistance in genuinely different ways, and it’s worth walking through, because a hospital lobby is exactly the kind of space where getting this wrong has consequences.
Why This Floor, Why This Test
Hospital entrances see a specific kind of foot traffic: patients with IV poles and unsteady gait, family members distracted by a crisis, staff moving fast in soft-soled shoes, wheelchairs and gurneys rolling through rain-tracked lobbies. Elderly and mobility-impaired visitors make up a disproportionate share of that traffic, and they’re also the population least able to absorb a fall without serious injury. Slip-and-fall incidents are one of the most common categories of adverse event hospitals track internally, and a lobby floor is one of the few surfaces every single visitor crosses.
We tested this lobby’s sealed terrazzo wet, at three locations along the entrance path, using both a BOT-3000E digital tribometer (per ANSI A326.3) and a British Pendulum Tester (per ASTM E303-22). Same floor, same day, same wet condition. Different instruments.
What Each Test Actually Measures
ANSI A326.3 sets the current U.S. benchmark for wet dynamic coefficient of friction (DCOF) on hard-surface flooring, measured with a self-propelled drag-sled tribometer like the BOT-3000E. For a level interior space like a hospital lobby, the standard requires a minimum wet DCOF of 0.42. The BOT-3000E drags a sensor across a wetted path at a slow, constant 20 cm/s. That slow, steady motion is exactly why it’s a strong tool for tracking how a floor’s traction changes over time or comparing one area against another. It’s repeatable and operator-independent.
ASTM E303-22 measures slip resistance with the British Pendulum Tester, which swings a spring-loaded rubber slider across the wet surface at roughly 10 km/h, close to the speed of an actual human heel strike. That higher speed lets the pendulum reproduce the hydrodynamic “squeeze-film” effect that happens when a shoe meets a thin layer of water: at walking speed, the water doesn’t have time to escape from underneath the sole, and friction drops. The pendulum is widely regarded as the gold standard for assessing slip resistance because its testing speed models how people actually slip, not just how a sensor drags across wet stone.
The Numbers
At all three tested locations, the wet DCOF readings from the BOT-3000E came in between 0.40 and 0.49. Two of the three spots cleared the 0.42 ANSI A326.3 action limit for interior wet surfaces. The third missed it narrowly, at 0.40.
The pendulum told a different story. All three of the same locations read a wet PTV (Pendulum Test Value) between 19 and 21. Under the accepted threshold, a PTV of 36 or higher for low slip potential when wet, every one of those readings falls well into High Slip Potential territory. Not one spot, not the narrow miss. All three.
Why the Gap
Polished, sealed stone floors are the surface type where this kind of split result shows up most often, and the physics explain why. A drag sled moving at 20 cm/s gives the water on a very smooth, low-porosity surface enough time to squeeze out from under the sensor before it measures friction — the reading comes back closer to a near-dry contact than what a fast-moving pedestrian actually experiences. The pendulum’s higher strike speed doesn’t give the water that escape window, so it captures the hydroplaning effect a slow-moving instrument can miss on this kind of finish.
Neither method is wrong. They’re built to answer different questions. The BOT-3000E is a strong, repeatable tool for monitoring a surface over time or comparing one area to another. The pendulum is the more sensitive, more conservative read on how that surface behaves under an actual footstep — which is why it carries the greater weight when the two disagree, particularly on smooth sealed stone.
What It Means for a Hospital Lobby
If this facility had relied on DCOF testing alone, the report would have shown a floor that mostly passed — one narrow miss out of three spots, easy to write off as a tolerance issue. The pendulum data tells facility management something different: every tested location in the busiest, wettest part of the building is a real slip hazard when the floor is wet, which in a hospital lobby is often.
That’s the value of testing a surface both ways, especially a polished or sealed finish where the two methods are most likely to diverge. One number in isolation can miss what’s actually happening under a person’s foot. Two independent readings, taken the same visit, close that gap.
Get Your Floors Tested the Right Way
If your facility has polished, sealed, or high-gloss flooring in any high-traffic wet area — a lobby, a pool deck, an entrance — a single test method may not be telling you the whole story. Walkway Management South Florida performs both DCOF and pendulum slip resistance testing, documents every reading, and gives you a defensible record of what your floor actually does when it’s wet. Request a slip test or a quote at wmgsouthfl.com.
