What are Slip Resistant Floors?
Slippery floors are a constant problem in manufacturing work environments. While a slip-resistant floor is safer for pedestrians and vehicles, especially in environments where liquids spill or accumulate, the downside is that highly slip-resistant floors are harder to clean. Scientists measure slipperiness with the coefficient of friction (COF), which is a scale ranging from 0.01 (the least friction) to 1.00 (or higher for rubber-coated floors). The ANSI minimum COF to be rated as “high slip resistance” is 0.43. Ramps are required to have a COF of 0.46.
Coefficient of Friction
The COF is the ratio of the friction force to the attractive force between two bodies. We are concerned here with the coefficient of kinetic friction, which measures the friction of bodies in motion relative to each other. The frictional force on each surface is a vector pointing in the direction opposite to that of the motion. COF must be determined experimentally, it is not a calculated quantity. Several different types of devices known as tribometers can measure a floor’s COF, and there are a couple of common strategies for raising a floor’s COF, either by broadcasting high-friction materials upon the wet surface or by incorporating special chemicals in the topcoat.
Broadcast Materials
Most modern epoxies and urethane cements can accept a gritty material broadcast over a newly applied surface that is subsequently grouted with one or more layers of topcoat. The choice ultimately comes back to the balance between slip-resistance and ease of cleaning. Here are three top choices:
1) Aluminum Oxide #54 (COF 0.8 to 0.9): The chemical formula for aluminum oxide is AL2O3. If you’ve ever used sandpaper, you immediately recognize that a 54 grit is a fairly coarse abrasive. According to ANSI standards, the particle size for this grit is 300 microns, which is 0.3 millimeter. The material has a very hard (9 on the Mohs scale of mineral hardness) crystalline structure with a flat, rather than angular, geometry. These characteristics help prevent aluminum oxide from wearing down or losing its slip resistance.
2) #00 Sand (COF 0.7 to 0.8): Sand is about 98.6 percent silicon dioxide, SiO2, mixed with trace amounts of other metallic oxides, including AL2O3. Size #00 graded sand is medium coarse and has a particle size range of 0.6 to 1 mm. While less expensive than aluminum oxide, its angular structure is vulnerable to wear that reduces its COF over time.
3) Micro/Macro Chip Broadcast (COF 0.7 to 0.9): Vendors such as Duraflex sell decorative colored vinyl chips in micro and macro sizes for broadcast over new floor surfaces. It’s available in smooth or slip resistant surface finishes. The sizes of the micro and macro chips are 1/16 and 1/4 inch, respectively. COF decreases with the number of top coats applied above the chips.
Orange Peel Finish
The orange peel finish is the result of a special hardener that is mixed with epoxy resin rather than broadcast over the wet surface. The rippled OP finish has a COF of 0.8. One good example is Duraflex Dur-A-Gard OPF epoxy coating, which is designed to be used as a first and/or second topcoat that produces a uniform orange peel finish. The finish is reliable and laborsaving.
Though the choices among non-slip finishes can seem bewildering, PennCoat has many years of experience and expertise to help you select the right product for your particular requirements.