QUESTIONI have a client looking to purchase an office building with limestone tile on exterior steps and at the exterior entry to the building. Is there any code or regulation that calls for the walking surface to meet a coefficient of friction or stay within a slippage factor in California? What we're finding in the code is pretty vague.
ANSWERANSWER - The CBC (California Building Code) and ADA (Americans with Disability Act) are vague and subjective regarding slip resistance requirements. There are quantitative standards for ceramic tile in ANSI A137.1 that prescribe a Dynamic Coefficient of Friction (DCOF) test protocol and a minimum requirement for interior, level wet surfaces. They are working on saying it is appropriate for natural stone but Marble Institute of American (MIA) or Tile Council of North America (TCNA) have not finalized that yet. On our projects we always specify both the DCOF test and the SCOF (static coefficient of friction test per ASTM C1028 even though it has been withdrawn). This way it demonstrates that due diligence was done. We can then give our interpretation of those findings.
Slip resistance has many factors to consider. The tile surface texture, the cleanliness of the tile surface and if it has contaminates, what maintenance it has been subjected to, what degree of traffic it has been subjected to, what kind of climatic conditions it has been subjected to, whether there are walk-off matts placed per standards, what type of foot ware is used, what the person is doing, and the dynamics of their physical configuration.
We are often retained as consultants by Real Estate holding companies to evaluate their properties prior to purchase relative to the tile, stone or terrazzo on their project.