ST-115 Standard
Internationally the concrete floor polishing industry has been searching for a better way to evaluate the refinement of polished concrete to reassure Architects, Engineers and building owners that they are getting the floor they expect.
The ST-115 Standard was produced by the American Concrete Sawing & Drilling Association (CSDA) along with other industry Governing Bodies & Authorities.
The documented specification was titled "Measuring Concrete Micro Surface Texture."
Referring to a physical measurement of the refined concrete surface. Rather than relying on "Grit Size" or "Gloss Number" which can produce inconsistent results from one floor to another, the ST-115 standard details methods and sets parameters for measuring the microscopic average roughness (RA) of a concrete surface using a Ra Meter.
"To date, the ST-115 is the only tool I know of that offers the Design Community - Quantifiable, Scientific & perhaps most importantly, Repeatable Results"
- Christopher Bennett, Husqvarna Construction Products
The ST-115 standard allows the Architects, Engineers and building owners to select a level of finish referenced to Surface Texture Finish Chart by specifying the desired Ra range that the contractor must reach.
The RA measure is key to achieving the desired appearance, performance, and sustainability of the finished polished floor. The surface texture is measured by running a Ra meter over the surface. The reading of the variations measured in microns can be expressed as a surface texture grade. These grades are not ratings of “good” or “bad”: they are objective, measurable levels that determine the level of refinement as heavy texture,” “ground,” “honed” and “polished.”
The Ra readings reflect two important aspects of the surface being created. The first is the effectiveness of the tooling to refine the surface. The second is the ability to fill all micro cracks and pinholes so an impervious surface is achieved when required in accordance with E3 Compliance of the NZ Building Code.
