Surface Roughness Test evaluates surface texture at a micro level by analyzing how the surface deviates from an average profile line. Large deviations indicate a rough surface, while small deviations indicate a smoother one. The test is mainly used to quantify roughness using two key values: Rz and Ra. Rz represents the average of the highest peak-to-valley distances across sampling lengths. Ra represents the average absolute deviation of the surface profile.
Surface roughness is directly related to friction behavior. Higher roughness generally increases friction.
The Rz parameter is particularly important for evaluating slip risk, especially for pedestrian movement. Roughness influences how a thin lubricating water film forms between the surface and contact point, which can increase slipping risk in wet conditions.
These measurements can also complement other slip assessments such as pendulum testing and can provide additional insight where full slip testing is not possible.
Effect on floor applications
Surface microroughness affects how different surface treatments perform. For example, coating systems may behave differently depending on the texture of the substrate. Roughness also influences the reliability of slip-related assessments and can be used as supporting data alongside other testing methods.
Effect on different floor uses
Certain automated systems such as G2P automation units, AMRs (Autonomous Mobile Robots), and robotic systems depend on controlled friction conditions. If the surface is too smooth or too rough, it may affect movement stability, especially during acceleration or stopping. Therefore, surface roughness is checked against operational requirements to confirm that the floor supports safe and efficient machine movement.
A Surtronic Duo II device is used. A diamond-tipped stylus physically moves across the floor surface using a controlled motorized system to maintain consistent travel distance.
As the stylus moves over peaks and valleys, its vertical movement is recorded using a piezo-electric sensor. This mechanical movement is converted into electrical signals, which are digitized and processed by an internal microprocessor.
The device then calculates surface parameters using standardized calculation methods.
Rz results are interpreted in relation to slip potential in wet conditions. Lower Rz values correspond to higher slip risk, while higher values indicate lower risk. The classification provided is:
Ra is used as an additional indicator of surface texture, especially when specific technical requirements must be met. Both parameters together provide a better understanding of surface behavior rather than relying on a single value.
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