A Comparison of the ASTM F2508 and ANSI/NFSI B101.3 Walkway-Safety Tribometry Standards Using Measurements from Two Different Tribometers

Abstract

Abstract In order to provide the safest possible built environment for pedestrian use, care must be taken to supply walking surfaces that are slip resistant. However, there remains an inability to establish a method of consensus for determining whether a surface is slip resistant. Two current walkway-safety standards illustrate two different approaches to this issue—ANSI A137.1, American National Standards Specifications for Ceramic Tile, and ANSI/NFSI B101.3, Test Method for Measuring Wet DCOF of Common Hard-Surface Floor Materials, promotes a numeric threshold model, while ASTM F2508, Standard Practice for Validation, Calibration, and Certification of Walkway Tribometers Using Reference Surfaces, is a validation standard based on the relative ranking of walkway surface materials. The goal of this study was to determine whether these two standards are compatible in how they rank/evaluate surfaces. To do this, two tribometers, (the BOT-3000E (BOT) (Regan Scientific Instruments, Southlake, TX, USA) and English XL Variable Incidence Tribometer (XL) (Excel Tribometers, Chesapeake, VA, USA)) were used to take slip resistance measurements using the four reference surfaces designated in the ASTM F2508 standard. Measurements for the BOT were taken under three conditions: (1) styrene–butadiene–rubber (SBR) test foot with distilled water and surfactant (consistent with ANSI/NFSI B101.3), (2) SBR test foot with distilled water, and (3) Neolite test foot with distilled water. Measurements for the XL were taken using a Neolite test foot with distilled water. Results indicate that the vinyl composite tile was the reference surface nearest to the ANSI threshold for high slip resistance but fell approximately 11 % below the threshold value of 0.42. The two most slippery reference surfaces (granite and porcelain) fell well below the ANSI threshold for high slip resistance, while the most slip resistant (ceramic tile) was well above the threshold. Unexpectedly, we also found a strong linear correlation (R2 = 0.99) between the measurements from the XL versus the BOT with SBR and surfactant test condition, which allowed for conversion of slip resistance readings between the two tribometers under these conditions. These results provide new data that allow aspects of the ASTM and ANSI standards to be directly compared.