Evaluation of three portable floor slipperiness testers

The validity, repeatability, precision and consistency of coefficient of friction (COF) measurements taken with three portable in situ floor slipperiness testers were evaluated. The selected test instruments represented three common operating principles, a towed-sled (Gabbrielli SM), a pendulum (Portable Skid Resistance Tester), and an articulated-strut with simultaneous application of normal and shear forces (Brungraber Mark II). The performance of these devices was studied against a force platform and a biomechanically validated slip simulator as reference equipment. The precision and consistency of the PSRT was acceptable but was reduced at higher COF levels. The validity of the PSRT for pedestrian slip resistance measurement must be improved. The BMII was more valid but less consistent and precise than the pendulum. The overall performance of the GSM was poor. The validity of this instrument can be seriously questioned. None of the testers was able to meet the technical specifications given in their appropriate instructions for use. The present study indicates that there is an urgent need to design more credible in-situ flooring slip resistance testers.