Footwear and walkway surfaces

The James machine is also used for testing the dry static coefficient of friction of shoe sole and heel materials. The tendency to slip may be influenced by other factors than those studied by testing in James machine (e.g lubricants or other foreign materials either on shoe material or on walking surface). The acceptable levels of slip resistance may not predict resistance to slipping while walking. 

Static slip resistance of footwear sole and heel materials can be measured using a horizontal pull slipmeter. The force required to cause one body in contact with another to begin to move is called static slip resistance. The ratio of the force required to initiate movement and the perpendicular force between surfaces is known as coefficient of friction. Coefficient of friction multiplied by a factor of 10 is known as slip index and this is measured by the horizontal pull shpmeter. Similarly, the result of measurement of slip resistance may not fully predict resistance to slipping while walking. Surface of tested materials is slightly sanded to remove the effect of mold release materials. 

A portable inclinable articidated strut slip tester, PIAST, was developed to test sole and heel materials against planar walkway surfaces, or walkway surrogates in laboratory, or field imder dry, wet, or contaminated conditions. Each measurement is specific to the conditions under which it is conducted but a variety 

A similar machine, known as a portable articulated strut slip tester, PAST, is also used to measure sole and heel materials in laboratory and field under dry conditions. The results of testing may be recalculated to the coefficient of friction using a simple formula and coefficient supplied by the manufacturer of the instrument. 

The method of reporting data and the methods of ranking results obtained on different surfaces are discussed in separate standards. 

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