A minimum coefficient of friction of 0.4, when measured with a standard sli
der, is often required for floors. There is a need for very simple apparatu
s for use by, for example, cleaning firms and the methods described here re
ly solely on the geometry of the slider. Particular geometries are associat
ed with specified friction values, the measurement criterion being whether
the device slides or tumbles. Various constructions based on this principle
are suggested. (C) 2001 Elsevier Science Ltd. All rights reserved.