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Coefficient of Friction Testing - Walkway Auditing

Slip and Fall incidents occur too often and most are preventable. Architects, Insurance Companies and Owners are becoming increasingly aware of the need to reduce slip and fall incidents where possible. There have been a variety of attempts to measure floor traction and the current standards are worth discussion.  However, any consideration of Coefficient of Friction (COF) should first be expanded into Static Coefficient of Friction (SCOF) and Dynamic Coefficient of Friction (DCOF). All Dynamic COF testing is performed on a wetted surface, while Static COF testing may be performed on a dry or wetted surface. All of the options makes understanding the issue all the more difficult.

The photo at above left depicts a BOT 3000E tribometer as utilized by this agency

An awareness of current COF test standards is the first step;

ASTM D2047 Standard Test Method for Static Coefficient of Friction of Polish-Coated Flooring Surfaces as Measured by the James Machine, is a laboratory test method measuring static coefficient of friction. The test is "not intended for use on wet surfaces" and therefore test results reflect a value for Dry SCOF. The James Machine is not portable and not applicable for floor systems created on-site such as polished concrete, poured terrazzo or other floor systems created on-site. 

ANSI B101.1 Test Method for Measuring Wet SCOF of Common Hard-Surface Floor Materials, is a test method with application both in a laboratory for uninstalled materials and in the field on installed flooring systems. The standard does not apply to "mechanically polished tile" and specifically notes polished porcelain and polished marble, inferring that  mechanically polished concrete may not be suitable for testing under this standard. Testing is performed utilizing a tribometer.

ANSI B101.3 Test Method for Measuring Wet DCOF of Common Hard-Surface Floor Materials, is a test method with application in a laboratory for uninstalled materials and in the field for installed floor systems. Testing under this method is intended for Hard-Surface, Resilient, Wood, Synthetic Laminates, Polished Concrete, Stone and such materials with coatings or polishes applied. Testing is performed utilizing a tribometer.

ANSI A137.1 American National Standard Specifications for Ceramic Tile contains a procedure for Dynamic Coefficient of Friction Testing. Wet DCOF Testing is required, Dry DCOF testing is discussed as additional test "if desired". This test method is intended for use in a laboratory, utilizing a tribometer.

One article trying to explain SCOF versus DCOF suggested that SCOF relates to a shoe sole leaving a floor surface while DCOF relates to the heel of shoe coming in contact with a floor surface. Clearly measuring two different things at two different times.

Floor surface traction testing is only one part of a safety program. The proper us of mats, where applicable, and maintenance procedures that maintain or enhance traction rather than effecting it negatively are equally important. Walkway auditing includes in-situ COF testing but goes much further, please call to discuss your needs.

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