U.S. Department of Labor
Occupational Safety & Health Administration
March 21, 2003
Thank you for your November 15, 2002 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs (DEP).
This letter constitutes OSHA’s interpretation only of the requirements discussed and may not be applicable to any questions not delineated within your original correspondence.
You had a question regarding the static coefficient of friction (COF) for walking/working surfaces.
Question: Can OSHA provide any perspective or background on how the COF 0.5 value came to be attributed to OSHA?
Response: OSHA does not have any standards that mandate a particular COF for walking/working surfaces. While there are devices to measure the COF, no OSHA standard specifically requires that employers use or have them. As you may know, there is a nonmandatory appendix (Appendix A to Subpart D) in the Notice of Proposed Rulemaking for Walking Working Surfaces for general industry that discusses COF. Although the notice of proposed rulemaking was published on April 10, 1990, the final rule has not yet been issued.
The pertinent portions of the nonmandatory appendix read as follows:
Note: The following appendix to Subpart D serves as a nonmandatory guideline to assist employers in complying with these sections, and to provide other helpful information. This appendix neither adds to nor detracts from the obligations contained in OSHA standards.
2. Slip Resistance. A reasonable measure of slip-resistance is static coefficient of friction (COF). A COF of 0.5, which is based upon studies by the University of Michigan and reported in the "Work Surface Friction: Definitions, Laboratory and Field Measurements, and a Comprehensive Bibliography," is recommended as a guide to achieve proper slip resistance. A COF of 0.5 is not intended to be an absolute standard value. A higher COF may be necessary for certain work tasks, such as carrying objects, pushing or pulling objects, or walking up or down ramps.
Slip-resistance can vary from surface to surface, or even on the same surface, depending upon surface conditions and employee footwear. Slip-resistant flooring material such as textured, serrated, or punched surfaces and steel grating may offer additional slip-resistance. These types of floor surfaces should be installed in work areas that are generally slippery because of wet, oily, or dirty operations. Slip-resistant footwear may also be useful in reducing slipping hazards.
Although this discussion of COF appears only in a nonmandatory appendix in a rulemaking proposal, it appears to have been the basis for a statement included in an advisory appendix to the ADA Accessibility Guidelines (ADAAG) of the Access Board.
The appendix statement (at A4.5) is as follows: “The Occupational Safety and Health Administration recommends that walking surfaces have a static coefficient of friction of 0.5.” Together, OSHA's rulemaking proposal and the reference in ADAAG probably account for the attribution of a 0.5 COF to OSHA.
Thank you for your interest in occupational safety and health.
We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations.
Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations.
This letter constitutes OSHA's interpretation of the requirements discussed.
Note that our enforcement guidance may be affected by changes to OSHA rules.
Also, from time to time we update our guidance in response to new information.
To keep apprised of such developments, you can consult OSHA’s website at www.OSHA.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202) 693-1850.
Richard E. Fairfax, Director
Directorate of Enforcement Programs