You may not think about slip resistance until it affects you. It is easy to take for granted the ability to walk on surfaces or take a shower without slipping or, worse, falling. Slip resistance testing demonstrates that products are safe for occupants to use and lowers the risk of a dangerous slip and fall or other harmful accidents. Unintentional slip and fall deaths accounted for roughly 13% of accidental deaths in the United States in 2020. To reduce these accidents, the Americans with Disabilities Act (ADA) requires floors accessible to people with disabilities to be slip-resistant to minimize hazards, especially for those who use walking aids. The ADA defines a slip-resistant surface as “providing a sufficient frictional counterforce to the forces exerted in walking to permit safe ambulation.”
Slip resistance testing applies to a wide variety of surfaces, including:
- Porcelain tile
- Polished and unpolished concrete
- Synthetic laminates
Slip-resistance testing determines the traction of a surface by measuring its coefficient of friction (COF). The coefficient of friction is the ratio of the frictional force to the force, usually gravitational, acting perpendicular to the two surfaces in contact. COF is broken down into two categories: static coefficient of friction (SCOF), and dynamic coefficient of friction (DCOF). The static coefficient of friction measures the amount of force required to move a stationary object, while the dynamic coefficient of friction measures the amount of force required to keep moving an object that is already sliding.
The Occupational Safety and Health Administration (OSHA) says a COF of 0.5 is recommended to achieve slip resistance. OSHA also notes that 0.5 is not the standard and a higher COF may be needed for certain work tasks (i.e., carrying, pushing, or pulling objects, and walking up or down ramps).
Additionally, there are standards dedicated to slip-resistance testing, including but not limited to:
- ANSI A326.3 -American National Standard Test Method for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials
- NFSI B101.3 – Test Method for Measuring the Wet DCOF of Hard Surface Walkways
The versatility of slip-resistant testing allows surfaces to be tested in a laboratory or field, and some standards also include requirements to test surfaces in wet or dry conditions. ANSI A137.1 and NFSI B101.3 provide requirements for slip-resistant testing to find the wet DCOF. Both standards use a solution of sodium lauryl sulfate (SLS) as part of the test procedure.
ANSI A326.3 provides requirements for laboratory and field testing. Specimens tested in the field must take the surface’s high and low traffic conditions. Identifying the areas that can be exposed to contaminants or other risks is important. Field testing requires the tester to determine if the test will be conducted under clean conditions or under prevailing (without pre-cleaning the surface) conditions.
Understanding the need for slip resistance testing can be potentially lifesaving in both the workplace and at home. For manufacturers, knowing the slip-resistance of their materials and products helps them manage and mitigate the risk associated with normal customer use of their products. While many codes and standards may not strictly require COF values, manufacturers interested in managing their risk often work with experienced, accredited third-party agencies to discuss their needs and build a mutually agreeable test plan to put control of the risk back into the hands of the product manufacturer.
ANSI A137.1-2017. ANSI, 2017.
NFSI B101.3-2020. NFSI, 2020.
ASTM F462-79. ASTM, 2007.
“About Us.” NFSI, https://nfsi.org/about-us/. Accessed 10/12/2022.
“About ANSI.” ANSI, https://www.ansi.org/about/introduction. Accessed 10/12/2022.
“2010 ADA Standards for Accessible Design.” Department of Justice, https://www.ada.gov/regs2010/2010ADAStandards/2010ADAstandards.htm. Accessed 10/12/2022.
Standard Number 1910.22. OSHA, https://www.osha.gov/laws-regs/standardinterpretations/2003-03-21. Accessed 10/13/2022.
“Underlying Cause of Death through 2020.” CDC Wonder, https://wonder.cdc.gov/controller/datarequest/D76;jsessionid=F3A5DA8EE891BA01C90613F371BA. Accessed 10/13/2022.