In Part 1 of this series, ANSI A326.3 was introduced as a widely used standard for measuring the dynamic coefficient of friction (DCOF) of different hard surface flooring materials. However, ANSI A326.3 isn’t just a test method; it also establishes a five-category “product use classification system” used to communicate where a product manufacturer expects the product can be used based on slip resistance-related criteria.
These product use categories provide architects, specifiers, designers, and consumers in general with information from the manufacturer to help choose appropriate hard surface flooring products, ultimately benefiting all end-users of flooring through better choices.
A326.3’s classification system is unique in the North American marketplace. It requires manufacturers to define their own “internal product selection criteria” and “declare” products for one or more of the five categories.[1] Rather than relying on single threshold values for each category, this approach encourages clearer communication by allowing multiple traction-related factors to be considered.[2] This is crucial, as slip resistance is influenced by a myriad of factors and cannot be boiled down to a single numerical value. However, several reliable testing options are available to assess surface friction. When used together, these methods can provide a complete picture of a product’s frictional profile. Some of the most common methods are detailed below.
- Wet DCOF testing per ANSI A326.3. This method utilizes an automated “dragsled” tribometer[3] to measure product DCOF. This method is controlled by using a validation surface, can be readily applied in laboratory and field settings, and is especially useful for nominally flat surfaces. It is also specified in ceramic tile industry standards ANSI A137.1, A137.2, and A137.3,[4] and codified in ICC’s ISPSC[5] and IAPMO’s USPSHTC.[6]
- Shod ramp testing per DIN/EN 16165 Annex B. This method requires a “variable angle ramp” to determine angle of slip.[7] This methodology can only be used in a laboratory and requires two operators to walk upon an oiled test piece while wearing standardized footwear. It is a useful test for evaluating 3D-patterned, profiled, or highly textured surfaces.
- Pendulum testing per DIN/EN 16165 Annex C. This method employs a “pendulum skid resistance tester” to assess loss of energy upon swinging a rubber testfoot across a test specimen’s surface.[8] Like A326.3, the method can be used in either the lab or in the field and is useful for nominally flat surfaces and surfaces having small scale texture.
Because ANSI A326.3’s DCOF methodology is widely used in North America, it can be effectively combined with ramp and pendulum testing to provide significant insight into product surface friction. The manufacturer-declared framework established by A326.3 supports this approach by providing a DCOF method as a consistent baseline while allowing additional tests to characterize performance for specific applications.
Other surface characteristics such as roughness, texture/profile, wearability, and more can be considered in conjunction with test results to enhance the producer’s internal assessment. This comprehensive approach supports better decision making and clearer communication throughout the supply chain, helping architects, specifiers, designers, and consumers to make decisions that align product performance with the manufacturer’s expected application.
Resources and Testing
As part of IPA Laboratories’ commitment to providing clarity on slip resistance topics, future articles in this series will continue to explore standards, codes, friction test methods, and more. For key industry resources on slip resistance and DCOF, please visit TCNA’s Resource Center. For testing resources, please visit IPA Laboratories’ webpage on slip resistance services.
Notes
[1] Per A326.3, an “internal product selection criteria” could potentially consist of DCOF limit values established using A326.3 or other test methods, internal reference standards and practices, the presence of abrasive grain and/or surface structure, and more. For additional info on “manufacturer-declared” and “internal product selection criteria,” see Section 3.4 of ANSI A326.3.
[2] In addition to using data from certain measurements, examples of other factors that could be considered for product classification include, but are not limited to, expected footwear, expected contaminants, flatness or incline of the flooring after installation, how the flooring is used and maintained, flooring structure, and how drainage occurs if liquids are involved.
[3] A dragsled tribometer is a device that drags a standardized rubber slider across a test specimen to measure DCOF.
[4] ANSI A137.1, A137.2, and A137.3 are the American National Standard Specifications for ceramic tile, glass tile, and gauged porcelain tile panels/slabs, respectively.
[5] International Code Council’s International Swimming Pool & Spa Code.
[6] International Association of Plumbing and Mechanical Officials’ Uniform Swimming Pool, Spa & Hot Tub Code.
[7] A variable-angle ramp is an adjustable plane that enables harnessed operators to walk over a test piece. The device is used to produce “R” values based on angle of slip; these “R” values are utilized in Germany for specific product use applications.
[8] The pendulum device is widely used in the UK, Australia, and throughout Europe. It is standardized in several test methods, including DIN/EN 16165 Annex C, ASTM E303, and AS 4586.
This article and our prior article are for informational purposes only. They are intended solely as a basis for discussion and as an overview of aspects of the ANSI A326.3 standard and other slip resistance-related topics, not to provide legal advice. You can visit TCNA’s site for more information or reach out to IPA Laboratories for assistance with any testing requests.
