As construction and floor safety expert witnesses we want to bring our clients up-to-date on the state of coefficient of friction testing. Over the past year there have been significant changes in the area of testing for Coefficient of Friction (COF).
For years the standard for the industry fell within a limited range:
Static COF (SCOF) testing where 0.50 COF or greater was noted by Underwriters Laboratory (UL), the American Society of Testing and Materials (ASTM) D 20474, OSHA and the Slip and Fall Handbook, by Stephen I. Rosen, Hanrow Press, as traditionally recognized providing nonhazardous walkway surfaces.
The American with Disabilities Act (ADA) when passed by Congress in July 1992 Title III noted: For all businesses open to the public, ADA and The Architectural and Transportation Barriers Compliance Board (ATBCB) recommends flooring and walkways have a Static COF test level of 0.60 or greater and 0.80 for ramps. However, the ADA values were only a recommendation and never published as an absolute requirement. In 2004 the ADA standards were withdrawn though still referred to during some testing protocols.
Dynamic Coefficient of Friction (DCOF)
In 2012 an additional method for measuring COF was introduced by the American National Standards Institute (ANSI) for testing of ceramic tile known as the A137.1-2012 DCOF AcuTest℠.
SCOF measures the resistance of a surface when one body slides against another body from a starting point.
DCOF stands for Dynamic Coefficient of Friction. DCOF measures the resistance of a surface when one body is in motion over another body.
According to the A137.1-2012 DCOF AcuTest℠ protocol ceramic tiles which are chosen for “level” interior spaces only must have a minimum wet DCOF result of 0.42. It should be noted that the A137.1-2012 DCOF AcuTest℠ does not address exterior walking surfaces and only addresses tile floors.
The industry has been recently rattled by rumors that the Static testing protocol is no longer going to be used. As rumors go this one is only partially true. DCOF testing certainly has a place in floor safety testing but it is not replacing Static COF testing any time soon. One reason is that the DCOF as is currently governed only affects ceramic tile and does not address other walking surfaces such as polished concrete, marble, granite, limestone, vinyl, and a multitude of other floor finish surfaces.
So where are we now? Basically changes are coming and there are as many opinions on the subject as there are floor safety experts. Manufacturers of the $7,000 DCOF testing equipment would certainly love to push their theory and equipment onto the industry as the only “approved” method for COF testing. That is not likely to take a hold due to the thousands of floor testing machines in the United States and other places around the world. What is more likely to occur is that the industry will adopt a dual standard for testing COF, static and dynamic. Both have their place in the industry and both provide useful information, albeit somewhat limited with dynamic testing, regarding floor safety.
Recently OSHA has been considering a new standard for SCOF of 0.60 which will replace the 0.50 widely recognized standard up to now and enforce the ATBCB’s and ADA’s previous recommendation of 0.60. The final decision on that standard is expected in November or December of 2013. Once OSHA publishes a recommended standard of 0.60 it is likely that all future testing for SCOF will depend on this base minimum level. A higher SCOF requirement may require property owners to significantly increase their awareness of floor maintenance.
In order to smoothly transition into the new reality in COF testing we recently sent our COF testing equipment back to to the manufacturer, American Slip Meter, for upgrading and calibration to the new Static COF testing standards. The upgraded equipment, ASM 825A , follows ANSI/NFSI B 101.1-2009 directly and is recognized by the National Floor Safety Institute (NFSI). The NFSI is accredited body from the American National Standards Institute (ANSI). The ASM 825A also follows test procedures in the ASTM F609-05 and ASTM C1028-07 with the exception of that we use the ASM 825A.
Our equipment follows all test procedures, materials and operating procedures with one distinct and important improvement: A digital gauge was developed for the meter to read out direct COF numbers instead of slip index numbers which than would need to be converted to COF numbers. Another advantage is that our ASM 825A can be used for both dry and wet testing using specific meter settings. All XL Services’ tests will be in accordance with the current ASTM C1028-07 (or ASTM F609-05) and ANSI/NFSI B 101.1-2009 using the ASM 825A as the test apparatus.
American Slip Meter is currently developing new equipment to field test for the Dynamic COF. XL Services will obtain additional equipment as soon as they have been verified ready for field testing of ceramic tile. In the meantime rest assured that all our testing is being conducted to current standards and we ask you to ignore any rumors. If you do have any questions please do not hesitate to call us at any time.