Page 108 - Occupational Health & Safety, September 2017

FOOT PROTECTION
Stand Your Ground
Slip resistance is a challenge. It’s ideal to work with a safety footwear provider who understands the tradeoffs and can help advise your organization on the right product for the work environment.
BY LORI HYLLENGREN
When it comes to footwear, the topic of slip resistance is almost as treacherous as the slick floors, wet surfaces, and uneven terrain employees encounter every day. Confusion surrounds the definition of slip resistance, as well as the accepted method to evaluate slip resistant footwear. This puts employers in a dif- ficult position because slips, trips, and falls are among the most reported—and most costly—injuries in many industries.
Navigating the Standards
Slip resistance requirements for footwear do not exist as they do for other protective aspects of safety foot- wear, such as toe protection or puncture resistance. There are a variety of methods for testing slip resis- tance, and there are guidelines that manufacturers can choose to follow (or not) during product testing. However, there is no current U.S. regulatory body with enforcement power, such as OSHA, that defines or quantifies the slip resistance of footwear.
The relevant testing standard set forth by ASTM International is ASTM F2913, “Standard Test Method for Measuring the Coefficient of Friction for Evalu- ation of Slip Performance of Footwear and Test Sur- faces/Flooring Using a Whole Shoe Tester” (“Whole Shoe test”). This Whole Shoe test standard is applica- ble to a variety of footwear materials and test surfaces, including those that are contaminated with slippery substances. As such, it offers a comprehensive picture of the slip resistance of footwear. The following text summarizes the standard:
This test method determines the dynamic coefficient of friction between footwear and floorings under repro- ducible laboratory conditions for evaluating relative slip performance. The method is applicable to all types of footwear, outsole units, heel top-pieces (top-lifts) and sheet soling materials.
In the Whole Shoe test, the footwear sole and un- derfoot surface are brought into contact, subjected to a specified vertical force for a short period of static contact, and then moved horizontally relative to one another at a constant speed. The horizontal frictional force is measured after movement starts, and the dy- namic coefficient of friction is calculated.
An older slip resistance method employers may know is ASTM F1677, also known as the “Mark II” or “Brungraber” test because it was performed with a slip tester developed by Dr. Robert Brungraber. For many years, this test was an accepted standard for measuring slip resistance of walkway surfaces and evolved into testing footwear. This method was with- drawn by ASTM in 2006 and replaced with ASTM F2913 Whole Shoe test in 2011. The Mark II test is no longer supported by ASTM. Employers accustomed to requesting Mark II test data from safety footwear providers should instead ask for Whole Shoe test data according to F2913.
Exploring a Slippery Issue
Measuring slip resistance for safety footwear can be challenging. Excerpts from the Whole Shoe test docu- mentation illustrate three reasons why:
1. “Surface contaminants include, but are not lim- ited to, water, ice, oil, grease and other chemicals.” These contaminants are among the most prevalent, but em- ployers cannot predict changes in slip resistance when the contaminant is food, gravel, cleanser, mud, or con- struction material.
2. “The test does not account for the risk of tripping due to footwear/ground interlock.” This language re- fers to special-purpose footwear with spikes or metal studs. When footwear is too slip resistant for the task, it can raise additional risk of injury.
3. “The standard does not address all safety con- cerns.” A variety of other factors may affect the risk of slipping, including ambient temperature, lighting, surface irregularities, stairs and handrails, floor mats and runners, and human factors such as age, overall health, inattentive behavior, taking shortcuts, or car- rying objects that obstruct your view.
96 Occupational Health & Safety | SEPTEMBER 2017
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