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Get a grip

By Stefan Dubowski
| www.cos-mag.com

Deciphering the different slip resistant footwear for winter weather

Looking for the best slip resistant shoe on the market? Buy a pair with circles on the soles for superior grip. No, wait. Shop for soles with squares, they bite better. Be sure to get soles with rubber for excellent traction. Scratch that. Polyurethane is better. What was the question?

Finding the right slip resistant footwear can be confusing. The options seem endless with numerous materials, tread designs and countless different opinions about what makes a shoe or boot particularly grippy. But this is an important decision, one well worth the hassle of investigating. More than 42,000 workers are injured each year due to slips, trips and falls. That number translates into 17 per cent of the time-loss injuries covered by workers’ compensation boards and commissions, according to the Association of Workers’ Compensation Boards of Canada.

Better footwear may help reduce the number of slips and trips among Canadian workers. It’s time for some sole searching.

Winter grip

With winter fast approaching, many companies and managers seek slip resistant footwear to help ensure employee safety. That search should start from the bottom: look for soles designed for high grip. Yet already, this is where confusion may set in. For instance, some footwear experts recommend soles that feature circles, arguing that the rounded edges allow liquid and debris to escape from beneath the foot more effectively than squares.

But Jeff Huckle, for one, isn’t completely sold on circles.

“Circles work alright,” says the product manager for Dickies footwear at Kodiak Group Holdings in Cambridge, Ont. “In our experience, 90-degree angles are best. They create biting edges that make contact with the ground.”

Further confounding matters is the question of material: what should the soles be made of? In a 2010 study, the Center for Inclusive Design and Environmental Access at the University of Buffalo found that on wet and lubricated floors, polyurethane soles provide more grip than synthetic, nitrile and natural rubbers. But the study also found that polyurethane does not perform significantly better than those other materials on ice.

Meanwhile, “flat cleats with the largest possible apparent contact area resulted in the highest friction readings on dry ice, and sharp cleats with very hard heel materials provided the highest friction on wet ice due to the formation of scratches,” the report read.

Thankfully, the task of identifying the best slip resistant footwear need not be completely baffling. SATRA, a United Kingdom testing company, offers helpful guidelines for manufacturers of slip resistant soles — and those guidelines can inform buying decisions for people who seek slip resistant footwear, too.

According to SATRA, look for these tread traits:

• a raised tread pattern on the heel and sole with a crosshatch or similar design

• cleats or protrusions between 3 mm and 20 mm wide

• grooves or channels at least 2 mm wide

• a square heel breast, which is the heel’s leading edge.  

Additionally, consider tread depth, which is the distance from the bottom of the tread to the sole. Look for treads that are 2 mm to 5 mm deep.

Makers of slip resistant footwear also provide the coefficient of friction (COF) measurements for their products that can help employers, employees and safety managers find the most appropriate shoes for the job. The COF is a measure of slip resistance — the higher the COF number, the more slip resistant the footwear.

“Anything above 0.75 is considered to have good slip resistance,” Huckle says.

He explains that Dickies provides six COF measurements for its slip resistant offerings. Each number results from a test of the product on slick walking surfaces including steel, dry tile and wet tile.

He notes that some customers request his company, Kodiak, test footwear on specific surfaces, such as ice.

Kodiak uses a test developed by SATRA. The test takes into account the average weight and size of a wearer (91 kilograms, size 9 foot). It measures slip resistance in two ways: for the heel strike specifically and for the entire sole.

The test also complies with the test method described in the CSA standard Z195-14, which covers protective footwear.

Traction aids

People who work mostly outdoors in winter conditions may need boots or traction aids with studs that can penetrate snow- and ice-covered surfaces. Some footwear manufacturers now use tungsten carbide instead of carbonite steel for studs, with good reason.

“Tungsten lasts about eight times longer than steel, so you’ll get more longevity,” says John Savio, partner with Geroline in Fonthill, Ont., importer of Heelstop, a traction aid developed by Finland’s Devisys.

As with other slip resistant products, the wearer’s work is the key to finding the best fit. For instance, people who spend most of their workdays outdoors traversing snow and ice would benefit from traction aids that feature studs over the entire sole, says Jordan Bell, executive vice-president at Winter Walking, a traction aid maker in Horsham, Penn.

“You’re pushing off with your toes,” he says, describing the way people walk. If a traction aid only offers grip at the heel, “you’re leaving half your foot out of the equation.”

But heel-only traction aids have their place. If a worker frequently transitions from outdoors to the cab of a vehicle, a heel traction aid provides grip on snow and ice, yet leaves the boot’s rubber free to connect with the car or truck pedals.

“It won’t get caught on the brake or the gas,” says Savio. “When you’re climbing on and off equipment, it won’t become a slipping hazard or a tripping hazard.”

Grip at the back of the foot is always important. Heel slips are the most common causes of falls, Savio says.

“In a slip and fall, the weight transfers to the heel and the heel slides out to the front or the side and that’s when you lose your balance. You can fall forward, but generally you have your hands to break the fall. You get hurt when you’re not able to brace yourself properly,” which is what happens when your foot slips out and you fall back or to the side.

But what if a worker needs full-sole traction as well as the ability to walk safely on surfaces not covered with winter’s worst? The “transitional” traction aid might be the answer, says Bell. This product features low-profile studs that are long enough to grip snow and ice, but recessed so the sole’s rubber components grab onto bare surfaces.

“Even with minimal exposure of the stud, you still have better traction than footwear that has no studs,” he says.

Unlike slip resistant shoes and boots, no standards exist for traction aids. That lack of an industry benchmark muddies matters for safety managers in charge of identifying the right product, Bell acknowledges. But he says standards would be difficult to establish.

“The complication is the number of variables. No two walking surfaces are identical. No two job tasks, no two snow storms are identical.”

So employees, employers and safety managers can’t rely on standards for help when it comes to traction aids. Instead, company representatives have to do their research and figure out which footwear is most appropriate based on the job.

Effectively, “it’s up to the safety professional to understand that not all traction aids are created equal,” Bell says.

That’s true for all winter-weather slip resistant footwear, in fact. As Huckle points out, variables such as air temperature, walking surface and any prevalence of a substance that might spill and transform a surface into an ice rink all matter.

So even though manufacturers provide COF measurements for certain products, safety managers and employers should still take the time to assess the wearer’s job, carefully think about his footwear needs and use that information to identify the best option.

Stefan Dubowski is a freelance writer based in Ottawa. He can be reached at dubowski@stiffsentences.com.

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Comments (1)

  • Operation Supt - Garth Niehaus
    0
    2/16/2017 1:36:01 PM
    Is there a concern with them being intrinsically safe?