[Image above] Credit: letthedeadburytheirdead; Flickr CC BY-NC 2.0
It’s starting to look a little like Christmas. Or at least winter.
Winter Storm Caly is blowing her frigid breath across the United States now, bringing cold temperatures and winter weather to much of the country.
While some of the cold-adverse population will choose to lock their doors and shun the outdoors this weekend, that’s not an option for many—holiday parties, shopping, and errands mean that some of us will have to suit up to brave the elements.
Just like working in a lab, part of the trick to surviving winter conditions is in your equipment. The key is having proper personal protective equipment to dodge the hazards and keep your body in one whole, healthy piece.
As the ground gets icy this winter, one of the most important pieces of protective equipment is what’s on your feet—smooth and slippery soles are sure to spell disaster when put up against an icy sidewalk.
A good pair of winter boots, however, can keep your feet warm and cozy and provide good grip even in the face of frozen precipitation. But like most things in life, not all winter boots are created equal.
In fact, when put to the test, 90% of winter boots fail in experiments to test their slip resistance in icy conditions.
How do you test a boot’s resistance to slip on ice? Simple: enlist volunteers to wear new boots and observe them attempt to walk across a tilted slab of ice.
Cruel? Maybe—but it’s all in the name of science.
And that’s precisely what a one-of-a-kind winter weather laboratory at the Toronto Rehabilitation Institute in Canada does.
The lab, aptly named WinterLab, is part of the Challenging Environment Assessment Laboratory (CEAL), a special laboratory platform that allows researchers to test various real-world conditions.
CEAL is literally a moving laboratory—it consists of a self-contained laboratory pod perched atop a movable platform that can shift and tilt the laboratory at will. WinterLab is one of the laboratory pods, which can be switched out atop the CEAL platform to specifically test icy conditions.
The brisk WinterLab pod is essentially a 5 m x 5 m cold room, complete with an ice floor. The lab can maintain temperatures below 0º and supply winds up to 30 km/h.
According to the lab’s website, “We are the only human-oriented slip resistance testing method in the world that has real people walking on a floor made entirely of ice. Our scientists have developed this test so that it better relates to real people walking and therefore more relatable to you, the general consumer. We wear and test the boots before you do!”
And the testing protocol is no simple walk across the ice.
The researchers use a maximum achievable angle test—a published experimental technique—to test the ability of boots to stay put on the real-world-reality of either bare ice (which is “dry,” like an ice rink) or melting ice.
Boot testers lace up with a pair of brand new boots and start off in WinterLab by walking on level ice. The lab only tests brand new boots to avoid the confounding factor of tread wear.
As the boot tester walks back and forth, researchers gradually increase the slope of the floor up to a steep maximum angle of 25º—tilting steeper and steeper as the tester walks across the ice. Eventually, the boots’ ability to grip the ice gives way, and the volunteer slips. As the lab says, “We tip till you slip.”
While boot testers may slip, however, there are no falls in WinterLab—testers are secured in a harness that prevents any injury upon the ice. (WinterLab knows the value of personal protective equipment!)
The tilt of the lab immediately before the boots slip is their maximum achievable angle and provides a measure of the boots’ ability to grip slippery surfaces.
Boots that slip at angles of <7º essentially fail the winter boot test—a 7º angle meets accessibility guidelines in Ontario for a curb ramp, according to the lab’s website.
The lab rates boots that hold their grip at ≥7º angles, ranking them with one, two, or three snowflakes. Read the lab’s top boot picks from the testing results, or check out the full list of almost 100 pairs of boots the lab tested.
Do your winter boots pass the test?