Not having the right footwear and slipping at work can be SOLE destroying. See what I did there? The sole unit is one of the most important footwear features, especially for safety footwear and wellingtons. Different industries need different sole specifications, so it’s important to understand what you should be looking for in your safety footwear and wellingtons and why.
Now, most companies who require you to wear safety footwear require that footwear to be slip resistant. The sole unit of a shoe is what gives you the slip resistance, so how can a sole be designed as slip resistant?
There are a number of factors that go into making a great slip resistant work shoe. The main features of footwear and wellingtons with high SRC ratings tend to be the design, tread and material used for the sole. Also its important to check whether the sole is soft and versatile or hard and stiff. Usually, a softer sole means that it will have better grip.
A good sole pattern for footwear is a flat bottom, as this increases the surface area. Having a flat, large surface area increases the contact the shoe has with the ground, giving you more protection against slips. The tread pattern and design of a sole will significantly improve the slip resistance, however, it will not solely increase the traction.
Today, the majority of shoe soles are crafted with either rubber or polyurethane (PU), with PU recently overtaking rubber as the go to material for safety footwear.
PU is a composite material made of two layers. This manmade material is a combination of two chemicals that uses natural elements to bring it together. It is a naturally soft material with flexible grip in numerous areas resulting in PU soles being comfortable, slip resistant and inevitably gripping more.
PU soles tend to be good and tough. Also, as the material foams, it tends to not get worn out like rubber sometimes does. PU is soft, pliable and flexible, which basically makes it a good product for grip.
Chemical Structure of Polyurethane
It is important to note though that you can get different type of PU soles. Double density PU is a hard PU and more resistant, anti-static and has a host of other benefits compared to single density PU. So when you’re buying footwear, you want to make sure you’re buying products that have been made with the highest quality materials.
Rubber soles on the other hand offer more secure balance (which might be better if you’re not the best on your feet). Traditionally, rubber has been used for the sole units of shoes and is typically known for being durable, sturdy and water resistant.
Chemical Structure of Rubber
The type of sole you should go for is all relative to your environment. Rubber has some specialist features such as high levels of heat resistant. Rubber soles can withstand temperatures of up to 300 degrees Celsius, whereas PU can only go up to 120 degrees. So if you’re working in construction, or laying tarmac, it’s important that you protect yourself with the right sole, which will most likely be rubber.
A sole unit being rubber though doesn’t necessarily mean that it is hard wearing. Rubber soles tend to wear easily, which has an adverse effect on slip.
It is abSOLEutely (great word play, I know) possible to incorporate both PU and rubber into a sole, just like our Fusion boot. With a PU rubber sole, the first layer is PU to give the shoe a spongy feel and the second layer is rubber.
The Fusion Boot which boasts a PU Rubber sole.
There are other innovative techniques used in safety footwear manufacturing today, such as integrating a Thermoplastic Polyurethane (TPU) element somewhere in the sole. For example, our Tenaci wellington has a red TPU element that gives it an extra bit of security along with the PU sole. This means that the sole still has a soft and flexible grip but the TPU element just to give that extra support.
The Tenaci sole
Be careful though, you can end up over protecting. If you’re wearing footwear with high levels of grip in a dry environment, you could suddenly stop and go head over heels, which is why you need to make sure your footwear is right for your environment. You need to make sure that a flooring slip test has been carried out so you can be confident that you've chosen appropriate footwear for those required to wear it. Oh, and didn’t you know we wrote a blog on that? Don’t say we don’t spoil you.
So now it's time to answer the age old question, what material gives you the best slip resistant sole? Simply, it is down to your environment. Which is why it's important to know your surfaces, their slip ratings and also the SRC rating of the shoe. Don't know what either of these things mean? Don't worry, we've got you covered.
Also, here's a tip for you: if you look at the sole of your safety footwear and wellingtons, it should tell you all the features there.
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