In any industry that requires personal protective equipment (PPE), steel midsoles are essential in ensuring the guaranteed safety of both yourself and your workforce. These midsoles, also referred to as ‘protective insert plates’, protect against sharp objects which may be encountered on-site – such as nails, glass, needles, and metal fragments.
These ‘sharps’, aside from being painful and having the potential to cause great harm, can drive contamination like dirt, rust, oil, etc. into the foot – adding the risk of possible infection to any injury.
There are two types of midsoles found in safety footwear which are steel midsoles (metallic), and composite midsoles (non-metallic). Metallic midsoles are foot-shaped pieces of steel cut in one shape from a roll of steel sheeting. They are generally around 0.5mm thick and have a degree of flexibility that makes them comfortable and easy to wear.
Stainless steel midsoles (also called ‘high chromium steel’) will not corrode or break down over time. These typically contain a minimum of 10.5% chromium – an element that prevents corrosion and deterioration of steel.
Steel midsoles are put through a series of thorough and rigorous tests to ensure that they meet acceptable industry standards. The first of these tests involves a 4.5mm nail which is driven into the shoe at a force of 1100N. In order to pass this test, the nail must not pierce the test piece at all.
The second test dictates that these midsoles must undergo one million flexes to make sure that they do not show any signs of cracking, delaminating, or disintegrating. Also, steel midsoles are tested for corrosion resistance by spending 48 hours in a 1% sodium chloride solution.
Once all tests have been completed and the footwear is successful, the safety boots or shoes are ready to enter hazardous work environments to protect your valuable workforce.