Selection of Safety Footwear
Before selecting any PPE, a basic assessment must be made to identify and evaluate the risk.
The employer must inform his workers of the risks in the workplace he must supply appropriate and correctly fitting PPE which complies with recognised standards (EU, SABS, BOBS) and give adequate instruction in its use. Note that SABS certification indicates that the product is taken from the manufacturer on a regular basis for testing to ensure that it is consistently manufactured according to the SABS quality requirement. The NRCS has been established to police and ensure that all safety footwear sold in South Africa complies with SANS 20345:2011. They have the right to seize and destroy products that do not comply with compulsory specifications.
The employer should further ensure that the PPE supplied is used only for the purpose intended by the manufacturer.
The employer is required to audit the workplace hazards and assess the level of risk to the employees.
The employer is required to define the properties in the PPE necessary to protect the employees.
The employer must ensure that all PPE used in the workplace conforms to recognised standards.
The employer must compare the merits of the various types of protection available.
The employer must keep records of assessments and reasons for selecting the particular type of PPE.
If the risk should alter in any way, for instance by the introduction of a new chemical or process, the assessment must be repeated.
Safety footwear should be selected according to the work environment. There are 6 main categories of hazards.
- Impact and Compression
- Splashes and Spills
- Extreme temperature
- Electric Shock / Static
- Slip Resistance
Impact and Compression. The safety footwear should protect against impact and compression from falling equipment and material. SANS 20345:2011 specifies that all safety toecaps must be resistant to 200 joules. They may be made from Steel, Carbon fibre or Composite Plastic. Some boots are available with Metatarsal protectors and they are available separately.
Splashes and spills. Safety footwear should protect against fluids on the floor or as raw material in the process. They should also protect against hot metal in the process of welding and grinding. The upper materials should be resistant to Acids and Alkalis, have bellows tongues and a speed lace system. The laces should have a maximum strength to enable breaking in emergencies.
Polyurethane and Nitrile rubber are resistant to chemicals in accordance with the chemical resistance chart which is available on request. Leather is not resistant to corrosive chemicals unless protected by surface sprays.
High Heat footwear is used in high heat applications. Polyurethane withstands heat up to 90°C and does not freeze. Nitrile rubber, grade dependent, can withstand heat from 150°C to 750°C for short periods. Kevlar stitching is used. No polyester is used. This footwear is used in Smelters, power stations etc.
Antistatic Footwear allows static electricity to pass through footwear but at the same time provides protection against mains voltage up to 240 volts. Antistatic footwear will contain high level of Carbon in the sole and a carbon insole in the construction. There will also be a silver carbon thread running across the inner sole for good conductivity.
Areas where this type of footwear is worn includes hospitals and grain stores where high static charges build up but wearers are using electrical equipment.
Conductive footwear allows all electricity to pass through to the ground and is not designed to give any protection against mains shock. This type of footwear is more effective than antistatic footwear for dissipating static electricity, but it should not be worn where there is risk of electrical shock.
Slip Resistance of industrial footwear is determined by various factors. The contact surface and the sole material adhesion to the surface, the type of liquid on the surface, the type of sole material, the amount of contact area the sole has with the surface and the sole design. The most effective slip resistant sole is polyurethane.
Penetration. Where there is a cut or puncture hazard the sole must either be rubber or Polyurethane with mid sole steel plate. Note that Kevlar mid sole is not as resistant to spike penetration as steel.
Non-metallic footwear is used predominantly in gaseous areas where a spark could cause an explosion.
There are three main types of Safety Footwear construction,
- Goodyear welted – Stitched on soles
- Injected – Polyurethane
- Stuck on – Rubber
The main types sold are injected and stuck on. The stitched on are the CAT type and very expensive.
The most common is injected Polyurethane which provide exceptional comfort while remaining light weight and extremely durable. The sole is resistant to acids, alkalis, oil, petrol, solvents and heat up to 90°C. They may also have inserts of Thermoplastic Polyurethane which is fashion driven.
The Stuck on type is more specialised high heat, hard wearing, resistant to cuts but is heavy, less flexible and not as comfortable as the injected. It must be noted that the fuel range from Bagshaw is one size larger than the international standard. Some of the stuck on shoes are also stitched . This will hold the sole in place if the glue melts.
Rubber is denser than polyurethane and more resistant to cuts. A cut will grow in a Polyurethane sole but not in a rubber sole..
The cost difference in shoes is based on the quality of the leather. Leather may be split up to 6 layers with the outer layer being the highest quality (full grain). This layer has the most natural oils with the worst quality having no natural oils and the most sinew. The full grain leather splits must be 2mm to 2.2mm thick while the cheaper splits will be between 1.7mm to 1.8mm thick. The lower the quantity of natural oil in the leather, the less resistant it is to water. Cement dust is deadly for leather as It draws moisture from the leather. It is very important that footwear is polished regularly. The Suade leather is one of the innermost splits and therefore not a good quality. Leather is a fibrous substance and if wet should be allowed to dry out naturally. Any application of heat will make the leather brittle.
Polyester uppers are fashion driven and should not be used in the safety footwear. It offers no resistance to hot metal, chemicals sharp shards, etc.
Sizing of footwear is determined by international norms. The problem in South Africa is that we have the widest feet in the world. We have an extra wide category that is not used elsewhere. Shoes manufactured for the European Market are made with E (average) and EE (Wide) joint girth fitting. Shoes manufactured in South Africa are manufactured with EE (Wide) and EEE (Extra Wide) Joint Girth Fittings. The old half sizes denote extra wide shoes and these have fallen away with South African Manufacturers as all their shoes are made extra wide. Correct sizing of footwear is very important.
Le Maitre/Fuel Sole Design.
There are five main sole designs in this range. No one sole will cover 100% of the requirement. You must choose the best fit for the application.
General use – Maxeco range. Best sole design for wide range of use. Built in arch support for long hours on the feet. Large percentage surface contact and designed to move water from under the sole for good slip resistance. Maxeco boot account for 55% of all Le Maitre footwear sales. They Last longer than other footwear as they look like safety footwear and the workers only wear them for work.
Comfort – Parabolic Range. Thick concave sole for comfort and spring. Little sole contact with surface with deep cleats making the sole cooler as the air passes under the sole. Not for use with tile or slippery surface. Ankle roll from side to side will relieve stress on feet. Used by worker on their feet all day.
Slip Resistance – Apollo Range. Designed for maximum sole contact with surface and liquid dispersion. Tiring to wear if standing all day as 85% of the sole is in contact with the surface.
Torsion Control – Raptor Range. The inserts make the sole more rigid and gives ankle support. Used in areas of rough terrain, ladders and scaffolding.
Heat – Fuel Range. Good for heat, chemical use and in areas where resistance to sharp object on the ground.
Common Problems with footwear and feet.
Burning Feet. Less than 0.05% of the population have burning feet, the rest of the population jump on the band wagon trying to get more stylish footwear. There are two types of burning feet, those that feel like they are burning and those that are actually hot from heat. The false perception of burning feet is due to two main factors – ill fitting footwear or changes in the nervous system. The common causes of burning feet are dampness, perspiration, Athletes foot, fungal infection, Alcohol use, Diabetes, Smoking, Neuroma, trapped nerves , gout, with the most common being ill fitting footwear. Always wear good cotton socks to absorb sweat and when selecting size, allow for your feet to expand in our heat.
Hydrolysis in Polyurethane soles. Hydrolysis is double decomposition action with water as one of the reactants. It is accelerated by moisture, temperature, darkness and time. Oxygen in water bonds with the carbon atoms and the esters in the polyurethane soles making them unstable and breaks down the polyurethane. This makes the polyurethane environmentally friendly as it breaks down over time. The length of time for the hydrolysis to take effect depends on the environment. Large temperature changes, humidity and darkness accelerate hydrolysis. Wet soles are an indication that it is beginning. It is therefore very important that the safety footwear stock is rotated and issued on the first in first out basis and not stored for extended time.
Footwear must be properly aerated after use and do not wear polyurethane footwear where gumboots would be more suitable.