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Designing Safety Footwear

Published: 29th Oct 2014

From its military roots to the technologies employed in today's oil and gas safety footwear, Phillip Nutt looks at the history and development of industrial footwear.

Generating revenue and fuelling innovation – devastating as it may be – war is good for business. This is no less the case than for the development of footwear for use in the oil and gas industry, which has evolved directly from military footwear.

The industrial footwear industry has been a sleeping giant for the last century and a half, save for various wars that needed footwear. Military footwear is often in short supply due to the specialised nature of the terrains' demands.

From these wars came demand for new products to meet the needs of the military and industrial consumers. From military footwear evolved industrial footwear and fashion’s obsession with boots, both pull on and lace up.

It was essentially the military that gave us nine inch work boots, cowboy boots, engineers boots, cold weather pack boots and wellington boots to name but a few.

Two materials prevailed in the 19th century, namely leather and vulcanised rubber. From these two materials evolved two distinctively different industrial footwear businesses, which have to this day remained relatively separate in how they do business.

Leather footwear

Leather footwear manufacturers relied very heavily on the Goodyear welted construction, a process that Charles Goodyear Junior refined using existing machinery techniques to produce a more standardised quality of product execution.

It was a patented machine concept that brought shoemakers from all parts of the western world to look, learn and license the concept. Hundreds of family shoe businesses used the process, becoming wealthy as a result of the world wars that followed. The soling of choice was primarily vegetable tanned leather, as that was readily available at low cost.

Rubber footwear

As for the rubber manufacturers, applications were limited initially to built-up assembly. This evolved into direct vulcanised soling for bottoming and eventually completely moulded boots.

The nature of the vulcanising process limited the selection of product styling to mass-produced items. The wellington rubber boot became the Henry Ford Model T of the industrial and safety footwear industry, in that it was the first item mass-produced in its industry. Just like the Ford T, you could find it in any colour - as long as it was black.

Impact of wars

Ahead of the second world war came the invention of rubber sole units for the mass manufacturing of both leather and rubber upper products. Today, some of the most sought after vintage shoes are the rubber press vulcanised soles with both canvas and distressed leather uppers from the 1920s and 1930s.

The second world war saw some of the best scientific and engineering minds of the day look at footwear in a new light. The concept of job fitted footwear was born, as domestic manufacturers were asked to create boots for use by pilots, as well as soldiers in the jungles, deserts, mines and other challenging terrains.

After the second world war the family shoemaking concerns returned to the civilian lifestyle, which was not as conducive to invention and the development of new technologies. Money had been made in the second world war, but exporting was still a limited activity that required lengthy boat trips and frequently stopping commercial airlines. It was at this point that demand exceeded domestic supply.

The shake up

There was a short period in the late 1950s of note to footwear innovation when, inspired by American marketing developments, an upstart company launched an industrial brand TUF that shook some of the old school British boot makers to their very roots. What came from this shake up was the adoption of a new process of welding PVC unit soles to a PVC welt, via a form of Goodyear welt production.

At its inception, there were nine shoe-making organisations in the Northamptonshire area of the UK that produced footwear using this new process. All nine organisations had the same basic boots and differentiated their products by brand, heel loop, tag and name only.

This can be argued as the only major new process patented in the past fifty years of industrial safety leather footwear production, as later inventions came from the development of synthetic compounds and chemical innovations, rather than from the actual production process itself.

Chemical innovations include:

• Rubber with blowing agents became micro-cellular

• PVC with blowing agents became expanded PVC

• EVA sheeting became the first compression-moulded midsoles, which later evolved into controlled expansion EVA and injection moulding

• Polyurethane injection moulding went from unstable caste moulding systems to controlled density processes and new methods of mixing the primary chemicals involved in the process

• Ceramic toes evolved from the metal toe concept

I would further argue that historically most new materials and compounds came from the rubber technology side of the industrial safety market, with the automotive industry striving to find a suitable replacement for rubber tyre production. It is still hard to believe how few major companies employ direct injected soling for modern day work boot needs. My own theory is that it is costly to set up off shore direct injection processes and these machines are not high labour users. As a result, it has helped to tempt major brands to bring home the production using imported uppers.

Sporting influence

As far back as the late 1970s, many of the new approaches to industrial and safety footwear have taken inspiration from sport shoes. While standard boot patterns changed very little, the industrial market was quick to adopt the biomechanical analysis of the sports market. Much of the new technology in safety footwear is hidden from consumers’ eyes, however, so as a sector it lacks the glamour of the athletic boom.

When compared with fashion and sport footwear, the external styling of industrial footwear is often quite mundane. Instead of the designs afforded in more image-lead industries, many technical features of safety footwear are locked into the inside or midsole of products.

Examples of technical innovations:

• Linings are now often impregnated with anti bacterial agents

• Insoles have become footbeds

• Midsoles now offer strategically placed differing densities of rubber sheeting compounds for foot support

Producers of rubber safety footwear have also achieved technical features such as advancements in injection moulding, and the ability to inlay steel toecaps and steel insoles into moulds and inject over and around. Despite these features, they too lack the visible ‘bells and whistles’ of sports and fashion footwear.

Today’s mould making expertise allows for a greater external sculpting effect and more and more vendors are now moving away from the very classic wellington boot shape in favour of much more modern looks.

With the invention of new chemical compounds that can be synthesised and injected, the footwear industry is now able to cater to the specific needs of industrial users.

Soles no longer hold only non-slip attributes. Features can now be selected for every accident-prone possibility and chemical reaction that a worker could encounter.

By the mid 1990s, two aspects of socio-political decision-making began to take effect on the previously somewhat idyllic domestic manufacturing of industrial and safety footwear.

Globalisation

Discounting and off-price retailing as we know it today was a 1960s invention, but when combined at the end of the 1980s with globalisation it began to take hold on a vast scale. This new retailing method began to challenge domestic resources to make cheaper products and it demanded classics with a twist.

For many local producers it was a hard course to tack, with discounters eagerly seeking off shore resourcing as an alternative, first in South Korea then Taiwan and China, while still continuing to look for cheaper manufacturing in areas such as Bangladesh and parts of Africa.

The classic work boot leather products were one of the first mass footwear product categories to be out sourced to Asia. As a result, many domestic makers closed down, merged with others or sold their equipment to Asian vendors.

The same thing happened with the domestic rubber industry. Faced with ever increasing domestic health and safety issues, some moral standards of the time were such that it was okay to poison new resources with unhealthy work conditions while putting domestic employees out of work.

The advent of off shore, lower cost basic products and globalised free trade most certainly changed the face of the industrial and safety footwear market.

Today, basic footwear products often come from far away places and domestic vendors are mostly now both importers and local specialty producers.

Domestic production will require more and more imported leather uppers and they don't have to be relying simply on ideas borrowed from the athletic performance market.

On the synthetic rubber production side, which before was primarily concerned with soling materials, the effort now is on addressing fully moulded boots.

Free of the shackles of being known as wellington boot manufacturers, invention and good product design have become strong features of domestic makers.

Mould making has become more intricate, with the actual moulding more skeletal. The compounds for moulding have become customised to the point where one can specify any number of job related attributes into formulae, increasing suitability and comfort for end users.

Lining materials have also become job fitted and feature driven. Nowadays, footwear not only warms, cools and insulates, it also transfers perspiration, dries, infuses vapours and provides daily anti bacterial treatment.

Footwear for the oil and gas industry is job fitted just like any other area of industry. There is no one shoe that fits all as used to be considered the case.

A spark from a metal cleat can set off a calamitous explosion, a foot can easily slip and get trapped on an oily surface, certain materials can melt on contact with gasoline products, and metal shanks can quickly heat up to unbearable temperatures, as can metal toe caps. Equally, cold weather can have similar prospects.

I defy anyone to say they can sit down and electronically advise on footwear needs for any industrial occupation without a thorough understanding of the direct and individual functional needs of the operator. I would recommend that one learns from athletic performance shoe development procedures, but does not just blindly follow what they design.

Footwear for a specific occupation has its own needs. These needs are best identified by talking to users and examining their old worn shoes and boots.

The three legged stool

The oil and gas industry is no different to any other footwear segment in terms of how one approaches product design. Footwear, as one of my mentors John Thornton hammered home to me, always needs a sound structural design formula. Thornton, the head of Northampton College’s shoe department equated correct shoe design - regardless of its industrial market - to that of a simple three legged stool.

The first leg is related to function or purpose. Far too often in this day and age of celebrity designers have we chosen form over function, only to later wonder why such forms are quickly out dated by newer shapes.

The second leg is of material choice. In the past it used to very be much a case of looking simply at what was available. Today, however, we have access to a plethora of new materials from global suppliers. The challenge now is about what we can ask for as we learn from research of functional needs.

This is most certainly an area where biomechanical gait analysis and traction needs can be scientifically examined and translated into actual functional benefits for the tasks at hand.

The third leg is the role that construction plays in deciding what is best for the functional challenges of the job fitted needs of industry. Today we are seeing new applications to old constructions. As an example, welted footwear now is able to cement specific functional needs of sole units to compatible midsole runners. Whip stitch machines can create a moccasin-like highly flexible inner structure and a lighter boot. Direct injection PU soling is a strong adhesive attachment.

In the moulded boot arena great strides have been made in area moulding, as exemplified by the use of heavy duty Neoproene shafts, lower area injected foam moulded overlays and cemented rubber soles.

The fourth leg

My mentor also talked of recommending a fourth leg for improving the stability of a good design. He referred to this as the leg of fashion, but for me both the words design and fashion have been over employed - to the point that most designs we use today are in fact stylised versions of existing known models. Fashion then becomes a bloated term for a product update that can easily be forgotten with time and the introduction of newer versions.

Looking ahead

What of the future? I see much more of an exoskeletal approach to the design of occupational needs at all levels, both in leather and moulded footwear. I believe the very nature ofour highly specialised industries will see us creating skeletal overshoes with a variety of required features built in. The inner boot will be practical for walking or indoor use, while the exterior shell will contain the safety elements required for that specific job.

Not, of course, that this is a new idea. The medieval period was full of wooden clog patterns to protect lightweight turn shoes from getting fouled by the heavy garbage disposed on cobbled walking routes.

Looking ahead, I see these developments coming from domestic injection moulding vendors, at the expense of leather boot makers. Sadly, I see the latter side of the industry as being too reliant upon the athletic and outdoor industries for direction and not relying on their own conviction as to the role of function in an industrial, safety or even military scenario. Too often in my career I have seen the catwalks render leather work boots as temporary fashion items, with certain brands running after these easy to sell efforts at the expense of their bread and butter industrial collections.

Published: 29th Oct 2014 in Health and Safety Middle East

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Phillip Nutt’s family background in work boots, along with Northampton’s reputation for Goodyear Welts and Doc Martens, exposed him to many of the in depth basics of industrial footwear.