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From workwear to respiratory protection, Gary Cheung discusses the history and development of personal protective equipment.
What comes to mind when you think of personal protective equipment (PPE)? A hard hat? Safety boots? Perhaps a reflective vest? These are all forms of PPE, but not all PPE is as easily donned as the above and certain PPE requires extensive training and customisation for its use. Before we discuss PPE, however, it is important to first understand and appreciate the origins of PPE and the inception of its usage.
History of PPE
The definition of PPE often refers to protective clothing, helmets, goggles, and other garments that are worn to protect an individual from injuries. Before PPE was used in the work environment, PPE was often used during wars.
When was PPE introduced?
One of the first large scale and well documented uses of PPE was respiratory protection against chemical warfare during World War One. The use of chemical gases shifted the dynamics of the war, and the use of respirators allowed troops to nullify the toxic and harmful effects of the gas.
The first respirator is thought to have been invented in the Sixteenth Century by Leonardo da Vinci, with a view to protecting the wearer from inhaling harmful agents such as dusts or chemicals from toxic weapons made of powder. As technology evolved, respirators became less expensive to purchase, less cumbersome, easier to use, more comfortable, and more durable. In addition, safety standardisation and respirator fitting requirements developed by agencies such as the National Institute for Occupational Safety and Health (NIOSH) have made respirators safer and more reliable.
Aside from respirators, other personal protection initially developed for combat also evolved into what has become PPE for everyday use, such as protective coveralls. As early as the Fourth Century, the Japanese conceptualised the idea of using iron plates strapped with leather to soldiers’ and horsemen’s torsos during combat to prevent injuries. Industrial revolution, commercial development and the evolution of technology have changed the landscape of protective armour. Now, modern industry has translated armour into protective workwear, such as disposable coveralls to prevent contamination from biological, chemical and physical hazards.
The main principles of PPE are to prevent hazards from entering or contacting workers’ bodies, and to prevent hazardous materials attaching to workers’ personal clothing from where it may subsequently enter their homes.
As we strive for higher standards of safety, the use of PPE will increase and continue to evolve, so that workers will experience greater protection from their personal protective clothing.
Another form of PPE which has evolved from its initial use in combat protection into an item of everyday industrial personal protection is the helmet. According to historical literature, the oldest known helmet was made out of leather or bronze and was used in approximately 900 BC. Today, materials used in soldiers’ helmets range from lightweight plastics to various types of synthetic fibres.
In North America, hard hats are mandatory when working on a construction site or in mining. Sources of many hazards in these industries are strikes to the head from foreign objects, such as falling equipment, debris and moving mechanical machinery. In addition, secondary injuries such as slips, trips and falls can also cause head injuries if the worker then strikes their head on or against an object.
Helmets were a direct result of war. The importance of an individual’s head (including the neck) consists of the brain, as this controls every aspect of our bodies – from motor skills to cognitive behaviour. Our central nervous system (CNS) is the part of the nervous system that integrates the information that it receives and coordinates the activities of our bodies. In wars, in order to not only sustain attack but also to have the ability to retaliate requires an army of soldiers, therefore protective equipment is of vital importance for minimising the risk of injury or death.
In the early 1800s, shipbuilding workers would paint their hats in tar and cure them under the sun to solidify. When they hardened they would be strong enough to protect their heads from being struck by falling objects. Nowadays, hard hats are mandatory in all construction, industrial and mining sites. More importantly, in Canada, all hard hats being worn in these contexts must be certified by the Canadian Safety Association (CSA). This is to ensure that PPE meets the minimum safety standard to withstand trauma to the head.
It should be noted that similar to NIOSH, the CSA are not a governing body; however, governing bodies in North America often stipulate or cite that CSA standards are required for hard hats when working on the aforementioned sites. The benefits of this standardisation are to give confidence that these hard hats have been tested many times and to ensure that the maximum level of protection is provided.
Using the correct PPE
Firstly, we must understand that occupational PPE and combat protective wear are not interchangeable. The similarity of processes, however, to achieve safety in both fields cannot be dismissed. In the case of a solider, they face extreme risks and hazards such as violent explosions. As a result, to reduce the levels of danger, standard operating procedures or protocol (SOPs) are often used in conjunction with protective equipment.
Similarly, construction workers must follow safe work procedures, along with equipping themselves with the correct PPE. The equipment and procedures may not be as extreme in comparison to combat protective equipment; however, where occupational PPE and safe work procedures are concerned, the objective is to achieve optimal safety when working in high risk or hazardous areas.
The following sections are to provide a more in depth look at the use of PPE and its applications.
Fitting respirators
To ensure workers’ health and safety in areas where respiratory hazards may present, often employers will provide workers with respirators, along with a set of safe work procedures to follow. In most healthcare settings the N95 mask is mandatory as, in the event of a respiratory disease or outbreak occurring, all individuals working in the hospital – from caretaking staff to physicians – are susceptible to exposure via airborne contaminants. With this in mind, it is vital that any worker who may need to use personal respiratory protection has their mask fit tested.
Respiratory fit testing, or mask fit testing, is essentially a testing method to determine whether the person is wearing the right mask for the shape of his or her face. Respirators come in various sizes and while they are adjustable, the shape and size may differ between manufacturers. Prior to wearing a respirator, a qualified health and safety professional should conduct a respirator fit test.
Testing can be completed using either quantitative or qualitative fit testing. These are two very different techniques. The end results are the same, however – to ensure that the respirator is preventing contaminants entering through the respirator and being inhaled by the individual.
In quantitative fit testing a specific protocol is required. Rather than relying on the sensitivity of the individual being tested, quantitative fit testing uses an instrument to provide a quantitative measurement of the amount of face seal leakage present when a given respirator is used.
This type of testing is accurate as the method is not subject to the user’s sensitivity or bias. It is also the most scientific method with regards to proving the face seal of the mask. This is often the preferred method; however, in comparison to qualitative fit testing it is more time consuming and also requires a power source to operate the instrument.
Qualitative fit testing is the opposite of quantitative fit testing, as qualitative tests rely on the sensitivity of the individual being tested, often requiring less instrumentation. Test agents used in the most common and accepted qualitative fit testing protocols include the use of Saccharin, a sweet tasting aerosol; Isoamyl acetate, a liquid that produces a sweet smelling vapour similar to the smell of bananas; and Bitrix TM, a bitter tasting aerosol and irritant smoke made of stannic oxychloride, which produces hydrochloric acid when it comes into contact with water vapour. Exposure to the hydrochloric acid produces an involuntary cough reflex and as such, NIOSH does not recommend the use of irritant smoke due to the potential health risk associated with exposure to irritant smoke.
Qualitative fit testing is considered to be a simpler testing method. Once the individual has donned their respirator the testing agent will then be aerosolised, and the individual will try to detect the scent and the taste of the testing agent through the respirator. If the individual can taste the agent, then rather than using a quantitative method to determine the face seal, the testing method will be solely based on the individual’s reaction to these agents.
The argument against this method is that as some individuals may be desensitised to a particular agent in the course of their lives, often this test may produce a false positive result. In many cases, a sensitivity test is often conducted prior to donning the respirator, although this is also dependent on the individual’s ability to taste or smell these specific sensitivity agents, as this is also biased towards the user’s ability to detect this sensitivity agent.
Another factor that may also need to be taken into consideration when conducting qualitative respiratory fit testing is that some individuals may not cooperate with the testing; for example, certain individuals may want to get the process ‘over and done with’ – resulting in another false positive result during respiratory fit testing.
The positive side of using qualitative respiratory fit testing, however, is that the testing equipment is extremely portable and does not rely upon any power source. This is often used for onsite respiratory fit testing, allowing workers to quickly be fit tested and resume work without much delay.
Environmental hazard protection
There are two main objectives when workers are required to wear disposable coveralls. Firstly, establish if the PPE is intended to protect the individuals themselves from exposure to harmful containments, such as mould (biological), asbestos (chemical) and extreme temperatures (physical). Secondly, ask if this is more pertinent to biological and chemical contaminations? When working in a contaminated environment, disposable coveralls are disposed of upon completion of work. As a result, contaminants are not brought home and individuals are properly decontaminated. In this section, we will discuss the importance and the selection requirements for types of coveralls.
Disposable coveralls can protect workers from biological and chemical contaminants such as mould and asbestos, and often these coveralls are made of high density polyethylene fibres to prevent migration of contaminants onto workers. These suits can often be extremely pliable, allowing workers to manoeuvre freely with minimum restrictions.
Certain disposable suits are also equipped with elasticated wrists and ankles to ensure no cross-contamination. In addition, those suits constructed from a polyethylene material are water and moisture impermeable, meaning no contaminants can penetrate through the suit onto the worker. These suits are designed to be disposable, and as a result, each time a workers doffs their suit it must be disposed of as contaminated waste.
Employers should keep in mind that these suits are not one size fits all. They come in various sizes ranging from extra small to double extra large, and if larger suits are required employers can always contact manufactures directly for sizing requirements.
Lastly, while these suits are excellent for protecting workers against exposure to contaminants, workers must follow safe work procedures in conjunction with using PPE, to achieve maximum protection and optimal safety results.
There are also protective coveralls that protect workers from being exposed to physical hazards such as extreme temperature, and often these materials are either thermally insulating or thermally ventilating. In Canada, working outdoors can often leave workers exposed to extreme conditions, including heat stress and cold stress.
In the case of heat stress, workers are required to wear protective clothing appropriate for being exposed to biological or chemical contaminants, although based on the intensity, temperature and duration of work, a worker wearing this protective equipment may encounter heat stress. As a result, special breathable coveralls maybe required.
In some cases, protective suits may feature ice pack compartments, allowing workers to continue working in extreme heat while not being exposed to other biological or chemical contaminants. The same idea can be applied to cold stress. Workers operating in cold and hazardous environments can wear protective suits with heat pack compartments to ensure they remain warm during working periods.
According to one consultancy in British Columbia, when working in environments with extreme temperatures such as kilns and refineries, specialised heat protective clothing may be required. This type of protective clothing can also be used in moderately hot environments to allow longer work periods between breaks. A proper assessment of all heat sources is required to determine if any specialised clothing would be effective in reducing heat stress.
Specialised heat protective clothing should be worn only by properly trained workers who are following a manufacturer’s instructions and complying with safe work procedures. It should be noted that heat protective clothing may not provide a complete solution to the problem of heat stress; precautions such as close supervision should be maintained until the effectiveness of the clothing is known.
Head protection
The purpose of the hard hat is to protect a worker’s head, without compromising on comfort or visibility. As mentioned earlier, in Canada all head protection used on construction, industrial and mining worksites must be CSA certified. It should be noted that CSA certification only measures the safety standard of the hat itself – comfort and fit are not taken into account.
The majority of hard hats are adjustable and designed to fit different head shapes, so it would be wrong to assume that all hard hats will offer the same fit. It is important that a hard hat should be comfortable and not impede a worker’s vision, because workers must wear their hard hats for the entire time while on a worksite. A hard hat should be comfortable and secure, fitting snuggly to the user’s head.
Another important note on hard hats is that of maintenance. Hard hats in good condition may last up to seven years, depending on usage. According to the CSA, most hard hats have a recommended work life of between three to seven years; however, the effective life of a hard hat varies with the make and model. In accordance with the CSA Standard CAN/CSA Z94.1-05, Industrial Protective Headwear – Performance, Selection, Care and Use, each manufacturer is supposed to provide this information with every hard hat sold.
The CSA Standard recommends that manufacturers inform consumers that once a hard hat has exceeded its effective life, it should be replaced. The Standard also recommends that users should check their head protectors daily. If there is any damage to the shell or to the suspension, it should be replaced immediately. If the protector has been subject to a heavy blow or heavy compression it should also be replaced.
Conclusion
All personal protective equipment needs to be selected correctly for the type of hazard that a worker may encounter. While today’s occupational protective equipment is a derivative of combative protective equipment, we should never consider that occupational PPE provides the same level of protection as combative protective equipment. Despite the violence and horror of war, the development of combative protective wear has directly benefitted industrial protective equipment.
