Textiles for personal protective equipment
Modern clothing for the workplace has to satisfy a wide range of different requirements. It must be ideally suited to specific working conditions, promote a sense of identification with the company and be accepted unreservedly by the wearers. This applies particularly to textiles for personal protection equipment (PPE), because this can only do its job if it is worn correctly.
Quite apart from its special functional properties, high-quality protective clothing must be comfortable to wear and fit well. It must also be kind to the skin and, even after long periods of use and repeated cleaning in commercial laundry conditions, still comply with the requirements and safety regulations for its particular purpose.
Personal Protection Equipment (PPE)
Personal protection clothing protects the wearer from risks at work where these risks cannot be averted by other means. Personal protection equipment can only be marketed if it complies with the health and safety regulations in Appendix II of EU Directive 89/686/ EEC. The criteria which the PPE must meet include the following:
- It must offer adequate protection against the risks which it is hoped to prevent, without itself becoming a risk
- It must be suitable for conditions in the workplace
- It must take account of ergonomic requirements and health and safety expectations of the employee, and fit the wearer well
It is also essential for personal protection clothing to bear the EU mark of conformity (CE) and any other markings such as manufacturer information, type designator, retail name, size, number of relevant European standard, care in-structions and pictograms to indicate areas of use.
Depending on the potential risks from which it is intended to offer protection, personal protection clothing is divided into three categories:
- Category 1: simple PPE (e.g. weatherproof clothing)
- Category 2: other PPE, which falls into neither the first nor the third categories (e.g. warning clothing)
- Category 3: complex PPE to protect from irreversible injury and fatal accidents (e.g. protective clothing for firefighters)
All three categories of personal protection equipment require an EU declaration of conformity from the manufacturer or their agent, in accordance with Appendix II of EU Directive 89/686. PPE in Categories 2 and 3 is also subject to EU typespecific approval. For complex PPE in Category 3, a quality assurance procedure in compliance with Article 11 of the EU Directive also has to be followed, i.e. regular product monitoring at yearly intervals.
The regulations in EU Directive 89/686/ EEC have been converted into harmonised European norms. For notified centres, these form the basis for their work in testing and certification. The norms control aspects such as the area of application for protective clothing, safety-relevant properties of the material (e.g. colour, luminance in warning clothing), or the design specifications and performance of the textiles. However, certification as PPE is always given exclusively on the basis of Directive 89/686/EEC. That is to say, manufacturers of protective clothing may deviate from the norms, so long as they can prove that their products comply with the requirements of the Directive in ways other than those quoted in the norm.
The starting point for development, and the essential prerequisite when buying protective clothing, is for a risk assessment to be carried out. The next step is then to produce a requirements and performance profile for the PPE, with the risk-relevant criteria being taken mainly from the EU Directive 89/686/ EEC and the required properties from the harmonised norms. When producing innovative textiles in practice, reasonable compromises have to be found between the ideal design specification for the planned protective clothing and the materials technology that is actually available, combined with economic costing. What is important is that the last stage in the development of new PPE is always an acceptance study, because if the clothing is not worn it cannot provide protection from the hazards in the workplace.
Protective clothing with excellent comfort characteristics
Protective clothing that is comfortable to wear plays an important part in ensuring that the wearer feels physically at ease doing his job and is motivated to perform well. If physiological comfort is overlooked, it not only makes for a low level of acceptance by the employees, but physical and mental performance also suffer. This is a factor that is all the more important, the greater the risks to which the wearer of protective clothing is exposed in the workplace.
Many different aspects are involved in defining physiological comfort, but it is no longer correct to assume that this is a subjective criterion. Comfort characteristics can be measured objectively.
In their clothing physiological research, the scientists at the Hohenstein Institutes have been working for years on developing objective methods of assessment and drawing up guidelines for the design of occupational and protective clothing which support bodily functions as well as possible. They study three aspects of comfort:
thermophysiological comfort, skin sensorial comfort and ergonomic comfort.
It is essential for thermo-physiological comfort that body temperature remains within a range that people find comfortable and that puts little strain on the body. The limits are determined by the physiological processes that go on in the body. Since heat exchange in the human body takes place to about 90% through the skin, clothing, which covers most of the surface of the skin, plays a crucial role in the way the body’s own temperature-equalising function works. It is therefore the aim of the scientists and manufacturers of protective clothing to develop garments which ensure that the wearer maintains a reasonable body temperature in the widest possible range of ambient temperatures and degrees of exertion.
The materials which are used are an important factor in effective and rapid heat exchange. In order to be able to make predictions about the comfort characteristics of the finished garment or range of clothing, the Hohenstein Institutes also have a life-size thermoregulatory model of man, in the form of the thermal manikin “Charlie”. This simulates heat production in the human body and, in a climate-controlled room, also imitates certain sequences of movements.
The figures that are worked out from particular measurements can then be extrapolated by the scientists using predictive modelling techniques. This allows them to make reliable predictions about the range of utility for the garment, i.e. information about maximum and minimum ambient temperatures where it could be used.
The skin sensorial comfort of occupational clothing also plays an important role in the acceptance of protective clothing. Clothing that clings to skin which is wet with sweat is perceived as dragging and restrictive when people move about. Textiles to be worn next to the skin should therefore be napped on the side next to the skin and designed so that they do not stick to the surface of the skin. They should also be made so that they can wick large quantities of sweat away to layers that are not in contact with the skin.
To meet these requirements the most important thing is the construction of the underlying textile from which a garment is made. Sensorial comfort for the skin can also be quantifiably assessed by special measuring procedures. For example, the extent to which a textile “clings“ to skin that is wet with sweat is simulated on apparatus to measure adhesiveness, resulting in a wet cling index. Other pieces of apparatus are used to measure the number of contact points between the textile and the skin, and the sorption index.
Ergonomic comfort includes among other things the fit of the clothing. In fitting tests at the Hohenstein Institutes, ARTICLE | Protective Clothing garments are tried on by models whose measurements match the size given on the label. The fitting tests for protective clothing, as for everyday wear, are based on sizing charts for ladies’ outer clothing and for men’s and boys’ clothes. Experienced clothing specialists assess the garments for length and width, fitness for purpose, ease of movement and functionality, as well as for their appearance. This test is carried out not only on new garments but also after they have been cleaned, i.e. washed, cleaned and dried. Ideally, the fit of a garment, like the condition of the material, seams etc. should remain unchanged.
In practice it is important to evaluate not only individual garments but also complete outfits, consisting of underwear, outer clothing and outdoor wear such as jackets, in terms of all three comfort factors. Only where there is a combination of the right thermophysiological, skin sensorial and ergonomic comfort characteristics will the wearer feel good wearing them, resulting in better performance.
Protective clothing that is tested for harmful substances
In view of the many specific risks and health hazards to which the wearer of protective clothing is exposed in his workplace, it is important that the clothing should not only have excellent functional properties but should not itself be a source of any danger to health. This is why, for over eleven years, the label which says “Textile confidence - textiles tested for harmful substances according to Oeko-Tex Standard 100” has served as a reliable guide when buying protective clothing.
An important benefit of the Oeko-Tex System is the application-based risk assessment of possible harmful substances in textiles. In general the rule is that the more closely a textile is in contact with human skin, the stricter are the human/ecological requirements that have to be met in testing. Because protective clothing sometimes comes into direct contact with the skin and is also often worn for long periods, it has to satisfy the criteria for Oeko-Tex Product Class II (Textiles in direct contact with the skin). Only for baby articles (Product Class I) do stricter regulations apply.
An additional factor in the all-round safety of Oeko-Tex certificated textiles is the principle that a product can only bear the Oeko-Tex label if all its components, including non-textile parts such as buttons and zips, have also passed the tests. True-to-life simulated tests also ensure that all conceivable ways of absorbing the harmful substances (inhaling, swallowing, skin resorption) are taken into account.
The list of tests, which is the same worldwide and currently includes over 100 separate parameters, is updated annually in line with current legislation and the latest scientific findings. It includes not only substances which are banned but also substances which may be harmful to health and parameters to do with preventive measures. Products bearing the Oeko-Tex label contain no azo dye-stuffs and no carcinogenic or allergy-inducing dyes. Pesticides and chloro-organic dye carriers are also prohibited. Heavy metals which may be released from the textile under the effect of sweat are strictly controlled. Formaldehyde in baby articles must be “non-detectable“, while the maximum levels for Product Classes II-IV are well below the legal limit for declaration. All certificated textiles also have to have a pH value that is kind to the skin and good colour fastness.
At the level of textile and clothing manufacturers, the Oeko-Tex Standard 100 is contributing to ever improving safety standards, because it improves the exchange of information about possible problem substances and defines consistent delivery standards. The idea that textile products can be tested and certificated at all stages of processing is a definite advantage in terms of greater planning security. Using preliminary products that have already been certificated avoids duplicated testing and cuts costs.
This is how a network of about 8,000 companies has come into being which are involved in an on-going certification process. With over 62,000 certificates issued for millions of individual products, the Oeko-Tex Standard 100 has established itself as a reliable safety benchmark in the textile industry and is the most well-known test mark of its type in the world. The focus for certification is on clothing, soft furnishings and baby articles, but more and more manufacturers of occupational and protective clothing are using the Oeko-Tex label to show that their products are not harmful to health, and offer the wearer human/ ecological security.
Protective clothing with extra UV protection
An additional benefit of modern protective clothing is reliable protection against harmful UV radiation. Groups such as builders and street cleaners, gardeners, electricians or foresters, who do their work in the open air or who work in particularly sunny parts of the world are exposed to higher levels of natural UV radiations. In other industries such as welding, UV drying (e.g. manufacturing computer chips or flooring) and the manufacture of UV machines (e.g. sun-beds), employees come into contact with dangerous UV radiation from artificial sources.
In view of the global increase in skin cancer cases, the Hohenstein Research Institute, in partnership with the Austrian Institute for Ecology, Technology and Innovation ÖTI and the Swiss Textile Testing Institute Testex, has developed the UV Standard 801. This independent and internationally valid testing and certification system makes it possible to calculate the UV protection factor of textiles objectively. An important advantage of this measuring process is that, unlike other test methods, for example the Australian/New Zealand norm, it also takes account of the condition of the textile product in use, i.e. criteria such as the strain imposed on a fabric by stretching or wetting, or mechanical wear due to wearing and washing.
Many textile and clothing manufacturers around the world have already taken advantage of the opportunity to have their products certificated by the International Test Association for applied UV protection (in Europe currently six well-known textile testing institutes in Germany, Austria, Switzerland, Spain, Italy and Portugal). The scientifically based benchmark of UV Standard 801 guarantees the end-user realistic and reliable predictions about the UV protection provided by textiles and clothing of all types.
Proper care of protective clothing / textile hygiene
In order to maintain the functional properties of protective clothing for long periods and to keep them hygienic, textiles must be properly cared for. The Hohenstein Institutes offer advice on this, for example, to the manufacturers of protective clothing, on choosing materials for the planned application, providing special care instructions or carrying out technical wash tests to ensure that the textiles are fit for the purpose and can be used for the long term. The experts at Hohenstein are also involved in writing norms and validating appropriate treatment processes.
One example of such validated treatment processes is the proper washing of textiles and clothing in accordance with the requirements of the RAL quality labels RAL-GZ 992/2 (hospital laundry) and RAL-GZ 992/3 (laundry from food processing factories). Laundries are awarded these marks of quality if they can demonstrate that the process complies with RAL-GZ 992/1 (domestic and catering trade linen).
Another area of work where textile hygiene is of great importance concerns barrier textiles for medical use. Operating theatre textiles such as the patients’ robes, and theatre gowns, caps and masks should protect both the patient and hospital staff from infection. The scientists work firstly on optimising the barrier effect of textiles and researching suitable methods for testing the protective effect of medical textiles. At the same time, however, they are working on developing and validating new cleaning methods so as to improve existing standards of hygiene still further.
The Hohenstein scientists bring together core competencies in the specialist areas of clothing manufacture, clothing physiology, materials testing, textile care, textile finishing and textile hygiene, in a way that is unique in the world. Among the quality tests for textiles are the Oeko-Tex Standard 100 and the UV Standard 801. The Hohenstein Research Institute is also notified as European Test and Certification Centre for Personal Protection Equipment in accordance with EU Directive 89/686 (Notified Body 0555).
Personal Protection Equipment Test Centre
Tel: +49 7143 271-500
You can find more information about the activities of the Hohenstein Institutes on the Internet at www.hohenstein.de/
Published: 01st Feb 2008 in Health and Safety Middle East