Exclusive: Burning issues with the safety of PPE
Iain Hoey
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Mark Gamble, PPE Technologist at SATRA discusses the company’s role in ensuring the safety of PPE
According to the World Health Organization (WHO), there are an estimated 180,000 deaths every year caused by burns and many more individuals who suffer life changing injuries. Damage to people by burning occurs mainly in domestic settings and in places of employment. Importantly, most burn injuries are preventable. Satra Technology plays its part in the process of helping manufacturers and suppliers of Personal Protective Equipment (PPE) provide products that protect against contact against thermal risks.
SATRA’s role
SATRA Technology acts as an international services provider to those who wish to sell safety products into EU, British and other world markets. SATRA assists companies by supplying a wide range of testing and certification services, including the heat and flame testing of products that are used to protect the whole body. These products include, face and neck coverings, body clothing, gloves, footwear and headwear.
SATRA’s CEO, John Hooker, has stated previously that the company’s approach is to offer comprehensive “top-to-toe” testing services, especially as so many product suppliers offer PPE ranges that are intended to give comprehensive, all-body, protection. The provision of products that are designed to be used in conjunction with each other are often superior in fit. This is because they will have been designed for ergonomic efficiency as well as ensuring the protection of specific areas of the body.
The assessment of products and their fitness for use also describes the role of SATRA as a product certifier. SATRA Technology Europe Limited, based in Dublin, operates as a Notified Body for certifying products that require them to be CE marked for sale within the European Union. SATRA is also an ‘Approved Body’ (reference AB0321) that offers product certification against the requirements of the British UKCA marking regulations. SATRA’s technologists and certifiers are also engaged in the activities of International (ISO), European (CEN) and British (BSI) standard making committees and working groups, as well as developing and publishing SATRA guidelines and test methods.
Heat and flame testing of clothing
There are many International (ISO), European (EN), and British (BS) standards in use whose respective scopes are intended to address the heat and flammability responses of materials and products. Amongst the standards that SATRA regularly uses to test the performance of clothing products and their component materials are: BS EN ISO 14116:2015 – ‘Limited flame spread materials, material assemblies and clothing’. BS EN ISO 11611:2015 – ‘Protective clothing for use in welding and allied processes’. BS EN ISO 11612:2015 – ‘Clothing to protect against heat and flame’. BS EN 469:2020 – ‘Performance requirements for protective clothing for firefighting activities’. BS EN ISO 15384:2020 – ‘Laboratory test methods and performance requirements for wildland firefighting clothing’.
Each of the above product standards reference test method standards that are used to determine a variety of specific properties of materials. For example, the tensile strength and tear resistance of materials are evaluated. If a material meets the minimum performance levels specified in a standard, this may indicate that a garment will remain durable during its time in use. Although it is difficult to predict the wear that any single garment may undergo, the durability of materials is also assessed by subjecting them, and finished garments, to repeated after-care treatments, such as domestic washing (ISO 6330), industrial washing (ISO 15797), and commercial dry cleaning (ISO 3175). SATRA has the facilities to carry out all of these tests.
Importantly, there is a test method common to each of the above clothing standards that provides two procedures for assessing the ignition responses of materials to a standard flame. The standard – BS EN ISO 15025:2016 – ‘Method of test for limited flame spread’ – permits a single layer of material, or composite layers of materials, used in a garment to be tested. The test flame can be applied to the surface or to the bottom-edge of a material. The latter test is primarily designed to determine the response of the hem of a garment to a flame. This test can be used to show if materials within a structure are susceptible to ignition.
The application of a test flame to different materials produces varied physical responses, the standard requires the recording of information about a response to a flame. If a material melts, forms a hole, or ignites, or if debris or flaming debris is observed this is recorded. If a material continues to burn after the removal of the igniting flame (afterflame) or if non-burning combustion (afterglow) is exhibited, these details are also recorded. Depending on how a material is intended to be used, certain flammability features are allowed whilst other are prohibited, as individual product standards require.
For example, a single layer of material that is susceptible to holing would not be used in a PPE garment that was next to the skin. Materials that support combustion for more than two seconds after the removal of an igniting flame are not used. Materials that exhibit afterglow more than two seconds after testing would be likely to suffer from re-ignition in a real-world situation and are therefore not used.
After-care testing
Flame testing may be carried out on material in a manufactured state or after it has been subjected to after-care treatments. After-care testing is undertaken after a minimum of five standardised cleaning cycles, as specified by a material manufacturer, or may be undertaken according to the claim of performance made for a product. If a material or garment has been treated with a flame retardant (FR) repeat cleaning is a way of demonstrating the durability of an FR application.
The evaluation of other properties such as contact, radiant, and convective heat of molten metal splash materials is also assessed after the application of after-care treatments. Washing in particular can cause physical changes in materials that may easily degrade protection against sources of heat.
Fibre loss from materials or fillings; material compaction (loss of loft), particularly of wadding materials; and the movement of materials with a garment structure, may mean that heat becomes more easily transmitted through a structure. If this is discovered in testing then remedial actions can be taken, such as the sourcing of different fillings or waddings, using different types of quilting, or employing different layers in a construction.
Determining that the performance characteristics of a heat and flame protective material is appropriate to a particular garment type is only one aspect of ensuring that a person is protected. All PPE clothing standards are based upon the evaluation of a finished product. This is because the safety of an individual is only achieved by having products whose design and construction also protects a wearer.
Heat and flame protective garments are designed to cover vulnerable parts of a body, and where required neck and sleeve openings are designed to ensure close fit around a body. For example, firefighting clothing is required to have close-fitting collars that prevent the ingress of burning materials into a garment. Similarly, garments used in welding activities are required not to have points in their construction that could trap hot or molten materials. Complying with all the minimum design requirements of a PPE standard is essential to achieving a SATRA test report that shows that a product is fit for the purpose for which it is intended.
Product limitations
When product certification or approval is sought, a SATRA product assessor will require reports that have been produced under the exacting requirements of those placed on an ISO 17025 accredited laboratory. The manufacturer or supplier of PPE needs to demonstrate that their product is ergonomically sound and that it has instructions for use that ensure it offers the best level of protection. A user also has to be made aware of any limitations.
The failure to protect a person has consequences for the user and employer, who may be obliged to involve outside agencies in a serious accident, and also lose the service of an employee. A PPE supplier may also find that they come under public scrutiny if it is made known that one of their products is implicated in a case of personal injury. It is therefore important to ensure that garments are tested and given appropriate oversight through a process of certification.