EN ISO 20471: 2013
High-visibility warning Clothing for professional use
Professional use clothing must withstand the tough environments in which they are used.
High visibility garments can be manufactured from different types of materials, warp or weft knitted materials or woven fabrics. These materials must be sufficiently robust to withstand the rigours of their use; therefore they may be tested for burst, tensile or tear strength.
In order to maintain the conspicuity of a wearer the background fabric of a garment must not fade or lose colour. Consequently, the ability of a high-visibility garment fabric to withstand the effects of sunlight is assessed by exposing it to a Xenon arc lamp. Similarly, materials are assessed for colourfastness to agents such as a wash liquor or dry cleaning solvent.
Three fluorescent colours are defined for use; they are yellow, orange-red, and red. These colours are specified in terms of their colour co-ordinates and their luminance. The defined colours are assessed by spectrophotometer measurement; this is carried out under specific conditions, on both new material and Xenon arc exposed specimens.
Standard EN ISO 13688: 2013, the general requirements for PPE clothing, assumes that garments will provide an adequate level of performance during their time in use. This includes a provision to assess the dimensional stability of materials to after-care treatments, such as domestic or industrial washing, and dry cleaning.
The light reflective properties of tape are assessed using a photometer which measures the amount of light that is reflected back towards its point of origin. The instrument determines how light is reflected when garment tape is seen, effectively, at different distances and at different entrance angles. Retro-reflectivity is measured on both new and pre-treated materials.
High visibility is not simply a function of using the correct materials in a garment’s construction. The design of a garment also influences visibility aspects of a garment, and so this is assessed. Garment assessment requires classification of a garment, which determines its likely end-use. Garments are also examined to determine if they are ergonomically sound.
The PPE Directive demands that materials used in PPE clothing are not harmful to a wearer. Therefore, a certain amount of chemical testing is required of high-visibility materials. Tests are usually conducted to determine whether substances that are prohibited from use are present, or whether substances that are present are there in limited amounts.