UNI EN ISO 20471
High-Visibility Workwear
When we find the pictogram corresponding to the UNI EN ISO 20471 standard, we are talking about high-visibility personal protective equipment. This standard, which replaces the previous ones, has eliminated the distinction between high-visibility safety clothing for personal and professional use. The standard also provides for three classes with increasing levels of protection.
When using High-Visibility Safety Workwear
There are many workplaces where this type of clothing is used.
Generally, these are workplaces where part of the operations take place near moving vehicles, cranes or other motorized vehicles, or in poor visibility conditions. Specifically, the workers who must wear this type of clothing are:
- Operators working on road construction sites;
- Airport operators;
- Operators working on construction;
- Surveyors;
- Engineers;
- Ecological operators.
General characteristics and types of High-Visibility Clothing
According to the UNI EN ISO 20471 standard, high-visibility clothing is divided into three categories based on the degree of protection they guarantee and must have certain minimum areas of retro-reflective, fluorescent and/or combined material. In particular:
- Class 1, defines the lowest level of visibility suitable only for operations on private roads. Garments belonging to this class must have 2 meters of 5 cm wide reflective tape; 0.10 m2 of retro-reflective material and 0.14 m2 of fluorescent background. Braces belong to this class;
- Class 2, defines an intermediate level of visibility. This type of clothing is suitable for couriers and those who work near suburban (B, C), urban (D, E) and local (F) roads. The garments of this class must have a reflective tape of 2.60 meters, 5 cm wide; 0.13 m2 of retro-reflective material and 0.5 m2 of fluorescent background. Trousers, vests, bibs and tunics open on the hips belong to this class;
- Class 3, defines the highest level of visibility. This class includes all operators who work or are located near airports, urban roads (D, E), suburban roads (B, C) or motorways (A). Workwear of this class must necessarily cover the chest and have at least 4 meters of 5 cm wide reflective tape, 0.2 m2 of retro-reflective fabric and 0.80 m2 of fluorescent background material which must be attached to sleeves and trousers.
Class 2 garments, when properly combined, can be considered as Class 3, such as the combination of dungarees and jacket or trousers and jacket.
Technical details on the EN ISO 20471 standard
According to the EN ISO 20471 standard, the manufacturer must carry out specific tests relating to the retro-reflective tape and put the result on the label, indicating the maximum number of washing and drying cycles the garment can be subjected to, guaranteeing its high-visibility characteristics intact.
Visibility in light conditions
Visibility in light conditions is guaranteed by the fluorescent colours. The UNI EN ISO 20471 standard recognises three types of colours: red, orange and yellow. This type of material must guarantee:
- UV exposure and resistance;
- Mechanical and water vapour resistance;
- Colourfastness.
Defined colours are evaluated by measurement with the spectrophotometer, a measuring tool that captures the DNA of the colour: the spectral values. Colour professionals use this data to specify, communicate and monitor colour consistency within the production process.
Night-time visibility
Night-time visibility is provided by retro-reflective bands, which can be made of glass microspheres or prismatic micro-reflective material.
The glass microspheres are placed on a support of resistant fabric such as cotton or nylon coated on one side with a transparent flexible resin in which more than 60 million glass microspheres, each with a diameter of 40 microns, partially sink. The light impacts the internal surface and returns to its source, working like many tiny mirrors.
Curiosities
The American company 3M, which began working on road signs in 1939, developed the first “Scotchlite” film, consisting of glass microspheres deposited on reflective plastic material. The product was improved by making the surface perfectly smooth and protected by a film to avoid the accumulation of dirt.
The prismatic micro-reflective materials are made in such a way that the light hits each of the three surfaces of which the micro prism is composed in turn, before returning to its source. The trihedral micro prism structure is engraved on the lower surface of the transparent resin film using special moulds. The active layer is welded to a substrate, the back of which is coated with an adhesive layer protected by the liner.
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