EN ISO 20471 explained for Swiss employers on construction sites

For Swiss employers, correct selection and use of high-visibility clothing are central to ensuring visibility and safety on construction sites, in municipal depots and in logistics. EN ISO 20471 sets minimum requirements for high-visibility clothing. This guide explains in practical terms what the standard requires, how Classes 1–3 should be understood and which steps employers in Switzerland should implement to manage responsibility and compliance systematically.

Quick overview: purpose, version and structure of EN ISO 20471

EN ISO 20471 defines requirements for fluorescent material areas and retroreflective elements, test methods and marking. Its purpose is to make people more visible by day and night. In this article we refer to EN ISO 20471:2013 + A1:2016 (last reviewed on 3 August 2026). Standards can be updated, so check the latest edition before procurement or request a supplier test report.

Classification of high-visibility classes and typical application scenarios

The standard distinguishes three classes, which should be selected according to the risk profile:

• Class 1: lowest visibility (smallest areas). Suitable for low traffic volumes and short, clearly visible work. In practice, rarely recommended as the sole protective measure on heavily trafficked construction sites.
• Class 2: medium visibility. A common choice for many construction sites, municipal depots and logistics areas with moderate traffic or where additional protective measures are in place.
• Class 3: highest visibility. Recommended for work with high traffic volumes, poor lighting or where employees are in the immediate vicinity of fast-moving vehicles.

For quick orientation, we recommend the product overview on our page about High-visibility vests (EN ISO 20471 compliant), which is structured by classes.

Specific minimum areas and measurement quantities (relevant in practice)

The standard specifies minimum areas for fluorescent material as well as requirements for retroreflective elements. As a practical guide (based on EN ISO 20471:2013 + A1:2016), the following minimum areas typically apply:

• Fluorescent material area (daytime visibility) – approximate guide values:
  - Class 1: approx. 0.14 m² (1,400 cm²)
  - Class 2: approx. 0.50 m² (5,000 cm²)
  - Class 3: approx. 0.80 m² (8,000 cm²)
• Retroreflective elements (night visibility) – the standard defines minimum areas and arrangement requirements; strips on the back, chest and around the torso are typical. Retroreflective performance is measured in units such as cd·m⁻²·lx⁻¹ (or RL/RA in test reports).

Note: these values are intended as practical guidance. For binding requirements and interpretation, consult the relevant edition of the standard or request the test report/test number from the supplier. Korntex can provide product data sheets and test reports on request.

Conformity & marking: what employers should check

Compliant high-visibility clothing carries labels stating the standard and class as well as test numbers or certificate references. On receipt of goods, we recommend:

• Request a test report or declaration of conformity (manufacturer information).
• Check labels: verify the reference to the standard (EN ISO 20471), the class and, where applicable, the batch number.
• Carry out sample or spot checks where there is uncertainty.

Further information on the standard is available from Korntex: EN ISO 20471 explained briefly.

Swiss legal framework and employer obligations

Switzerland does not have its own national version of EN ISO 20471; the standard serves as a recognised technical benchmark. Employers are nevertheless required under statutory duties of care (e.g. the Swiss Code of Obligations and accident-prevention duties) to implement appropriate protective measures. SUVA publications and sector-specific guidelines provide supplementary recommendations. This article does not replace legal advice; if in doubt, we recommend a legal review or consultation with the competent supervisory authority.

Measurement, inspection intervals and testing bodies

Recommendations for visibility inspection and measurement:

• Measurement values: retroreflective performance is generally stated in cd·m⁻²·lx⁻¹. Test reports contain measurement methods and values (e.g. RA values).
• Measuring instruments: retroreflectometers / photometers in accredited laboratories; simple test devices are available for spot checks on site.
• Inspection intervals: visual checks before every shift; for intensive use, documented measurement of retroreflection at least once a year is recommended. For very heavy use (e.g. continuous daily use), shorter intervals may be appropriate.
• Test reports: look for certificates from accredited laboratories (e.g. ISO/IEC 17025) showing the measurement method, date and batch identification.

If you are planning certification or recurring laboratory checks, we will be happy to assist in selecting accredited testing bodies.

Risk-based selection: decision aid for the right high-visibility class

The key factors are the activity, traffic volume, lighting conditions and duration of exposure in the hazardous area. A simple checklist for preliminary selection:

• Work on public roads or near fast-moving vehicles → Class 3
• Medium-intensity work on construction sites or at municipal depots → Class 2
• Inspection or short accompanying tasks with very low traffic volumes → Class 1 (only in combination with additional measures)

For specific roles such as site managers or signallers, Identification vests (visible & printable) for identification and additional information.

Material, visibility & performance

Important practical points:

• Fluorescent base colour (signal yellow, orange or red) – signal yellow provides strong daytime visibility.
• Retroreflective strips: width, position and continuous arrangement across the chest, back and torso are relevant for night and twilight visibility.
• Material resistance to dirt and weather: moisture and dirt can reduce visibility performance – careful maintenance prolongs functionality.

Care, inspection and documentation (specific)

Specific care recommendations and documentation steps:

• Washing: follow manufacturer instructions. Typical recommendation: max. 40 °C on a gentle cycle; no fabric softener; close zips; do not bleach; dry gently. (Always check the product care label.)
• Effect of fabric softener: avoid it – fabric softeners can reduce retroreflection and the adhesion of fluorescent coatings.
• On-site check: visual inspection before each use (tears, open seams, detached reflective strips, heavy soiling).
• Measurement & replacement: for intensively used garments, document retroreflection measurements (e.g. annually); replace items if measured values or visual inspection reveal defects.
• Documentation: keep issue records, cleaning records, test reports (internal or external) and replacement history available for audits.

Korntex provides a practical one-page compliance checklist and sample inspection protocol as a downloadable asset that we can send by email. Contact us for a copy and for on-site analysis.

Procurement & cooperation with resellers

When purchasing, employers and procurement managers should:

• Require test reports and batch identification.
• Carry out sample tests or arrange spot checks.
• Set clear specifications for class, colour and reflective area in tenders.

For specific requirements, Korntex offers solutions for Custom production / personalised high-visibility vests, including batch identification and custom marking options.

Practical examples from Switzerland

• Road maintenance construction site: workers near moving traffic → Class 3, signal yellow, jacket or vest with wide back and chest strips.
• Municipal winter service: night and fog work → Class 3 or 2 depending on vehicle speed; additional reflective leg bands if required.
• Logistics terminal: loading and unloading zones with forklifts → Class 2; functional vests (pockets, zip) make work easier.

In brief: cost/benefit and service life

High-visibility clothing is an investment in safety. Plan replacement intervals based on frequency of use and document the service life of individual items. Regular cleaning and proper storage extend useful life.

Checklist download, sample protocol & practical support

We provide:

• One-page compliance checklist (sent by email).
• Sample protocol for issue, cleaning and inspection results (available on request by email).
• Advice & on-site analysis: contact our team for an individual quotation.

Conclusion: EN ISO 20471 in practice

EN ISO 20471 provides a reliable basis for selecting high-visibility clothing in Switzerland. Risk-based selection, regular inspections, documented care and trustworthy suppliers are crucial. Korntex supports customers with compliant products, custom solutions and advisory services to improve visibility and safety on Swiss construction sites, in municipal depots and in logistics.

Further information and product overviews can be found in our explanation of the standard: EN ISO 20471 explained briefly as well as in the product category High-visibility vests (EN ISO 20471 compliant). For individual requirements, we will be happy to advise you on Custom production / personalised high-visibility vests.

Note: this information is practice-oriented and does not replace legal advice. Information on the standard is based on EN ISO 20471:2013 + A1:2016 (review status: 3 August 2026). Before making binding procurement decisions, please check the current edition of the standard and request test reports.