How to achieve high-visibility (hi‑vis) Class 3 in summer

Many decision-makers ask: how do I achieve high-visibility Class 3 in summer? Especially on construction sites, at municipal depots, in logistics or with public authorities, combining maximum visibility with heat suitability is important. This guide explains the requirements clearly, provides practical figures for EN ISO 20471, describes summer solutions and shows how to check and request certified Korntex options.

Quick answer: can high-visibility Class 3 be achieved in summer?

Yes. High-visibility Class 3 can also be achieved in summer temperatures, provided the clothing combination meets the area and reflectivity requirements of EN ISO 20471 and is worn correctly. Material choice, cut and sensible layering are decisive. This page is for guidance; a legally binding occupational assessment should be clarified with your occupational safety specialist or the responsible cantonal authority (see disclaimer).

Important note / Disclaimer

This guide provides professional guidance but is not a legally binding interpretation of EN ISO 20471 or cantonal regulations. Employers, buyers and safety managers must consult specialists or the competent authority in individual cases. Korntex is happy to advise on products, provides certificates on request and supplies samples: Contact & sample request.

Legal framework: brief guide to EN ISO 20471 (with specific figures)

EN ISO 20471 defines minimum areas for background material (signal colour) and retroreflective surfaces as well as their arrangement. For an initial assessment, the following applies (standard information based on the commonly used edition):

• Class 3 (highest visibility level): minimum background material area (signal-coloured fabric) approx. 0.80 m² (8,000 cm²).
• Retroreflective area: minimum area approx. 0.20 m² (2,000 cm²).
• Arrangement: reflective strips must be positioned so that the person is clearly recognisable from the front, back and sides (including strips over the shoulders and around the waist).

Note: the standard text, measurement methods and certification bodies are authoritative. If in doubt, check the product certificate or data sheets, or contact us: EN ISO 20471 explained briefly and Contact & sample request.

Technical requirements for high-visibility Class 3 – practical guidance

• Background material: check the total area stated in the manufacturer information or certificate (for Class 3 typically ≈ 0.80 m²).
• Retroreflective strips: the total retroreflective area should meet the Class 3 requirements (for Class 3 typically ≈ 0.20 m²).
• Overall configuration: with layering, the visible area of the combination counts – add the uncovered areas. Overlaps that cover reflective surfaces reduce effectiveness.

Important: lightweight Mesh vests must explicitly state Class 3 in their certificates, or manufacturer information must clearly show that the required areas are achieved when combined with undergarments.

How do I read an EN ISO 20471 certificate? (Quick guide)

• Look for the explicit wording “EN ISO 20471” and the stated class (Class 3).
• Check the stated areas for background material and retroreflective materials (in cm² or m²).
• Check the test number, date and notified testing or certification body. Reputable certificates list the measurement methods and test results.
• If product detail pages or data sheets are insufficient, request the certificate from the supplier or use our Sample request.

Summer-specific solution principles

Materials

Breathable, lightweight fabrics such as polyester mesh or technically finished functional textiles support sweat transport and evaporation. Mesh areas on the back and under the arms improve air circulation without reducing visibility, provided the required surface areas remain available.

Cut and ventilation

Loose cuts promote cooling. Avoid cuts that are too tight and reduce air exchange. Lightweight long-sleeved versions with UV protection are possible, provided they do not cover the visible areas required for Class 3.

Layering

Layering remains a practical solution: a certified lightweight high-visibility vest over breathable summer clothing. The key is that the combined visible areas meet the Class 3 area requirement and reflective strips are not covered. Trial tests with normal work clothing are recommended.

Temperature-based recommendations (as guidance)

• At moderate temperatures (approx. 18–25 °C): lightweight functional vests or high-visibility polo shirts combined with an additional certified vest are often comfortable and compliant.
• From around 25–30 °C: Mesh vests with a large background area and wide reflective strips improve cooling. Note that not all Mesh models automatically achieve Class 3.
• At very high temperatures (>30 °C): additional organisational measures (work scheduling, breaks, hydration) are important; technical solutions alone may not be sufficient.

These temperature ranges are intended as practical guidance; individual strain, activity and local requirements should be taken into account.

Practical tips for different application scenarios

• Construction & civil engineering: where traffic volumes are high, Class 3 is often required. Use certified ventilated jackets/vests or combine visibility with a vest plus reflective elements on workwear.
• Municipal depot & public services: movement-intensive tasks benefit from functional vests with Mesh inserts. Keep replacement reflective strips as accessories to compensate for wear.
• Logistics & traffic: ensure visibility in all directions; combined reflective strips around the waist and shoulders are important.
• Families & events: for children, correct size, good fit and visible reflectors are important. If you have questions, you can request samples from Korntex.

Korntex product solutions for summer

Our categories support selection: lightweight, certified Identification vests (suitable for Class 3), breathable Functional vests (breathable options) and suitable Summer clothing & layering. If you require specific product certificates or test reports, please contact us directly: Contact & sample request. Accessories and spare parts can be found under Accessories for high-visibility vests.

Buying guide & checklist

• Check the certificate and manufacturer information (EN ISO 20471) and the stated surface areas.
• Pay attention to the total visible areas when worn (not covered).
• Size & fit: test the combination with your regular work clothing.
• Breathability values: compare mesh, ventilation zones and material specifications.
• Care instructions: wash correctly and do not use fabric softener so reflectivity is not impaired.
• If in doubt: request certificates or samples via Contact & sample request on.

Care & durability

Wash high-visibility clothing according to manufacturer instructions. Avoid fabric softener and strong bleach; these can reduce retroreflection and signal colour. Carry out regular visual checks: tears, fading or damaged reflective strips indicate that replacement is needed. Keep spare reflectors and strips available to maintain long-term visibility.

FAQ (extended and verifiable)

Can lightweight/mesh high-visibility clothing meet the requirements for Class 3?

Lightweight Mesh high-visibility clothing can form part of a Class 3 configuration if the combined visible area of background material and retroreflective strips meets the requirements of EN ISO 20471. The stated area in the certificate or manufacturer information is decisive.

What minimum areas of background material and reflective strips are required for Class 3?

For Class 3, the standard typically specifies a minimum background material area of around 0.80 m² (8,000 cm²) and a retroreflective area of around 0.20 m² (2,000 cm²). Please check the specific product certificate and consult your occupational safety specialist if in doubt.

Can layering (e.g. T-shirt + high-visibility vest) achieve Class 3? If so, how must it be combined?

Yes, layering can achieve Class 3 if the visible areas of the combination meet the required values. Make sure reflectors and background material are not covered and that the total visible area when worn is documented or verified.

How do I check before buying whether a product is genuinely EN ISO 20471 certified?

Ask the supplier for the certificate or a copy of the test reports. Look for clear manufacturer information on the standard, the class (Class 3) and the named testing bodies. Korntex provides test documentation on request and offers samples for testing purposes: Contact & sample request.

Which materials and cuts are suitable for high temperatures without compromising visibility?

Breathable polyester mesh, lightweight functional fabrics and loose cuts are ideal. Make sure ventilation zones do not cover the required visible areas and that reflective strips remain intact. At extreme temperatures, additional organisational protective measures should be implemented.

Are there special care instructions to prevent loss of certification?

Wash according to manufacturer instructions, avoid fabric softener and bleach, and regularly inspect reflective strips for wear. Serious damage or faded signal colour can reduce protection and requires replacement.

When is Class 3 often required in Switzerland?

Class 3 is often required where there are high traffic volumes, heavy machinery or reduced visibility — for example on roadside construction sites, during traffic-control work or in certain logistics areas. Exact requirements depend on the application and cantonal rules; consult your safety managers.

Conclusion: how do I achieve high-visibility Class 3 in summer?

High-visibility Class 3 can be achieved in summer if you use compliant combinations of lightweight, breathable background material and correctly positioned retroreflective areas. Choose certified products, check certificates (EN ISO 20471, Class 3) and use layering strategies deliberately. 

#HighVisibility #PPE #Construction #Visibility #Korntex