Introduction to EN 172 Standard – Solar Protection for Industrial Eye Protection
1. Overview of EN 172 Standard
- Full Name: EN 172 – Personal Eye Protection: Sunglare Filters for Industrial Use
- Purpose: Specifies the requirements for sunglare filters used in industrial settings, ensuring adequate protection from excessive visible light (glare) and UV radiation.
- Scope: Covers safety eyewear intended for outdoor industrial environments, including:
- Safety glasses
- Safety goggles
- Face shields
Unlike regular sunglasses, EN 172-certified eyewear must meet stricter impact resistance and optical quality requirements, making them suitable for hazardous workplaces.
2. Importance of Sun Glare Protection in Industrial Work
Industrial workers who spend long hours outdoors are exposed to intense sunlight and glare, which can cause:
🔴 Eye strain and fatigue
🔴 Reduced visibility, increasing accident risk
🔴 Long-term UV damage (cataracts, retinal damage)
🔴 Discomfort from excessive brightness
EN 172 ensures that lenses:
✅ Reduce excessive light and glare
✅ Block harmful UV radiation
✅ Maintain color recognition and optical clarity
✅ Are impact-resistant for industrial use
Applications of EN 172-Certified Eyewear
- Construction & Road Work – Protection from intense sunlight during outdoor tasks
- Agriculture & Forestry – Reducing glare from open fields and water surfaces
- Aviation & Maritime – Preventing glare from sky and water reflections
- Mining & Oil Industry – Safeguarding against harsh sunlight in open mining areas
- Sports & Outdoor Activities – Used in extreme conditions like mountain climbing
3. Key Requirements of EN 172
The EN 172 standard defines specific performance criteria, ensuring that industrial sunglare filters provide:
✅ Sufficient reduction of visible light intensity (glare control)
✅ Adequate UV protection (complementing EN 170 UV standards)
✅ Minimal distortion to maintain clear vision
✅ Impact resistance according to EN 166 safety standards
Solar Protection Scale (EN 172 Marking)
| Scale Number | Visible Light Transmission (VLT %) | Application |
|---|---|---|
| 3-1.1 | 74.4 – 100% | Low brightness (mild sun) |
| 3-1.4 | 65.2 – 74.4% | Moderate brightness |
| 3-1.7 | 57.2 – 65.2% | Standard sun protection |
| 3-2.5 | 29.1 – 57.2% | High brightness (outdoor industrial use) |
| 3-3.1 | 8.0 – 29.1% | Intense sunlight (mountain, desert, sea) |
- Lower numbers (3-1.1, 3-1.4): Allow more light, suitable for partly cloudy conditions.
- Higher numbers (3-2.5, 3-3.1): Block more light, ideal for intense sunlight exposure.
4. Testing Methods in EN 172
EN 172 defines rigorous test methods to ensure that lenses meet glare protection, UV filtering, and optical quality standards. The key tests include:
- Luminous Transmission Test (Glare Reduction Efficiency)
- Ultraviolet (UV) Transmission Test
- Optical Quality & Distortion Test
- Color Recognition Test
- Impact Resistance Test
A. Luminous Transmission Test (Glare Reduction Efficiency)
Purpose
- Measures how much visible light the lens allows through, ensuring appropriate glare reduction.
Test Procedure
- A calibrated light source is directed through the lens.
- A photometer measures the percentage of visible light passing through.
- The result is compared to the EN 172 protection scale (3-1.1 to 3-3.1).
Pass/Fail Criteria
- Luminous transmission must match the defined range for its protection level.
B. Ultraviolet (UV) Transmission Test
Purpose
- Ensures that UV radiation (UV-A, UV-B) is effectively blocked, preventing long-term eye damage.
Test Procedure
- A UV light source (280-400 nm) is directed through the lens.
- A spectrophotometer measures UV transmission.
- The lens must block 99.9% of UVB radiation (280-315 nm) and a significant portion of UVA (315-380 nm).
Pass/Fail Criteria
- The lens must meet minimum UV blocking standards while still allowing sufficient visible light.
C. Optical Quality & Distortion Test
Purpose
- Ensures that the lens does not introduce blurriness or visual distortion.
Test Procedure
- The lens is placed in front of an optical grid pattern.
- Observers check for waviness, warping, or image distortion.
Pass/Fail Criteria
- The image must remain clear and undistorted.
D. Color Recognition Test
Purpose
- Ensures that natural color perception is maintained, preventing misidentification of signals and signs.
Test Procedure
- A color chart (red, green, blue, yellow) is viewed through the lens.
- Observers check if colors appear altered or faded.
Pass/Fail Criteria
- Colors must remain recognizable for safe industrial work.
E. Impact Resistance Test
Purpose
- Confirms that sunglare protection lenses can withstand industrial hazards, such as flying debris and impacts.
Test Procedure
- The lens is tested under EN 166 impact standards, including:
- Low energy impact (ball test at 45 m/s)
- High-speed impact (ball test at 120 m/s, optional for reinforced lenses)
- The lens is inspected for cracks, fractures, or failures.
Pass/Fail Criteria
- The lens must remain intact after impact, ensuring worker safety.
5. Marking & Certification of EN 172 Eyewear
Once an industrial sunglare lens passes EN 172 tests, it is certified and marked accordingly.
EN 172 Marking System
- Sunglare Filter Scale Number (e.g., 3-1.4, 3-3.1)
- Optical Class (1, 2, or 3, indicating distortion levels)
- Manufacturer’s Mark (e.g., “Uvex,” “Bolle”)
- CE Marking (Compliance with EU Safety Standards)
For example, “3-2.5 1 CE” means:
- Sunglare Filter: 3-2.5 (High-brightness industrial protection)
- Optical Class: 1 (highest clarity level)
- Certified for European safety regulations (CE mark)
6. Comparison with Related Standards
| Standard | Focus | Key Features |
|---|---|---|
| EN 166 | General Eye Protection | Covers optical & mechanical safety |
| EN 167 | Optical Test Methods | Tests clarity, refraction, and lens quality |
| EN 168 | Non-Optical Test Methods | Evaluates heat, impact, and chemical resistance |
| EN 170 | UV Protection | Defines UV-filtering requirements |
| EN 171 | IR Protection | Defines IR-filtering requirements |
| EN 172 | Sun Glare Protection | Specifies industrial sunglare filter requirements |
7. Conclusion
The EN 172 standard ensures that industrial workers have effective protection against sun glare and UV radiation, while maintaining optical clarity and impact resistance. Its strict testing methods guarantee that industrial sunglare lenses are durable, distortion-free, and safe for hazardous environments.
