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EN166

EN166 is the core technical standard which applies to all safety eyewear including spectacles, goggles and visors. It does not apply to eye protection for which separate standards exist (anti-laser eye protection; sunglasses for general use)

 

The main tests for this standard are: Optical Requirements and Mechanical Protection/Impact Resistance

Optical requirements

1. Optical Requirements
Tests include, transmission and diffusion of light, refractive properties, resistance to aging (stability to heat and resistance to UV), corrosion and ignition. Results of the testing define the Optical Class of the eye protector: which falls into 1 of 3 categories, where 1 is the highest and 3 is the lowest as indicated in the table. These categories define the quality of the lens in terms of how much or how little distortion is experienced by the wearer.

Tolerance of the optical power
Optical Class
Application
 
±0.06 dioptres
1
Works all the time (distortion free)
 
±0.12 dioptres
2
Works occasionally
 
±0.25 dioptres
3
Works briefly
Mechanical protection and impact resistance

2. Mechanical Protection/Impact Resistance
This test (applicable to both lens and frame) determines the impact resistance of the eye protector (spectacles, goggles or visors) to withstand flying objects without cracking or shattering. This test is performed with steel balls of different diameters and weights which are used to strike the lens and frame at different speeds as indicated in the table.
This results in 4 levels of mechanical protection denoted by the markings: S, F, B or A on the eye protector where S is the lowest grade offering the least amount of protection and A is the highest grade offering maximum protection under the standard.

Marking
Mechanical Protection
Test Details
Possible on:
 
S
Minimal Impact Resistance
22mm diameter steel ball at a speed of 5.1 m/s
Spectacles
Goggles
Visor
 
F
Low Energy Impact
6mm diameter steel ball at a speed of 45 m/s
Spectacles
Goggles
Visor
 
B
Medium Energy Impact
6mm diameter steel ball at a speed of 120 m/s
 
Goggles
Visor
 
A
High Energy Impact
6mm diameter steel ball at a speed of 190 m/s
 
 
Visor
 
Note: Spectacles can only get an S or F marking; goggles can have an S, F or B; grade A is applicable to visors only.
 
Visor

Optional Requirements

EN166 also describes other optional tests which must be applied should the manufacturer wish to make additional claims regarding protection. For example the Impact Against High Speed Particles At Extreme Temperatures is conducted on spectacles, goggles and visors conditioned at extreme temperatures from -5°C to +55°C, resulting in similar markings as the above table, with a T denoting temperature: FT/BT/AT. This does not apply to the S marking category.
 

Other Optional Requirements

and markings are described in the table below.
 
Marking
Type of Protection
Test - Resistance against:
Possible on:
 
3
Chemical Risk
Liquids (droplets and splashes)
Spectacles
Goggles
 
 
3
Chemical Risk
Resistance to projections
 
 
Visor
 
4
Chemical Risk
Coarse dust particles (>5µm grain size)
 
Goggles
 
 
5
Chemical Risk
Gas, vapours, mist, smoke and fine dust particles (<5µm grain size)
 
Goggles
 
 
8
Electrical Risk
Short circuit arc resistance
 
 
Visor
 
9
Thermal Risk
Molten metal splashes and hot solid projections
 
Goggles
 
 
K
Lens Treatment
Resistance to surface damage by fine particles (anti-scratch treatment)
Spectacles
Goggles
Visor
 
N
Lens Treatment
Resistance to fogging (anti-fog treatment)
Spectacles
Goggles
Visor