Additional Certifications for Safety Glasses and Goggles can be confusing and the information on it can be dense and hard to understand. We have set out below some of the additional certifications that you might require from your glasses if you are working in certain conditions.

Any glasses that are deemed to be safety glasses must be able to withstand specific measures to be classed as such.

Hazards for employees can vary greatly across industry and job type and many jobs often present a combination of hazards at one site.  Each pair of safety glasses must be approved via individual testing procedures to gauge its protection level.

Possible hazards at the workplace may include:

• Mechanical hazards due to debris and moving parts
• Biological and chemical substances
• Optical radiation such as UV or IR radiation
• Laser beams
• Electrical hazards

The test of the mechanical strength is classified into protection class S or F. 

Frames and lenses are tested and certified separately. In another article you will find an overview of the EN 166 classifications. 

Some other certifications such as CE Marks also provide rigorous testing to ensure standards are adhered to.  You should consider when purchasing safety glasses whether you require a CE mark on your glasses. 

Additional Certifications for Safety Glasses that may be carried out

Flammability

For this test the safety glasses must withstand a steel rod which is heated to +650 degrees.  The rod is then placed on the glasses or lens for 5 seconds and is considered viable if it does not ignite or glow.

Resistance to increased temperature / aging

The glasses are placed in a furnace or heating cabinet at temperatures in excess of 55 degrees for 60 minutes.  At the end of this period they are inspected for deformation, aging and optical changes.

Corrosion Resistance

For this test to be successful the glasses or goggles must withstand placement into boiling sodium chloride solution for at least 15 minutes.

The frame is then removed and placed into sodium chloride at room temperature for an additional 15 minutes before being removed, rinsed and inspected.

If all surfaces of the metal parts are corrosion free, the frame will have been deemed to have passed.

Resistance to aging by UV Exposure

The lens to be inspected is exposed to 50 hours of strong radiation from a UV lamp.  This will provide reassurance that the frames and lenses can withstand UV exposure in simulated sunlight for 2 years.  The inspector will be measuring whether transmission and stray light meet the specific requirements.

Field of Vision

All glasses and goggles must have a sufficient field of vision for the wearer.  This test is carried out via a laser in a fixed head position which simulates fixed viewing directions.  The glasses or goggles will only be deemed certified if the minimum field of vision is observed.

Side Protection / Side Shields

This test is similar to the field of vision test and ensures that the field of vision is not obstructed by any side protection that is included on the frames.  It also requests that the side shields are fit for purpose and restrict foreign objects from going into the eye or frame from the side.

Additional Test Procedures

Resistance to damage from small particles.

In this test a sand trickle test in used, where 3kg of natural quartz sand is sieved onto the lens.  The lens is then checked using the Scattered Light test to ensure its clarity after exposure to small particles.

Additional Certifications for Safety Glasses and Testing for Occupational Safety Glasses

UV Protection

UV exposure is a very real threat to eyesight and can be amongst one of the most common risks that an employee is subjected to.  Should a person be exposed to UV without adequate protection they are likely to experience serious eye damage which might include retinal damage and lens opacity and irreversibly damage their eyesight.

Scattered Light / Stray Light

Scattered light is an optical effect whichmay cause vision loss of small detail, hazy vision, increased glare hindrance, loss of contrast and colour, etc.   This light scattering reduces the contrast of the image projected on the retina, thus decreasing the quality of vision.  In short, more straylight means worse vision.

A lens can be tested for Stray light by using a laser beam which is shone through the lens at a determined angle.  The laser beam is then picked up using a radiation receive and is assessed for deviation of the beam to ensure it is within the tolerance level.

Light Transmittance

A spectrophotometer is used to quantitatively measure the transmission or reflection of visible light, UV light or infrared light. Spectrophotometers measure intensity as a function of light source wavelength.

For glasses which are used for mechanical or chemical hazards, the light transmission must be higher than 74.4%.

Refractive index / spherical and astigmatic effect

A lens is created using specific correction values matched against an apex refractive index and must be within tolerant levels. 

Should it pass the minimum requirements it will be designated as Class 1, which is suitable for occasional wear and has a refractive power of ± 0.06 dioptres.  This is the normal optical quality for all safety spectacles & goggles.

Material and Surface Quality

The surface of the lens is inspected for any defects that might affect the vision of the wearer.  These defects can include scratches, bubbles, inclusions or cloudiness.

The CE Certificate

After successful completion of the rigorous testing procedures, the glasses will be awarded a CE certificate and approved for use as safety glasses.  Each model will have its own tests carried out and its own certificate issued.

If a safety frame or lens is CE marked it will carry its own markings to provide this information to the wearer.  The markings will be on both the lenses and the frame.