Lasers amplify light in various intensities of radiation, usually in the form of a concentrated beam. The beam retains its power, independent of the distance from the radiation source. Depending on the power of the laser, this concentration of light can be extremely hazardous when seen directly by the eye or even when viewing a diffuse reflection. That’s why eye protection is such an essential aspect of laser operation.
Hazard Classes
EN-60825-1 categorises lasers into hazard classes depending on the Accessible Emission Limits (AELs). AELs are classified from Class 1 (eye-safe under all operating conditions) to Class 4 (very dangerous and capable of setting fire to materials onto which they are projected). From Class 1M upwards, a degree of eye protection for laser operation is required.
What Protection?
Before you can choose the right safety glasses or windows for your laser, you need to know its specification. The essentials are:
- Wavelength (or wavelength intensity)
- Laser type e.g. continuous wave or pulse
- Maximum laser power
- Maximum pulse power (if applicable)
For safety glasses, you have to consider whether the need is for operator safety or for alignment. The standard EN 207 covers operator safety with regulations relating to the optical density (OD) and stability to laser radiation of the eyewear. Both filter and frame must be able to take a direct hit from the laser and provide eye protection from this for at least 5 seconds or 50 pulses.
EN208 covers alignment safety and allows the user to see the beam spot whilst aligning the laser. Alignment eye protection must be able to withstand a direct hit and limit its effect to that of a Class 2 laser i.e. safe for accidental viewing.
All safety windows supplied by TLM Laser provide alignment protection.
Marked for Safety
Univet laser safety eyewear from TLM is marked with the appropriate eye protection level. For EN 207 protection, the eyewear will carry the following information:
- Wavelength the filter protects against
- Laser type
- Protection level
- Manufacturer’s ID
- Mechanical resistance symbol (where applicable)
- C E conformity
For EN 208, the frames will also be coded with information relating to:
- Maximum laser power
- Maximum pulse power
- Wavelength (or wavelength interval)
- Protection level
- Manufacturer’s ID
- Mechanical resistance symbol (where applicable)
- C E conformity
This coding allows you to check and make absolutely sure that you and your operators are wearing the right eye protection for the laser you’re working with and operate it with safety.