Laser Safety Classifications

All laser devices must be labelled to identify the level of laser safety hazard, called the laser safety class.

There are 4 laser safety classes according to the degree of risk, Class 1 is the lowest risk and Class 4 is the highest. Within these classes are a number of sub-classes specific to the system configuration, in particular the laser wavelength and/or its AEL (Accessible Emission Limit) i.e. the degree of power emitted from the laser and the exposure time before it becomes hazardous.

The greatest hazard to the user is the risk of damage to eyesight. This can be permanent or temporary depending on the power and wavelength of the laser as well as the AEL. Other risks relate to damage to materials biological, for example damage to skin, or non-biological as well as the risk of and/or explosion when coming into contact with flammable or combustible materials. 

Within a laser marking, laser engraving, or laser cutting machine the laser source at any wavelength is always Class 4. The Class 4 laser hazard can be reduced by the addition of extra safety measures and devices built around the laser source.

Class 1 defines the laser marking or laser cutting machine as being of the lowest risk. A Class 1 laser machine can be operated in almost any environment suitable for an electronic device and emits no harmful laser radiation whatsoever.

To meet the requirements of Class 1 the laser hazard must be contained within a ‘light tight’ enclosure with all access panels being used for general operation interlocked and all service panels being secured with screws, or similar semi permanent fixings, so that opening of the service panels requires the use of a tool.

When an interlocked access panel is open an indicator must show that the system has moved from Class 1 to Class 4 and power to the laser must be removed so as to prevent accidental operation.

Class 4 is the most dangerous of all the laser safety classes. A Class 4 laser marking machine exposes the user to potentially immediate and harmful laser radiation and there is greater risk of damage to materials that can combust and/or explode. Use of a Class 4 laser must be restricted to a specifically designated and appropriately signed area, segregated from the general work area. Operators of Class 4 lasers should be specially trained and advised of the risks, they should also wear specifically configured PPE while working in the designated Class 4 area.