Glossary · Technology
Laser classes
A classification of how dangerous a laser is for eyes and skin. It ranges from class 1 (harmless in normal operation) to class 4 (very dangerous).
Explained in more detail
The laser classes are defined in the standard DIN EN 60825-1: 1, 1M, 2, 2M, 3R, 3B and 4. For visible continuous-wave lasers, roughly: class 2 up to 1 mW, 3R up to 5 mW, 3B up to 500 mW, class 4 above that. Class 4 can damage the eyes even through scattered reflections, burn skin and start fires. Open engraving lasers with several watts are therefore class 4. Enclosed devices can be classified as class 1 if the enclosure shields the beam completely and safety switches turn the laser off when it is opened.
Where does the term come from?
The classification comes from the international standard IEC 60825-1, adopted in Germany as DIN EN 60825-1. With the 2001 revision, classes 1M, 2M and 3R were added, and 3R replaced the former class 3A. M stands for magnifying, meaning magnification through optics.
In practice
- Class 1 applies only with the lid closed. With a riser, an open flap or a removed cover, a device effectively becomes class 4.
- With class 4, everyone in the room needs suitable laser safety glasses, including spectators.
- The laser class is on a yellow warning label on the device. If it is missing, that is a warning sign about the device's credibility.
- Pets and children do not belong in the room with open class 4 devices.
Not to be confused
The laser class says nothing about smoke and fire risk. Even a class 1 machine needs extraction and supervision.
Frequently asked questions
Which laser class do laser engravers have?
Open diode and CO₂ machines are almost always class 4. Enclosed machines with safety interlocks are often rated class 1, as long as the enclosure stays closed.
Do I need safety glasses with Class 1?
Not in normal operation with the enclosure closed. If you work with the lid open, the cover removed or a riser fitted, the rules for class 4 apply.