Laser safety

Due to the specific characteristics of laser radiation and the biological and physical effects this has, special protection and cautionary measures are required in the use of lasers. To define the individual measures to be taken in each case, lasers are assigned to classes based on their hazard potential. The authoritative documents on laser device assignments to the classes 1, 1 M, 2, 2 M, 3 R, 3 B and 4 are the accident prevent regulation "Laser Radiation" BGV B2 and the DIN EN 60825-1 standard (VDE 0837 Part 1).

Laser class	Hazards
	Accessible laser radiation is harmless.
	The accessible laser radiation is harmless providing no optical instruments such as magnifying glasses or binoculars are used.
	The accessible laser radiation is only in the visible spectral range (400 nm to 700 nm). It is also safe for the human eye in case of short term exposure to radiation (up to 0.25 s). A longer exposure is prevented by the natural eyelid closing reflex.
	Like class 2 providing no optical instruments such as magnifying glasses or binoculars are used.
	The accessible laser radiation is dangerous to the human eye.
	The accessible laser radiation is dangerous to the human eye and in special cases also to the skin.
	The accessible laser radiation is dangerous to the human eye and dangerous to the skin. Diffuse radiation can also be dangerous. The laser radiation can cause a danger of fire or explosion.

*) Comments on laser classes 2 and 2M: scientific research (FH Cologne) have discovered that the eyelid closing reflex (which incidentally occurs within 0.25 s - longer exposure damages the eye) only occurred by <20 % of the test candidates. In other words, one cannot assume that an eyelid closing reflex exists to protect human eyes. Thus, if class 2 or 2M laser radiation hits your eye, you should deliberately close your eyes or turn away immediately. Additionally, note that the eyelid closing reflex is only triggered by visible light. Laser radiation in the infrared range, e.g., does not trigger eyelid closing as the eye does not perceive the radiation. For this reason, particular care must be taken in handling invisible laser radiation.

The accident prevention regulations "Laser Radiation" BGV B2, and other documents on safe use of lasers

• Laser protection measures (Federal Office for Radiation Safety)
• Accident prevention regulations "Operating Laser Equipment" BGV B2
• Guidelines for implementing accident prevention regulations BGI 832
• Registration form for registering a laser
• Safety instructions on operating class 4 lasers

Observe the precautions stated in the accident prevention regulations (BGV B2). They include:

• Do not look into the beam or direct reflections, also do not look with optical instruments.
• Clear marking of the laser area with warning signs at all access points.
• Route the laser beam clearly below or above eye level, but not at eye level.

The owner/operator of the laser equipment is responsible for compliance with protection measures. The owner/operator must, among other things, ensure that the laser device is assigned to a laser class and marked accordingly. Operations using laser equipment classes 3R, 3B and 4 must be registered with the trade supervisory office and the mutual indemnity association. When operating lasers of these classes, the laser area must be cordoned off and marked. Additionally, owner/operators of laser equipment classes 3R 3B and 4 must appoint an expert as the laser protection officer. Staff operating laser equipment classes 1M, 2, 2M, 3R, 3B or 4, or who have access to the laser area of laser classes 3R, 3B and 4, must be instructed in the effects of laser radiation and required protective measures. The owner/operator must provide suitable laser goggles, protective clothing and protective gloves for operations with laser equipment classes 3R, 3B and 4. The owner/operator is also responsible for compliance with the special safety requirements for operating various laser types.