Safety and Maintenance • Laser Safety • 9
Laser Classes
Class 2M laser components
Class 2M laser components would not cause
permanent damage to the eye under
reasonably foreseeable conditions of operation,
provided that any exposure can be terminated
by the blink reflex (assumed to take 0.25
seconds). Because classification assumes the
blink reflex, the wavelength of light must be in
the visible range (400 nm to 700 nm). The
Maximum Permissible Exposure (MPE) for
visible radiation for 0.25 seconds is 25 watts per
square meter, which is equivalent to 1 mW
entering an aperture of 7 mm diameter (the
assumed size of the pupil).
Class 3R laser components
Class 3R laser products emit radiation where
direct intrabeam viewing is potentially
hazardous, but the risk is lower with 3R lasers
than for 3B lasers. Fewer manufacturing
requirements and control measures for 3R laser
users apply than for 3B lasers.
Class 3B laser components
Class 3B components are unsafe for eye
exposure. Usually only ocular protection will be
required. Diffuse reflections are safe if viewed
for less than 10 seconds.
Labels reprinted here are examples only. For accurate specifications, refer to the label on your
sensor.
Precautions and Responsibilities
Precautions specified in IEC 60825-1 and FDA CFR Title 21 Part 1040 are as follows:
Requirement Class 2M Class 3R Class 3B
Remote interlock Not required Not required Required*
Key control Not required Not required Required – cannot remove
key when in use*
Power-on delays Not required Not required Required*
