A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as from paper or other matte surfaces are not harmful. Continuous lasers in the wavelength range from 315 nm to far infrared are limited to 0.5 W. For pulsed lasers between 400 and 700 nm, the limit is 30 mJ. Other limits apply to other wavelengths and to ultrashort pulsed lasers. Protective eyewear is typically required where direct viewing of a class 3B laser beam may occur. Class-3B lasers must be equipped with a key switch and a safety interlock.

According to the revised ANSI Z136.1 Safe Use of Lasers, laser area warning signs should be posted around Class 3 laser areas and is required to be posted around all Class 3B and 4 laser areas. Additionally, NOTICE signs are required for Class 3B and Class 4 lasers during maintenance, servicing, and similar situations.

LIA has a laser area warning sign for any type of laser. LIA signs are 10" x 14" in size are are available in plastic material. All signs meet the ANSI Z136.1 requirement for laser safety and can be customized with your laser's specifications and warning statements for only $5.00 per sign.