Laser Safety Manual

10 Laser Safety Manual Lasers used as pointers in classrooms and auditoriums at Iowa State University are restricted and must not be rated higher than Class 3R. Class 3B Lasers Class 3B laser systems may be hazardous under direct and specular reflection viewing conditions, but are normally not a diffuse reflection or fire hazard. Class 3B continuous wave lasers are ultraviolet, infrared, or visible laser systems with power levels of 5 mW to 500 mW but cannot emit an average radiant power greater than 500 mW for more than 0.25 s or cannot produce a radiant energy greater than 0.125 J (joules) for an exposure lasting less than 0.25 s. Class 3B pulsed lasers are visible or near infrared systems with power levels of 5 mW to 500 mW but cannot emit an average radiant power greater than 500 mW for longer than 0.25 s or cannot produce a radiant energy greater than 0.03 J per pulse. These lasers bear a sign warning against direct exposure to the beam. Specific control measures covered in Class 3B lasers shall be used in areas where entry by unauthorized personnel can be controlled. Entry into the area by personnel untrained in laser safety may be permitted if accompanied by the laser operator, instructed in applicable safety requirements prior to entry, and provided with appropriate protective eye wear. Class 4 Lasers Class 4 lasers are systems with power levels greater than 500 mW. These laser systems are a hazard to the eye or skin from the direct beam and may pose a diffuse reflection or fire hazard. They may also produce laser-generated air contaminants (LGACs) and hazardous plasma radiation. These lasers/laser systems shall bear signs warning against eye and skin exposure from direct or scattered radiation. Lasers Classified Under Previous Standards There is no requirement to reassess lasers that were previously classified. Products that were previously in Class 1 remain in Class 1. Laser products previously classified as Class 3A are now Class 3R unless the emergent beam diameter exceeds 7 mm, in which case they could be Class 1M or 2M. The reclassification of a laser by the LSO may provide regulatory relief in labeling and signage.