© Imperial College LondonPage 1 Laser Safety Dr Fred Carleton Laser Safety Supervisor

© Imperial College LondonPage 2 Laser Safety Class 1 –MPE less than 7 microwatts of visible radiation –Considered “safe” under reasonably foreseeable conditions of operation and they present no hazard to the eye or skin –Includes systems which cannot emit hazardous levels of radiation because of the design –Note : the system may contain a more hazardous laser and additional precautions may be necessary if it is opened up

© Imperial College LondonPage 3 Laser Safety Class 2 –MPE less than 1mW of visible radiation –Only emits visible radiation –Momentary viewing by the eye is protected by the “blink reflex” –Intentional extended viewing is considered hazardous

© Imperial College LondonPage 4 Laser Safety Class 3A –MPE less than 5 mW visible and less than 25 mW/m 2 –Safe for accidental viewing, the “blink reflex” will provide protection –Viewing or accidental exposure using an optical aid is dangerous

© Imperial College LondonPage 5 Laser Safety Class 3B –Less than 500 mW of visible radiation –Also covers pulsed lasers and invisible radiation –Direct intra-beam viewing is always hazardous –Viewing diffuse reflections from a distance is normally safe if exposure is less than 10 seconds

© Imperial College LondonPage 6 Laser Safety Class 4 –More than 500mW of visible radiation –Capable of producing hazardous diffuse reflections –May cause skin injuries and also constitute a fire hazard