FOCUS ON LASERS Philip Campbell RADIATION SAFETY: Principles, Practice, and Emerging Issues March 2018
DISCLAIMER This is a very basic training on laser safety. This training will not provide enough information to be an Laser Safety Officer. 2
TOPICS Laser Basics Hazards Biological Effects Non-beam Hazards Laser Classifications Control Measures 3
LASER BASICS 4
LASER BASICS 5
LASER BASICS 6
LASER BASICS Continuous Wave (CW) - 0.25 seconds Pulsed - <0.25 seconds Q-switch produces very short intense laser pulses (~10 to 250 ns) 7
BIOLOGICAL EFFECTS The wavelength will determine which part(s) of eye are damaged 8
Photochemical effect Retinal Damage Not Eye Safe Heating Surface of the Eye (thermal effects) Nd:YAG CO 2 UV-B/C UV-A Visible IR-A IR-B IR-C Photo-keratitis, cataract Retinal damage Corneal burns Erythema (sunburn) Accelerated skin ageing Pigmentation Cataracts Skin burn reflected off a mirror. Permanent vision damage
BIOLOGICAL EFFECTS Burn similar to thermal and solar burns 10
REFLECTION HAZARDS 11
NON-BEAM HAZARDS Electrical Non-Laser Radiation Fire Chemicals/air contaminants Human Factors
LASER CLASSIFICATION All wavelengths Incapable of causing injury during normal operation Low power or enclosed beam May be higher class during maintenance or service Class 1M may be hazardous when viewed with collecting optics Nd:YAG Laser Marker 13
LASER CLASSIFICATION Visible lasers only Staring into beam is eye hazard Eye protected by aversion response (blink reflex) Laser Scanners Class 2M may be hazardous when viewed with collecting optics Laser Radiation Do Not Stare Into Beam Helium Neon Laser 1 milliwatt max/cw CLASS II LASER PRODUCT 14
LASER CLASSIFICATION All wavelengths Potentially hazardous under some direct and specular viewing conditions Probability of actual injury is small Aversion response may not provide adequate protection Reduced control requirements Laser Pointers Small Beam (Class 3R) 15
LASER CLASSIFICATION All wavelengths May be hazardous under direct or specular viewing conditions Normally not a hazard for Fire Diffuse reflection Laser generated air contaminant (LGAC) 16
LASER CLASSIFICATION All wavelengths Hazard to eye or skin from direct beam May be a hazard for Fire Diffuse reflection Laser generated air contaminant (LGAC) Plasma radiation 17
CONTROL MEASURES 18
HIERARCHY OF CONTROLS 19
CONTROL MEASURES Emergency Shutoff Interlock Key Protective housing Labels 20
CONTROL MEASURES Nominal Hazard Zone Area in which the direct, reflected or scattered radiation may exceed permissible exposure levels without PPE Access Control Barriers Warning devices and signs Safety Interlocks Location of controls 21
CONTROL MEASURES 22
CONTROL MEASURES Visible and/or audible Inside and outside controlled area 23
CONTROL MEASURES Enclosed Beam Path/Protective Housing Beam Attenuators/blocks/traps Additional Safety Interlocks Barriers/Curtains Window Protection 24
CONTROL MEASURES Documented Safety Program with defined responsibilities Standard Operating Procedures (SOPs) Alignment procedures Output emission limits Education and Training Authorized personnel Key Control Service Personnel 25
LASER SAFETY TRAINING Fundamentals of laser operation Biological effects of laser radiation on the eye and skin Significance of specular and diffuse reflections Non-beam hazards of lasers Laser and laser system classifications Control measures Overall responsibility of management and employee Consider awareness training for other laser classes 26
CONTROL MEASURES Optical Density (OD) measure of the transmittance of the wavelength of interest 27
REFERENCES ANSI Z136.1 2014 American National Standard for the Safe Use of Lasers ANSI Z136.3 2011 American National Standard for the Safe Use of Lasers in Health Care ANSI Z136.5 2009 American National Standard for the Safe Use of Lasers in Educational Institutions 28
REFERENCES ANSI Z136.6 2005 American National Standard for the Safe Use of Lasers Outdoors ANSI Z136.8 2012 American National Standard for the Safe Use of Lasers in Research, Development, or Testing ANSI Z136.9 2013 American National Standard for the Safe Use of Lasers in Manufacturing Environments 29