FOCUS ON LASERS
Philip Campbell
RADIATION SAFETY: Principles, Practice, and Emerging Issues
March 2018
This is a very basic training on laser safety. This training will not provide enough information to be an Laser Safety Officer.
DISCLAIMER
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• Laser Basics
• Hazards– Biological Effects
– Non-beam Hazards
• Laser Classifications
• Control Measures
TOPICS
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LASER BASICS
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LASER BASICS
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LASER BASICS
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• Continuous Wave (CW) - ≥ 0.25 seconds
• Pulsed - <0.25 seconds– Q-switch – produces very short intense laser pulses (~10 to 250 ns)
LASER BASICS
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BIOLOGICAL EFFECTS
The wavelength will determine which part(s) of eye are damaged
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Nd:YAGCO2
UV-B/C UV-A Visible IR-A IR-B IR-C
Photo-keratitis, cataract
Erythema (sunburn)Accelerated skin ageing
Pigmentation
Retinal damage Corneal burns
Cataracts
Skin burn
Photochemical effect Retinal Damage Not “Eye Safe” Heating Surface of the Eye (thermal effects)
reflected off a
mirror. Permanent
vision damage
BIOLOGICAL EFFECTS
Burn similar to thermal and solar burns
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REFLECTION HAZARDS
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NON-BEAM HAZARDS
• Electrical
• Non-Laser Radiation
• Fire
• Chemicals/air contaminants
• Human Factors
LASER CLASSIFICATION
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Nd:YAG Laser Marker
• 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
LASER CLASSIFICATION
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• Visible lasers only– Staring into beam is eye hazard
• Eye protected by aversion response (blink reflex)
Class 2M – may be hazardous when viewed with collecting optics
CLASS II LASER PRODUCT
Laser RadiationDo Not Stare Into Beam
Helium Neon Laser1 milliwatt max/cw
Laser Scanners
LASER CLASSIFICATION
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• 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)
LASER CLASSIFICATION
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• All wavelengths
• May be hazardous under direct or specular viewing conditions
• Normally not a hazard for– Fire
– Diffuse reflection
– Laser generated air contaminant (LGAC)
LASER CLASSIFICATION
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• 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
CONTROL MEASURES
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HIERARCHY OF CONTROLS
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CONTROL MEASURES
• Emergency Shutoff
• Interlock
• Key
• Protective housing
• Labels
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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
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CONTROL MEASURES
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CONTROL MEASURES
• Visible and/or audible
• Inside and outside controlled area
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CONTROL MEASURES
• Enclosed Beam Path/Protective Housing
• Beam Attenuators/blocks/traps
• Additional Safety Interlocks
• Barriers/Curtains
• Window Protection
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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
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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
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CONTROL MEASURES
• Optical Density (OD) – measure of the transmittance of the wavelength of interest
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• 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
REFERENCES
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• 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
REFERENCES
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