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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