Laser Safety Presentation David Baer – Former Laser Safety Officer Centre for Lasers & Applications Macquarie University - April 2004.

Laser Safety Presentation

David Baer – Former Laser Safety OfficerCentre for Lasers & Applications Macquarie University - April 2004

Plan your experiment Source correct optics and mounting

hardware Map out beam paths Do the Laser Safety Calculations

The First Step in Laser Safety

The Old Classification System

Ap

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imits for

CW

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Class 4Unsafe for eyes

Unsafe for skin

0.5 W Class 3B Unsafe for eyes

Generally safe for skin

5 mW Class 3A Safe with (0.25 s.) aversion response no viewing aids

1 mW Class 2Visible wavelengths only

Safe with (0.25 s.) aversion response including viewing aids

220μW to 0.4μW

Class 1 No precautions required

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CW

Visible

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Class 4Unsafe for eyes

Unsafe for skin

500mW Class 3B Unsafe for eyes

Generally safe for skin

5mW Class 3R Safe with (0.25 s.) aversion response no viewing aids

5mW Class 2MVisible wavelengths only

Safe with no viewing aids

1mW Class 2Visible wavelengths only

Safe with (0.25 s.) aversion response including viewing aids

1mW Class 1M Safe with no viewing aids

39μW to 390μW

(depending on λ)

Class 1 No precautions required

The New Classification System

Why Lasers Are Hazardous

2 Main Factors.

Collimation Effects : More light can be introduced into the eyes compared to other light sources.

Spot Size Effects : Radiation in the 400 – 1400nm region is brought to a sharp focus on the retina. This can increase the radiant exposure (irradiance) by approx 100,000 times.

To Determine the Laser Hazard

6 main factors need to be taken Consideration.

Wavelength

CW or Pulsed Operation

Power or Pulse Energy

Repetition Rate (PRF)

Beam Diameter & Profile

Beam Divergence

Eye Effects Video

Please follow the link on the Laser Safety web site to watch a video on laser radiation effects on the eye (46 MB, 5 min).

From Laser Safety Video from Uni. of Southampton.

Laser Effects on Eyes and Skin

Lasers Safety Precautions

Class 1 & 1M Lasers : - No Precautions

Class 2 & 2M Lasers : - No Staring

Class 3R Lasers : - No Staring

(also old Class 3A lasers) - No Magnifiers

Lasers Safety Precautions

Class 3B & - Avoid Exposure

Class 4 Lasers : - Know the NOHD

- Controlled Area

- Use Beam Stops

- Diffuse Reflections Hazardous

- Use Eye Protection

- Interlocks Required

- Chemical / Electrical hazards

Laser Safety @ the Faculty of Science

Majority of lasers are High Power Class IV Lasers Research lasers may have many wavelengths

Laser, Chemical and Electrical safety procedures must be followed

No Laser maintenance after hours

Laser Safety Video

Please follow the link on the Laser Safety web page to

watch a Laser Safety Video presentation from the Laser

Institute of America (230MB, ~30 min).

Visit the LIA websites – valuable information on lasers

and safety is available here.

www.lasersafety.org

www.laserinstitute.org

General Laboratory Safety

Clothing: No watches & rings. Long sleeve clothing encouraged. Wear enclosed footwear in labs.

Tripping hazards: cables, equipment on floors. Use cable trays whenever possible.

Housekeeping: When finished with equipment, put it away. If equipment is broken, get it fixed (see your supervisor).

General Laser Lab Safety Never directly view a laser beam.

Never remove covers from equipment without approval from supervisors – laser, high voltages and other hazards are present.

Although no deaths have been recorded from laser beam exposure, a number of people have been killed by Laser HV Excitation circuits.

Familiarise yourselves with the Australian laser safety standard (present in most labs) and the MSDS folders regarding chemicals and materials you use. If relevant MSDSs are missing inform your Supervisor.

Optical – Research Lasers Research Lasers

present additional dangers Multiple wavelengths –

complicates selection of laser eyewear

No Aperture stickers – be aware of beam paths

Optical – Table Hardware

Avoid the use of periscopes, keep laser beams in the one horizontal plane on optical tables. (A researcher at a university was permanently blinded aligning a periscope)

Never use horizontal beam posts. (if a mirror is knocked, it can deflect a beam off the horizontal plane)

Optical – Laser Monitoring Use alignment jigs and attenuators during set

up

Consider using remote monitoring (cameras, laser beam analysers, fluorescent crystals and cards)

Optical – Laser Labs

No line of sight between optical tables and hallways. (use internal partitions and optical barriers on tables)

STAGED

Optical – Laser Labs A labyrinth style entryway into labs, giving a safe

area to put on safety equipment (PPE).

A storage rack for laser safety eyewear (labeled with wavelengths etc).

Laser Generated Air Contaminants

Machining polymers can release acidic and carcinogenic by-products

Familiarise yourself with any potential by-products

Consult MSDS, reference books and supervisors

Use adequate extraction

Other Lab Hazards - Chemical

Laser dyes – most dyes are carcinogenic

Insulation Materials – Dusts, Fibres (Wear Masks)

Optical Fibers – Eye hazards

Solvents – flammability

Other Lab Hazards - Electrical High voltages – Always ensure covers are in place. 240 v – No uninsulated connections permitted. Use removable insulated covers on experimental

circuits. Don’t leave live circuits unattended. Safety Concerns - Contact Greg Yates from METS.

Other Lab Hazards - Gases Vacuum system – implosion issues with glass

vessels. Safety glasses must be worn.

Compressed gases – toxicity, flammability and asphyxiation hazards.

Other Lab Hazards - Cryogenic

Liquid nitrogen – burns and asphyxiation hazards.

Liquid N2 can condense O2 from the atmosphere and may cause an explosion.

Ensure you have been trained in the correct way to handle liquid N2.

Do not accompany full Liquid N2 Dewars in Lifts.

Other Lab Hazards - Combinations

High Volts and Solvents/ Oils – Fire risk.

High Voltages and Water – Electric shock.

High Voltage40 kV

Water Cooling

Insulation Materials

Oil Cooling(Hot Oil)

Laser Beam200W

Vacuum System

High Temp 800C

Ionising Radiation from Thyratron

Toxic Gases

UV from Discharge

Plan your experiment Source correct optics and mounting

hardware Map out beam paths Do the Laser Safety Calculations

The First Step in Laser Safety

Conclusion

Always wear correct Laser Safety Glasses

Consider all the implications of your project.

Always think what your doing.

Report any lab problems or concerns to your supervisor and/or Susan Law (E7B-351, x8126).

Updated Jan 2010