ucsd eh&s laser safety. topics laser safety program / responsibilities laser classifications and...

UCSDEH&S

Laser Safety

Topics

• Laser Safety Program / Responsibilities

• Laser classifications and light properties

• Engineering controls / administrative controls

• Laser exposures / biological effects

Laser Safety Program

• American National Standard for the Safe Use of Lasers (ANSI Z136.1)

• Cal OSHA• Laser Safety Information

– http://blink.ucsd.edu/go/lasersafety

PI Responsibility

• Principal Investigator– Overall Responsibility– Ensure Safety – Ensure Compliance– Notify EH&S as necessary

General Users Responsibility

• Attend training• Wear proper protective equipment• Follow laser standard operating

procedures• Ensure all laser engineering and

administrative controls are in place• Ensure room security to laser area• Notify EH&S as necessary

Laser Use Authorization (LUA)

Laser Use Authorization (LUA)

DocumentationLUA Amendment

• http://blink.ucsd.edu/go/lasersafety

• Laser Use Authorization Application(LUA)• Laser User Enrollment Form• Laser Equipment Registration Form• Standard Operating Procedure Template• LUA Amendment

DocumentationLUA Amendment

• Annual audits– Engineering controls– Administrative controls– Personal protective equipment– Training– Follow up on previous violations

• LUA annual renewal

Audits

Laser Classifications

• Four laser classes– Class 1, 2, 3a, 3B, and 4– Classifications are based on the laser’s

capability of injuring personnel.– Classified according to its accessible laser

radiation during operation.• Worldwide classification scheme

– Class 1M, 2M, and 3R

Laser Classifications

• Class 1 &1M– Incapable of causing

injury, unless viewed with optical instrument (eye-loupe/telescope)

– Exempt from control measures other than to prevent optically aided viewing.

Laser Classifications

• Class 2 & 2M• Visible spectrum

(400-700nm)• Not exceeding

accessible power of 1mW

• Human aversion response, 0.25 second– Not safe for viewing

more than 0.25 second

– Potentially hazardous if viewed with certain optical aids.

Laser Classifications

• Class 3R formerly 3a• Between 1 - 5mW• Visible or invisible

Laser Classifications

• Class 3B• Direct beam hazard

and specular reflection hazard

• Operates at any wavelength

• Max average power of 500mW

Laser Classifications

• Class 4• All hazards of class

3B• Diffuse reflection

hazard• Fire hazard• Average power

exceeds 500mW

Laser Light Properties

• Monochromatic

• Directional• Coherent

– The combination of these three properties allows laser light to be focused 100 times better than ordinary light.

Beam Types

• Continuous (CW)– Constant

power– Higher

average power

• Pulsed– High peak

power– Generally

more hazardous

Beam Types

Control Measures

• Control measures– Engineering– Administrative– Personal Protective

Equipment

Engineering Controls

• Engineering control– Laser Curtain– Beam enclosures– Beam blocks– Interlocks

• Beam Blocks– Durability– Reflectivity– Combustibility– Optical density

• What effect will the wavelength have on the material?

Engineering Controls

Engineering Controls

Engineering Controls

Engineering Controls

Engineering Controls

Engineering Controls

Fiber Optic

• Fiber optics used to transmit class3B and 4 laser should be treated as a laser of that power

• Cap off fiber when not in use• Do not look at fiber end while laser is on• Cutting and trimming strands

– Glass/plastic fragments– Chemical cleaners– Wear gloves/safety glasses– Work in well ventilate area

Administrative Controls

• General Laser Safety Training– System Specific Laser Safety Training

• Laser Warning Signs• Emergency Procedures• Standard Operating Procedures

Administrative Controls

• Warning signs– Design specific to

ANSI standards– Type of laser– Power output– Wavelength

Administrative Controls

• Emergency Procedures– Posted inside the

laser controlled area– Emergency numbers

for laser injuries– Incident reporting

Administrative Controls

• Standard operating procedures (SOP)– Required for class 4

lasers– Beam alignment– Laser controlled area– Non-beam hazards– Laser maintenance– Training

requirements– Emergency

procedures– Additional safety

measures– Signatures

Laser Eyewear

• Optical density– Visible light

transmission• Wavelength• Exposure time• Comfort and fit• Femtoseconds

rated goggles

Laser Eyewear

Laser Eyewear

Laser Eyewear

• If you have a laser operating at 633nm with an optical density requirement of 1.5. What is the best optical density?

• OD = 1 at 633nm and 4 at 400nm• OD = 2 at 633nm and 5 at 190-

380nm• OD = 2 at 633nm and 4 at 400-

550nm

Laser Eyewear

• Most critical for laser hazards– The lens

concentrates light up to 100,000 times at 400-1400 nm

– If irradiance entering the eye is 1 mW/cm2 the irradiance at the retina will be 100 W/cm2

Ancillary Hazards

• Ancillary hazards– Electrical – Fire– Compressed gases– Laser dye and

solvents– Laser Generated

Air Contaminants (LGAC)

– Trip hazards

Laser Exposures

MPE / NHZ

• MPE (maximum permissible exposure) - The level of laser radiation to which a person may be exposed to without adverse biological effects in the eye

or skin.• NHZ (nominal hazard zone) – The

distance which the level of direct, reflected or diffuse laser radiation exceeds the MPE.

MPE

• Wavelength• Power / Energy of

laser• Exposure duration

• HeNe laser– 10mW at 633nm– Exposure time = 0.25

Sec– MPE = 2.55E-3 W/cm2 – Irradiance at eye =

2.60E-2 W/cm2

– 10.20 time the MPE– Intrabeam NHZ = 30

meters

Laser Exposures

• Alignment• Not using laser eyewear or wearing improper

eyewear for the wavelength being used• Inadequate training of laser personnel• Stray reflections off badges, jewelry…• Failure to follow approved standard operating

procedures• Failure to contain laser beams• Taking short cuts, rushing the job, fatigue,

illness…

Laser Exposures

• Hazardous acts – beam alignment– Failure to wear eye

protection– Wearing inappropriate

eyewear– Wearing watches,

rings…during alignment

– Elevating (vertical) beams

– Stray beams– Using high power beam

Laser Accident

• Turn off the laser• Inform PI and EH&S• UCSD employee contact

Occupational Medicine Clinic 858-657-1600

• Students contact Student Health Service 858 -534-3300

• Not sure of employment status 858-534-2454

• File an incident report• Do not modify the laser

system

Biological Effects

Wavelength Eye SkinUV-C (180 - 280 nm)

Corneal burn Accelerated skin aging, sunburn, skin cancer

UV-B (280 – 315 nm)

Corneal burn Increased pigmentation

UV-A(315 – 400 nm)

Cataract Pigment darkening, skin burn

Biological Effects

• Commercial sun block is designed for UV that penetrates the ozone layer.– Common wavelength

that can penetrate sun block

– 157, 193, 254, 266 nm

Biological Effects

Visible (400-780 nm)

Photochemical and thermal retinal injury

Pigment darkening, photosensitive reactions, skin burn

IR-A (780-1400 nm)

Cataract through thermal burn, retinal burn

Skin burn

IR-B (1400-3000 nm)

Corneal burn Skin burn

IR-C (3.0 um – 1 mm)

Corneal burn Skin burn

Biological Effects

Biological Effects

• Most hazardous retinal region.– Invisible– Eyes do not react to

invisible spectrum– Energy still deposits onto

the retina– Most common is the

Nd:YAG at 1064nm

Biological Effects

Staying In Compliance

• Principal investigators (PIs) with class 3b or 4 lasers or laser systems must have a Laser Use Authorization (LUA).

• All users must have the appropriate UCSD laser safety training.

• All class 3B and class 4 lasers must be registered with EH&S.

• Have the proper engineering and administrative controls in place .

Staying In Compliance

• Personal Protective Equipment– Laser safety eyewear– Long sleeve clothing & face shield if required

(UV)• Security into the laser controlled area• Who has primary responsibility for laser

safety anytime a laser is operated?– The person operating the laser always has the

primary responsibility for all hazards associated with laser use.

Review Laser Safety

1.What standard is the laser safety program based on?

A. The guide to common senseB. The ANSI Z136.1C. California Code of RegulationsD. Code of Federal Regulation

B. The ANSI Z136.1

Review Laser Safety

2.Laser pointers can potentially be hazardous to the eyes?

A. TrueB. False

A. True

Review Laser Safety

3.When is the most hazardous moment in laser operation?

A. Day to day operationB. Setting up new opticsC. AlignmentD. Turning the laser on

C. Alignment

Review Laser Safety

4. What should be considered when choosing beam blocks?

A. DurabilityB. ReflectivityC. Optical densityD. All of the above

D. All of the above

Review Laser Safety

5.Which is not safe laser practice?

A. Wearing normal lab safety glasses for laser operation

B. Not following SOPC. Peeking through laser gogglesD. All of the above

D. All of the above

Review Laser Safety

6.I don’t need laser eyewear, I am standing across the room.

A. TrueB. False

B. False

Review Laser Safety

7.Which of the following is the most appropriate laser eyewear for a 700 nm laser with a minimal optical density (OD) of 4?

A. 600-800 nm OD 7B. 532-600 nm OD 3C. 600-800 nm OD 3D. 650-750 nm OD 5

D. 650-750 nm OD 5

Review Laser Safety

8. What is the first this you should do in an event of a laser incident?

A. Continue working using the other good eye

B. Call for helpC. Turn off the laser system immediatelyD. Contact the PI

C. Turn off the laser system immediately

Review Laser Safety

9.Which wavelength range is the most hazardous retinal region?

A. 400-700 nmB. 700-1400 nmC. 200-400 nm D. 1500-3000 nm

B. 700-1400 nm

Review Laser Safety

10. Who has primary responsibility for laser safety anytime a laser is operated?

A. The PIB. The laser operatorC. EH&SD. The new guy

B. The laser operator

EH&SLaser Safety

http://blink.ucsd.edu/go/lasersafety

Trung Let16le@ucsd.edu

858-822-2850