UCSD EH&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 –

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)

Documentation LUA Amendment

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

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

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 nm OD = 2 at 633nm and 4 at nm

Laser Eyewear Most critical for laser hazards –The lens concentrates light up to 100,000 times at nm –If irradiance entering the eye is 1 mW/cm 2 the irradiance at the retina will be 100 W/cm 2

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/cm 2 –Irradiance at eye = 2.60E-2 W/cm 2 –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 Students contact Student Health Service Not sure of employment status File an incident report Do not modify the laser system

Biological Effects WavelengthEyeSkin UV-C ( nm) Corneal burnAccelerated skin aging, sunburn, skin cancer UV-B (280 – 315 nm) Corneal burnIncreased pigmentation UV-A (315 – 400 nm) CataractPigment 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 ( nm) Photochemical and thermal retinal injury Pigment darkening, photosensitive reactions, skin burn IR-A ( nm) Cataract through thermal burn, retinal burn Skin burn IR-B ( nm) Corneal burnSkin burn IR-C (3.0 um – 1 mm) Corneal burnSkin burn

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 sense B.The ANSI Z136.1 C.California Code of Regulations D.Code of Federal Regulation B. The ANSI Z136.1

Review Laser Safety 2.Laser pointers can potentially be hazardous to the eyes? A.True B.False A. True

Review Laser Safety 3.When is the most hazardous moment in laser operation? A.Day to day operation B.Setting up new optics C.Alignment D.Turning the laser on C. Alignment

Review Laser Safety 4.What should be considered when choosing beam blocks? A.Durability B.Reflectivity C.Optical density 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 SOP C.Peeking through laser goggles D.All of the above

Review Laser Safety 6.I don’t need laser eyewear, I am standing across the room. A.True 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 nm OD 7 B nm OD 3 C nm OD 3 D 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 help C.Turn off the laser system immediately D.Contact the PI C. Turn off the laser system immediately

Review Laser Safety 9.Which wavelength range is the most hazardous retinal region? A nm B nm C nm D nm B nm

Review Laser Safety 10. Who has primary responsibility for laser safety anytime a laser is operated? A.The PI B.The laser operator C.EH&S D.The new guy B. The laser operator

EH&S Laser Safety Trung Le