640 likes | 860 Vues
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)
E N D
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
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
Audits • Annual audits • Engineering controls • Administrative controls • Personal protective equipment • Training • Follow up on previous violations • LUA annual renewal
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
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?
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 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
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
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 Exposures
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 • 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 • 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