Laser Safety

Purpose of this Program: To increase awareness in laser safety

History American National Standard for Safe Use of Lasers Z136.1-2000 (ANSI Z136.1-2000) American National Standard for Safe Use of Lasers in Education Institutions (ANSI Z136.5-2000)

Program Outline What is a laser? Laser Incidents/Accidents Laser hazards – Eye, Skin, Chemical and Electrical Hazards Safety Guidelines/Controls

What is a laser? – Block Diagram

What is a laser? LASER- Light Amplification by Stimulated Emission of Radiation Laser light differs from ordinary light in 3 ways: Monochromatic Directional Coherent Lasers can pose more of a hazard than ordinary light because the can focus a lot of energy onto a small area

Laser Accidents The times when accidents happen: During alignment During maintenance Under stress or pressure When tired Failure to pay attention to work

Laser Accidents by Percentage Activities Non beam In use exposure Incorrect eyewear Alignment

Exposure Incidents If the incident causes injury or could potentially have caused injury, the person or persons who have received an exposure should inform their supervisor who should call 9-911 immediately University Safety and Assurances will assist in an investigation of the accident

Laser Classifications Class 1 – Exempt lasers or laser systems that cannot, under normal operation conditions, produce a hazard Example: Compact disc player

Laser Classifications Class 2 – Low power visible lasers or lasers systems which, because of normal human aversion responses, do not normally present a hazard, but may present some potential for hazard if viewed directly for extended periods of time Example – most alignment lasers should be Class 2

Laser Classifications Class 3a – A laser that normally would not produce a hazard if viewed for only momentary periods with the unaided eye. Example – HeNe up to 5 mW total power

Laser Classifications Class 3b – Lasers or laser systems that can produce a hazard if viewed directly. Example – HeNe from 5 mW up to 500 mW total power

Laser Classifications Class 4 – Lasers that can produce a hazard not only from direct reflection, but also from diffuse reflection. In addition such lasers may produce fire hazards and skin hazards Example – High power Argon Ion lasers

Laser Exposure Limits -- Terms MPE (Maximum Permissible Exposure) The highest laser energy to which the eye or skin can be exposed for a given laser NHZ (Nominal Hazard Zone) Area within which the MPE is equal to or exceeded

Laser Hazard – Nature of Light The output of the laser will help to determine its interaction with a target. The greater the power, the more energy that will be delivered to the target and the greater the possibility of injury.

Laser Hazard – Eye

Laser Hazard – Eye Both acute and chronic exposure Corneal, optical nerve, retinal injury, lens damage Vision damage is usually severe and may result in blindness Direct viewing of the laser source and its reflections should be avoided Eye tissues are susceptible to various forms of laser radiation and should be protected by appropriate eye protection

Laser Hazard – Skin Burns, skin cancer, and acceleration of skin aging are possible from exposure to laser radiation Chronic exposure can cause increased pigmentation Photosensitive reactions may occur

Laser Hazard – Hazardous Materials Reaction induced by lasers can release hazardous particulate and gaseous products Ignition of gases or fumes from the laser Engineering controls (i.e. ventilation) should be used All hazardous materials must be properly used, stored and controlled Obtain MSDS for all materials Wear lab coat, eye protection and gloves

Laser Hazard – Dyes and Solutions Vary greatly in toxicity Some are flammable All dyes must be treated as hazardous chemicals Obtain MSDS for all dyes and solvents Use and store all dyes and solvents in accordance with the University’s Chemical Hygiene Plan Wear lab coat, eye protection and gloves

Laser Hazard – Electrical Hazards Lethal electrical hazards are particularly present when high-power laser systems are used Fire Hazard

Precautions for all lasers in Preventing Electrical Shock Learn CPR rescue procedures for high voltage shock Avoid wearing rings, metallic watchbands and other metallic objects When possible, use only one hand in working on a circuit or control device Never handle electrical equipment when hands, feet or body are wet, perspiring or when standing on wet floor

General Safety Practices While Working Wear appropriate protective eyewear Use minimum power/energy required for project Enclose beam as much as possible Reduce laser output with shutters/attenuators Terminate laser beam with beam trap Use diffuse reflective screens, remote viewing systems, etc., during alignment if possible Remove unnecessary objects from vicinity of laser Locate beam at waist level or below. Keep beam path away from eye level (sitting or standing) Don’t put your body parts (particularly your eyes) in the beam path!

Great Housekeeping

Overview of Safety Controls for Class 3b and 4 lasers Registration – Complete on-line form Laser Classifications Training of operators and personnel working on or near lasers Periodic safety inspections Access Restrictions Posting and labeling Medical Monitoring Protective eyewear and clothing Administrative/Engineering Controls

Training of operators and personnel working on or near lasers Required for all Class 3b and 4 users. Complete on-line training course, read manual, and complete and submit on-line exam

Laser Audits Periodic Safety Inspections Laser Audit Form

Access Restrictions Only allow trained individuals, wearing appropriate personal protective equipment, into the Nominal Hazard Zone

Medical Monitoring All Class 3b and 4 laser users must receive a baseline eye exam prior to using lasers and laser systems

Access Restriction Master Switch – Class 3b and 4 lasers must have a master switch that is controlled by a key or coded access. Access by key or code must only be provided to trained operators Interlocked Entry or laser barrier screen/curtain Posting and labeling of rooms and equipment, to include a warning light in the hallway or access entrance

PPE Control Measures Appropriate eyewear Eyewear must be for the appropriate laser wavelength, attenuate the beam to safe levels, yet be comfortable enough to wear Gloves Special Clothing

Administrative Safety Practices Standard operating procedures Authorized personnel only in vicinity of laser (Access Restriction) Designate NHZ for Class 3b and 4 lasers Address non-beam hazards

Standard Operating Procedures All Class 3b and 4 lasers are to have written Standard Operating Procedures (SOP). SOP’s will contain the following information: System Information (description, location, class) General Information (equipment owner, inventory control Operating procedures Alignment Procedures

Standard Operating Procedures (continued) Maintenance/services procedures Hazards Summary (beam, non-beam) The nominal hazard zone (NHZ) for the above procedures Required Control Measures (access controls, system controls, personnel controls, emergency instructions) Protective eyewear and other personal protective equipment

Nominal Hazard Zone

Engineering Safety Practices Beam enclosures whenever practical. This will significantly reduce the need for other engineering or administrative controls Activation warning system outside the control area Window and door barriers (typically curtains at the doorways) Ventilation Panic button

Curtains

Ventilation Local or other exhaust ventilation may be needed depending upon your operation due to vapors or dusts that may be emitted.

Panic Button Panic Button (remote interlock connector) Class 4= required Class 3b= should be used

Laser Safety Signs and Labels Signs & Labels

Illuminated Sign

Notice – Laser Alignment/Repair

Class 2 – Caution

Class 3a -- Caution

Class 3a -- Danger

Class 3b -- Danger

Resource Laser Institute of America (LIA) Phone: 1.800.34.LASER Email: lia@laserinstitute.org Web: www.laserinstitute.org LIA guide for the selection of laser eye protection (78 pages)

For additional information: Click to view these resources: Laser Safety Web Page Laser Safety Manual UWM Laser Safety Officer Phone: 229-5808

Acknowledgements Some photos courtesy of Samuel M. Goldwasser, Drexel University