RADIOLOGICAL AND ENVIRONMENTAL MANAGEMENT

PURDUE UNIVERSITY

Laser Safety Retraining

Updated: 09/2012

Laser Safety Program

When using a Class 3B or Class 4 laser, potential hazards from the direct beam exist to the eye and skin.

Purdue Executive Memorandum D-2 mandates the use of Class 3B and Class 4 lasers to be compliant with the Purdue Laser Safety Program.

Each laser project must complete the necessary paperwork, meet the training requirements, and be evaluated by the Purdue LSO (Laser Safety Officer)

Laser Classifications

Class 1, 1M, 2, 2M, and 3R: low to lower-medium powered lasers that will not produce eye/skin injury under manufacturer-intended use, and if not intentionally focused on the eye. Lasers with one of these classifications are

exempt from the laser registration requirements of Purdue University.

Note: Class 3R was formerly known as Class 3a.If ANY laser is modified (e.g. power,

focusing, etc.), regardless of its initial classification, the LSO will need to perform an analysis to determine classification.

Laser Classifications (cont’d)

Class 3B (medium power): viewing hazard under direct or specular reflection conditions, normally not a diffuse reflection or fire hazard

Class 4 (high power): Hazard to eye or skin from the direct beam, and May be a diffuse reflection or fire hazard May also be a source of laser generated air

contaminants (LGACs) and hazardous plasma radiation.

Laser classifications are now only reported in Arabic Numerals; Roman Numerals are no longer accepted.

Required Paperwork

Each project must submit the following forms to the LSO Form LU-1: For laser project (must include SOPs) Form LF-1: For each facility used Form LS-1: For each Class 3B and 4 laser (note: a

laser cannot be approved for multiple laser projects) Form LU-2: Must be completed by the LPI (Laser

Principal Investigator) and all unrestricted personnelThese forms can be sent through campus mail

to: Jerry Gibbs/REM/CIVL It is necessary for the LSO to review the paperwork prior

to the required LSO site evaluation.

Required Training

All Restricted and Unrestricted Users on laser projects must complete Purdue’s Online Laser Safety Training. The LPI is not exempt.

Initial Training is 3-part step: Successful completion of the Online Training Attendance of the Classroom Training, unless you are a

Restricted User Laser-specific training provided by LPI or Unrestricted

User on project.Retraining (at 2-year intervals) must be

completed by all Restricted and Unrestricted Users, and is completed online.

Laser Safety Program Personnel

Restricted User: work with a Class 3B or 4 laser only under direct

physical supervision of their Laser Principal Investigator or an Authorized Unrestricted User, or

do not operate the laser, but work within the Nominal Hazard Zone (as defined by the Laser Safety Officer) of a Class 3B or 4 laser while the laser is in operation.

Unrestricted User: Has been approved by the LSO and the LPI to use the

laser without supervision Can supervise Restricted Users

Laser Safety Program Personnel

LPI (Laser Principal Investigatory) manages their own project, once it has been approved by the Purdue LSO. Must qualify as an Unrestricted User, and be a full-time permanent

Purdue faculty/staff member (e.g. cannot be a Post-Doc, Visiting Professor, etc.), and submit all required paperwork to the Purdue LSO.

There can be only 1 (one) LPI for a laser. Many projects have multiple faculty members as Unrestricted Users under the LPI.

Laser Safety Program is managed by the Purdue LSO Currently the LSO is Mary Handy, but will always be someone in

REM (Radiological and Environmental Management)Laser Safety Program is overseen by the Purdue LSC

(Laser Safety Committee). This committee is made up of representatives, mostly LPIs and

safety personnel, from multiple departments

Personnel Requirements

Laser Principal Investigator (LPI) Issue appropriate instruction and training materials

on laser hazards and their control to all personnel who may work with lasers that are operated within supervisor’s jurisdiction.

Not permit the operation of a laser unless there is adequate control of laser hazards to employees, visitors, and the general public.

Ensure all individuals working have submitted a completed LU-2 form, including LPI

Ensure LU-1 (that must be submitted to LSO) has all authorized individuals listed. Subsequent users may be listed with all required information either as an LU-1 addendum, or by written documentation to LSO.

Personnel Requirements

Laser Principal Investigator (LPI) – cont’d For any known or suspected accident relating to a laser

under his/her authority, enact appropriate response plan, which includes notification of the LSO.

If necessary, assist in obtaining appropriate medical attention for any employee involved in a laser accident.

Not permit operation of a new or modified Class 3B or Class 4 laser under his/her authority without LSO approval.

Shall submit plans for Class 3B and Class 4 laser installations/modifications of installations to the LSO for review.

Shall be familiar with the Standard Operating Procedures (SOPs) for each Class 3B and Class 4 laser under his/her authority, and ensure that that they are provided to all users of such lasers.

Personnel Requirements

Employees working with lasers Not energize or work with or near a laser unless

authorized to do so by the laser’s supervisor. Comply with Purdue University Laser Safety

Guidelines, LSO and LPI safety rules and procedures.

Inform his/her LPI of any known or suspected accident involving a laser under their LPI’s jurisdiction. If the LPI is not available, notify the LSO.

Laser Safety Regulations

OSHA (Occupational Safety and Health Act – Title 29 of the Code of Federal Regulations)

ANSI (American National Standards Institute) Z136.1 – American National Standard for the Safe Use of Lasers – NOT a regulation, BUT:

OSHA will use “General Duty Clause”, citing the ANSI Z136 standard.

If you do not have a copy of your own ANSI Z136, you may come to the LSO’s office and read the copy that is kept there.

Stuff You Need to Know

What lasers have the LSO and LPI approved you to use?Have you been trained on how to use your lasers by the

LPI, or another Unrestricted User on the your project?Where are your SOPs located? Are you following the

SOPs?Are you having laser service personnel contact LSO prior

to service on the laser(s)?Do you have records maintained (e.g. project personnel,

training records, etc.)?Do you know what type of eyewear to use with each laser?Are the keys in the key control, or computer access code

ONLY available to Unrestricted Users on the project? (e.g. keys are not left in key control on laser when not being directly supervised by an Unrestricted User)

Criteria for Exposures of Eye and Skin

Maximum Permissible Exposure (MPE) limits are below known hazardous levels.

Exposures at the MPE limit may be uncomfortable.

The LSO calculates the MPE limit for each Class 3B and Class 4 laser, upon receipt of the Form LS-1.

Mechanisms of Eye Injury

A laser can produce a beam injury to the eye through these 3 mechanisms: Thermal

Potential effects: charring, edema, hemorrhage Photochemical (blue light and UV)

Potential effects: production of toxins and biochemical changes which may cause inflammation, lesions and lens opacities

Photoacoustic (short intense pulses) Potential effects: explosive forces due to expanding gases

This is why we are required to always wear appropriate eyewear for Class 3B and Class 4 lasers, if we are in the NHZ (Nominal Hazard Zone) when the laser is in operation.

Eye Hazard vs. Wavelength

TARGET: CorneaFar IR (IRC): 3000 nm – 1 mmMid IR (IRB): 1400 nm – 3000 nmMid UV (UVB): 280 nm – 315 nmFar UV (UVC): 100 nm – 280 nm

EFFECT:Mid IR and Far IR: ThermalMid UV and Far UV: Acute inflammation and conjunctivitis, fluorescence of lens, corneal and lenticular opacities (“clouding”)cataractogenesis (peaks at 300 nm)

Eye Hazard vs. Wavelength

TARGET: RetinaNear IR (IRA) : 700 nm – 1400 nmVisible Light: 400 nm – 700 nm

EFFECT:Thermal burns, hemorrhage, scotoma (“blind spot”), photoretinitis (“blue light damage”)

Eye Hazard vs. Wavelength

TARGET: LensNear UV (UVA): 315 nm – 400 nm

EFFECT:Development of cataracts

Special Considerations for Ocular Exposures

Lower MPE limits may be required when normal protective mechanisms such as eye movement and pupil constriction are hindered. Inform your LPI if you think that you have a condition that may impact your susceptibility to the laser beam. For example, individuals who have had pupil

dilation performed will not have the natural defenses of the constricting iris which could limit that amount of radiation entering their eye.

Also, advanced age of an individual may reduce the ability of the iris to contract.

Mechanisms of Dermal Injury

A laser can produce a beam injury to the skin through these 2 mechanisms:1. Thermal (from direct beam

or specular reflection) for Near UV, Visible, and IR wavelengths

Potential effects: mild reddening (erythema) to blistering

Severity is dependent upon exposure dose rate, exposure dose, and conduction of heat away from the site of absorption

Mechanisms of Dermal Injury

A laser can produce a beam injury to the skin through these 2 mechanisms:2. Photochemical (from

scatter of beam, specular or diffuse reflection) for Mid UV and Far UV wavelengths

Potential effects: erythema to blistering, possibly carcinogenic

Effects are dependent upon wavelength and exposure dose

Specular (Mirror-Like) Diffuse

Reflected wavelength is near same shape and intensity as direct beam

Occurs when wavelength of laser beam is greater than the irregularities of the surface the beam hits

Reflected wavelength is blurred and weaker than direct beam

Occurs when wavelength of laser beam is smaller than the irregularities of the surface the beam hits

Specular vs. Diffuse Reflection

Important Notes Regarding Reflections

Avoid having objects that may produce a specular reflection in or near laser beam (e.g. jewelry, tools, computer screens, etc.), unless deliberately used as part of laser system (e.g. mirrors)

Surfaces that appear dull and pitted to our eyes may be a specular surface to beams of larger wavelengths

Non-Beam Hazards

Include physical, chemical, and biological agents, as well as human use issues.

May occur when: material is exposed to a laser beam. laser-related materials are released into the

atmosphere. Individuals contact system components. Note: the beam does not have to be on for there to

be a non-beam hazard.Written SOPs shall address non-beam

hazards, as well as beam hazards.

Non-Beam Hazards: Physical Agents

Electrical HazardsCollateral and Plasma RadiationFire HazardsExplosion HazardsMechanical Hazards Associated with

RoboticsNoise

If you need a review regarding the contributing factors and effects, please review the Initial Laser Training for Class 3B and Class 4 Lasers.

Non-Beam Hazards: Chemical Agents

Laser Generated Air Contaminants (LGACs)Compressed GasesLaser Dyes and SolventsAssist Gases

If you need a review regarding the contributing factors and effects, please review the Initial Laser Training for Class 3B and Class 4 Lasers.

Non-Beam Hazards: Chemical Agents (cont’d)

Control Measures: Engineering controls preferred Exhaust Ventilation

avoid recirculation of LGACs. use enclosing hoods, if possible.

Respiratory Protection for brief exposures or interim control measure. If used, must comply with 29 CFR 1910.134 (OSHA), and Purdue

Respiratory Protection Plan. Process Isolation

physical barriers, master-slave manipulators, or remote control apparatus. certain applications (e.g. biomedical applications) require

disinfection/sterilization of equipment after use. Sensors and Alarms

Shall be installed in hazardous gas cabinets and other locations as appropriate (including exhaust ventilation ducts).

Should be used for toxic and corrosive chemical agents (e.g. halogens), and be able to detect the hazardous gas in a mixture of emitted gases.

Must be properly shielded to minimize susceptibility to electromagnetic interference (EMI).

Non-Beam Hazards: Biological Agents

LGACs: may be generated when a high-powered lasers interacts with biological tissue.

Infectious Materials: may survive beam irradiation and become airborne.

Consult ANSI Z136.3, Appendix F.

Non-Beam Hazards: Human Factors

Ergonomics (e.g. workstation layout, worker-machine interface, handling techniques, area illumination, visual distractions)

Limited Work Space: There must be sufficient room for personnel to turn around an maneuver freely, without trip/fall hazards (e.g. wires or cables on floor).

Work Patterns: Unusual or long hours may affect worker alertness.

Disposal (i.e. donation, remove all means of activation and disposed, destruction) Laser Waste Disposal: waste disposal shall conform

with Purdue University disposal requirements (see REM’s Hazardous Material Management webpage)

Chillers

May be employed to reduce heat load produced by lasers.

Chiller types: conductivity-cooled, air-cooled, or cooled with a closed loop chiller.

If using chilled water, filter the incoming water to ensure that minerals and particulate matter are removed to minimize damage to equipment.

General Project Rules

Use minimum laser radiation required for the application.

Maintain beam height at a level other that the position of the user’s eye standing or sitting.

Prefer engineering controls, however must have administrative and procedural controls.

Accident Trends

Reported incidents related to lasers are most often associated with: Unanticipated eye exposure during alignment Misaligned optics and upwardly directed beams Available eye protection not used Equipment malfunction Improper methods of handling high voltage Intentional exposure of unprotected personnel Operators unfamiliar with laser equipment Lack of protection for non-beam hazards

Accident Trends (cont’d)

Reported incidents related to lasers are most often associated with (cont’d): Improper restoration of equipment following

service Eyewear worn not appropriate for laser in use Unanticipated eye/skin exposure during laser

usage Inhalation of laser generated air contaminants

and/or viewing laser generated plasmas Fires resulting from the ignition of materials Eye or skin injury of photochemical origin Failure to follow SOPs

Unattended Use

Operate lasers under direct supervision or control of an authorized user – operator shall maintain visual surveillance of conditions for safe use and terminate laser operation in the event of malfunction or other unsafe condition.

Unattended operation may ONLY be allowed under LSO-approved control measures are in place; control measures MUST provide adequate protection so that unprotected spectators shall not receive eye or skin exposures that exceed the MPE limits. Service Personnel Emergency Personnel Administrative/Other Personnel Students/General Public

Engineering Controls

Protective Housing – Require interlocks and appropriate labels.

Service Access Panels – Shall only be removed by service personnel; interlocked or removal tool and warning label required.

Key Control – Master switch that can initiate and terminate system operation shall be operated by a key or coded access. The key (or code) shall only be accessible to authorized personnel.

Viewing Windows, Display Screens, and Collecting Optics –shall incorporate suitable means to maintain the exposure to below MPE.

Beam Paths –separate requirements for fully open, limited open, and enclosed.

Engineering Controls (cont’d)

Remote Interlock Connector – Class 3B should and Class 4 shall have this control to eliminate accessible radiation to below the MPE

Beam Stop or Attenuator - Class 3B should and Class 4 shall have this permanently attached control to eliminate accessible radiation to below the MPE when laser output is not required.

Warning Area Warning Signs and Activation Warnings - Class 3B and Class 4 areas shall be posted with the appropriate signage, both for beam and non-beam hazards.

Activation Warning Devices - Class 3B should and Class 4 shall use this control during activation or startup.

Engineering Controls (cont’d)

Indoor Laser Controlled Area – Analysis shall be performed by the LSO Requirements for Class 4 more strict than Class 3B. Emergency Conditions – For emergencies, there shall be a

clearly marked “Emergency Stop” available for deactivating the laser or reducing output to below the MPE.

Entryway Controls – Class 4 laser areas shall have one of the following Non-Defeatable: for deactivation of laser or reducing output to

below MPE in the event of unexpected entry into laser controlled area.

Defeatable: only if clearly evident that there is no laser radiation hazard at the point of entry.

Procedural: only when safety latches or interlocks are not feasible or are inappropriate (e.g. Surgery).

Engineering Controls (cont’d)

Outdoor control measures - Lasers are not to be used outdoors without evaluation and approval by LSO.

Temporary Laser Controlled Areas – in case of service or other conditions where housing, panels are removed and MPE is exceeded

Controlled OperationEquipment Labels – in accordance with FLPPS or

IEC 60825-1 Housing, Control Panel (if separated from housing by more than 2

meters), and Long Distance Beam Conduit (at intervals of 3 meters)

Administrative and Procedural Controls

Standard Operating Procedures (SOPs) – shall be written and maintained with the laser(s) for reference regarding operation and alignment, maintenance and service, emergency for personnel injury and fire, and all applicable non-beam hazards (including electrical safety).

Output Emission Limitations – LSO may require if excessive power or radiant energy is deemed excessive.

Education and Training – required, must cover topics required by ANSI, records must be maintained.

Authorized Personnel – LPI authorizes, training and registration are conditions of authorization.

Administrative and Procedural Controls (cont’d)

Alignment ProceduresSpectators – Shall not be permitted unless

LPI has approved, Spectators are informed of the hazards by

authorized users, and Appropriate protective measures are taken.

Service Procedures – Only those with the education and safety training commensurate with the laser contained within protective housing. Typically, certified technicians from the manufacturer.

Special Considerations

General Public – Class 3B and 4 require a laser light show variance issued by the Center for Devices and Radiological Health (CDRH), other requirements.

Optical Fiber Transmission Systems – considered enclosed within cable, if disconnecting where MPE is exceeded, NHZ requirements implemented.

Robotic Installations – working envelope included in NHZ.

Protective Equipment

General – enclosure of beam is the preferred method of control.

Eyewear – Required within NHZ for Class 3B and 4 lasers Non-beam hazards may exist which require

additional eye protection (ANSI Z87.1) LSO shall determine the OD for eyewear based

on laser specifications. Shall be permanently labeled with the OD and its

corresponding wavelength. Shall be cleaned and inspected to ensure proper

condition. Only use eyewear that is in proper working condition (e.g. no cracks, bleach marks, missing/broken straps, etc).

Protective Equipment (cont’d)

Window Protection – within NHZ shall be provided with an appropriate filter, barrier, or screen with reduces laser radiation to below all applicable MPE.

Barriers and Curtains – material shall be selected to withstand direct and diffuse reflection of beam, must not support combustion or release toxic fumes upon laser exposure.

Labeling of Protective Equipment – Shall be permanently labeled with: Eyewear – OD and corresponding wavelength. Protective Windows – OD and corresponding wavelength,

exposure time, and conditions under which protection is afforded.

Collecting Optics Filters – OD and corresponding wavelength, threshold limit (TL) and corresponding exposure time, and conditions under which protection is afforded.

Barriers (unless integral part of laser system) – TL and corresponding exposure time, and conditions under which protection is afforded.

Viewports and Films (unless integral part of laser system) – OD and corresponding spectral region which shall be provided by the manufacturer.

Protective Equipment (cont’d)

Skin Protection - mostly applicable to Class 4 UV lasers LSO shall determine if skin protection is needed.

Best achieved through engineering controlsOther Protective Equipment – respirators,

local exhaust ventilation, fire extinguishers, and hearing protection may be required.

DA N G E R !

L A S E R R A DIA T IO NE xamples of P ertinent Information:A void eye or sk in exposure to d irec t or sc attered rad iation.Invis ib le L aser R ad iation.K noc k before enter ing .If light is on:-Do not enter if not an author ized laser user for this p rojec t.-L aser p rotec tive eyew ear is required upon entry.

L as er T ype, E mitted W avelength and O ptic alD ens ity, P uls e D uration (if app lic ab le), andMaximum P ow er/E nergy O utput

C las s 4 L A S E R

Area Warning Sign Example

A warning sign that is similar in characteristic to the image at the right MUST be placed on the Nominal Hazard Zone of Class 3B and Class 4 lasers. Other warning sign designs are NOT allowed. The LSO can help you with the design of the sign.

General Project Requirements

Training and retraining (at 2-year intervals) must be completed by all restricted and unrestricted users. The LPI is not exempt.

LSO must perform an assessment of the facility.

LPI will ensure all required engineering, administrative, and procedural control measures are in place.

Purdue: Common Non-Compliances

Unauthorized service of lasersEyewear, improper (OD and/or wavelength incorrect,

disrepair), or unusedSOPs not followedUnattended laser operation (for Class 4 lasers)Improper visible alerts (e.g. wrong sign format)Lasers not interlocked to NHZ access pointAdministrative (forms not submitted, users not

trained)Improper barriers (e.g. cardboard, store-bought

fabric)Skin exposure, either deliberate or inadvertentWorking conditions – long/unusual hours, poor

housekeeping, ergonomics

Consequences of Non-Compliance

The LSO has the authority to suspend, restrict, or terminate the operation of a laser system if the LSO deems that controls are not adequate.

LPIs, authorized users, and/or associated personnel found in non-compliance of the Purdue Laser Safety Program and/or applicable governmental regulations may be subject to review by the Laser Safety Committee, at a minimum.

Penalties for non-compliance shall be determined by the Laser Safety Committee and/or other applicable bodies of authority.

Incidents/Emergencies: Injury

Turn off the laser system with the “Emergency Button” or power switch.

If injured personnel require medical assistance, don appropriate Personal Protective Equipment (PPE, i.e. gloves), and provide minimum assistance, as needed. Ensure someone remains with the victim until medical personnel arrive.

Contact medical personnel (call 911). Inform them of the accident. Once medical personnel have been contacted, inform REM (49-

46371), and Complete an incident report, and complete a First Report of Injury.

If a suspected or actual laser-induced injury occurs, medical surveillance must be performed as soon as possible, but no later than 48 hours after the incident.

Incidents/Emergencies: Fire

Sound fire alarm.Contact fire department (call 911).

Inform them of the incident.If fire has gone out, call the Purdue

University Fire Department (PUFD) at the non-emergency number (49-46919)

Turn off the laser system with the “Emergency Button” or power switch.

Evacuate area.Contact REM (49-46371).Complete incident report.

Contact Information

Zach Tribbett, Laser Safety Officer 494-1478 ztribbet@purdue.edu

Jerry Gibbs, Laser Training and Authorization Information 494-0207 jjgibbs@purdue.edu

Other Radiation Safety Staff: 494-6371

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