Laser Safety Retraining

Updated 01/2014

Radiological and Environmental Management

Laser Safety Retraining

Laser Safety at Purdue

• Laser safety at Purdue University is managed by the University Laser Safety Officer (LSO) and Radiological and Environmental Management (REM)

• The laser safety program is overseen by the Purdue Laser Safety Committee (LSC)– This committee is made up of representatives, mostly LPIs and safety personnel,

from multiple departments

• The Purdue program follows:– Occupational Safety and Health Administration (OSHA) is responsible for laser

safety– OSHA adopts the American National Standards Institute (ANSI) guidelines, using

the General Duty Clause– Laser regulations come from ANSI Z136.1 – American National Standard for Safe

Use of Lasers


Laser Safety Program Personnel

• 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 Safety Program

http://www.purdue.edu/policies/pages/facilities_lands/d_2.html

• 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 Classes – 1, 1M, 2, 2M, and 3R

• Class 3B (powers from 5 mW to 500 mW): – Can cause eye injury with direct exposure to beam– 3B lasers close to the maximum power of 500 mW may also cause eye injury by

reflections of the beam– Normally not a fire hazard

• Class 4 (powers greater than 500 mW):– Can cause eye injuries with the direct beam or with the reflected beam– Can cause injuries to the skin– Can be a fire hazard– May also be a source of laser generated air contaminants (LGACs) and

hazardous plasma radiation.


Laser Classes – 3B and 4

• All restricted and unrestricted users on laser projects must complete Purdue’s Online Laser Safety Training.

– The LPI is not exempt, even if their use of the laser systems are infrequent

• Initial Training requires completion of three steps:– Successful completion of the Initial Online Training– Attendance of the Classroom Training, unless you are a restricted user – Laser-specific training provided by LPI or by an experienced unrestricted user on

the project


Required Training

• Restricted User:– Someone who works with a Class 3B or 4 laser only under direct physical

supervision of their laser principal investigator or an authorized unrestricted user, or

– Someone who does not operate the laser, but does 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


User Categories

Laser Principal Investigator (LPI)• Issues appropriate instruction and training materials on laser hazards of their specific

laser• Ensures that operation of the laser meets all safety requirements, both for the lab

members and anyone else who may enter the lab (custodial staff, visitors, etc.)• Ensures all individuals working have submitted a completed LU-2 form, including LPI• Ensures 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.

• Notifies the LSO of any known or suspected injuries• If necessary, assists in obtaining appropriate medical attention for any employee

involved in a laser accident• Will not permit operation of a new or modified Class 3B or Class 4 laser under his/her

authority without LSO approval.• Shall submit all required paperwork for new laser or facilities• Shall ensure that SOPs are available for each laser


LPI Responsibilities

Employees working with lasers• Will not energize or work with or near a laser unless authorized to do so by the laser’s

supervisor• Shall comply with Purdue University Laser Safety Guidelines, LSO and LPI safety

rules and procedures• Will inform his/her LPI of any known or suspected accident involving a laser under

their LPI’s jurisdiction. If the LPI is not available, the employee will notify the LSO


Employee Responsibilities

8 Things Every Laser User at Purdue Should Know if Asked

The following slides highlight information that every laser user should know if asked. If you do not know the answer to one of these questions, and you would like some more information after you have gone through this retraining, feel free to contact someone from the laser safety group at REM.

8 Things to Know

Introduction

Who is the current laser safety officer?

Zach [email protected] B173H

8 Things to Know

Number One

mailto:[email protected]

What types of safety measures are in place in your lab?

Examples include:TrainingStandard operating procedures Barriers when requiredAccurate signageProper Eyewear

8 Things to Know

Number Two

Where can I get a copy of the laser regulations (ANSI Z136.1)?

1) You may purchase a copy of your own from ANSI or the Laser Institute of America for approximately $150

2) You may make a request to view REM’s copy

8 Things to Know

Number Three

What types of lasers does your lab have and what are they used for? What is the hazard class of each laser?

If you don’t know this, then you should not be working with the laser! This information should be included in your unit-specific training. This information is also found on the laser signage and in the standard operating procedures. Laser safety measures (ie. eyewear, barriers, safe distances, etc.) are determined by hazard class and are unit specific.

8 Things to Know

Number Four

Where is your laser inventory?

All users should know what types of lasers and how many lasers are located in their lab. This information can be found with the LPI or by contacting REM. Please keep in mind though, that REM’s records are only accurate if proper registration is completed for each laser.

8 Things to Know

Number Five

Do you have appropriate laser safety eyewear for your laser?

Proper eyewear is critical to safety if no engineering controls are in place. Eyewear is specific to the laser you are using. A pair that works for one laser may not work for another. They need to be OD and wavelength appropriate.

Proper eyewear for your laser should be addressed in:

1. Your unit-specific training

2. Standard operating procedures

3. Signage

Number Six8 Things to Know

Where are the training records for your lab?

Training records are required for all safety training, including laser safety. A binder should be kept in your lab that has records of the safety trainings for all lab members.

For laser safety training, the best approach is to print your confirmation email that you receive after successful completion of the trainings. You may also contact REM to obtain verification that you have completed the required trainings.

8 Things to Know

Number Seven

Are your laser warning signs accurate, ANSI compliant, and correctly posted?

If the proper notifications have been made to the LSO, this will be taken care of. If you notice that they are not appropriate, contact your LPI or the LSO to get replacements. These signs are specific to the lab and to the lasers found in that lab. A general laser warning sign is not appropriate. The signs should be posted at the nominal hazard zone, which is determined by the LSO during the evaluation of the laser. The sign shown below is an example of compliant laser signage.

8 Things to Know

Number Eight

Laser Beam Hazards

• Any laser that is Class 3B or 4 has the potential to cause permanent eye damage, and in certain cases, can cause injuries to the skin

• The hazard potential of a laser is based of the Maximum Permissible Exposure (MPE), which is specific to the unit you are using

• In order to determine the level of hazard associated with a specific laser, the LSO will calculate the MPE and the irradiance or radiant energy of the laser beam. These two values are then compared in order to determine the nominal hazard zone, the optical density of the eyewear required, and the barriers that are required. This is why it is critical that all lasers are properly registered with REM and evaluated by the LSO.

Laser Beam Hazards

When is a laser hazardous?

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

Laser Beam Hazards

Mechanism of Injury

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)

Laser Beam Hazards

Corneal Hazards

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

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

Laser Beam Hazards

Retinal Hazards

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

EFFECT:Development of cataracts

Laser Beam Hazards

Lens Hazards

• 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 helps limit that amount of radiation entering their eye.

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

Laser Beam Hazards

Increased Sensitivity of the Eye

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

Laser Beam Hazards

Skin Injuries - Thermal

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

Laser Beam Hazards

Skin Injuries - Photochemical

• Reflected wavelength is blurred and weaker than the direct beam

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

Diffuse

• Reflected wavelength is nearly the same shape and intensity as the direct beam

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

Specular (Mirror-Like)

Laser Beam Hazards

Types of Reflections

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

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

Laser Beam Hazards

Avoiding Injuries from Reflections

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

Different Categories

• Electrical Hazards• Collateral and Plasma Radiation• Fire Hazards• Explosion Hazards• Mechanical Hazards Associated with Robotics• Noise

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

Physical Agents

• Laser Generated Air Contaminants (LGACs)• Compressed Gases• Laser Dyes and Solvents• Assist 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

• 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, M-S 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

Chemical Agents – Control Measures

• 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

Biological Agents

• 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 and maneuver freely, without trip/fall hazards (e.g. wires or cables on floor)

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

Non-Beam Hazards

Human Factors

Protection from Hazards

• 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.

Protection from Laser Hazards

Engineering Controls – 1/4

• 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.

• 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



• 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).



• 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 Operation

• Equipment 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)



• 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 & Procedural Controls – 1/2

• Alignment Procedures– Procedures shall be written for each laser requiring beam alignment. These

procedures must include methods for alignments as well as protective measures required.

• Spectators – 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.


Administrative & Procedural Controls – 2/2

• Required within the 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. These cannot be written on the eyewear with a marker or pen, or affixed to the eyewear on a label. The markings have to be etched into the eyewear so they cannot be removed. New eyewear should be purchased when these etching can no longer be read.

• 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 - Eyewear

• Window Protection– windows within NHZ shall be provided with an appropriate filter, barrier, or screen

with reduces laser radiation to below all applicable MPE– must be labeled (etched into the window) with OD and corresponding

wavelength, exposure time, and conditions under which protection is afforded

• 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.– must be labeled with threshold limits and corresponding exposure time, and

conditions under which protection is afforded.

• Viewing ports– must be labeled with OD and corresponding spectral region which shall be

provided by the manufacturer.

• Collecting Optics Filters – must be labeled with OD and corresponding wavelength, threshold limit and

corresponding exposure time, and conditions under which protection is afforded.


Protective Equipment - Barriers

• Skin Protection - mostly applicable to Class 4 UV lasers– LSO shall determine if skin protection is needed.– Should be flame-retardant when working with a Class 4 laser

• Best achieved through engineering controls that prevent access to the beam or reflections


Protective Equipment – Skin Protection

• 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)

Non-Beam Hazards

Disposal of a Laser

http://www.purdue.edu/rem/hmm/hmm.htm

Non-Compliance and Injuries

• Unauthorized service of lasers• Eyewear, improper (OD and/or wavelength incorrect, disrepair), or unused• SOPs not followed• Unattended laser operation (for Class 4 lasers)• Improper visible alerts (e.g. wrong sign format)• Lasers not interlocked to NHZ access point• Administrative (forms not submitted, users not trained)• Improper barriers (e.g. cardboard, store-bought fabric)• Skin exposure, either deliberate or inadvertent• Working conditions – long/unusual hours, poor housekeeping, ergonomics


Common Non-Compliances

• 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.


Consequences of Non-Compliance

• 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.

• Do not operate the laser again until the LSO has evaluated the incident and corrective actions have been taken.


What do you do if an injury occurs?

• If a fire starts near or in the laser system:– 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.


Fire

Laser Safety Contact Information

• Zach Tribbett, Laser Safety Officer– 765-494-1478– [email protected]

• Jerry Gibbs, Laser Training and Authorization Information– 765-494-0207– [email protected]

• Other Radiation Safety Staff: 765-494-6371

REM Laser Safety Staff

Contact Information



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Laser Safety Retraining

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