laser system description - harvard john a. … · web viewlaser system description& special...

Laser System Description& Special Safety Concerns

Provide a brief summary of the purpose and application of the laser system.Include the identified hazardsand the possible damages.

Laser Permit Holder Date

Department/Division Location (Building & Room)

Laser Standard Operating Procedure (LSOP)

1. Laser Safety Contacts

Principal Investigator or Lab ManagerNamePhone #

Laser Safety Officer or Lab Safety OfficerNamePhone #

Emergency Response Phone NumbersFire/Medical Emergency 911Harvard University Police (617-49) 5-1212University Operations Center (617-49) 5-5560Environmental Health and Safety (EHS) (617-49) 5-2060

2. Laser Identification

RPO Laser ID NumberLocation Room NumberManufacturerModel No.Serial No.Laser MediaLaser ClassMode* (CW/Pulsed/Q Switch)CW Power OutputEnergy Output (J) Per PulsePulse LengthPulse RepetitionWavelength (nm)Required Minimum OD

Laser Standard Operating Procedure of 15

3. Authorized Personnel Requirements

1) Only Authorized Personnel are permitted to operate this laser system. 2) To be an Authorized Personnel, one must:

Complete EHS Initial Laser Safety Training; refer to www.ehs.harvard.edu. o Complete Refresher Laser Safety Training every two years.

Complete lab-based hands-on laser operating training from the Permit Holder(PI) or designee.

Read and fully understand this Laser Standard Operating Procedure,including signing the Authorized Personnel Review page at the end of this document.

3) Follow all written standardoperating procedures, alignment procedures, and safe work practices.

4) Notify the PI and RPO (Radiation Protection Office) when anyone is accidentally exposed to laser radiation or non-beam hazards.

5) Inform visitors and untrained personnel of proper safety protocol for the lab and provide supervision by authorized personnel. All visitors must wear appropriate laser safety eyewear.

4. Hazard Overview

1) Beam HazardsThe eye and skin can be damaged by exposure to the direct beam, specular reflection or diffuse reflection from a laser. Intrabeam exposures and specular reflection exposure fromClass 3b and Class 4 lasers may causea blindinginjury, skin burns, andmay set fires.

2) Electrical HazardsPotentially lethal electrical hazards may be possible in a laser system during installation, maintenance, or repair.High voltage components such as power supplies and discharge capacitors may present an electrical hazard.The contact with these systems may cause serious and even fatal electric shocks.

3) ChemicalHazardsSome materials used in laser systems, especially gases and chemicalsolutions, may be hazardous or toxic substances. In addition, laser processing of materials may produce hazardous particles or gases.

Most notable among these chemical hazards are dyes and solvents, compressed gases, and Laser Generated Air Contaminations (LGAC). Some of these substances may be acutely or chronically toxic, others noxious or carcinogenic.

4) Fire hazardsClass 4 laser systems and some focused Class 3B lasers represent a fire hazard. Organic solvents used with dye lasers may be combustible. Class 4 laser beams may ignite the enclosure, building and target materials, as well as system components. Fire potential occurs with irradiances exceeding 10 W/cm2or beam powers exceeding 0.5 W.

5) Biological Hazards


http://www.ehs.harvard.edu/

These include LGAC generated as a result of the laser operation and infectious materials. LGAC may be generated when high power laser beams interact with tissue and biological samples. Infectious materials, such as bacterial and viral organisms, may survive beam irradiation and become airborne.

Users should consult the biological safety officer for biosafety advice.

6) Other Hazards.Collateral radiations (X-Rays, UV, visible, infrared (IR)), radio-frequency radiation,extremely low frequency electric and magnetic fields may be produced by laser system components.

Plasma radiation is generated when the beam from a powerful laser interacts with matter. This involves emission from Class 4 lasers, such as: CO2, Nd:YAG, Nd:Glass, and excimer lasers.

Non-beam explosions may occur as a result of flammable or combustible materials which come in contact with an ignition source.

5. Identified Laser Hazards

(A comprehensive hazard identification and hazard analysis must be performed by the Lab to identify the potential hazards associated with the laser system and the user’s activity. The relationship of the identified hazards and their potential effects on the experimenter, proximate personnel, the public, and environment should be analyzed. The hazards should include beam and non-beamexposure hazards corresponding with the hazards listed in Section 4 Hazard Overview above. An example entry is provided below.)

Example: A. BeamHazards: The 532nm, 633nm, and 785nm lasers are Class 3b lasers. Another

532nm laser is a Class 4 laser. Severe eye damage (including blindness) and skin damage can result from direct beam and specular reflections. Eye damage can also result from diffuse reflections of Class 4 532nm laser.

B. Electrical Hazards: Electrical shock or electrocution could result from direct contact with high voltage from the system power unit. Be careful to make sure there are no liquids on your gloves or hands when plugging laser power cords into power supply.

C. ChemicalHazards: Keep flammable solvents out of beam path.D. FireHazards: Class 4 laser systems represent a fire hazard.E. Biological Hazards: None.F. Other Hazards: None.

6. Mitigation of Hazards


(Describe in detail the controls necessary to mitigate the identified hazards. Controls may include engineering controls (such as barriers or interlocks), administrative controls (such as lab procedures, special training), and Personnel Protective Equipment (PPE).)

Example:A. Beam Hazards

1. The laboratory doors must be closed when the laser is operating.2. During alignments, the laboratory doors will be closed and a sign posted stating

“Laser alignment in progress. Do not enter. Eye protection required.”3. Laser protective eyewear for sufficient protection against 532nm, 633nm, 785nm

lasers at OD 5are located in the cabinets across from the optical table in room 127D. Laser protective eyewear must always be worn when the laser is in operation. No filters or other optics will provide suitable protection; use only laser safety protective eyewear. PLEASE NOTE: Laser protective eyewear is wavelength specific and proper selection is important.

B. Electrical Hazards1. Enclosures for protection from the laser high voltage power supply or laser head

may only be removed after the power supply has been unplugged from the outlets, storage capacitors discharged and after following the safety procedures outlined in the manufacturer’s safety and operations manual.

2. Every portion of the electrical system, including the printed circuit cards, should be assumed to be at dangerous voltage hazard.

C. Chemical Hazards1. Always check the flash point of a chemical and the temperature of a flammable

solvent before it is placed the laser beam to reduce the ignition and/or combust hazards under laser exposure.

D. Fire Hazards1. Utilize flame resistant laser curtains while class 4 lasers are in use. 2. Remove solvents and combustible materials from laser area prior to turning on

the laser.

E. Biological Hazards: None

F. Other Hazards: None

7. Beam Alignment Procedure (if applicable)


(Class 3B lasers should and Class 4 lasers shall have corresponding alignment procedures. Appropriate steps must be taken to minimize the risk to beam injuries occurring during the alignment.)

1. Consider having at least one other person present to help with the alignment.2. Persons conducting the alignment have been authorized by the responsible individual.3. Review the manufacturer’s operating manual and safety instructions;4. Determine potential hazards before beginning alignment;5. Notify lab personnel that you are doing an alignment;6. Limit lab access to only authorized personnel and exclude unnecessary personal from

the laser control area;7. Enable warning devices and post warning signs;8. Stage all needed equipment near the laser before starting;9. Remove watch and jewelry;10. Remove all unnecessary items from the work area;11. Wear laser eye protection and ensure all personnel in the lab are wearing the appropriate

laser protective eyewear;12. Wear appropriate skin protection, including to cover the face, especially when working

with UV wavelengths;13. Use indirect means to see visible wavelengths while wearing laser protective eyewear;14. When aligning invisible laser beams, use beam display devices such as image converter

viewers or phosphor cards to locate beams;15. Use the lowest power possible, or use a lower power alignment laser;16. Use materials that yield only diffuse reflections;17. Clearly mark beam paths, and barricade against personnel passage;18. Block the beam before placing optics into the beam path;19. Use a shutter or beam block to block high-power beams at their source except when

actually needed during the alignment process.20. Used a laser-rated beam block to terminate high-power beams down range of the optics

being aligned;21. Use beam blocks and/or laser protective barriers in conditions where alignment beams

could stray into area with uninvolved personnel;22. Use beam blocks behind optics to terminate beams that might miss mirrors during

alignment;23. Locate and block all stray reflections before processing to the next optical component or

section;24. When finishing beam alignment, restore any normal laser safety controls disabled during

the alignment process;25. Be sure all beams and reflections are properly terminated before high-power operation;26. Any additional requirements


8. Normal Operating Procedures

(This section shall include the following 5 procedures.

1. Initial preparation of laboratory environment for normal operation (key position, outside status indictor on, interlock activated, warning sign posted, personnel protective equipment available, etc.)

2. Target area preparation3. Special procedures (alignment procedures if applicable, safety tests,

maintenance tests, etc.)4. Operation procedures (power settings, working mode, other parameters setup,

etc.)5. Shutdown procedures

You shall add anything which is in the operation but not included in above sections.)

Example: (a lab-made laser microscope)

Important Read: Remember that you are not the only person who uses the laser microscope. If you are making adjustments (realigning or making major changes) to the system please leave detailed notes of your actions in the laser microscope log. If there is a danger of laser beams straying from the laser table for any reason, remove the interlock key and keep it in your possession until the problem or changes are corrected/completed.

1. Obtain the interlock key.2. See that all unauthorized people leave the room.3. Secure the lab door and turn on the laser-in-use-sign. Be ready to turn off the

laser if any unauthorized person or persons without eyewear enter the lab.4. Ensure all people remove wristwatches or other reflective jewelry from their body.5. Set up the optical components necessary for the experiment.

If you are making major changes, see Important Read above. For doing realignments or making changes in the laser path adhere to good laser safety practice of using beam stops. Check that all beam stops are in place and that there are no reflective surfaces in the optical path. One block should be placed behind the first optical component. A second beam stop should be placed behind the second optical component, etc.

6. Turn on the cooling water to the lasers.7. Set the laser power control to the lowest power possible. Or if the laser has one

power setting, attenuate the beam to achieve a low power output.8. Insert the interlock key into the laser switch and unlock the laser.9. Announce to others in the room you are about to turn on the laser.10. Turn the laser on.11. If optical components need alignment, start with the component nearest to the laser.

When it is aligned, move the first beam stopper behind the third optical component. Repeat this procedure until the entire optical system is aligned. It is important that the laser beam be limited to one new component at a time until the system is aligned. This will minimize uncontrolled reflections during the alignment procedure.


NOTE: DO NOT REMOVE YOUR SAFETY EYEWEAR DURING THE ALIGNMENT PHASE. IF YOU CANNOT SEE A FAINT IMAGE OF THE BEAM YOU HAVE THE WRONG OPTICAL DENSITY EYEWEAR. TURN OFF THE LASER AND OBTAIN THE CORRECT OPTICAL DENSITY EYEWEAR.

12. Increase beam power as necessary for the assigned experimental task. Always use the lowest beam power necessary for the experiment.

13. Turn off the laser.14. Allow the laser to cool down and turn off the cooling water.15. Turn off the laser-in-use-sign.16. In case of emergency, shut off the laser and remove the interlock key (if possible).

In case of fire emergency follow evacuation plan.

For beam alignment or working with the open beam safety, refer to the Beam Alignment Procedures.

9. Emergency Procedures

1) Laser Accidents1. Bring the laser to a safe shutdown condition while minimizing any system or

configuration changes.2. Immediately call 911 for help. Do not drive yourself to the hospital.3. Remain in a sitting position to minimize further damage to the retina.4. Notify coworkers and ask for assistance.5. Contact the PI and Radiation Protection Officetoreport the accident.

2) Chemical AccidentsWhen the employees are accidentally exposed to chemical materials such as optics cleaning solvents, laser dyes, or chemical agents liberated through laser introduced plasma radiations, follow the procedure below:

Ensure the laser power is shut off Consult the Emergency Response Guide Contact the PI and Radiation Protection Office to report the accident.

3) Compressed Gas AccidentsWhen there is a sudden release of compressed gas, follow the procedure below:

Ensure the laser power is shut off Consult the Emergency Response Guide Contact the PI and Radiation Protection Office to report the accident.

FireWhen the laser beam ignites materials, proceed to the following procedure:

Ensure the laser power is shut off. Consult the Emergency Response Guide Contact the PI and Radiation Protection Office to report the accident.


Attention

After the Incident, Do Not Resume Use of the Laser System until the Laser Safety Officer has Reviewed the Incident, and Radiation Safety Committee has Approved Resumption.

10.Personnel Protective Equipment

Use laser safety eyewear with a low enough OD to allow viewing of the diffuse reflection of the beam. The RPO will provide recommendations on the appropriate laser safety eye wear.

Use appropriate body shields (gloves, lab coat, and face shield) to protect against laser beam scatter.

The users are recommended to use the safety goggles which can completely enclose the eyes for the high-power lasers.

Laser Safety EyewearFor This Laser Wear This Eyewear

Laser

OperatingWavelengt

h(nm)

OperatingPower(mW)

AttenuatedWavelength

(nm)

OpticalDensity Manufacturer


Appendix A. Preparation for Beam Alignment

1. To reduce accidental reflections, remove watches, rings, dangling badges, necklaces, and reflective jewelry before any alignment activities begin. Use of non-reflective tools should be considered.

2. Access to the room or area is limited to authorized personnel only.3. Consider having at least one other person present to help with the alignment.4. All equipment and materials needed are present prior to beginning the alignment.5. All unnecessary equipment, tools, and combustible materials (if the risk of fire exists) have

been removed to minimize the possibility of stray reflections and non-beam accidents.6. Persons conducting the alignment have been authorized by the responsible individual.7. A notice sign is posted at entrances when temporary laser control areas are set up and when

unusual conditions warrant additional hazard information being available to personnel wishing to enter the area.


Appendix B. Beam Alignment Considerations

1. Whoever moves or places an optical component on an optical table (or in a beam path) is responsible for identifying and terminating each and every stray beam corning from that component (i.e., reflections--diffuse or specular).

2. There must be no intentional intrabeam viewing with the eye.3. Coaxial low-power lasers should be used when practical for alignment of the primary

beam.4. Reduce beam power with neutral density filters, beam splitters, dumps or by reducing

power at the power supply. Whenever practical, avoid the use of high-power settings during alignment.

5. Laser protective eyewear must be worn at all times during the alignment, within the parameters and notes specified in the accompanying laser table.

6. Beam blocks must be secured (and labeled if possible).7. Have beam paths at a safe height, generally below the eye level when standing or sitting.8. The LSO has authorized eyewear with reduced optical density (OD) to allow the beam

spot to be seen. Measures shall be taken and documented to ensure that no stray hazardous specular reflections are present before the lower-OD eyewear is worn. Maximum-OD eyewearis to be worn again once alignment is complete. The reduced-OD eyewear is labeled as alignment eyewear and is stored in a different location than the standard laser eyewear for this operation.

9. Skin protection should be worn on the face, hands, and arms when aligning at ultraviolet (UV) wavelengths.

10. The beam is enclosed as much as practical. The shutter is closed as much as practical during course adjustments. Optics and optics mounts are secured to the table as much as practical. Beam stops are secured to the table or optics mounts.

11. Areas where the beam leaves the horizontal plane must be labeled.12. Any stray or unused beams are terminated.13. Invisible beams are viewed with infrared (lR)/UV cards, business cards, card stock, craft

paper, viewers, index cards, thermal fax paper, or Polaroid film or by a similar technique. Operators are aware that such materials may produce specular reflections or may smoke or burn.

14. Pulsed lasers are aligned by firing single pulses when practical.15. Intrabeam viewing is not allowed unless specifically evaluated and approved by the

LSO. Intrabeam viewing is to be avoided by using cameras or fluorescent devices.


Appendix C. General Laser Controls

1. All lasers must display a current RPO inspection certificate before being placed in service.

2. All laser operations must be conducted in accordance with the SOP.3. All operating personnel should be considered for baseline eye exams before use of a

Class 3b and Class 4 laser. Harvard University Health Services Eye Clinic provides baseline eye examinations in accordance with the Massachusetts Department of Public Health and Harvard University Radiation Protection Office requirements.

4. All laser-operating personnel must have completed approved laser safety training prior to working with class 3b or class 4 lasers as well as an orientation to the laser experiment by the PI, or his or her designate, including an explanation of the beam path, reflective surfaces, and hazards associated with the work.

5. The PI must be responsible for ensuring that all personnel, visitors, and students with access to the laser use area have a clear understanding of the controls associated with laser operation.

6. Laser operators must use appropriate OD laser protective eyewear.7. This eyewear must be stored in such a manner as to protect its physical integrity. There

must be sufficient laser protective eyewear on hand for users and expected visitors.8. Laser areas must be kept as clean as possible. Reflective objects such as tools, optics,

screws, and so on must be kept away from laser beams.9. Appropriate laser warning signs, approved by the LSO, must be posted on all entrances

to the laser use area.10. In laser use areas that have room access interlocks, the interlocks must be tested

quarterly. The results must be noted by the PI or designee on the interlock check sheet kept in the interlock check section of the SOP in the EH&S binder.

11. Laser beams should not be directed toward the entrances of any laser use area. In such cases, beam confinement or barriers must be in place to protect anyone entering the laser use area from direct exposure to laser radiation.

12. Whenever possible (within experimental considerations), appropriate enclosures, barriers, beam blocks, or beam tubes must be applied to contain laser radiation above the threshold that could cause eye or skin damage.

13. Any beam paths between tables or between laser tables and targets where an open walkway exists must have a control in place to block those in the room from crossing the pathway (e.g., hinged tubes, beam tubes, retractable tapes, or chains).

14. Whoever manipulates or moves optics is responsible for checking for stray reflections. When found, those reflections must be contained to the optical or experimental table(s), even if they are below an eye hazard level.

15. The RPO must be notified if any lasers are added or any experimental changes are made to an approved laser set-up that impact safety. At such times, the LSO must perform a hazard evaluation.


Appendix D.Laser Setup Considerations

1. Securely fasten all beam path mountings2. Use beam shutters and laser output filters3. Keep items out of the beam path, particularly reflective objects 4. Block optical cells and chambers before looking inside5. Block the laser beam before placing new components into the beam6. Mark where beam travels out of the horizontal plane and use a solid stray beam shield

above the area7. Prevent a pulsed laser from inadvertently energizing8. Discharge capacitors and turn off power


Appendix E. Summary of Safe Work Practices

1. Never look directly into a laser. a. Do not stare at the light from any laser;b. Allow yourself to blink if the light is too bright.

2. Beam Controla. Position the laser so that it is well above or well below eye level;b. Terminate beams at the end of its use path;c. Never direct the beam toward other people;d. Block the beam with a diffuse reflecting beam block;e. Remove all unnecessary reflective objects from the area near the beam’s path;f. Never allow a laser beam to escape its designated area of use.

3. Do not view any laser with optical instruments;4. Operate lasers only in the area designed for their use;5. Wear the correct laser safety eyewear.


Authorized Personnel Review

I have read and understand this Laser Standard Operating Procedure (LSOP) and its contents, and agree to follow this LSOP each time I use the laser or laser system.

Name Signature Date PI/PI Designee Initial


Instructions:

• Use this template to create a standard operating procedure for Class 4 lasers. If you possess a Class 3b laser, a written SOP is advisable, but not mandatory according to the ANSI standard Z136.1-2014.

NOTE: If your SOP(s) is already documented in another form and it includes the information indicated in this template, you may use your current documents.

• This SOP shall address specific safety considerations during beam alignment, normal operations, servicing and any non-beam hazards that might exist.

• Complete the SOP by first saving the file to your computer. Then fill in the information that is highlighted in yellow. Do not change the information that is not highlighted in yellow.

• Keep this SOP in a common location readily available to the Laser User.

• This SOP should always be available for review upon request of the Laser Safety Officer.

• For specifications or operating conditions that frequently change, list anticipated ranges of specifications or operational settings.

• After completing the SOP, please email a copy back to Radiation Protection Office at [email protected] with the following description in the subject heading:

Laser SOP for (insert PI name and laser system name)


mailto:[email protected]

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