Laser Standard Operating Procedures

Standard Operating Procedures (SOPs) are required for all Class 3B and Class 4 lasers and laser systems (including imbedded lasers if hazards are accessible), and must be approved by the Laser Safety Officer (LSO). The SOPs must be written and maintained with the associated laser for reference by operators, maintenance, and service personnel. The manufacturer's laser manual is not an acceptable substitution.

It is the responsibility of the Laser Principal Investigator to submit these procedures to the Laser Safety Officer when registering the laser into the Laser Safety Program, or when changes to the procedures have been implemented. The SOPs must include the following procedures:

• Operation and Maintenance
• Service
• Alignment (if applicable)
• Emergency
• Non-Beam Hazards (as applicable)
  • Physical
  • Chemical
  • Biological
  • Human-Use Factors
  • Waste Disposal

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Operation and Maintenance

General:

Laser Principal Investigators, Restricted Users, and Unrestricted Users, if fully authorized for a laser project, is authorized for operation and maintenance of Class 3B and Class 4 lasers. These individuals are NOT authorized for maintenance of a Class 3B or Class 4 laser, or lesser rated lasers that may exceed the Class 3R AEL while serviced. Please see the Service Procedures for additional information.

If the laser is modified in such a manner that these operational instructions do not apply, the Laser Safety Officer shall be informed and will reevaluate the laser. The laser's new SOPs shall be submitted to the Laser Safety Officer for approval.

Operation:

The laser shall be operated in a manner that is defined by the manufacturer's manual located in Drawer X of File Cabinet X; see pp. XXX -XXX for detailed instruction.

Maintenance:

The laser shall be maintained in a manner that is defined by the manufacturer's manual located in Drawer X of File Cabinet X; see pp. XXX -XXX for detailed instruction.

If the laser is modified in such a manner that these operational instructions do not apply, the Laser Safety Officer shall be informed and will reevaluate the laser. The laser's new SOPs shall be submitted to the Laser Safety Officer for approval.

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Service

The Laser Safety Training given by the Laser Safety Officer at Purdue University limits the application of the trainees to the normal operation and maintenance of a laser. However, a laser may need service, such as repair or replacement of components. Under these circumstances, additional parameters must be met.

Service personnel must:

• Be appropriately trained in (and documentation must be on hand and verifiable by the LSO):
  • The safe use of lasers and laser systems, and the assessment and control of laser hazards.
  • Cardiopulmonary Resuscitation (CPR), if working with high-voltage power supplies or system components.
• Maintain all applicable conditions of a "temporary laser control area", as defined by ANSI Z136.1 (latest version).
• Maintain written and available Standard Operating Procedures (SOPs) for service of the laser(s).
• Post ANSI Z535 compliant "Notice" sign(s) at area boundary (see below).

• Employ the classification associated with the maximum level of accessible laser radiation.
• Use a "buddy system" or equivalent safety measure.
• Employ the use of laser barriers and/or blocks, as feasible.
• Employ the use of temporary beam attenuators, as feasible.
• Ensure proper restoration of equipment (e.g. on laser(s) containing interlocks, the interlock must be operative when the system is restored).

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Alignment

Laser beam incident occurrence has been reported during beam alignment procedures (DOE, RLI). Appropriate steps must be taken to minimize the risk to beam injuries occurring during the alignment procedure. Class 3B lasers should and Class 4 lasers shall have corresponding alignment procedures written and maintained with the laser for reference.

For Class 3B and Class 4 lasers, alignments:

• Shall be performed only by those who have received laser safety training.
• Shall be performed in a manner that the primary beam, or a specular or diffuse reflection of the beam, does not expose the eye to a level above the applicable Maximum Permissible Exposure (MPE) - this condition also applies to Class 2 and Class 3R lasers or laser systems.

The following procedures should be followed when performing a laser alignment:

1. Exclude unnecessary personnel from the laser area during the alignment process.
2. Use low-power visible lasers for path simulation of higher-power lasers (both visible and invisible), whenever possible.
3. Wear appropriate eyewear, and skin protection to the extent practical.
4. For invisible lasers, use beam display devices (e.g. image converter viewers, phosphor cards).
5. Perform alignment at the lowest power possible.
6. User shutter or beam block to block high-power beams at their source, except when beam is actually required.
7. Use shutter or beam block to terminate high-power beams down range of the optics being aligned.
8. Use a laser-rated beam block to terminate barriers in conditions where alignment beams could stray into areas with uninvolved personnel.
9. Place beam blocks behind optics (e.g. turning mirrors) to terminate beams that might miss mirrors during alignment.
10. Locate and block all stray reflections before proceeding to the next optical component or section.
11. Be sure all beams and reflections are properly terminated before high-power operation.
12. Post appropriate area warning signs during alignment procedures where lasers are normally Class 1 (enclosed).

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Emergency

Personnel 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), and provide minimum assistance, as needed. Ensure someone EHSains with the victim until medical personnel arrive.
• Call 911 and inform the dispatcher to advise medical medical personnel that the accident involved lasers .
• Contact Environmental Health and Safety (EHS) at 49-46371.
• Complete incident report.

Fire:

• Call 911 for the Purdue University Fire Department (PUFD). If the fire has gone out, call PUFD at the non-emergency number (49-46919).
• Turn off the laser system with the "Emergency Button" or power switch.
• Evacuate area as stated in your Building Emergency Plan.
• Contact EHS at 49-46371.
• Complete an incident report.

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Physical Hazards

Electrical:

Live parts to which an employee might be exposed shall be put into an electrically safe work condition before an employee works on or near them, unless the employer can demonstrate that de-energizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. If live parts are not placed in an electrically safe work condition (i.e., for the reasons of increased or additional hazards or infeasibility), work to be performed shall be considered energized electrical work and shall be performed by written permit only. If you have questions on whether a piece of equipment may contain a high voltage power supply, talk to your supervisor or project director prior to working on or near this piece of equipment.

• Grounding
  • Non-current carrying metallic parts (e.g. frames, enclosures) should be properly grounded.
• Electrical Fire Hazards
  • Components in electrical circuits are periodically evaluated with respect to fire hazard potential (e.g. unprotected wire insulation).
  • Non-metallic materials surrounding the laser (e.g. barriers) are flame retardant, and comply with UL 746C - Polymeric Materials.
• Electrical Explosion Hazards
  • Gas tubes and laser lamps are mounted in such a fashion to ensure their terminals shall not make accidental contact should their be tube or lamp failure.
  • System components shall never be used in a capacity that would exceed their ratings.
• Marking
  • The laser shall be marked to display its primary electrical rating.
  • If additional hazards are present, such as high radiofrequency or magnetic field, these markings shall also be present.
  • Markings shall be in English, legible, and easily recognizable.
• In addition, all electrical work shall comply with 29 CFR 1910 Subpart S, and 29 CFR 1910.147 (Lockout/Tagout). 
  Energized Electrical Work Permit (If there are any questions concerning this form or energized electrical work contact Dan Dunbar (Electric, Electronic and Elevator FoEHSan), 44881 or Jon Biggs (Chairman, Electrical Safety Committee), 44637.)

Collateral:

• Ionizing Radiation:
  • X-rays from electronic components of lasers (e.g. high voltage vacuum tubes exceeding 15 kV).
  • X-, gamma, and neutron radiation may be emitted from targets upon interaction with high irradiance laser beams.
  If this type of radiation is produced, registration of this project as a radiation project may be required, and may also have additional shielding requirements.

• Nonionizing Radiation
  • Electromagnetic - If there is a strong electromagnetic field (EMF) produces by the laser, appropriate precautions must be taken. Obey all posted warning signs.
  • Visible and Ultraviolet (UV) - may be emitted from discharge tubes, and pump lamps and shall be maintained at levels below ACGIH TLVs, if present.

Plasma:

Lasers interacting with metals and potentially other materials may induce plasma production (ultraviolet or "blue light"), which may be an ocular hazard. If the laser produces plasma, inform the Laser Safety Officer who will perform an analyses of this potential hazard. If the analysis indicates that a hazard does exist, ensure individuals that may be exposed to viewing plasma radiation wear appropriate eyewear.

Fire:

• Class 3B laser should and Class 4 lasers shall always be attended by authorized users for the laser project while the laser is in operation.
• Only flame retardant material shall be used near potential ignition sources.
• Class 3B laser should and Class 4 lasers shall have an emergency switch/mechanism for emergency shutdown or shuttering of laser.
• Appropriately rated beam blocks shall be used to stop the beam; laser barriers and curtains are not considered beam blocks.

Explosion:

• Laser system components shall be properly maintained to prevent component disintegration.
• Protective housing shall be interlocked to prevent access to component during system operation.
• An enclosure or equivalent protection shall be used around the target and elements of the optical train in case of shattering.
• Chemical laser reactants shall be handled and stored as stated on their respective MSDSs and the Purdue Chemical Hygiene Plan.

Mechanical (Associated with Robotics):

Robotics used within the laser laboratory setting may introduce mechanical hazards. Robotics can damage laser housing, misalign the laser, or pin or pinch personnel. If robotics are introduced into the lab, the Laser Safety Officer shall perform an analyses and may require additional control measures, which shall be adhered to by laboratory personnel.

Noise:

Laser systems have the potential for producing noise levels that exceed the OSHA Action Level of 85 dBA. If you suspect that your system approaches or exceeds this level, please contact the EHS Industrial Hygiene Group for analyses.

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Chemical Hazards 

When using chemicals associated with lasers and laser systems, consult the Purdue Chemical Hygiene Plan. If chemical hazards exist that are directly or indirectly associated with the laser beam, then these hazards and LSO-approved procedures must be included in SOPs. The SOPs should be written and available near any Class 3B or Class 4 laser or laser system.

Chemical hazards associated with lasers and laser systems may include, but is not necessarily limited to, the following:

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

If additional assistance is needed regarding chemical safety, please contact EHS at 765-494-6371.

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Biological Hazards

Laser Generated Air Contaminants (LGACs) may be produced when a laser beam interacts with biological targets. Infectious material that is present in a biological target may survive beam exposure and possibly become airborne. The Laser Safety Officer will not approve Class 3B or Class 4 laser use projects using biological materials without written approval from the Biological Safety Officer.

This hazard analysis may include an industrial hygiene assessment, and additional control measures may be required. All control measures shall be followed as directed by the Laser Safety Officer, the Biological Safety Officer, and possibly the Industrial Hygiene Staff regarding these matters.

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Human Use Factors

Ergonomics:

• Workstations should be designed and maintained to encourage good posture and provide a natural or neutral body position when working. Factors to consider are reducing the need for bending, twisting, stretching, awkward positions and eye strain. In addition, limit repetitive movements to best extent possible.
• Machinery shall be properly guarded to prevent pinning, pinching, or cutting of workers.
• The working area shall be properly illuminated for worker safety. If an area requires low-light, the Laser Principal Investigator shall ensure workers are aware of any unseen potential hazards.
• The working area shall have minimal visual distractions such as reflections, flickering, and bright/blinding lights.

Work Space:

• There shall be sufficient room for individuals to turn around and maneuver freely, also allowing for rapid egress of the work area (i.e. 3 foot minimal clearance free of objects in path).
• The work area shall be free of trip/fall hazards, and shall maintain good housekeeping practices in order to prevent additional potential injuries or safety violations (e.g. unnecessary objects located around laser that may ignite or reflect the beam out of its intended alignment).

Work Patterns:

Unusual or long hours may affect worker alertness. Discuss with your supervisor the work duration and times you are expected to work. Any decrease in worker alertness must be addressed immediately by the Laser Principal Investigator.

Other:

Laser workers should inform their Laser Principal Investigator of other issues that may affect their ability to work safely around the laser on their project. Factors such as preexisting eye injuries, pupil dilation, nervous twitches, other physical injuries, etc., may affect the individual's ability to perform laser-related work. Also, individuals may also be photosensitive from industrial chemicals or medications, resulting in greater susceptibility to the effects of ultraviolet lasers, as well as collateral and plasma radiation.

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Waste Disposal

Disposal of chemically contaminated laser-related waste must be done in accordance with Purdue policy in order to comply with federal, state, and local regulations. The Hazardous Materials Management (HMM) section of EHS concerns itself with the proper disposal of hazardous material, and provides an excellent resource for information regarding procedures that should be followed upon disposal of material.

If the laser itself is to be EHSoved from service from a laser project, either through disposal, transfer, donation, or storage, contact the LSO prior to doing so. There are many issues that need to be addressed if a laser is EHSoved from service, including proper paperwork, placement, handling, and lockout.

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