Georgetown University Laser Safety Manual



 

 

 

Catalina E. Kovats, LSO - Donald J. Mullins, DLSO

(202) 687-4712

 

Table of Contents

 

Chapter 1

Georgetown University Laser Safety Program 1 - 1

1.1 Executive Management 1 - 1

1.2 Laser Safety Committee (LSC) 1 - 1

1.3 Laser Safety Officer (LSO) 1 - 1

1.4 Deputy Laser Safety Officer (DLSO) 1 - 3

1.5 Laser Principal Investigators (LPI) 1 - 3

1.6 Assistant Laser Principal Investigators (ALPI) 1 - 4

1.7 Laser Operators (LO) 1 - 4

 

Chapter 2

Laser Classifications 2 - 1

2.1 General 2 - 1

2.2 Classifications 2 - 1

Class 1 2 - 1

Class 1M 2 - 1

Class 2 2 - 1

Class 2M 2 - 1

Class 3R 2 - 2

Class 3B 2 - 2

Class 4 2 - 2



 

Chapter 3

Laser Safety Training Requirements 3 - 1

3.1 General 3 - 1

3.2 Basic Laser Safety Training (BLS) 3 - 1

3.3 Laser Safety Refresher Training (LSR) 3 - 1

3.4 Laser Standard Operating Procedures (SOPs) Training 3 - 2



 

Chapter 4

Laser Registration and Inventory 4 - 1

4.1 General 4 - 1

4.2 Laser Fabrication 4 - 1



 

Chapter 5

Laser Hazard Evaluation and Classification 5 - 1

5.1 Hazard Evaluations 5 - 1

5.2 Laser Classification 5 - 1

5.3 Laser Key Control 5 - 1



 

Chapter 6

Laser Safety Audit Program 6 - 1

6.1 Laser Safety Officer (LSO) Audits of Lasers and Laser Systems 6 - 1

6.2 Laser Safety Officer (LSO) Audit Responses 6 - 1



 

Chapter 7

Laser Control Measures 7 - 1

7.1 General 7 - 1

7.2 Engineering Controls 7 - 1

7.2.1 Protective Housing 7 - 1

7.2.2 Interlocks 7 - 1

7.2.3 Remote Interlock Connector 7 - 1

7.2.4 Beam Paths 7 - 1

7.2.5 Beam Height 7 - 2

7.2.6 Beam Stops or Attenuators 7 - 2

7.2.7 Activation Warning Systems 7 - 2

7.2.8 Viewing Windows 7 - 2

7.3 Administrative and Procedural Controls 7 - 2

7.3.1 Laser Operation 7 - 2

7.3.2 Visitors and Spectators 7 - 2

7.3.3 Training 7 - 3

7.3.4 Standard Operating Procedures (SOP) 7 - 3

7.3.5 Laser Controlled Areas (LCA) 7 - 3

7.3.6 Outdoor Control Measures (All Classes) 7 - 3

7.3.7 Service Personnel 7 - 4

7.4 Alignment and Other Open Beam Procedures 7 - 4

7.5 Laser Optical Fiber Use 7 - 5

7.6 Personnel Protective Equipment 7 - 5

7.6.1 Eye Protection (Class 3B and Class 4) 7 - 6

7.6.2 UV Laser Protection 7 - 6

7.7 Facility Window Protection 7 - 7

7.8 Laser Protective Barriers and Curtains (Class 3B and Class 4) 7 - 7

7.9 Warning Signs 7 - 7



 

Chapter 8

Non-Beam Hazards 8 - 1

8.1 General 8 - 1

8.2 Non-Beam Hazards - Physical 8 - 1

8.2.1 Electrical Hazards 8 - 1

8.2.2 Collateral and Plasma Radiation 8 - 2

8.2.3 Fire Hazards 8 - 3

8.2.4 Explosion Hazards 8 - 4

8.2.5 Noise 8 - 4

8.2.6 Glass Particle Hazards 8 - 4

8.3 Non-Beam Hazards - Chemical Agents 8 - 5

8.3.1 Laser Generated Air Contaminant (LGAC) 8 - 5

8.3.2 Compressed Gases 8 - 5

8.3.3 Laser Dyes and Solvents 8 - 5

8.3.4 Cryogenic Liquids 8 - 5

8.3.5 Nanoparticles 8 - 6

8.4 Non-Beam Hazards - Biological Agents 8 - 6

8.5 Non-Beam Hazards - Human Factors 8 - 6



 

Chapter 9

Emergency Response 9 - 1

9.1 General 9 - 1

9.2 Laser Incident Procedure (With Beam Exposure) 9 - 1

9.3 Laser Incident Procedure (With Non-Beam Hazards) 9 - 2



 

APPENDIX A

STATEMENT OF AUTHORITY A - 1



 

APPENDIX B

GUIDELINES FOR SAFE LASER USE B - 1



 

APPENDIX C

GLOSSARY OF TERMS AND ACRONYMS C - 1



 

 

Chapter 1

Georgetown University Laser Safety Program

1.1 Executive Management

The Georgetown University (GU) executive management's written statement to the Laser Safety Officer (LSO) providing requisite authority to communicate, establish, monitor, and enforce control of Laser Hazards is detailed in Appendix A of this manual. The LSO is provided the authority and responsibility to effect the knowledgeable evaluation and control of laser hazards, and to monitor and enforce control of those hazards. The LSO shall have the authority to immediately suspend, restrict, or terminate the operation of a laser system if laser hazard controls are inadequate.

The Radiation Safety Officer (RSO) or designee serves as the LSO for the University. The LSO is a staff member of the Office of Environmental Health & Safety (EH&S). Any required laser registration to local, state and federal agencies is the responsibility of the LSO. The duties and responsibilities of the LSO are specified, meaning that the LSO performs the stated task or ensures that the task is performed by qualified individual(s).

1.2 Laser Safety Committee (LSC)

Currently GU does not have a Laser Safety Committee (LSC). The Radiation Safety Committee (RSC) is available to assist the LSO with policy development and enforcement. At the discretion of the LSO, a LSC may be established as a subcommittee of the RSC. If needed, membership will consist of at least four individuals, the LSO, the Chairman, a representative of management, and, a Laser Principal Investigator (LPI). Other members may be included as the LSO deems appropriate.

1.3 Laser Safety Officer (LSO)

The LSO's duties, responsibilities and authority include but are not limited to the following:

  •  Laser Safety Program: Establish and maintain a Laser Safety (LS) Program for the control of laser hazards. The program requirements will be consistent with the applicable American National Standards Institute (ANSI) Standards for Safe Use of Lasers (Z136 series).
     
  • Classification: Classify, or verify classifications, of laser and laser systems used at GU.
     
  • Hazard Evaluations: Perform hazard evaluations of lasers, laser systems and the associated standard operating procedures (SOP) to ensure that the hazards are mitigated by verifying implementation of appropriate control measures at the boundaries and within the Laser Controlled Area (LCA).
     
  • Control Measures: Ensure that the prescribed control measures (including barriers, screens and interlocks as required) are implemented and maintained. The LSO will recommend or approve alternate control measures when the primary ones are not feasible or practical.
     
  • Procedural Approvals: Approval of all Class 3R, Class 3B and Class 4 lasers and laser systems (including embedded lasers) Standard Operating Procedures (SOPs) and other procedures that may be part of the administrative and procedural controls.
     
  • Protective Equipment: Recommend and approve Personal Protective Equipment (PPE) (including eyewear and clothing) for personnel safety. Perform periodic audits of PPE and protective equipment to ensure proper working condition.
     
  • Safety Signs and Equipment Labels: Ensure that the appropriate safety signs and equipment labels are posted with the required format and wording in accordance with the applicable ANSI standards.
     
  • Facility and Equipment: Prior to use and after modification, review all Class 3R, Class 3B and Class 4 laser installations, facilities, and laser equipment.
     
  • Training: Develop and provide laser safety training for Laser Principal Investigators (LPI), Assistant Laser Principal Investigators (ALPI) and Laser Operators (as defined below).
     
  • Approval of Alignment Eyewear: The use of eyewear for the alignment of lasers must be reviewed and approved by the LSO. Alternate means of viewing the beam, such as CCD and web cameras, will be considered before allowing the use of alignment eyewear.
     
  • Medical Assessment: The LSO will determine whether a medical examination is required (usually within 48 hours) when a suspected injury or adverse effect from a laser exposure has occurred.
     
  • Records: The LSO will ensure that all appropriate records are maintained.
     
  • Audits, Surveys and Inspections: The LSO will periodically audit and inspect the operability and control measures of each Class 3R, Class 3B and Class 4 laser or laser system. The LSO will accompany regulatory agency inspectors reviewing the laser safety program or investigating an incident. The LSO will ensure that corrective action is taken, when required.
     
  • Accidents: Upon notification of instances in which actual or suspected exposure to laser radiation has occurred, including non-beam accidents. The LSO will respond, investigate, recommend and require corrective actions, and properly document the incident.
     
  • Approval of Laser Systems: Approval of Class 3R, Class 3B and Class 4 laser and laser systems will be given when the LSO is satisfied that hazard control measures and SOPs are adequate.

1.4 Deputy Laser Safety Officer (DLSO)

The LSO may appoint a DLSO who may perform the duties and fulfill the responsibilities of the LSO when the LSO is not available. In those instances, the DLSO is directly responsible to the LSO. The DLSO will have training and experience commensurate with their duties.

1.5 Laser Principal Investigators (LPI)

A LPI is a principal investigator or researcher who has registered a laser or laser system with the LSO. For Class 3R, Class 3B and Class 4 lasers and laser systems (including embedded lasers), the LPI must have the basic knowledge of laser safety requirements for the lasers under his/her supervision. The general responsibilities of an LPI include, but are not limited to the following:

  • Registration: Registering each laser or laser system with the LSO, including all new acquisitions. Ensure LSO approval is obtained prior to the operation of a new, modified or fabricated Class 3R, Class 3B or Class 4 laser or laser system.
     
  • Standard Operating Procedures (SOP): Responsible for the development and submission of laser SOPs and laser specific training documentation.
     
  • Laser Use: The LSO must be notified of any new or modified beam paths that may impact safety so that a new hazard analysis can be performed. A new SOP must be generated and available for reference.
     
  • Laser Hazard Controls: Ensure adequate controls of laser hazards are implemented prior to laser operation, thereby ensuring the safety of employees, visitors and the general public.
     
  • Laser Installations: Submit plans prior to installation or modification of a Class 3R, Class 3B or Class 4 laser or laser system. LSO review and approval must be obtained.
     
  • Laser Transfers and Disposals: Submit prior notification to the LSO for laser transfers and disposals, both on campus and off campus. Provide date, transfer/disposal location and contact information. The LSO will ensure proper disposal of all hazardous materials.
     
  • Training Documentation: Ensure all ALPIs and LOs complete all applicable training requirements.
     
  • LSO Notifications: Provide immediate notification to the LSO if an accident or suspected accident occurs from a laser operated under his/her purview. Immediately report any unsafe conditions.
     
  • Medical Attention: Assist in obtaining appropriate medical attention for any individual involved in a laser accident.
     
  • Laser Servicing: Prior to servicing any Class 3B or Class 4 (including embedded systems) the LSO must be notified to ensure proper controls are instituted.

1.6 Assistant Laser Principal Investigators (ALPI)

The ALPI assists the LPI with the development and implementation of the LPI responsibilities. The general responsibilities of an ALPI include, but are not limited to the following:

  • Completing all appropriate laser safety training sessions.
     
  • Managing laser safety program compliance for the LPI.
     
  • Documenting laser specific training for LOs.
     
  • Ensuring each LO has attended the appropriate laser safety training class.
     
  • Immediately reporting unsafe conditions to the LSO.

 

1.7 Laser Operators (LO)

A LO is a person who works with Class 3R, Class 3B and Class 4 lasers and laser systems (including embedded lasers). The general responsibilities of a LO include, but are not limited to the following:

  • Completing all appropriate laser safety training sessions.
     
  • Not energizing or working with any laser unless authorized to do so by an LPI or ALPI.
     
  • Being familiar and complying with SOPs and safety rules prescribed by the LSO, LPI and/or ALPI.
     
  • Immediately reporting an accident or suspected accident involving any laser to the LPI or ALPI.
     
  • Immediately reporting unsafe conditions to the LSO.

 

Chapter 2

Laser Classifications

2.1 General

A laser's classification is based on several factors including wavelength (180 nm to 1 mm), power output, accessible emission level and emission duration. These factors are considered in the applicable American National Standards Institute (ANSI) - Standard for Safe Use of Lasers (Z136 series).

There are seven laser classifications: Class 1, Class 1M, Class 2, Class 2M, Class 3R, Class 3B and Class 4. The basis of the classification scheme is the ability of the laser radiation to cause biological damage to the eye or skin during use. This is a general overview and is not to be confused with the hazard evaluations or laser classifications performed by the Laser Safety Officer (LSO) (refer to Chapter 3).

2.2 Classifications

Class 1

  • Cannot emit laser radiation at levels that are known to cause eye or skin injury during normal operation.
  • Exempt from control measures and other forms of surveillance.
  • Prior to servicing a Class 1 laser system containing embedded Class 3B or Class 4 lasers, the LSO must be contacted.

Class 1M

  • Considered to be incapable of producing laser radiation at levels that are known to cause eye injury during normal operation unless the beam is viewed with optical instruments (i.e. binoculars, eye-loupes, microscopes or telescopes).
  • If optically aided viewing is desired, contact the LSO for a hazard evaluation.
  • Prior to servicing a Class 1M laser system containing embedded Class 3B or Class 4 lasers, the LSO must be contacted.

Class 2

  • Emits laser radiation in the visible portion of the laser spectrum (400 to 700 nm).
  • Eye protection is normally afforded by the aversion response time (0.25 seconds).
  • Prior to servicing a Class 2 laser system containing embedded Class 3B or Class 4 lasers, the LSO must be contacted.

Class 2M

  • Emits laser radiation in the visible portion of the laser spectrum (400 to 700 nm).
  • Eye protection is normally afforded by the aversion response for unaided viewing.
  • If optically aided viewing is desired, contact the LSO for a hazard evaluation.
  • Prior to servicing a Class 2M laser system containing embedded Class 3B or Class 4 lasers, the LSO must be contacted.

Class 3R

  • Capable of producing laser radiation at levels that may cause eye injury during some direct or specular reflection viewing conditions, if the eye is appropriately focused and stable.
  • Requires control measures to prevent potential eye injuries. If optically aided viewing is desired, contact the LSO for a hazard evaluation.
  • Prior to servicing a Class 3R laser system the LSO must be contacted.

Class 3B

  • Medium power lasers capable of causing eye injury for direct or specular reflection.
  • Normally not a diffuse reflection, fire or skin hazard.
  • Requires control measures to prevent potential eye injuries. Appropriate PPE must be worn as required by the SOP.
  • Prior to servicing a Class 3B laser system the LSO must be contacted.

Class 4

  • High power lasers capable of causing eye and skin injuries for direct, specular or diffuse conditions.
  • May potentially cause a fire hazard and/or produce Laser Generated Air Contaminants (LGAC).
  • Requires control measures to prevent potential eye and skin injuries. Appropriate PPE must be worn as required by the SOP.
  • Prior to servicing a Class 4 laser system the LSO must be contacted.
     

Chapter 3

Laser Safety Training Requirements

 

3.1 General

A thorough understanding of laser radiation hazards is an essential component of a safe laser work environment. The training shall include, at a minimum, all of the specific hazards a person will potentially be exposed to during their laser activities and how to protect themselves. Laser users must be able to evaluate hazards in a dynamic environment and be aware of the types of activities that have been involved in laser incidents. Most laser incidents are the result of user manipulation of objects in the beam path. The Laser Safety Officer (LSO) provides laser users the basic knowledge to work safely.

Training must be provided to each Laser Principal Investigator (LPI), Assistant Laser Principal Investigator (ALPI) and Laser Operator (LO) who work with or are potentially exposed to Class 3R, Class 3B and Class 4 lasers and laser systems (including embedded lasers). The level of training will be commensurate with the degree of potential laser hazards, from both laser radiation and non-beam hazards. The training may be in the form of lecture, video tape, hands-on, self-study, computer based or a combination thereof.

3.2 Basic Laser Safety Training (BLS)

The LSO will develop and provide initial Basic Laser Safety (BLS) training. The training will provide a basic knowledge of:

  • lasers and laser systems
  • beam and non-beam hazards
  • biological effects of laser radiation
  • laser control measures (including protective eyewear)
  • laser accidents and emergency response
  • laser safety program

A written exam of the presented material is mandatory, attendees must pass the exam with a minimum grade of 70 percent.

Laser users must attend prior to working with lasers or laser systems. Interim use (prior to next scheduled BLS training) will be permitted after all laser SOP training is completed and documented; and the work is performed under the direct supervision of a LPI or ALPI.

3.3 Laser Safety Refresher Training (LSR)

Laser Safety Refresher Training will be required for all laser users on a periodic basis. The LSR training will be an abbreviated version of the BLS training, and may include a review of laser safety incidents and the lessons learned. By completing LSR training the users will maintain the necessary laser safety awareness and knowledge to continue to work safely.

3.4 Laser Standard Operating Procedures (SOPs) Training

LPIs or ALPIs will provide a SOP for each Class 3R, Class 3B and Class 4 laser and laser system (including embedded lasers). Laser users require detailed knowledge about the potential hazards, control measures, and safe work practices for the applicable laser.

SOPs for each Class 3R, Class 3B and/or Class 4 laser or laser systems should include, but not be limited to:

  • laser location and notification of use to individuals in the lab
  • laser specific beam and non-beam hazards
  • Personnel Protective Equipment (PPE) requirements
  • laser access controls (door interlocks, warning signs, etc.)
  • laser beam controls (key locks, enclosures, curtains, shutters, beam stops, etc.)
  • high voltage controls
  • laser operating procedure
  • beam alignment procedures
  • laser specific emergency procedures
  • laser specific beam and non-beam hazards

The training is required for each laser operator and will be provided by the LPI or ALPI. The training will be documented on the Laser Standard Operating Procedure Training Record. All training will be commensurate with the highest potential for laser radiation exposure associated with each laser operation, and will be consistent with the results of the completed hazard evaluation performed by the LSO or DLSO.

 

Chapter 4

Laser Registration and Inventory

 

4.1 General

All Class 3R, Class 3B and Class 4 laser and laser system (including embedded lasers) must be registered with the Laser Safety Officer (LSO). A Laser Principal Investigator (LPI) and an Assistant Laser Principal Investigator (ALPI) must be identified for each laser. The registration form may be obtained from the LSO. An inventory of all Class 3R, Class 3B and Class 4 laser and laser systems (including embedded lasers) will be maintained by the LSO.

  • The registration requires the following information:
  • a description of the use location, and safety equipment available
  • laser manufacturer, model and serial number
  • laser classification
  • laser wavelength(s) and laser power
  • laser description (beam diameter, beam divergence, etc.)
  • laser use (purpose, modifications, interlocks, shielding, etc.)
  • associated non-beam hazards

4.2 Laser Fabrication

Each laser which is fabricated at Georgetown University (GU) for transfer to an entity outside the University must meet the US Food and Drug Administration requirements for certification in accordance with Title 21 Code of Federal Regulations Subchapter J - Federal Laser Product Performance Standard.

 

Chapter 5

Laser Hazard Evaluation and Classification

 

5.1 Hazard Evaluations

The Laser Safety Officer (LSO) will perform initial, and periodic audits, of each Class 3R, Class 3B and Class 4 laser and laser system (including embedded lasers). Several aspects of the laser or laser system influence the laser hazard evaluation and applicable control measures. These aspects include:

  • The capability of the laser or laser system to injure people
  • Establishing or verifying that the Laser Controlled Area (LCA) is appropriate for each laser or laser system
  • Ensuring that the LCA is properly identified and posted
  • Ensuring that all applicable laser control measures are implemented and maintained
  • Establishing or verifying the Nominal Hazard Zone (NHZ) within the LCA and ensuring proper identification
  • Process interactions between the beam and materials during operation (e.g., rapid oxidation, ionizing radiation or Laser Generated Air Contaminants (LGAC)).
  • Evaluation of non-beam hazards
  • Establishing or verifying that proper Personnel Protective Equipment (PPE) is available

5.2 Laser Classification

Laser Principal Investigators (LPI) or Assistant Laser Principal Investigators (ALPI) must submit plans prior to any modification of a Class 3R, Class 3B or Class 4 laser or laser system. The LSO will evaluate the planned modification to determine the proper laser classification.

5.3 Laser Key Control

All Class 3B and Class 4 lasers and laser systems must be equipped with a master switch, operated by a key or coded access, which will terminate the beam. Authority for access to the master switch is determined by the LPI or ALPI.

When lasers or laser systems are unattended, the master switch must be left in a disabled condition. Operation of unattended lasers is only permitted in accordance with a written Standard Operating Procedure (SOP) approved by the LSO.

 

Chapter 6

Laser Safety Audit Program

 

6.1 Laser Safety Officer (LSO) Audits of Lasers and Laser Systems

The LSO periodically performs audits of each Class 3R, Class 3B and Class 4 laser and laser system. The audit consists of:

  • Verification of laser inventory information
  • Verification of Assistant Laser Principal Investigators (ALPI) and Laser Operator (LO) training records
  • Reviewing the Standard Operating Procedures (SOP) to ensure they are up to date
  • Verification that all required laser safety control measures are satisfactory
  • Ensuring proper demarcation of Laser Controlled Areas (LCA) and Nominal Hazard Zones (NHZ)
  • Inspecting Personal Protective Equipment (PPE) for proper wavelengths, correct Optical Density, physical condition and storage conditions
  • Reviewing the audits findings with the LPI and/or ALPI

6.2 Laser Safety Officer (LSO) Audit Responses

 The following policy ensures that LPIs provide timely and adequate responses to the LSO audits:

  • Minor violations (i.e., procedural problems) are cited and resolved between the LPI and/or ALPI and the LSO.
  • Recurrence of a previously cited violation, a pattern of recurrent violations over time, or failure to promptly correct violations, may require a written response by the LPI.
  • Serious violations (imminent danger, excessive hazard or violation of regulations) may require immediate suspension or termination of laser activities pending implementation of adequate corrective actions. In these instances, the LSO will directly communicate with the LPI and/or ALPI, and the Department Chair or Center Director.

 

​Chapter 7

Laser Control Measures

7.1 General

Control measures are designed to reduce the possibility of eye and skin exposures to hazardous levels of laser radiation and other hazards associated with laser use. The Laser Safety Officer (LSO) has the authority to monitor and enforce the control of laser hazards. For all uses of lasers and laser systems the minimum laser radiation required for the application should be used.

7.2 Engineering Controls

Laser products manufactured in compliance with Federal Laser Product Performance Standard (FLPPS) will be certified and will incorporate required engineering controls. The LSO may require additional engineering controls to those listed below.

7.2.1 Protective Housing

Limits access to laser radiation levels greater than the Maximum Permissible Exposure (MPE). The protective housing interlock must not be defeated or overridden during operation unless all requirements of a LSO approved Standard Operating Procedure (SOP) are met.

7.2.2 Interlocks

Limit access to laser radiation levels greater than the MPE. Commercially certified laser products with enclosed Class 3B or Class 4 lasers or laser systems are equipped with an interlock system that is activated when the protective housing is opened or removed. If the interlock can be bypassed or defeated, a warning label must be located on the protective housing near the interlock. After servicing a laser or laser system containing interlocks, the interlocks must be operational.

7.2.3 Remote Interlock Connector

A remote interlock connector should be provided for Class 3B and must be provided for Class 4 lasers and laser systems. The interlock connector facilitates the electrical connections to an emergency master disconnect interlock, or to a room, entryway, floor or area. When the terminals of the connector are open-circuited, accessible radiation levels shall not exceed the applicable MPE.

7.2.4 Beam Paths

May be enclosed, limited open or fully open.
Enclosed: The entire beam path is enclosed, preventing human access to levels of laser radiation above Class 1 MPE (e.g., fiber optic or beam tubes).
Limited Open: The beam path is enclosed except for a small distance between the output aperture and the target material. There is insufficient space for human or tool access. Specular and diffuse reflections must be considered.
 Open: Lasers or laser systems with unenclosed beam paths are required to have a hazard evaluation performed by the LSO.

7.2.5 Beam Height

The beam height should be maintained at a level other than the eye level of a person in the standing or sitting position.

7.2.6 Beam Stops or Attenuators

A permanently attached beam stop or attenuator should be provided for Class 3B and must be provided for Class 4 lasers and laser systems. These prevent access to laser radiation in excess of the applicable MPE when the laser or laser system output is not required (i.e., warmup procedures). For those lasers or laser systems that do not require a warm up time, the main power switch may be substituted for the beam stop or attenuator requirement.

There may be a few instances, such as during service, when a temporary beam attenuator placed over the beam aperture can reduce the level of accessible laser radiation to levels at or below the applicable MPE. In this case, the LSO may deem that laser eye protection is not required.

7.2.7 Activation Warning Systems

An activation warning system (audible or visible) should be used with Class 3B, and must be used with Class 4 laser and laser systems. A visible warning device may be exterior to the Laser Controlled Area (LCA) and the Nominal Hazard Zone (NHZ). A common example is a single red light or lighted laser warning sign that flashes when the laser is operating.

7.2.8 Viewing Windows

A visually transparent part of a protective enclosure which contains the laser process. The laser processes may be observed through the viewing windows. Optical density, wavelength and damage threshold information must be labeled on or near the viewing window.

7.3 Administrative and Procedural Controls

Administrative and procedural controls are methods or instructions that specify rules or work practices and may specify the use of Personal Protective Equipment (PPE). Unless otherwise specified, administrative and procedural controls will apply to Class 3R, Class 3B and Class 4 lasers or laser systems.

7.3.1 Laser Operation

Lasers and laser systems must be operated by a Laser Principal Investigator (LPI), Assistant Laser Principal Investigator (ALPI) or Laser Operator (LO). These individuals maintain visual surveillance of the LCA and terminate laser emission in the event of equipment malfunction or any other unsafe condition. Unsupervised laser operation requires prior LSO review and approval.

7.3.2 Visitors and Spectators

 Visitors and spectators will be permitted within a LCA only when all of the following conditions have been met:

  • The LSO has approved the laser SOP, including visitor/spectator access
  • The degree of hazard and avoidance procedure has been explained
  • The NHZ has been explained
  • Appropriate PPE such as laser eyewear and barriers are in use
  • The direct supervision or control by a LPI, ALPI or LO who maintains visual surveillance of conditions of safe use

7.3.3 Training

Training must be provided for laser users. Refer to Chapter 3 for details.

7.3.4 Standard Operating Procedures (SOP)

The LSO approves required written SOPs which must be maintained with the laser equipment for reference by laser users. SOPs must include information regarding beam and non-beam hazards, laser system controls and operation, beam alignment procedures, visitor/spectator access, and, accident and emergency response information.

7.3.5 Laser Controlled Areas (LCA)

If the hazard analysis performed by the LSO determines that the laser classification is Class 3R, Class 3B or Class 4, a LCA must be established and associated control measures instituted. All LCAs must be posted with the appropriate warning sign.

Class 3B:

The warning sign will be posted at the entryway(s) and , if required by the LSO, within the LCA. In addition:

  • The LCA must be defined and controlled to prevent the laser beam extending outdoors and into a controlled airspace.
  • Be located to limit spectator access.
  • Potentially hazardous beams must be terminated in a beam-stop of appropriate material.
  • Do not have extraneous materials in or near the beam path which may reflect the beam.
  • All windows, doorways and open portals must either be covered or restricted such that the transmitted laser radiation levels are reduced below the applicable MPE.

Class 4:

In addition to Class 3B requirements, Class 4 areas or entryway safety controls must be designed to allow both rapid egress and ingress to the LCA under emergency conditions.

Emergency Conditions: A clearly marked "emergency stop" mechanism for terminating or reducing the laser radiation to levels at or below the applicable MPE is required.

Entryway Controls: A Class 4 LCA must incorporate one of the following alternatives:

  • Non-defeatable (non-override) Area or Entryway Safety Controls 
  • Defeatable Area or Entryway Safety Controls
  • Procedural Area or Entryway Safety Controls

7.3.6 Outdoor Control Measures (All Classes)

Prior to any outdoor use, the LSO must be contacted to evaluate the proposed use and perform a laser hazards analysis. If the maximum accessible level of radiation is Class 3B or Class 4, a LCA must be established and adequate control measures instituted. The LSO will ensure all appropriate control measures are in place prior to commencement of any outdoor use.

7.3.7 Service Personnel

Personnel requiring access to Class 3B and Class 4 lasers and laser systems enclosed within a protective housing or protected area enclosure must comply with the appropriate control measures of the enclosed or embedded laser or laser system. The LSO must be provided prior notification of the date and approximate time service personnel will present on campus. The LSO will confirm that the service personnel have the education and safety training commensurate with the class of the laser or laser system contained within the protective housing.

7.4 Alignment and Other Open Beam Procedures

An ocular hazard may exist during beam alignment procedures. Alignment of Class 3B and Class 4 laser optical systems (e.g. mirrors, lenses, and beam deflectors) must be performed in such a manner that the primary beam, or a specular or diffuse reflection of the beam does not expose the eye or skin to a level above the MPE.

There are instances, such as during service, troubleshooting, testing and experimenting when a temporary beam attenuator placed over the beam aperture can reduce the level of accessible laser radiation to levels at or below the applicable MPE.

Written SOPs outlining alignment operations must be approved by the LSO for Class 3B and Class 4 lasers and laser systems. They are also required for lasers that contain embedded Class 3B or Class 4 lasers (under conditions that would allow access during alignment or service operations). Other open beam procedures may include, but are not limited to, setting up, use of equipment within the laser beam to measure power/energy or other beam parameters (e.g., shape, spatial properties, size, divergence), and experimental laser runs.

During alignments, the following actions must be taken:

  • Exclude unnecessary personnel from the LCA during alignment.
  • Pay attention to housekeeping, remove unnecessary items.
  • When possible, use low-power visible lasers for path simulation of higher-power visible or invisible lasers.
  • Perform alignment tasks that use high-power lasers at the lowest possible power level.
  • Wear PPE (protective eyewear and clothing) as recommended by the LSO:

- Laser alignment eyewear, when required

- Lab coat or long sleeve shirts, with UV lasers

  • Remove jewelry (rings, watches, bracelets, necklaces, etc.), ID badges and items from shirt pockets.
  • When possible, align invisible (and in some cases visible) laser beams, using beam display devices such as image converter viewers or phosphor cards to locate beams.
  • Use of remote viewing devices (CCD, web cams) and automated devices (motorized mounts) should be considered.
  • Use a shutter or beam block to block high-power beams at their source except when actually needed during the alignment process.
  • Use a laser-rated beam block to terminate high-power beams down range of the optics being aligned.
  • Use beam blocks and/or laser protective barriers in conditions where alignment beams could stray into areas with uninvolved personnel.
  • Place beam blocks behind optics (e.g., turning mirrors) to terminate beams that might miss mirrors during alignment.
  • Locate and block all stray reflections before proceeding to the next optical component or section.
  • Ensure beam shutter is closed, or beam is blocked before reaching into beam path.
  • Be sure all beams and reflections are properly terminated before high-power operation.
  • Replace enclosures or beam blocks removed as part of the alignment process.
  • Post appropriate area warning signs during alignment procedures for embedded Class 3B and Class 4 lasers.
  • Isolate and demarcate beam alignment area.
  • Be aware of increased risk of exposure if beam is elevated.
  • View diffuse reflections only.

7.5 Laser Optical Fiber Use

Laser systems where radiation is transmitted through an optical fiber must be considered enclosed, with the optical cable forming part of the enclosure. Optical fibers or optical fiber cables attached to Class 3B or Class 4 lasers or laser systems should only be disconnected after termination of beam transmission into the fiber. In cases when power termination is not possible, and laser radiation above the applicable MPE may be made accessible by disconnection of a connector, the connector must have a label or tag bearing the words, "Hazardous Laser Radiation When Disconnected" (or similar message). When connection or disconnection requires a specific tool, this is equivalent to an interlocked system.

The following safety measures should be employed:

  • Always work with fiber optic cables as if they were active/live.
  • Do not look straight into the end of a fiber.
  • Ensure fibers are terminated into an instrument (power meter) or suitable end caps.
  • Due to glass particle hazards, do not touch eyes while performing fiber connector or splicing work. Thoroughly wash hands prior to touching contact lenses or eyes.
  • Do not eat in or near the work area. Thoroughly wash hands before eating. Glass particles from an optical fiber are the same as splinters and may cause internal hemorrhaging.
  • The fiber strand ends are extremely sharp and may easily penetrate skin or eyes. When broken off they are very hard to find and remove.

7.6 Personnel Protective Equipment

Enclosure of the laser equipment or beam path is the preferred method of control, since the enclosure will isolate or minimize the hazard. When other control measures do not provide adequate means to prevent access to direct or reflected beams at levels above the MPE, it may be necessary to use PPE such as goggles or spectacles, skin protection such as clothing, lab coats or gloves, as well as equipment such as barriers and filter windows.

7.6.1 Eye Protection (Class 3B and Class 4)

Eye protection devices that are specifically designed for protection against radiation from Class 3B and Class 4 lasers or laser systems are required within the NHZ. They must be used when engineering or other procedural and administrative controls are inadequate to eliminate potential exposure in excess of the applicable MPE.

Laser protective eyewear must be specifically selected to withstand either direct or diffusely scattered beams depending on the anticipated circumstances of exposure. The protective filter shall exhibit a damage threshold for a specified exposure duration, typically 10 seconds. Protection may vary within the same pair of protective eyewear based on the eyewear coating and incident angle of the laser beam. All laser users must understand the limitations of the selected laser protective eyewear.

Cleaning and Inspection

Periodic cleaning and inspection is required to ensure the satisfactory condition of protective eyewear. The frequency of the safety inspection should be at least once per year, or as determined by the LSO. This shall include:

  • Periodic cleaning of the eyewear. Care should be observed when cleaning lenses to avoid damage to the absorbing and/or reflecting surfaces. Consult eyewear manufacturers for proper cleaning methods.
  • Inspection of the attenuation material for pitting , crazing, cracking or discoloration.
  • Inspection of the frame and straps for mechanical integrity.
  • Inspection for light leaks and coating damage.

Eyewear in suspicious conditions must be tested for acceptability or discarded.

Alignment Eyewear

For alignment of laser beams, conditions may arise that require the user to see the beam through their protective eyewear (cases where remote viewing is not possible). The LSO shall approve the selection, use, and appropriate Optical Density (OD) values for all alignment tasks with the ultimate goal to adequately attenuate to levels below MPEs. Alignment eyewear is assigned an OD lower than that which will provide full protection from a direct accidental exposure. For continuous wave lasers the alignment OD shall be no more than 1.4 less than the full protection OD.

7.6.2 UV Laser Protection

Due to the potential for significant photochemical bioeffects and the high level of scattering of UV radiation by air molecules, particular care must be taken when using UV lasers or laser systems. In addition to other laser controls that apply to all laser systems, exposure to UV radiation must be minimized by using beam shields and clothing that attenuates the radiation to levels below the applicable MPE.

Special attention must be given to the possibility of producing undesirable reactions in the presence of UV radiation; for example, pharmaceuticals causing skin photosensitivity, skin sensitizing agents, ozone and LGACs. PPE must be used when working with open beam Class 3B and Class 4 UV lasers. This shall include both eye and skin protection.

7.7 Facility Window Protection

Facility windows (exterior or interior) that are located within the NHZ of a Class 3B or Class 4 laser or laser system shall be provided with an appropriate absorbing filter, scattering filter, blocking barrier, or screen that reduces any transmitted laser radiation to levels below the applicable level of MPE. Exceptions to this section are limited to outdoor uses.

7.8 Laser Protective Barriers and Curtains (Class 3B and Class 4)

A blocking barrier, screen, or curtain that can block or filter the laser beam at the entryway should be used inside the LCA to prevent the laser light from exiting the area at levels above the applicable MPE. For example, the barrier can be a perimeter guard around all or part of an optical table. In other cases, where the barrier does not extend completely to the ceiling or to the floor, the LSO shall conduct an NHZ analysis to ensure safety is afforded to all workers outside the barrier- protected area. There should not be a line of sight from the optics to the entrance way.

Laser barriers shall be specifically selected to withstand direct and diffusely scattered beams. The barrier shall exhibit a damage threshold for beam penetration for a specified exposure time as specified in the hazard evaluation for the facility and specific application. The penetration threshold level (PTL) is established as the highest irrradiance for which no penetration above the specified attenuation occurs for an exposure of 100 seconds for a given beam spot diameter (see ANSI Z136.7 for additional information). Important factors in the selection of the barrier are flammability and decomposition products of the barrier material. It is essential that the barrier not support combustion or release LGAC following a laser exposure.

7.9 Warning Signs

Sign dimensions, letter size and color shall be in accordance with ANSI Z136 series. The laser hazard symbol is a sunburst pattern consisting of two sets of radial spokes of different lengths and one large spoke, radiating from a common center. The LSO/DLSO will ensure proper warning signs are posted when appropriate.

 

Chapter 8

Non-Beam Hazards

8.1 General

Non-beam hazards (NBH) are all hazards arising from the presence of a laser system excluding human exposure to direct or scattered laser radiation. NBH include physical, chemical, and biological agents that may occur when a material is exposed to a laser beam (e.g. fire or airborne contaminants), when materials used to generate the beam (e.g. flow-through gases, dyes, and solvents) are released into the atmosphere, or when individuals contact system components (e.g. shock or electrocution). Some NBH can be life threatening (e.g. electrocution) and may require use of stringent control measures. All written Standard Operating Procedures (SOPs) shall address NBHs as well as beam hazards.

8.2 Non-Beam Hazards - Physical

8.2.1 Electrical Hazards

Electrical equipment presents potential hazards which must be identified and evaluated to reduce or mitigate the hazard. Electrical Hazards include:

Shock and Electrocution

Protection against accidental contact with energized conductors by means of a barrier system is the primary methodology to prevent electric shock accidents with laser equipment. A good rule in working on any electrical equipment where the voltage is on, is to work with one hand in your pocket thereby preventing the current from going through your heart.

Resistive Heating

Unchecked and increasing resistive heating can produce excessive heat buildup and potentially damage/corrode system components. While laser system designers generally provide sufficient cooling for routine operations, equipment should be regularly checked for excessive resistive heating (symptoms such as component warping, discoloration, or corrosion) and repaired as needed.

Electric Spark Ignition of Flammable Materials

Equipment malfunctions can lead to electrical fire. In addition, electrical sparks can serve as an ignition source in the presence of a flammable vapor.

Arc Flash

An electrical arcing fault can produce an arc flash that includes intense radiant energy, high temperature air, high-pressure wave, and high velocity shrapnel from the electrical apparatus and housing. Causes of arc flash are human error while working on energized electrical equipment and equipment malfunction (old, poorly maintained, poorly designed). Workers involved in arc flash may incur serious injury or death therefore the potential for arc flash must be evaluated and controlled.

Electrical Hazard Control Measures

Laser devices, systems and those working with them are subject to all applicable electrical safety requirements including equipment connection to electrical systems, electrical protection, SOP training and appropriate electrical safety training. Fire extinguishers for electrical fires and "emergency stop" switches should be available to minimize or eliminate electrical hazards in an emergency.

8.2.2 Collateral and Plasma Radiation

Collateral radiation, not associated with the primary laser beam, may be produced by system components like power supplies, discharge lamps and plasma tubes. The produced radiation may be x-ray, ultraviolet (UV), visible, infrared (IR), radiofrequency (RF) or extremely low frequency (ELF) electric and magnetic fields.

Collateral Radiation

The Laser Safety Officer (LSO) and Deputy Laser Safety Officer (DLSO) are qualified Health Physicists (HP) who must be consulted for the proper hazard evaluation and control measures which must be implemented.

  •  Ionizing Radiation

 X-rays may be generated by laser system electrical components such as vacuum tubes

(> 15kV) and laser-metal induced plasmas. The x-ray energy and exposure level should be evaluated and documented by a Health Physicist.

  • Ultraviolet (UV) and Visible Radiation

 UV and visible radiation may be emitted from laser discharge tubes and pump lasers. If the UV radiation is of short wavelength (< 220 nm), ozone production is possible and should be evaluated for comparison with the OSHA Threshold Limit Values (TLVs).

  • Radiofrequency (RF) Radiation

Some lasers contain RF excited components (e.g., plasma tubes and Q switches) and RF generators may be used as the energy pump for some molecular lasers (e.g., CO2 lasers). Evaluations of the potential for overexposure should use recognized standards.

  • Extremely Low Frequency (ELF) Fields

Power supplies and other electrical equipment associated with some lasers are capable of generating intense electric and magnetic ELF fields at the power frequency (50 or 60 Hz) and harmonics of the power frequency. Evaluation of potential exposures should use recognized standards. If interference with implanted medical electronic devices is a concern, consult with the manufacturer of the device for specific guidance.

  • Static Magnetic Fields

Faraday rotators, ion gauges, super conducting magnets and other devices that may be associated with laser work can produce intense magnetic fields that may attract loose ferromagnetic materials such as paper clips, tools, carts, trays, and compressed gas cylinders. These objects may accelerate toward the magnet with the potential to cause injury and facility damage. Evaluation of potential exposures should use recognized guidelines.

Plasma Radiation

Plasma emissions created during laser-material interaction processes may contain both ionizing or non-ionizing radiation. For laser-material interactions that are likely to produce ionizing radiation, the LSO or DLSO must be consulted for the proper hazard evaluation and control measures which must be implemented.

  • X-Ray and Gamma Radiation

High-intensity laser beam interactions may generate plasmas that consequently produce ionizing radiation. Typically this occurs when pulsed laser beams are focused on a target with peak irradiance of 1 TW/cm2 or higher.

  •  Particle Beams

 Laser interactions with materials can generate electric fields that are a million times stronger (1TV/m) than that which conventional accelerators can produce. At very high laser irradiances (e.g., > 1018 W/cm2), these fields accelerate a high fluence of energetic, charged particles at energies of millions of electronvolts (MeV) and billions of electronvolts (GeV). Similarly, electron beams can be generated from 1 MeV to 10 GeV energies at irradiances near 1015 W/cm2. Strong electron beams at laser irradiances greater than 1017 W/cm2 generate electromagnetic pulses when they interact with vacuum chamber walls or instrumentation. Electromagnetic pulses can damage safety monitoring equipment and control hardware.

  • Radioactivation

Particle beams produced as a result of laser irradiation of materials at high peak irradiances (>1017 W/cm2) have been shown to induce radioactivation of materials in the walls and instruments within vacuum chambers. When operating at high levels of peak irradiance, radiation monitoring of vacuum hardware (by LSO or DLSO) is required.

  • UV, Visible and IR (Non-Coherent Optical) Radiation

Sufficient UV and short wavelength visible radiation (180-550 nm) can be produced by laser-matter interactions raising concern about long-term viewing without protection. The types of lasers that may produce significant levels of non-coherent optical plasma radiation are the CO2, Nd:YAG and other near IR lasers such as fiber and diode lasers.

 Control Measures for Non-Beam Radiation

The Laser Safety Officer (LSO) and Deputy Laser Safety Officer (DLSO) are qualified Health Physicists (HP) who must be consulted for the proper hazard evaluation and control measures which must be implemented.

8.2.3 Fire Hazards

Class 4 laser beams represent a fire hazard as a source of ignition. Organic solvents used with dye lasers, laser enclosures, buildings, target materials, unprotected wire insulation and plastic tubing may be combustible. Fire potential occurs with irradiances exceeding 10 W/cm2 (0.5 W/cm2 for continuous wave lasers) or beam powers exceeding 0.5 W. The laser most often involved in fires is the Class 4 CO2 laser. Under some situations, where flammable compounds or substances exist, it is possible for fires to be initiated by Class 3B lasers. The LSO encourages the use of flame retardant materials wherever applicable.

Control Measures for Fire Hazards

Opaque laser barriers (e.g. curtains), can be used to block the laser beam. While these barriers are designed to offer a range of protection, they normally cannot withstand high irradiance levels for more than a few seconds without some damage (e.g. smoke production, open fire or beam penetration). Users of commercially available laser barriers should obtain appropriate fire prevention information from the manufacturer. Fire extinguishers should be located near the laser/laser system.

8.2.4 Explosion Hazards

Explosion hazards exist with certain system components (e.g. high pressure arc lamps, filament lamps, capacitor banks, optical components), associated equipment (e.g. components of local exhaust systems), and target materials. Two examples are explosions involving dirty zinc selenide lenses and ignition of dust that has collected in ventilation systems serving laser processes.

Control Measures for Explosion Hazards

Laser equipment should be enclosed in housings that can withstand the maximum explosive pressure resulting from component disintegration. The laser target and elements of the optical train that may shatter during laser operation should be enclosed or equivalently protected to prevent injury to laser users and visitors. The potential for damage to optics and ventilation systems can be minimized by good maintenance practices. Explosive reactions of chemical laser reactants and other laser gases are a concern in some cases.

8.2.5 Noise

Levels from certain lasers (e.g., pulsed excimer lasers) or system components (e.g., assist gas nozzles), and the work environment may be of such intensity that noise control may be necessary. Contact the LSO for any noise concerns.

Control Measures for Noise Hazards

An Industrial Hygienist should be consulted for the proper hazard evaluation and control measures which must be implemented.

8.2.6 Glass Particle Hazards

Small lengths and particles of optical fiber material may pose a risk of irritation or injury, particularly when cleaving fibers during splicing or connecting operations. Personnel should not eat in a fiber cleaving area.

Control Measures for Glass Particle Hazards

Personnel should be warned of glass particle hazards. The use of protective guards or shields should be considered, especially during cleaving operations. Discarded pieces of fiber should be collected in a sharps container to avoid subsequent embedding in clothing or skin. Contact the LSO or DLSO if you have any questions.

8.3 Non-Beam Hazards - Chemical Agents

8.3.1 Laser Generated Air Contaminant (LGAC)

Air contaminants may be generated when certain Class 3B or Class 4 laser beams interact with matter. The quantity, composition, and chemical complexity of the LGAC depend greatly on the target material, cover gas and beam irradiance. When the target irradiance reaches approximately 107 W/cm2 target materials including plastics, composites, metals, and tissues may liberate carcinogenic, toxic, and /or noxious LGACs.

LGACs may be in the form of particles, aerosols, gases or vapors and may include new compounds. The quantity of LGAC may be greater for lasers that have most of their energy absorbed at the surface of the material. After characterization of the contaminant, appropriate control measures must be instituted.

Control Measures for LGACs

Engineering control measures should be given priority for controlling the hazards (i.e., isolation, local exhaust ventilation and substitution of substances that produce less toxic byproducts).

Respiratory protection may be used to control brief exposures, or as an interim control measure until other engineering or administrative controls are implemented. If respiratory protection is required, the LSO and DLSO must be contacted for enrollment into the Georgetown University Medical Center (GUMC) Respiratory Protection Program.

8.3.2 Compressed Gases

Compressed gases may be used as part of a laser system. Depending on the particular gas, compressed gases may present both physical and chemical hazards. Hazardous gases include chlorine, fluorine, hydrogen chloride and hydrogen fluoride.

Control Measures for Compressed Gases

Follow the Safety Data Sheets (SDS) and manufacturers recommendations. Always secure compressed gas cylinders. Engineering controls for hazardous gases may include exhausted gas cabinets armed with alarm sensors to indicate leakage conditions.

8.3.3 Laser Dyes and Solvents

Dye laser systems utilize fluorescent organic dyes dissolved in organic solvents. Organic solvents are often flammable and may contain toxic chemicals.

Control Measures for Laser Dyes

Follow the Safety Data Sheets (SDS) for all dyes and solvents. Laser dyes should be prepared in a laboratory fume hood. and manufacturers recommendations. Dye pumps and reservoirs should be placed in secondary containment to minimize leakage and spills.

8.3.4 Cryogenic Liquids

Cryogenic liquids may be used to cool the laser crystal and associated equipment. Their primary hazards are extreme cold (skin and eye burns) and asphyxiation. Vaporization of cryogenic liquids can displace oxygen creating an oxygen deficient atmosphere.

Control Measures for Cryogenic Liquids

Include Personal Protective Equipment (PPE), insulated transfer lines, phase separators and ventilation. Oxygen sensors should be installed in storage areas.

8.3.5 Nanoparticles

Nanoparticles are intentionally produced or engineered materials having a dimension between 1 - 100 nanometers. Nano-aerosols that are generated from naturally occurring and man-made processes are called ultra-fine particles.

Control Measures for Nanoparticles

Specialized filter media have been demonstrated to control particles smaller than 100 nm. High Efficiency Particulate Airfilters (HEPA) may be required as determined by the LSO or DLSO.

8.4 Non-Beam Hazards - Biological Agents

LGAC may be generated when high power laser beams interact with tissue. Infectious materials may survive beam irradiation and become airborne. The LSO and DLSO must be consulted for potential biological hazards.

8.5 Non-Beam Hazards - Human Factors

Ergonomic and human factors must be evaluated and controlled. These factors include: poor work station layout; poor illumination; repetitive motion or static posture; material handling; and, work patterns.

 

Chapter 9

Emergency Response

 9.1 General

For Class 3R, Class 3B and Class 4 lasers, all actual or suspected laser incidents must be immediately reported to the Laser Principal Investigators (LPI) and Laser Safety Officer (LSO). A laser incident is an unseen or unplanned event involving laser beam or non-beam laser hazards (electrical, collateral & plasma radiation, fire, etc., as described in Chapter 8).

9.2 Laser Incident Procedure (With Beam Exposure)

In the event of an actual or suspected laser incident, do the following immediately:

  • When possible, close the laser beam shutter and/or turn off the laser system.
     
  • Provide for the safety of personnel.

NOTE: If a laser eye injury is suspected, have the injured person keep their head upright to restrict any bleeding in the eye.

  • Immediately inform the LPI and proceed to the Georgetown University Hospital Emergency Room. Remember to take the Laser Injury Information packet with you. This packet is located with the specific Laser Standard Operating Procedure.
     
  • For eye injuries, an ophthalmologist must evaluate laser eye injuries within 48 hours. For skin injuries, a physician should be consulted.
     
  • The LPI MUST inform the LSO as soon as possible. The LSO may be reached:

Between 8:00 am - 4:30 pm: Environmental Health & Safety (EH&S) (202) 687-6640

After Hours, Weekends or Holidays: Department of Public Safety (DPS) (202) 687-4343

Risk Management      (202) 687-5680

Occupational Health  (202) 687-4993

EH&S/Laser Safety     (202) 687-5046

For students, GU Student Health must be notified as well    (202) 687-2200.

  • Do NOT resume laser operations without LSO approval.

9.3 Laser Incident Procedure (With Non-Beam Hazards)

In the event of an actual or suspected laser incident, do the following immediately:

  • Close the laser beam shutter and/or turn off the laser system.
  • Obtain medical assistance for injuries that are not laser exposures (non-beam injuries). 
  • If an ambulance is needed, contact: ​​                                                     DPS    (202) 687-4343

Request Medical Emergency Response assistance.

  • The LPI must inform the LSO as soon as possible (ASAP). The LSO may be reached:

Between 8:00 am - 4:30 pm:                                                      EH&S   (202) 687-6640

After Hours, Weekends or Holidays:                                         DPS      (202) 687-4343

  • If there is a fire, pull the fire alarm, evacuate the building and contact: DPS  (202) 687-4343

Request DC Fire Department (DCFD) assistance.

Do not fight the fire unless it is small and you have been trained in fire fighting techniques.

    Risk Management     (202) 687-5680

    Occupational Health  (202) 687-4993

    EH&S/Laser Safety     (202) 687-5046

For students, GU Student Health must be notified as well (202) 687-2200.

Do not resume laser operations without LSO approval.

 

 

APPENDIX A

 

Statement of Authority

APPENDIX B

GUIDELINES FOR SAFE LASER USE

 

Laser Beams

  • Do not look directly into the primary beam or any reflection, regardless of the power.
  • Always use the lowest laser or laser system classification possible.
  • Always follow the applicable Standard Operating Procedure (SOP).
  • Terminate the beam immediately at the end of its useful path.
  • Locate the beam path at a point that is not eye level for persons standing or sitting.
  • Orient the laser so that the beam is not directed toward entry points to the Laser Controlled Area (LCA). Minimize the possibility of specular and diffuse reflections.
  • Utilize surfaces that scatter radiation and minimize specular reflection.

 

Laser Location

  • Securely mount the laser or laser system on a stable platform.
  • Clearly identify beam paths. Ensure the beam path does not cross into hallways or study, desk and traffic areas.
  • Enclose as much of the laser beam as possible.
  • Don't direct the beam towards doors or windows.
  • Locate controls so the laser operator is not exposed to beam and non-beam hazards.

Laser Beam Alignments

  • When performing beam alignments, use the lowest possible beam power and limit beam traverses.
  • Utilize appropriate eye protection during beam alignment and beam instrument manipulation.
  • If possible, view the beam application remotely (CCTV, etc.).
  • Main beams and reflected beams must be terminated or dumped with fire resistant beam stops.

Housekeeping

  • Minimize reflective objects near the beam path, on the optics bench or in the LCA.
  • Be aware that cooling systems and liquid condensates can provide a specular reflective surface.
  • Remove jewelry such as rings, bracelets and watches which may cause reflection.

Personal Safety

  • Ensure all activation warning systems and indicator lights are working properly.
  • Ensure laser eyewear is appropriately marked with the wavelength and optical density.
  • Never use laser eyewear for direct viewing of the beam.
  • Ensure the LSO is notified prior to servicing so that controls for a temporary LCA are specified and followed.
  • Request assistance from the LPI/LSO whenever you are unsure of laser system practices.

 

 

APPENDIX C

GLOSSARY OF TERMS AND ACRONYMS

administrative controls - Control measures incorporating administrative means (e.g., training, safety approvals, LSO designation, and Standard Operating Procedures [SOP]) to mitigate the potential hazards associated with laser use.

aperture - An opening, window, or lens through which optical radiation can pass.

Assistant Laser Principal Investigators (ALPI) - The ALPI assists the Laser Principal Investigator (LPI) with the development and implementation of the LPI responsibilities as listed in Section 1.5. In addition, the ALPI responsibilities are listed in Section 1.6.

attenuation - The decrease in the radiant flux as it passes through an absorbing and/or scattering medium.

aversion response - Closure of the eyelid, eye movement, pupillary constriction, or movement of the head to avoid an exposure to a noxious or bright light stimulant. In this standard, the aversion response to an exposure from a bright, visible, laser source is assumed to limit the exposure of a specific retinal area to 0.25 seconds.

beam - A collection of light/photonic rays characterized by direction, diameter (or cross-section dimensions), and divergence (or convergence) angle.

beam diameter - The distance between diametrically opposed points in that cross-section of a beam where the power per unit area is 1/e (0.368) times that of the peak power per unit area.

carcinogen - An agent potentially capable of causing cancer.

certified laser - A laser product that has been built to the laser product performance standard (CFR 29, part 1040.1) and such documentation has been submitted to the Food and Drug Administration (FDA), Center for Devices and Radiological Health (CDRH).

coherent - A beam of light characterized by a fixed phase relationship (spatial coherence) or single wavelength, i.e., monochromatic (temporal coherence).

collateral radiation - Any electromagnetic radiation, except laser radiation, emitted by a laser or laser system that is associated with its operation.

collimated beam - Effectively, a "parallel" beam of light with very low divergence or convergence.

continuous wave (CW) - A laser operating with a continuous output for a period > 0.25 seconds is regarded as a CW laser.

cornea - The transparent outer layer of the human eye that covers the iris and the crystalline lens. The cornea is the main refracting element of the eye.

Deputy Laser Safety Officer (DLSO) - appointed by the Laser Safety Officer, the DLSO will perform the duties and fulfill the responsibilities of the LSO when the LSO is not available. In those instances, the DLSO is directly responsible to the LSO. Refer to Section 1.4.

diffuse reflection - Change of the spatial distribution of a beam of radiation when it is reflected in many directions by a surface or by a medium.

divergence - The divergence is the increase in the diameter of the laser beam with distance from the exit aperture, based on the full angle at the point where the irradiance (or radiant exposure for pulsed lasers) is 1/e times the maximum value.

electromagnetic radiation - The flow of energy consisting of orthogonally vibrating electric and magnetic fields lying transverse to the direction of propagation. Gamma rays, X-ray, ultraviolet, visible, infrared, and radio waves occupy various portions of the electromagnetic spectrum and differ only in frequency, wavelength, and photon energy.

embedded laser - An enclosed laser that has a higher classification than the laser system in which it is incorporated, where the system's lower classification is appropriate due to the engineering features limiting accessible emission.

enclosed laser - A laser that is contained within a protective housing of itself or of the laser or laser system in which it is incorporated. Opening or removing of the protective housing provides additional access to laser radiation above the applicable MPE than possible with the protective housing in place (an embedded laser is an example of one type of enclosed laser).

engineering controls - Methods of protecting laser users from exposure to laser radiation (e.g., interlocks and barriers).

energy - The capacity for doing work. Energy content is commonly used to characterize the output of pulsed lasers. Unit: joules (1).

epithelium (of the cornea) - The layer of cells forming the outer surface of the cornea.

erythema - Redness of the skin due to exposure to laser radiation.

FLPPS - Federal Laser Product Performance Standard (FLPPS) located in Title 21 Code of Federal Regulations Subchapter J.

GU - Georgetown University

GUMC - Georgetown University Medical Center

Health Physicist - a radiation safety professional.

hertz (Hz) - The unit that expresses the frequency of a periodic oscillation in cycles per second.

infrared radiation - Electromagnetic radiation with wavelengths within the range 700 nm to 1 mm.

installation - Placement and connection of laser equipment at the appropriate site to enable intended

operation.

iris - The circular pigmented structure that lies between the aqueous and lens of the human eye. The iris is perforated by the pupil.

irradiance - Radiant power incident per unit area upon a surface, expressed in watts-per centimeter- squared (Wcm-2).

joule (J) - A unit of energy. 1 joule = 1 Newton meter; 1 joule = 1 watt second.

laser - A device that produces radiant energy predominantly by stimulated emission. Laser radiation may be highly coherent spatially, temporally, or both. An acronym for Light Amplification by Stimulated Emission of Radiation.

laser barrier - A device used to block or attenuate incident, direct, or diffuse laser radiation. Laser barriers are frequently used during times of service to the laser system when it is desirable to establish a boundary for a LCA.

laser classification - An indication of the beam hazard level of a laser or laser system during normal operation. The hazard level of a laser or laser system is represented by a number or a numbered capital letter. The laser classifications are Class 1, Class 1M, Class 2, Class 2M, Class 3R, Class 3B, and Class 4. In general, the potential beam hazard level increases in the same order.

Laser Controlled Area (LCA) - A Laser Controlled Area (LCA) is any area, permanent or temporary, where the occupancy and activity of those within is subject to control and supervision for the purpose of protection from laser radiation hazards.

laser diode - A laser employing a forward-biased semiconductor junction as the active medium.

Laser Operators (LO) - A person who works with or on lasers and laser systems. The general responsibilities of a LO are listed in Section 1.7.

Laser Principal Investigators (LPI) - A LPI is a principal investigator or researcher who has registered a laser or laser system with the LSO. For greater than Class 1 laser radiation, the LPI should have the basic knowledge of laser safety requirements for the lasers under his/her supervision. Refer to Section 1.5 for the responsibilities of an LPI.

Laser Safety Officer (LSO) - One who has authority and responsibility to monitor and enforce the control of laser hazards and effect the knowledgeable evaluation and control of laser hazards.

laser system - An assembly of electrical, mechanical, and optical components that includes a laser.

macula - The small uniquely pigmented specialized area of the retina of the eye, which, in normal individuals, is predominantly employed for acute central vision (i.e., area of best visual acuity).

magnified viewing - Viewing a small object through an optical system that increases the apparent object size. This type of optical system can make a diverging laser beam more hazardous (e.g., using a magnifying optic to view an optical fiber emitting a laser beam).

maintenance - Performance of those adjustments or procedures (specified in the user information provided by the manufacturer, and considered preventative to maintain optimal performance of the laser system) that are to be carried out by the user to ensure the intended performance of the product. It does not include operation or service as defined in this section.

maximum permissible exposure (MPE) - The level of laser radiation to which an unprotected person may be exposed without adverse biological changes in the eye or skin.

monochromatic light - Having or consisting of one color or wavelength.

nominal hazard zone (NHZ) - The space within which the level of the direct, reflected, or scattered radiation may exceed the applicable MPE. Exposure levels beyond the boundary of the NHZ are below the appropriate MPE.

nominal ocular hazard distance (NOHD) - The distance along the axis of the unobstructed beam from a laser, fiber end, or connector to the human eye beyond which the irradiance or radiant exposure is not expected to exceed the applicable MPE.

non-beam hazard - Hazards that result from factors other than direct human exposure to a laser beam.

ocular fundus - The concave interior of the eye consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels as seen upon ophthalmoscopic examination.

open beam path - A laser beam path where any portion of the beam is accessible without defeating an engineering control.

operation - The performance of the laser or laser system over the full range of its intended functions (normal operation). It does not include maintenance or service as defined in this section.

optically aided viewing - Viewing with a telescopic (binocular) or magnifying optic. Under certain circumstances, viewing with an optical aid can increase the hazard from a laser beam. See magnified viewing and telescopic viewing.

optical density - The logarithm to the base ten of the reciprocal of the transmittance at a particular wavelength: 

OD = log10λ

where (1/τλ)  is the transmittance at the wavelength of interest.

pigment epithelium (of the retina) - The layer of cells that contain brown or black pigment granules next to and behind the rods and cones.

plasma radiation - Emission created during laser-material interaction processes that may contain both ionizing and non-ionizing radiation.

power - The rate at which energy is emitted, transferred, or received. Unit: watts (W); watt = 1 joule-per-second.

procedural controls - Methods or instructions that specify rules, or work practices, or both, that implement or supplement engineering controls and which may specify the use of personal protective equipment.

protective housing - An enclosure that surrounds the laser or laser system and prevents access to laser radiation above the applicable MPE. The aperture through which the useful beam is emitted is not part of the protective housing. The protective housing limits access to other associated radiant energy emissions and to electrical hazards associated with components and terminals: and may enclose associated optics and a workstation.

pulse duration - The duration of a laser pulse, usually measured as the time interval between the half-power points on the leading and trailing edges of the pulse. Typical units:

microsecond (s) = 10-6 s

nanosecond (ns) = 10-9 s

picosecond (ps) = 10-12 s

pulse-repetition frequency (PRF) - The number of pulses occurring per second, expressed in hertz.

pulsed laser - A laser that delivers its energy in the form of a single pulse or a train of pulses. The duration of a pulse is less than 0.25 s.

pupil - The variable aperture in the iris through which light travels to the interior of the eye.

Q-switch - A device for producing very short (~ 10-250 ns), intense laser pulses by enhancing the storage and dumping of energy in and out of the lasing medium, respectively.

Q-switched laser - A laser that emits short (~ 10-250 ns), high-power pulses by means of a Q-switch.

radian (rad) - A unit of angular measure equal to the angle subtended at the center of the circle by an arc whose length is equal to the radius of the circle (sr). 1 radian ~ 57.3 degrees; 2 radians = 360 degrees.

radiance - Radiant flux or power output per unit area per unit solid angle expressed in watts per- centimeter squared per-steradian (Wcm-2 sr-1).

reflection - Deviation of radiation following incidence on a surface.

repetitive pulse laser - A laser with multiple pulses of radiant energy occurring in a sequence.

restricted location - An area where access is granted for authorized people and limited for the general public through administrative and engineering control measures. Laser radiation hazards at Class 3B levels or greater may be present and control measures are required. Administrative controls include posted warning signs, attending training, and following established standard operating procedures (SOPs) for laser system(s). Engineering controls include access control measures such as lockable doors, barriers, defeatable interlocks, and curtains to prevent laser radiation from leaving the restricted location.

retina - The sensory tissue that receives the incident image formed by the cornea and lens of the human eye.

retinal hazard region - Optical radiation with wavelengths between 400 and 1400 nm, where the principal hazard is usually to the retina.

service - The performance of procedures, typically defined as repair, to bring the laser or laser system or laser product back to full and normal operational status. It does not include operation or maintenance as defined in this section.

shall - The word shall is to be understood as mandatory.

should - The word should is to be understood as advisory.

solid angle - The three-dimensional angular spread at the vertex of a cone measured by the area intercepted by the cone on a unit sphere whose center is the vertex of the cone.

Unit: steradian (sr).

source - A laser or a laser-illuminated reflecting surface.

spectator - An individual who wishes to observe or watch a laser or laser system in operation, and who may lack the appropriate laser safety training.

specular reflection - A mirror-like reflection.

steradian (sr) - The unit of measure for a solid angle. There are 4 steradians about any point in space.

standard operating procedure (SOP) - Formal written description of the safety and administrative procedures to be followed in performing a specific task.

telescopic viewing - Viewing an object from a long distance with the aid of an optical system that increases the visual size of the image. The system (e.g., binoculars) generally collects light through a large aperture thus magnifying hazards from large-beam, collimated lasers.

testing - The act of measurement, evaluation, verification or assessment of any properties or parameters of a laser or laser system, i.e., life time test or beam specifications.

threshold limit (TL) - An expression of the "resistance factor" for beam penetration of a laser protective device, i.e., the maximum average irradiance or radiant exposure at a given beam diameter for which a laser protective device provides adequate beam resistance. Thus, laser exposures delivered on the protective device (e.g., laser protective eyewear filters, protective windows, and barriers) at or below the TL will limit beam penetration to levels at or below the applicable MPE. Unit: W·cm-2 or J·cm-2.

transmission - Passage of radiation through a medium.

transmittance - The ratio of transmitted power (energy) to incident power (energy).

ultraviolet radiation - Electromagnetic radiation with wavelengths between 180 and 400 nm (wavelengths shorter than those of visible radiation).

viewing window - A visually transparent part of an enclosure that contains a laser process. It may be possible to observe the laser processes through the viewing window(s).

visible radiation (light) - The term is used to describe electromagnetic radiation that can be detected by the human eye. This term describes wavelengths that lie in the range 400 to 700 nm.

watt (W) - The unit of power or radiant flux. 1 watt = 1 joule-per-second.

wavelength - The distance in the line of advance of a sinusoidal wave from anyone point to the next point of corresponding phase (e.g., the distance from crest to crest or trough to trough).

work practices - Procedure(s) used to accomplish one or more tasks.