Chapter 16
LASERS

Contents

Approved by Larry McLouth
Revised 03/07


16.1 LBNL Laser Safety Policy

The objective of the LBNL laser safety program is to prevent staff exposure to laser radiation in excess of the maximum permissible exposure (MPE) limit for the human eye or skin, and to ensure a safe working environment for laser-related research by effectively mitigating laser-related hazards. The LBNL policy on laser safety requires that all lasers and laser systems be operated in a manner comparable to the American National Standards Institute (ANSI) Z136.1, Standard for the Safe Use of Lasers. Additionally, the program is designed to see that adequate protection against collateral hazards is addressed. These collateral hazards include the risk of electrical shock, fire hazard from a beam or from use of dyes and solvents, and chemical exposures from use of chemicals and vaporization of targets.

In order to implement the policy and give the researchers’ flexibility in choosing controls, all laser operations at LBNL must be reviewed and approved by the LBNL Laser Safety Officer (LSO). Requirements for laser safety are multilevel and include engineering controls, administrative controls, and training.

This chapter does not describe the theory behind the laser or a number of laser safety related topics such as bio-effects and how to select laser eyewear. Additional laser safety information can be found on the Laser Safety Web site. Laser Safety Background and instructional material will be added to the LBNL Laser Safety Web Page, and will include information on:

16.2 Overview Chart

Laser Requirements

Table 16-1 indicates the requirements for operating lasers at LBNL. These items are more fully explained below.

Table 16-1. List of Requirements by Laser Class

Class of Laser

Requirements

Class 1-3A

  • EHS 280 (Laser Safety): recommended
  • Activity Hazard Document (AHD) not required

Class 3B & Class 4

  1. EHS 280 (Laser Safety): required
  2. Activity Hazard Document (AHD) required
  3. On-the-Job Training: documented
  4. All lasers listed in the Laser Inventory System.
  5. Use of approved laser protective eyewear when required. Baseline laser eye examination.
  6. See this chapter for other control measures.
  7. For necessity of room access interlocks, contact the LSO.

ALS users

EHS ALS 280 (Laser Safety),
Web-based course

Retraining

3-year frequency, can take Web-based EHS 281or special meeting with LSO.


16.3 Responsible Parties for Implementing the LBNL Laser Safety Program

16.3.1 Supervisor or Work Lead Responsibilities

The Supervisor represents line management and sets the tone for laser safety within a research group. Due to competing responsibilities, the Supervisor may spend little time in the actual laser use area. In these instances, the Supervisor may designate one or more Work Leads, who acts as a Laser Safety Supervisor (LSS). Work Leads take on the responsibilities of the Supervisor in terms of laser safety. This does not alleviate the original supervisor from the responsibility that safe work is carried out. The Supervisor or Work Lead must ensure that all laser users receive adequate and appropriate laser safety training on two levels: (1) EHS 280, LBNL’s fundamental laser safety course, and (2) training from the Supervisor, Work Leader, or designee with respect to the hazards and safe operation of the laser system(s), commonly called On-the-Job Training (OJT). A detailed list of supervisor responsibilities follows:

16.3.2 Laser User Responsibilities

Final responsibility for laser safety rests upon the individual laser user. They must have received proper fundamental laser safety training and OJT that allows them to perform their tasks, and be comfortable enough to speak up in times of question or doubt. They must also understand their work goals and be familiar with the LBNL “Stop Work Authority” policy. Users have the following responsibilities:

16.3.3 Laser Safety Officer Responsibilities

The key to effective laser safety per the ANSI Z136.1 standard is the role of the Laser Safety Officer (LSO). “An individual shall be designated the LSO with the authority and responsibility to monitor and enforce the control of laser hazards and to effect the knowledgeable evaluation and control of laser hazards. The LSO either performs the stated tasks or ensures that the task is performed.” This fits within the scope of the LBNL Integrated Safety Management plan. The LSO has the authority and responsibility to monitor and enforce the control of laser hazards. The LSO has the authority to suspend, restrict, or terminate the operation of a laser or laser system if he /she deems that laser hazard controls are inadequate. The LSO's duties, responsibilities, and authority include, but are not limited to:

16.3.3.1 Substitution of Alternate Control Measures

The ANSI Z136.1 Laser Standard establishes the LSO’s authority to modify the control measures required for Class 3B and Class 4 lasers or laser systems. Upon documented review by the LSO, control measures — engineering controls in particular — can be replaced by administrative or other alternate controls that provide equivalent protection. The approval of these controls is incorporated into the AHD for the laser experiment. An example would be the use of curtain maze or posting in place of an entrance interlock.

16.3.3.2 Temporary Control Area/Temporary Work Authorization

The concept of a Temporary Controlled Area (TCA) for laser operation comes from the ANSI Z136.1 standard, and is of great practical value in a research setting; its purpose is to allow an authorization of laser work in settings where a formal Activity Hazard Document (AHD) does not already exist. The term “Temporary Work Authorization (TWA),” as referenced in Chapter 6 of PUB-3000, is equivalent to a TCA. Examples would be acceptance testing of laser equipment in a lab during initial set up, a short-term change to an existing experiment, short-term laser repairs, or an appropriate laser safety plan to follow while an engineering control is being repaired. The LSO will generate a TCA/TWA memo listing the circumstances, and then create control measures to be followed by all parties in the TCA/TWA. All parties will sign the memo indicating they understand the controls and will abide by them. This memo is to be posted at the work site and usually has a two- to four-week duration, and limited extension capability. Sample controls might be:

16.3.3.3 Laser Safety Protocols and Interpretations

The LSO shall develop and issue laser protocols and or interpretations of ANSI Z136.1 requirements. These shall meet the spirit of ANSI Z136.1 and provide equivalent protection. Such protocols will be reviewed by the LBNL Laser Safety Committee to ensure they fit into LBNL’s research environment and needs. When deemed necessary, they will be forwarded to the LBNL Safety Review Committee (SRC) for approval. The protocols will be posted on the Laser Safety Web page. Examples of protocols are:

16.3.4 Laser Safety Committee (LSC)

The LBNL SRC has established a subcommittee to advise the laser safety program on laser safety issues. This subcommittee provides recommendations to the LSO and LBNL management (via the SRC) on laser safety policy and issues. This subcommittee is comprised of the LSO, other EH&S personnel, and experienced laser users from LBNL, and provides a mechanism for laser user input to the LBNL laser safety program. The responsibilities of the LSC are to:

16.3.5 EH&S Health Services Group

The role of the EH&S Health Services Group is to:

16.3.6 EH&S Professionals

EH&S Professionals provide guidance in handling and establishing controls for laser-associated hazards such as:

16.3.7 Purchasing

Purchasing notifies the LSO of all laser purchases and laser-related service requests.

16.4 Requirements for Laser Use at LBNL

16.4.1 Requirements for Class 1 Products, i.e., Laser Scanning Confocal Microscope, Cell Sorter, Laser Interferometer

The Center for Devices and Radiological Health, the Food and Drug Administration body tasked with developing laser light performance product safety standards, defines a Class 1 product as any laser product that does not permit access during the operation to levels of laser radiation harmful to eyes or skin. Class I levels of laser radiation are not considered to be hazardous.

Many times, these Class 1 laser products are used in work areas where no attention or training on laser safety has taken place. Therefore, when open for service, these Class 1 laser products may introduce a potential laser hazard in work areas and staff unaccustomed to the laser safety considerations.

During routine operation of a class 1 product where no laser radiation exposure is possible, no laser safety training, medical surveillance, or user restrictions from a laser safety perspective are required. Each unit should have an individual responsible for its proper use.

Service or Maintenance: Yielding accessible laser radiation, the following steps will be taken (this includes repair vendors):

  1. Notification of accessible laser radiation will be made by posting access doors with a “Notice Laser Service / Alignment in Progress” sign, or setting up an exclusion zone near the unit with the same posting.
    1. If necessary, doors, windows, etc., will be blocked.
  2. The user/service person will wear the appropriate laser protective eyewear for the wavelength and exposure output expected.
  3. The individual performing the work is responsible for the safety of anyone entering the use area.
  4. It is preferred that an LBNL staff member shall be present whenever a non-LBNL person (such as a vendor service person) is working on energized laser equipment
  5. Unattended open laser work is not allowed
  6. The LBNL LSO will be notified of the work.

16.4.2 Open Beam Class 1, 2, 3A, 3R, 1M, 2M Lasers or Laser Systems

By their classification or definition, and when used as intended, these laser or laser systems will not present a hazard to the user or those around them. When personnel not familiar with the low-hazard nature of laser operations are present, a sign advising of the low-hazard nature of the operation may be appropriate. In use areas where there is a likely chance of the beams being viewed through a telescope, microscope, binocular, eye loop, or collecting optics, a review by the LSO, or posting of “Caution” signs will be required.

16.4.3 General Requirements for Class 3B and Class 4 Laser Systems

Authorization to use Class 3B or Class 4 lasers or laser systems is granted to laser users through a formal authorization process. The authorizing document is referenced as an Activity Hazard Document (AHD). The AHD and AHD template can be accessed from the LBNL Web site (from the A–Z listing, under A for AHD, or under L for Laser Safety). Only the Supervisor can submit an AHD for review. There are situations where the LSO may approve use of Class 3B and Class 4 lasers or laser systems without an AHD. These are in selective or predetermined situations that will be described in the section on Temporary Work Authorization, or the ANSI term Temporary Control Area. Class 3B and Class 4 laser or laser system use in fiber-based communication systems are exempt from the AHD requirement, but training requirements do exist for service staff.

The requirements for Class 3B or Class 4 laser or laser systems are:

16.4.3.1 Class 3B and Class 4 Use Area Control Measures

The goals of Class 3B and Class 4 laser or laser system controls are to prevent the exposure of authorized and nonauthorized individuals who may enter the control area to hazardous levels of laser radiation. Each particular set of controls will be tailored to the hazards present. The laser hazard review will be conducted by the LSO (see Section 16.4.3.3.2 below for the hazard evaluation method) and the appropriate Supervisor:

16.4.3.2 Medical Surveillance

All Class 3b and Class 4 laser users who will be at LBNL for more than one month must complete a laser eye examination. This examination is performed by LBNL Health Services in Building 26. Alternatively, examinations performed outside of LBNL may be submitted to Health Services for approval and must meet the requirements of the ANSI Z136.1 Standard. For more information, call Health Services at extension 6266 or see PUB-3000, Chapter 3 (Health Services). Prior to receiving an eye examination, laser users can only work under the line-of-sight supervision of an authorized LBNL laser user. An optometrist or ophthalmologist must administer the examination.

Laser eye examinations will be performed as follow-up to suspected eye exposure, or at the request of the LSO or user. It is strongly recommended that the laser user receive an additional laser eye examination on termination of employment.

For those who routinely receive ultraviolet exposure as part of their experimental work, an annual skin evaluation is recommended.

16.4.3.3 Training

All employees and guests who are authorized to work unsupervised with Class 3b or Class 4 lasers must complete two laser safety classes.

16.4.3.3.1 Initial Training

EHS 280
EHS 280 (or its equivalent) is a fundamental laser safety course. In addition, it is highly recommended that anyone who regularly works in a Class 3B or a Class 4 laser area attend this course. The laser safety course is offered regularly and can also be customized for specific laser user groups. All laser operating personnel will have completed LBNL-approved laser safety training prior to working unsupervised with Class 3B or Class 4 lasers.

On-the-Job Training (OJT)
The Supervisor or work leader shall train/orientate staff on the hazards of the specific experimental work to be done as well as the proper alignment techniques and procedures for the safe operation of the specific laser system, experiment, and associated optics. Laser users are responsible for knowing the safety requirements that apply to their specific laser or laser system and for knowing the contents of the applicable activity hazard document. OJT shall include location and mitigation of potential hazardous beams /reflections, hazards associated with the work, and the proper use of all required personal protective equipment (PPE). The depth of OJT must be tied to the responsibilities and degree of hazard. It can apply to the entire experiment or elements of the research work (specific laser systems or experimental operations). This OJT must be documented and signed by the trainer. The format for documenting OJT can be as part of the AHD or as a paper document, which must be available for review. The supervisor/work team lead is ultimately responsible to ensure that all personnel, visitors, and students with access to the laser use area have a clear understanding of the controls associated with laser operation, and that the relevant laser safety procedures are diligently followed.

16.4.3.3.2 Refresher Training

Laser users must participate in refresher training at least once every three years. This is available through the Web as EHS 281. As an alternative, the LSO can offer group-specific refresher training.

16.4.3.4 Hazard Evaluation Method

The following method of safety analysis is recommended for both laser safety review by the LSO, and for laser users in self-assessment of their laser setup. The laser use area should be considered as four discrete components; each component should be evaluated, as follows:

  1. The Laser Source(s)
    1. What class laser(s) is being used?
    2. Does it have any inherent risks?
    3. Toxic gases (i.e., Excimer laser)
    4. Power supply
    5. Cooling lines
  2. Beam Path
    1. Is the beam path entirely enclosed?
    2. Is the beam path entirely open?
    3. Can sections of the beam path be enclosed?
      1. Covers
      2. Beam tubes
    4. Do wavelengths change along the path?
    5. Does the beam intensity change along the path?
    6. Does the beam diameter change along the path?
    7. Does the laser path leave the plane of the optical table (i.e., become vertical directed)?
    8. Does the beam propagate beyond the boundaries of the optical table?
  3. Environment
    1. What type of access control does the laser use area have or need?
      1. Interlock
      2. Posting alone
      3. Card access
    2. Does the beam have a possible direct route out of the control area?
    3. Where should protective eyewear be stationed
    4. Do nonbeam hazards exist in the area, and are they being mitigated?
      1. Electrical
      2. Seismic
      3. Housekeeping
      4. Chemical, etc.
  4. People
    1. Will all who work in the area be authorized laser users?
    2. Do all users have required training?

16.5 Special Topics

16.5.1 Guests and visitors

Guests, visitors, and new employees without LBNL-approved laser safety training (or with incomplete laser safety training) may use lasers ONLY under the line-of- sight supervision of an authorized LBNL laser user. New users may work under these conditions for a maximum of 30 days before completing the training and medical surveillance requirements

16.5.2 Service and Repair Providers

Service and repair providers, whether they are LBNL employees or outside vendors, must be qualified to perform the requested work. They shall receive an orientation to the hazards in the laser use area and be briefed on the AHD controls. Laser users must be aware that they are responsible for the safety of these individuals and their safety compliance with LBNL rules.

16.5.3 Laser Alignment and Beam Manipulation

The majority of laser accidents in research activities occur while aligning the laser or similar beam manipulation activities. All possible steps should be taken to prevent such accidents. These activities require carefully developed and detailed OJT covering hazard identification and mitigation techniques. Only laser users who have received OJT and are authorized by the supervisor, work lead, or designee shall perform laser alignment/beam manipulation activities unsupervised.

The following laser alignment protocols should be in every laser alignment procedure:

16.5.4 Suspected laser injury

Laser users must report all laser accidents no matter how minimal to their supervisor, Health Services, and LSO. Accidental or suspected laser beam exposure is a serious event. The key action is to keep the individual calm.

In the case of suspected laser injury:

The LSO will perform a follow-up investigation on all reported suspected injury incidents. The goal is to determine the factors that led to the incident, and to develop corrective actions to prevent its reoccurrence at any LBNL laser-use site. When appropriate, a Lessons Learned will be generated.

16.5.5 Laser Protective eyewear

The energy emitted from laser or the reflection of a laser beam can present a highly concentrated energy source, sufficient to cause permanent eye injury. Although engineering controls are preferred to mitigate this hazard, it may be necessary or prudent to use laser protective eyewear. The eyewear should be matched to the wavelength (s) emitted and for the laser intensity. Laser protective eyewear must be marked with the optical density of the lens for which protection is provided (OD and wavelength). Fit and visual light transmittance round out the remaining leading factors in selecting laser eyewear. Laser protective eyewear can either be full protection or alignment style.

Full protection will block a direct or reflective strike from the laser source in question for a minimum duration of 10 seconds. Full protection Must be worn whenever one is dealing with solely invisible beams.

Alignment eyewear is an option for use with visible beams and gives partial visibility for beam observation from diffuse or attenuated reflections, but not full protection from the direct beam. Authorization to use alignment eyewear will be specifically stated as part of an AHD. ANSI Z136.7 and European Norm 208 will be used as guidance in selecting the appropriate alignment OD.

In the research setting, there may be times when no commercial laser protective eyewear is available to meet experimental needs. At these times, the user and LSO must re-examine beam controls and, if necessary, select less-than-optimal protective eyewear. See the Laser Safety Web page for an extensive review of parameters for the selection of laser protective eyewear, including suggestions for alignment eyewear OD versus beam output.

16.5.6 Requirements for Laser Use by LBNL Staff Off Site from LBNL

The safety of laser users on site is extremely important to LBNL. Laser safety at off-site locations (even at other DOE facilities) should be equivalent to safety at LBNL. NO LBNL employee shall work in a facility off site where they feel their safety is at risk. If such an occasion arises, stop work and discuss with the LBNL Supervisor or Work Lead (line management) or local management, or contact the LBNL LSO to see what assistance LBNL can grant the host site. Off-site locations fall into two categories: (1) where LBNL has management responsibility and (2) where LBNL does not have management responsibilities. See Chapter 5, Section 5.5 (Off-Site Safety) of PUB-3000 for details on LBNL policy.

LBNL laser safety responsibility on the U.C. Berkeley campus will extend only to the training of LBNL employees working with lasers on campus, as part of their LBNL employment duties. The LBNL LSO will ensure these employees receive equivalent training (including on-the-job training) as LBNL employees working on site, and will have the discretion to grant training credit for equivalent training received on campus (or other institutions).

Consistent with the “Partnership Agreement between UCB and LBNL Concerning Environment, Health and Safety Policy Procedures,” all other laser activities on campus (including DOE-funded research involving lasers, or DOE-funded laser equipment) will be the responsibility of U.C. Berkeley. Also consistent with the agreement, operating safety procedures for lasers on campus will follow campus requirements, and these are expected to be equivalent to the operating procedures at LBNL, as both LBNL and UCB laser safety programs are based on the ANSI Z136.1 standard. Periodic visits, by the LBNL LSO, of LBNL laser users working on campus will be arranged by courtesy of the U.C. Berkeley LSO

16.6 Standards

American National Standards Institute (ANSI) Z136.1, 2000 (or later revision), American National Standard for the Safe Use of Lasers

American National Standards Institute (ANSI) Z136.2, 1997(or later revision), American National Standard for the Safe Use of Optical Fiber Communication Systems Utilizing Laser Diodes and LED Sources

American National Standards Institute (ANSI) Z136.3, 2005 (or later revision), American National Standard for the Safe Use of Lasers in Health Care Facilities

American National Standards Institute (ANSI) Z136.6, 2005 (or current revision), American National Standard for the Safe Use of Lasers in Outdoor Environment

American National Standards Institute (ANSI) Z136.5, 2001 (or current revision), American National Standard for the Safe Use of Lasers in Educational Facilities

29 CFR 1910, Occupational Safety and Health Standards for General Industry

16.7 Related LBNL/PUB-3000 Chapters

16.8 Regulations

Appendix A. Laser Supplies

Table A-1 lists reference sources for information on laser safety items.

Table A-1. Information Sources for Laser Safety Items

Item

Information Source

Warning signs

Laser Safety Web page or LSO

Laser labels

LSO

Eyewear literature

Laser Safety Web page or LSO

Eyewear holders

LSO

Curtain material

Laser Safety Web page


Appendix B. Phone Numbers

Table B-1. Phone Numbers

Job Title or Organization

Individual

Phone Number (510-486-xxxx)

Laser Safety Officer

Ken Barat

2544

Medical Department

6266

Emergency

7911
(or 911 on a cell phone)

_____________________

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