- ANSI Z136.8: Why R&D Labs Should Be Using It
KEN BARAT, CLSO LASERSAFETYSOLUTIONS@GMAIL.COM
In a research setting, whether academic or commercial, researchers and laser safety officers (LSOs) face many challenges and frustrations. One that they should not have to deal with is laser safety guidance that does not represent their work environment. And a new ANSI (American National Standards Institute) standard that has joined the Z136 (Laser Safety) series is ready to step in and save the day.
ANSI Z136.8 (Safe Use of Lasers in the Research, Development and Testing Setting) works in conjunction with ANSI Z136.1 (Safe Use of Lasers) to provide improved guidance to users and LSOs at facilities where research, development and testing of lasers and laser systems are actively performed. This type of laser usage can present many challenges to an LSO because there can be large variations in use by the facility’s personnel and their routine needs to manipulate the optical setup.
These challenges may include (among many others):
• Production of home-built lasers that have not been certified by the Center for Devices and Radiological Health (CDRH).
• Research lasers with varying output characteristics and beam path setups.
• Custom-built housings, barriers and curtains.
• A large volume of users to train and oversee.
• Selection of appropriate eye and skin protection.
• Ensuring the use of proper techniques and PPE (personal protective equipment) during alignment procedures.
• Operating a user facility.
Z136.8 manages to include all the relevant information from Z136.1 in a condensed format that, in conjunction with newly added guidance specific to research and development, acts as an invaluable tool to LSOs at R&D facilities. The standard allows for quick reference to proper guidance on the issues that an R&D LSO faces on a daily basis. It provides LSOs with better professional judgment and support, and increases their ability to be an effective safety consultant in the constantly changing world of research and development.
What is new?
• Discussion of alignment eyewear.
• A section on fiber optics.
• Information on export controls.
• Full-color signage and diagrams.
• New appendixes:
? Sample forms.
? CDRH rules.
? Frequently reported incidents.
• On-the-job training.
• A new approach to hazard analysis.
Since the first laser ANSI standard, laser hazard evaluation has been broken down into three factors: the capability
of the laser to injure people, the environment in which the laser is used and the personnel who may be exposed to laser radiation. These have served the laser-user community well for 40 years. But today’s advances in lasers and their applications in R&D call for an expansion of the hazard evaluation parameters. Therefore, Z136.8 adds the following two factors: the beam path and process interaction.
Today’s beam path can be in fiber; with nonlinear optics, wavelengths can change, laser techniques are tunable; and with chirped pulse amplification, the pulse duration and peak power can be manipulated over a wide range.
Because of these and other beam-path options, the standards committee felt it was important to call out the beam path of hazard evaluation. With process interaction, the use of laser beams to generate high harmonics and ionizing radiation made it clear that this element needed to be called out to the LSO and user for evaluation.
The use of alignment eyewear has been ongoing in the laser community from an early time. The goal is to visualize beams during alignment but still provide some eye protection to the user. This is preferable to having users remove their eyewear and look at the beam with no protection. The challenge for the LSO is what optical density to suggest that allows visibility and reduces the transited beam to a Class-3R level or less. Section 126.96.36.199, “Alignment Eyewear,” addresses the issues with suggestions for both CW and pulsed lasers:
• Use of noncertified lasers and the appropriate administrative, procedural and engineering controls are discussed.
• The special considerations section discusses visitors and spectators, laser-user facilities and export controls, as well as useful information on fiber optics and laser robotics.
• Education and training is expanded to include the importance of on-the-job training for users in the dynamic environment of R&D.
• Updates information on standard operating procedure requirements.
• Discusses the management of multiple types of laser-use areas, including indoor Class-3 and -4 lasers, laser exclusion areas and airspace (includes references to related Federal Aviation Administration and ANSI sources).
• Information on nonbeam hazards has been condensed to R&D-relevant information.
Z136.8 features full-color signage and diagrams, including current ANSI Z136.1- and Z535.2-compliant signage for Class-2 and -2M lasers; Class-3R, -3B and -4 lasers; temporary laser-controlled areas; unattended laser operations; warning signal words; and diagrams and explanations for exterior entryway controls, multiple entry point controls, and Class-4 entryway controls for labs with and without entryway interlocks.
The Z136.8 standard includes three new appendixes as well as all R&D-relevant appendixes from Z136.1. The new appendixes contain useful information not addressed in the main standard, while appendixes pulled from Z136.1 are modified to focus on information that is relevant to the R&D atmosphere.
Appendix B: Sample Forms
• Two sample laboratory audit forms.
• Sample laser program self-evaluation form.
Appendix C: Frequently Reported Incidents
• Discusses the most common causes of accidental eye and skin exposures to laser radiation, and accidents related to nonbeam hazards.
Appendix H: Laser Product Safety Rules
Many engineering controls present in Z136.1 are not found in this standard. To maintain proper emphasis on their importance, “CDRH Sec. 1040.10, Laser Products” is included as guidance for Appendix A: Supplement to Section 1.
• LSO requirements and responsibilities.
• Guidance on laser-safety committees.
• Personnel responsibilities (supervisors and employees).
Appendix D: Education and Training
• Class-1M, -2, -2M and -3R awareness training.
• On-the-job training.
• Laser-pointer awareness.
• Certifying laser products.
Is Z136.8 acceptable to regulatory authorities?
The current and upcoming versions of Z136.1 allow guidance from specialized/application standards, such as Z136.8, to take precedence within the scope of that standard. Therefore, guidance from Z136.8 can be used for R&D-specific applications that may not have been fully addressed or are in conflict with Z136.1. It is up to the discretion of the LSO to determine which specialized standard(s) apply to their particular environment. An outdoor range officer will look toward Z136.6, the Outdoor Laser Standard, rather than Z136.1; R&D safety officers should look to Z136.8 for their specific uses. Remember, Z136.1 is a horizontal standard and was designed to encompass a wide range of laser applications, but it is always expected that the generation of vertical/application standards will provide more specific and germane guidance.
Where are the MPE values?
Z136.8 deliberately does not contain any MPE (maximum permissible exposure) values. Because the Z136 series does not get published in unison, an application standard that contains MPE values may be out of sync with the latest MPE values. For Z136.8 to avoid giving outdated information, its standards committee decided to leave these values and charts out. The committee felt Z136.1 was the proper home for MPE values. This does mean facilities will have to buy two standards to get R&D guidance and the current MPE numbers, but proper safety is worth it.
Some special considerations
• On-the-job training is the most critical training a laser user can receive. Z136.1 has emphasized basic laser safety training and recently addressed refresher training, but hands-on training in the actual laser-use area really makes the difference. Passing a driving test is a far cry from knowing how to drive in traffic or on winter roads, and the same holds for laser-safety training: Knowing about classification is not the same as knowing where the optics on one’s table could direct reflections. Section 5.3 of Z136.8 addresses on-the-job training and underscores its importance and documentation.
• An LSO reviewing the typical home-made laser diode system will find it does not contain the same engineering controls of a commercial laser: It will be missing an emission indicator; there may be no key in the power supply; even at the Class-4 level, the system may not contain a remote interlock connector or emergency shutoff device. And the whole setup might be on a small movable breadboard.
• Prior to Z136.8, the only laser standard that addressed the use of laser fibers was Z136.2 (Use of Lasers & LEDs in Telecommunications). Today, the world of fibers transporting laser beams is well beyond communications, from sensors to turnkey femtosecond systems. For example, the initial pulse for the National Ignition Facility is transported from the master oscillator room (a few nanojoules) to the laser bay by fiber optics. This leads to amplification to the target chamber (1.9 MJ).
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