Laser Use at Subaru Telescope (NAOJ) Laser Safety... · 2018-04-17 · Subaru Telescope National Astronomical Observatory of Japan Rev.06/2017! ! page!3! • Class 3B lasers (Medium

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   1  

Laser Use at Subaru Telescope (NAOJ)

Laser Safety Policy

1. Introduction

This program applies to all lasers and laser systems operated by Subaru Telescope. This program maintains compliance with ANSI Z136.1-2007 American National Standard for Safe Use of Lasers (with the exception of baseline eye exams).

In accordance to the Subaru Telescope Safety Policy, Principal Investigator of any project who will be using a Laser inside Subaru Telescope facilities (Hilo Laboratory or in Subaru Telescope at MaunaKea), is required to read and follow the procedure related to the Laser Class used and described in this document.

The proper execution of this program will permit the laser use approval from the Laser Safety officer and will assure that laser exposures are always below the maximum permissible exposure (MPE) limits.

For any questions or remarks, please contact the Subaru Telescope Laser Safety Manager / Officer at [email protected].

2. The Role of Subaru Laser Safety Manager / Laser Safety officer

An individual designated as the Laser Safety Manager (LSM) and/or Laser Safety Officer (LSO) has the responsibility and authority to assure compliance with this program. The LSM /LSO shall:

◦ Assure the proper classification of all lasers ◦ Effect hazard evaluations for all class 3b and 4 lasers ◦ Determine appropriate control measures for all class 3b and 4 lasers ◦ Assure that all laser personnel receive appropriate safety training ◦ Monitor the program and assure compliance (audit shall be conducted annually). ◦ Maintain program records including:

§ Laser hazard analysis reports for all class 3b and 4 lasers § Training records for all operators of class 3b and 4 lasers § Standard Operating Procedures for all class 4 lasers § Approvals of alternate laser control measures, audit and report.

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   2  

The LSM/LSO has final authority in determining laser control measures and may approve alternate controls when these are appropriate based on the judgment of the LSM/LSO. Class 3b and 4 lasers shall be operated only with the written approval on the LSM/LSO. The LSM/LSO shall have the authority to terminate laser operations at any time.

3. Laser Classes definitions and procedurals requirements

• Class 1 lasers (exempt Lasers) and laser systems cannot emit laser radiation above the safe level during normal operation: visible light at a power level lower than 0.39 mW. Class 1 systems may contain higher class lasers and may produce laser hazards if operated with interlocks defeated. Only authorized personnel may operate class 1 laser systems with interlocks defeated. Operators are exempt from the requirements of the Laser Safety Program but shall follow the Laser Hazard Control Measures described in §6.

• Class 2 lasers (Low Power Visible Lasers) emit visible light only at a power level of 1 mW or less. All class 2 lasers operate in the visible portion of the electromagnetic spectrum of 400 – 700 nm : the normal aversion response to bright light is adequate protection. However, if the laser is viewed with certain optical aids or if the operator is staring into the beam of a class 2 laser more than 0.25 seconds, these lasers may present some potential hazard. Operators of class 2 lasers and laser systems shall receive a laser safety briefing and follow the Laser Hazard Control Measures described in§6.

• Class 3R lasers (Medium Power Lasers and laser systems) emit any wavelength and operate at 1 to 5 mW of continuous-wave. This class of lasers may produce laser hazards under some viewing conditions, but the hazards are limited and the control measures for safe use are straightforward. Most laser pointers fall in this class. Operators of class 3R lasers and laser systems shall receive a laser safety briefing from Subaru Laser Safety Officer, and follow the Laser Hazard Control Measures described in §6.

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   3  

• Class 3B lasers (Medium Power Lasers and laser systems) operate at 5 to 500 mW. This class of laser is eye hazards for intrabeam viewing, even for momentary exposures. Class 3b lasers shall be operated only in laser controlled areas by authorized operators. Principal investigators of a class 3B laser must meet the following requirements:

o Obtain a Laser use Authorization from the Subaru Laser manager/Laser safety Officer prior use: please fill-in the Laser Use Authorization application form.

o Provide and document laser safety training for personnel using class 3B laser equipment. If the personnel expected to use the laser is not trained, please contact immediately your laboratory and/or Subaru laser safety officer.

o Register all class 3B lasers to Subaru Telescope: please fill-in the Laser Equipment Registration form.

o Strongly recommended: write a Standard Operating Procedure (SOP) for the class 3B laser operation (see §5 in this document).

o Follow the Laser Hazard Control Measures for class 3B described below (§6).

• Class 4 lasers (High Power Lasers and laser systems) operate at greater than 500mW and can emit at any wavelength. Class 4 lasers are eye, skin, fire, and diffuse reflections hazard. The most stringent control measures have been established for these lasers. Specific control measures to prevent eye and skin exposure to direct and diffusely reflected beam are required. Class 4 lasers shall be operated only in laser-controlled areas by authorized operators. Principal investigators of a class 4 laser is responsible for meeting the following requirements:

o Obtain a Laser use Authorization from the Subaru Laser manager/Laser safety Officer prior use: please fill-in the Laser Use Authorization application form.

o Provide and document a laser safety training for personnel using class 4 laser equipment. If the personnel expected to use the laser is not trained, please contact immediately your laboratory and / or Subaru laser safety officer.

o Register all class 4 lasers to Subaru Telescope: please fill-in the Laser Equipment Registration form.

o Mandatory: write a Standard Operating Procedure (SOP) for the class 4 laser operation (see §5 in this document).

o Follow the Laser Hazard Control Measures for class 4 described below (§6).

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   4  

4. Operators Safety Training Requirements and medical surveillance

All operators of class 1, 2, and 3a lasers and laser systems and all incidental personnel who may be allowed to enter laser controlled areas shall receive a laser safety briefing before operating the laser or entering the controlled area.

All operators of class 3b and 4 lasers shall receive approved laser safety training and meet Subaru Laser Safety Officer before operating the laser.

Baseline eye exams are not required. An eye exam is required immediately following a suspected hazardous exposure.

For any questions concerning the Laser Safety training of your personnel please contact your laboratory and or Subaru Laser Safety Officer.

5. Standard operating procedures for class 3B and 4 Lasers

Standard operating procedure is mandatory for class 4 lasers and strongly recommended for class 3B lasers. The SOP can be written by the principal investigator of the project after reading the General Hazard Control Measures described in §6. A SOP draft is provided by the Subaru Laser Safety Manager/Officer.

The SOP will have to include the following information:

• A Statement that Class 3B and 4 Lasers may only be operated, maintained, and serviced by authorized personnel listed on the Laser User Authorization, or by the manufacturer’s representative

• A description of the safety features • A full description of the protective equipment that personnel operating the laser must use • A detailed operating procedure from the laser start-up to shut-down • A specific alignment procedure • A Safety checklist, either provided with the equipment or developed by the PI of the project • An Emergency call list (please contact Subaru Safety manager for local contacts) • Emergency instructions

The SOP will have to be kept near the laser, readily available for use by operators and service personnel.

In case of modification of the laser system procedure, please inform the Subaru Laser Safety Officer/Manager. An update of the SOP and Laser User Authorization might be required (see the Laser User Authorization amendment form).

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   5  

6. Laser Hazard Control Measures

Potential hazards exist to all individuals working near a laser system. Such individuals should be warned of the existence and location of lasers, and of the meaning of the warning labels for all classes of lasers.

The goal of control measures is to reduce the possibility of human exposure to hazardous laser radiation and non-beam hazards.

Particular attention should be given to the environment where the laser is used. This factor should be considered together with the class and application of the laser for determining the control measures to be applied. We describe in this paragraph the general considerations for work with lasers depending on the laser hazard class. Principal Investigators are required to follow these control measures when installing and using a laser at Subaru Telescope.

For ALL CLASSES, here a list of basic elements to be considered:

• The number and class of lasers • The laser location • The presence (access) of uninformed, unprotected personnel • The permanence of beam paths • The presence of objects that may have specular surfaces or reflecting objects near the beam path • The use of optical devices such as lenses, etc.

Note: control measures may be broken down to two types administrative controls, such as signage, procedures, etc., and engineering controls, such as beam housings, shutters, etc. Tables 1 and 2 (ANSI Z136.1-2007) at the end of this paragraph, provides a summary of these control measures required for ALL CLASSES LASERs:

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   6  

Class 1

Class 1 Lasers are exempt from any control measures in absence of additional hazardous optically aided viewing system (additional optics in the path). If optically aided viewing is to be conducted, control measures shall be followed to prevent exposure of laboratory personnel to levels in excess of the Maximum Permissible Exposure (MPE)1 for direct irradiation of the eye.

Many Class 1 lasers are composed of more powerful lasers contained within a protective housing. If the Class 1 laser has an enclosed Class 3B or 4 laser, interlocks should be provided on any removable parts of the housing, or the laser should have a service access panel that is either interlocked or requires a tool for removal.

If the protective housing is removed, control measures appropriate for the enclosed laser class shall be followed.

Class 2

The laser beam should not be purposefully directed toward the eye of any person. Alignment of the laser optical systems (mirrors, lenses, beam deflectors, etc.) should be performed in such a manner that the primary beam, or specular reflection of the primary beam, does not expose laboratory personnel to levels above the MPE1 for direct irradiation of the eye.

Work areas should be posted with a warning label or sign cautioning users to avoid staring into the beam or directing the beam toward the eye of individuals.

If the MPE1 is exceeded, design viewing portals and/or display screens to reduce exposure to acceptable levels.

If the Class 2 laser has an internal Class 3B or Class 4 laser, interlocks should be provided on any removable parts of the housing, or the laser should have a service access panel that is either interlocked or requires a specialized tool for removal. If the protective housing is removed, control measures appropriate for the enclosed laser class should be followed.

Class 2 warning sign : DANGER, Laser Radiation – Do Not Stare into Beam or View Directly With Optical instruments

                                                                                                               1  If  the  Maximum  Permissible  Exposure  (MPE)  of  your  laser  is  unknown  at  the  time  of  the  laser  installation/test  inside  Subaru  Telescope  facilities,  please  contact  immediately  the  Subaru  Laser  safety  officer.  

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   7  

Class 3R

The work area should be posted with a warning label or sign cautioning users to avoid staring into the beam or directing the beam toward the eye of individuals.

Removable parts of the housing and service access panels should have interlocks to prevent accidental exposure. A permanent beam stop or attenuator may also be used.

If the MPE2 is exceeded, design viewing portals and/or display screens to reduce exposure to acceptable levels. Alignment procedures should be designed to ensure the MPE is not exceeded.

Class 3R laser equipment warning sign: DANGER, Laser Radiation (or laser symbol) - Avoid Direct Eye Exposure

Class 3B : Medium Power Laser !

These lasers are used in areas where entry by unauthorized individuals can be controlled. If an individual who has not been trained in laser safety must enter the area, the laser operator or supervisor should contact require the Subaru Laser Safety officer authorization, instruct the individual as to safety requirements and must provide protective eyewear, if required.

If the entire beam is not enclosed or if a limited open beam exists, the laser operator, supervisor or laser safety officer should determine a Nominal Hazard Zone (NHZ). An alarm, warning light or verbal countdown should be used during use or start up of the laser.

The controlled area should

• have limited access to spectators, • have beam stops to terminate potentially dangerous laser beams, • be designed to reduce diffuse and specular reflections, • have eye protection for all personnel, and not have a laser beam at eye level, • have restrictions on windows and doorways to reduce exposure to levels below the

MPE2, and require storage or disabling of the laser when it is not being used.

If the MPE2 is exceeded, design viewing portals and/or display screens to reduce exposure to acceptable levels. Alignment procedures and collecting optics should be designed to ensure the MPE is not exceeded.

                                                                                                               2  If  the  MPE  of  your  laser  is  unknown  at  the  time  of  the  laser  installation/test  inside  Subaru  Telescope  facilities,  please  contact  immediately  the  Subaru  Laser  safety  officer.  

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   8  

Only authorized, trained individuals should service the laser. Approved, written standard operating, maintenance and service procedures should be developed and followed (see §3).

Class 3B laser equipment warning sign: DANGER, Laser Radiation (or laser symbol) - Avoid Direct Exposure to Beam

Class 4: HIGH Power Laser !

In addition to the control measures described for Class 3B, Class 4 lasers should be operated by trained individuals in areas dedicated to their use.

Failsafe interlocks should be used to prevent unexpected entry into the controlled area, and access should be limited by the laser operator to persons who have been instructed as to the safety procedures and who are wearing proper laser protection eyewear when the laser is capable of emission.

Laser operators are responsible for providing information and safety protection to untrained personnel who may enter the laser controlled areas as visitors. Note that any untrained personnel visit requires a Subaru Laser Officer authorization.

The laser area should be

• restricted to authorized personnel only • designed to allow for rapid emergency access • equipped with a device that allows for deactivation of the laser or reduction of the output

to below the MPE • designed to fulfill Class 3B controlled area requirements • designed with entry safe controls • designed such that the laser may be monitored and fired from a remote location • (for pulsed systems) have interlocks designed to prevent firing of the laser by dumping

the stored energy into a dummy load • (for continuous wave systems) have interlocks designed to turn off the power supply or

interrupt the beam by means of shutters. • The beam path must be free of specular reflective surfaces and combustible objects and the beam

terminated in a non-combustible, non-reflective barrier or beam stop.

Class 4 laser equipment warning sign: DANGER, Laser Radiation (or laser symbol) - Avoid Eye or Skin Exposure to Direct or Scattered Radiation

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   9  

TABLE1: Engineering Control Measures for the Four Laser Classes

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   10  

TABLE 2: Administrative and Procedural Control Measures for the Four Laser Classes

                          Subaru Telescope National Astronomical Observatory of Japan

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7. Additional Requirements for Invisible laser Radiation – i.e. IR and UV Lasers

Since infrared (IR) and ultraviolet (UV) wavelengths are normally invisible, particular care must be taken when using these types of lasers. In addition to the recommended control measures that apply for each laser classification, the following should also be employed:

Infrared

The collimated beam from a Class 3 laser should be terminated by a highly absorbent backstop wherever practicable. Many surfaces which appear dull visually can act as reflectors of IR.

The beam from a Class 4 laser should be terminated in a fire resistant material wherever practicable. Periodic inspection of the absorbent material is required since many materials degrade with use.

Areas that are exposed to reflections from Class 3 or 4 lasers, at levels above the MPE, should be protected by appropriately screening the beam or target area with IR absorbent material. This material should be fire-resistant for use with Class 4 lasers.

Ultraviolet

Exposure to UV should be minimized by using shield material which attenuates the radiation to levels below the appropriate MPE for the specific wavelength.

Special attention should be given to the possibility of producing undesirable reactions in the presence of UV, for example, ozone formation.

8. Note for Laser optical fiber Laser systems, which employ optical fiber, are considered enclosed systems with the optical fiber forming part of the enclosure.

Take these special precautions in addition to the laser control measures required by hazard classification:

• If disconnection occurs and the resulting laser radiation is below the applicable MPE by engineering controls, connection or disconnection can be done in an uncontrolled area.

• Connection or disconnection must be done in an appropriately controlled area during operation if the laser radiation is greater than the applicable MPE.

                          Subaru Telescope National Astronomical Observatory of Japan

Rev.  06/2017       page   12  

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For any questions regarding these measures,

please contact the Subaru Laser Safety officer:

[email protected]

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