Laser SOP's Training & Safety

Standard Operating Procedures and Interlocks

Laser Safety Standard Operating Procedure

Each laser shall have a Laser Safety Standard Operating Procedure (SOP) written for its operation. An SOP is the same as a laboratory/laser/research specific protocol that specifies safe use and procedures for the laser system. The SOP must be present at the operating console or control panel of the laser. The SOP shall include, at a minimum, operating instructions, safety eyewear parameters and instructions for proper use, interlock instructions, and a checklist for operation. The SOP shall include clear warnings to avoid possible exposure to laser and collateral radiation in excess of the MPE. The SOP shall be available for inspection by the University LSO at any time.

Safety Interlocks and Warning Systems

A safety interlock is a device that automatically prevents human access above MPE limits.

Safety interlocks shall be provided for any portion of the protective housing that by design can be removed or displaced without the use of tools during normal operation or maintenance, and thereby allows access to radiation above MPE limits.

Adjustment during operation, service, testing, or maintenance of a laser containing interlocks shall not cause the interlocks to become inoperative except where a laser controlled area, as specified in subparagraph §289.301(r)(3)(E) of the referenced regulation, is established.

For pulsed lasers, interlocks shall be designed to prevent firing of the laser; for example, by dumping the stored energy into a dummy load and for CW lasers, the interlocks shall turn off the power supply or interrupt the beam (i.e., by means of shutters).

Each class IIIb or IV laser system shall provide visual or audible indication during the emission of accessible laser radiation. The indication shall occur prior to emission of radiation with sufficient time to allow appropriate action to avoid exposure. Any visual indication (e.g., lights) shall be visible through protective eyewear for the wavelength of the laser so that eyewear need not be removed to see it.

Alternatives to Safety Interlocks

The regulations recognize that in situations where an engineering control (automatic safety interlock) may be inappropriate.

Where safety latches or interlocks are not feasible or are inappropriate a controlled area shall be established and the following shall apply:

  1. All authorized personnel shall be trained in laser safety and appropriate personal protective equipment shall be provided and worn upon entry.
  2. A door, blocking barrier, screen, or curtains shall be used to block, screen, or attenuate the laser radiation at the entryway. The level at the exterior of these devices shall not exceed the applicable MPE, nor shall personnel experience any exposure above the MPE immediately upon entry.
  3. If a laser is energized and operating at class IV levels then at the entryway there shall be a visible or audible signal and other appropriate signage indicating laser operations. This indicator may be interfaced with the laser itself, the power supply, or manually operated in accordance with the SOP requiring its use.
    1. For indoor controlled areas, during tests requiring continuous operation, the individual in charge of the controlled area may momentarily override the safety interlock. The sole purpose is to allow access to other authorized persons if it is clearly evident that there is no optical hazard at the entry area and protective eyewear is worn by the entering person.
    2. For outdoor controlled areas (such as atmospheric tests) the Permittee or Laboratory LSO must contact the appropriate agency as necessary and must notify the University LSO three working days prior to operation of class IV levels of laser energy.
    3. When removal of panels or protective covers and/or overriding interlocks becomes necessary, such as for servicing, testing or maintenance and laser radiation exceeds the MPE, a temporary controlled area must be established and posted.

Signage

Click Here for Template

The Laboratory Laser Safety Officer is responsible for ensuring that appropriate signage is displayed at all potential entrances to the area where lasers are in use.  The signs must be designed in accordance with ANSI Z535. 

A CAUTION sign should be used for Class 2 and 2M Lasers.

A DANGER sign should be used for Class 3R and MUST be used for class 3B and 4 Lasers.

Sign information shall conform to the following specifications:

  1. Above the sunburst, precautionary instructions or protective action details are inserted such as:
    1. Laser Protective Eyewear Required
    2. Invisible Laser Radiation
    3. Knock Before Entering
    4. DO NOT ENTER when light is illuminated
    5. Restricted Area
  2. Below the sunburst, the type of laser (i.e. Nd:YAG, Helium-Neon, etc.), the emitted wavelength, pulse duration (if applicable), and maximum output SHALL be written
  3. The bottom right hand corner SHALL include the class of laser or laser system.

Laser Safety Sign Example

Training

Every person who operates or works with a laser shall complete training in laser safety provided by the University or University LSO-approved equivalent. This training is referred to as the General Laser Safety Training is offered as an online course through Environmental Health and Safety in The Office of Risk Management. Persons completing General Laser Safety Training shall also complete specific laser safety training given by the Permittee or Laboratory LSO. No person may work in a NHZ prior to completing both laser safety training classes. All training must be documented.

Other Safety Training Considerations

Persons working in a laboratory with lasers but not working directly in the NHZ shall be made aware of the various wavelengths and other operating parameters by the laser operator/users. Training shall include general hazard awareness and precautions to be followed. This training will be given and documented by the Permittee or Laboratory LSO.

Persons working with tunable lasers, or any laser which is frequency doubled or frequency tripled, shall be aware of the effect of frequency manipulation and shall choose protective eyewear which will provide protection for the effective wavelength of the laser. This training will be given and documented by the Permittee or Laboratory LSO.

Personal Protective Equipment

Protective Eyewear

Each Permittee shall provide protective eyewear that meets the requirements of 25 TAC §289.301(t)(1). The eyewear shall be located where persons who operate the laser have unrestricted access to the eyewear. The eyewear shall be worn during any operation where a class IIIb or IV beam is not enclosed. This normally includes alignments. Training on identification, proper fit, location, and use of eyewear shall be included in the specific laser safety training.

Protective eyewear shall meet the following requirements:

  1. Provide a comfortable and appropriate fit all around the area of the eye
  2. Be in good physical condition to ensure the lenses retain all protective properties during its use
  3. Be of optical density adequate for the laser energy involved
  4. Have the optical density or densities and associated wavelengths permanently labeled on the filters or eyewear
  5. Be examined at intervals not less than 12 months, to ensure the reliability of the protective filters and integrity of the holders. Unreliable eyewear shall be discarded and replaced.
  6. The optical density of the protective eyewear shall be appropriate for the specific frequency and pulse length of the laser beam in use, and shall provide reduction of the incident energy to less than the MPE of the laser. It is important to include the pulse length and frequency of pulse repetition of pulsed lasers in selecting appropriate protective eyewear.

Skin protection

When there is potential for skin exposure to levels exceeding the skin MPE for the laser, persons in the controlled area shall wear appropriate clothing, gloves, and/or shields.

Surveys and Records

Each Laboratory LSO shall survey the laboratory containing the laser(s) for which the Permittee is responsible.  The survey shall be performed using the Laser Survey Form.  The survey shall be performed at least annually, and shall be performed prior to operating a laser for the first time after assembly, maintenance, or modification of the beam path, operating wavelength, or power level.  Surveys are to be performed by the Permittee or the Laboratory LSO.  Survey records shall be retained for inspection by the University LSO.  The University LSO or their designee will perform an annual survey as well. 

Records of Surveys, Training, NHZ and MPE calculations, and other laboratory-specific information shall be maintained in the laboratory, and shall be available for inspection/review by the University LSO at any time.