Laser Safe Operation Protocol

A safety -approved Laser Safe Operating Protocol (LSOP) is required for all Class 3b and 4 lasers. 
The Site safety Leader may, however, recommend or require a LSOP for any laser or laser
application where it is deemed necessary for ensuring adequate safety controls.

The investigator prepares the LSOP. The LSOP shall include all information outlined in Appendix 8-
B and shall receive safety committee approval before the laser is operated.

General Safety Requirements

2. Each laser and laser application shall meet the safety standards of ANSI Z136.1 or an
equivalent level of safety approved by the safety committee.

3. Each Class 3a, 3b, and 4 lasers shall be used in a controlled area in order to restrict access
of unauthorized personnel. The level of control depends on the laser class.

Laser Safety Training

All users of Class 2, 3a, 3b, and 4 lasers shall receive training by the investigator and read "Laser
Safety Training" (see Appendix 14). All users of Classes 3b and 4 lasers shall be re-certified in laser
safety at intervals not to exceed two years.

Upon completion of training, the investigator and user must complete an "Authorized Laser User
Certification" form (Appendix 8-D).

Laser Medical Surveillance

All investigators and users who are routinely engaged in work where they may be exposed to laser
radiation from a class 3b or 4 laser must participate in the laser medical surveillance program.

The purpose of laser medical surveillance is two fold. The first purpose is to establish a baseline of
ocular conditions before exposure to laser radiation. The second purpose is to detect and document,
as early as possible, ocular damage in the event of a suspected exposure incident. Both purposes
serve to assess the effectiveness of control measures and to promptly institute appropriate
therapeutic measures.

Laser medical surveillance includes a preliminary baseline eye exam. Additional eye exams are
required immediately in the event of exposure or suspected exposure to laser radiation above the
 Maximum Permissible Exposure (MPE) established in 105 CMR 121.600 (pulse and wavelength
dependent). An eye exam may be required upon termination of laser work or upon termination of
employment at Hampshire College.  

Investigators should contact the environmental health and safety office to schedule baseline eye
exams and to report suspected exposures above the MPE.

Laser Warning Signs

Laser warning signs must meet the standards of ANSI Z136.1. Class 1 lasers do not require a sign.
The word CAUTION shall be used with all Class 2 and Class 3a lasers. The word DANGER shall be
used with all Class 3b and Class 4 lasers. Signs, including the appropriate precautionary statements
detailed in ANSI Z136.1, must be described in the LSOP.

All warning signs and labels shall be displayed conspicuously in locations where they best serve to
warn individuals of potential safety hazards. Normally, warning signs are posted at entryways (e.g.,
on doors) to laser controlled areas. 

Warning labels are affixed to the lasers in a conspicuous location. The laser investigator should
remove laser warning signs if the laser has been removed from the room or area. 

Safe Laser Practices

The following control measures are recommended as a guide to safe laser use. If any of these
control measures cannot be accomplished, the LSOP must describe alternative controls to provide
comparable protection. These practices are taken from ANSI Z136.1. Refer to that document for
additional details.

The purpose of controls is to reduce the possibility of exposure to the eye and skin to hazardous
laser radiation and to control other hazards associated with operation and maintenance of laser
devices.

Engineering controls (physical features incorporated into the design or installation of the laser
system) are the preferred method of control. If engineering controls are not feasible, then
administrative and procedural controls and personal protective equipment should be used.  

Engineering Controls

1. Protective housings should be provided for all classes of lasers.

2. Protective housings that enclose Class 3b or 4 lasers should have an interlock system that is
activated when the protective housing is opened.

3. Enclosure of the laser equipment or beam path is the preferred method of control.
4. Service access panels intended to be removed by service personnel only and which permit
direct access to laser radiation associated with Class 3b or 4 lasers should either be interlocked or
require a tool for removal and have an appropriate warning sign.

5. Class 3b lasers should be provided with a master switch. Class 4 lasers must have a master
switch. The master switch should be operated with a key or coded access (e.g., computer
authorization password).

6. Lasers with viewing portals should have means, (e.g., interlock, filter, attenuators), to
maintain laser radiation below the MPE.

7. Class 3b lasers should be provided with a remote interlock connector. Class 4 lasers must
be provided with a remote interlock connector. The interlock connector provides electrical connection
to an emergency master disconnect or to a room, or area interlock.

8. Class 3b lasers should be provided with a permanently attached beam stop attenuator. A
Class 4 laser must be provided with such an attenuator.

9. An alarm, warning light, or verbal countdown command should be used with a Class 3 laser
and must be used with a Class 4 laser to signal activation. For Class 4 lasers there must be an
emission delay to allow action to be taken to avoid exposure.

10. When possible, Class 4 lasers should be fired and monitored from a remote position.

Administrative and Procedural Controls

1. In applications using Class 3b or 4 lasers with unenclosed beam paths, the Nominal Hazard
Zone (NHZ: space within which the level of direct, reflected, or scattered radiation during operation
exceeds the applicable MPE) must be established. A laser-controlled area must be established in
this zone, and appropriate control measures established.

2. Class 3a, 3b, and 4 lasers must only be operated and maintained by authorized investigators
and users. Student users must be directly supervised when working with Class 4 lasers.

3. LSOPs are required for all Class 3b and 4 lasers.

4. User training is required for all Class 2, 3a, 3b, and 4 lasers.

Recommended Work Area Controls

1. Entry controls must prevent unauthorized people from being present when the laser is
energized or about to be energized.

2. The illumination in the area should be as bright as practicable in order to constrict the eye
pupils of users. 

3. The potential for specular reflections should be minimized by shields and by removal of all
unnecessary shiny surfaces.

4. Windows to hallways or other outside areas should be provided with adequate shades or
covers.
5. The main beams and reflected beams should be terminated by material that is non-specular
reflective and fireproof. This is required for any accessible laser for which the MPE could be
exceeded.

6. An active laser should never be left unattended unless it is part of a controlled environment. 

7. Good housekeeping should be practiced to ensure that no device, tool, or other reflective
material is left in the beam. 

Recommended Laser Use Controls

1. The manufacturer's recommendations for safe laser use must be followed unless alternative
methods are described and approved in the LSOP.

2. Avoid looking into the primary beam at all times.

3. Do not aim the laser with the eye; direct reflections can cause retinal damage.

4. Avoid looking at the pump source.

5. Clear all personnel from the anticipated path of the beam.

6. Before operating the laser, warn all personnel and visitors of the potential hazard, and
ensure all safety measures are satisfied.

7. Be especially cautious around lasers that operate at invisible light frequencies.

8. Do not wear bright, reflective jewelry or other objects. 

Laser Protective Equipment

Normally, all persons who work in areas where there is radiation from Class 3b or Class 4 lasers
must wear approved laser eyewear if the potential exists for exposure in excess of the MPE.
Exceptions may be approved if wearing protective eyewear produces a greater safety hazard than
when it is not worn. Exceptions shall be described in the LSOP.

The eyewear to be used will depend on the wavelength(s) and intensity of the accessible radiation.
Keep in mind:

 No matter how good the glasses, no protection is provided unless worn.

 All safety glass may shatter, and all plastic lenses may melt when maximum irradiance or
radiant exposure for the particular lens is exceeded.
 Laser safety glasses may not provide eye protection other than with the laser for which they
are specified, unless the frequency produced is the same and power output is not greater.

In some cases, other protective equipment, such as clothing to protect the skin, may be
required. Such requirements must be addressed in the LSOP.