CHAPTER V- Laser Hazard Control
5.1 Overview of Hazard
In general, the following control measures are required for
Class IIIb and IV lasers:
- Access restrictions including key master switch,
interlocked entry or beam enclosure.
- Training of operators and personnel working on or near
lasers (on site or general).
- Posting and labeling of rooms and equipment, to include a
warning light in the hallway or access entrance.
- Protective eye wear and clothing.
- Engineering controls such as beam stops, curtains, and
The exact combination of these control measures depends on
the power and type of laser, laser environment, and procedures
conducted with laser equipment. The LSO approves control
measures prior to operation of lasers.
5.2.1 Master Switch
Class IIIb and IV lasers must have a master switch that is
controlled by a key or coded access. Access by key or code must
only be provided to trained operators and other personnel
approved by the LSO. Exceptions to this requirement may be
approved by the LSO provided other engineering and
administrative controls are used to prevent unauthorized use of
laser equipment. 5.2.2 Interlocked Entry
Entry to rooms containing Class IV lasers and laser systems
must be interlocked with the laser to prevent unexpected entry
of personnel while the laser is in operation. These interlocks
must be engineered such that:
- Rapid egress is allowed at all times and admittance to the
laser area is allowed under emergency conditions.
- For emergency conditions, a control disconnect switch,
panic button, or equivalent device must be available for
deactivating the laser.
- During continuous operation of a laser, the individual in
charge of the interlocked room may momentarily override the
safety interlocks to allow access to other authorized
personnel if it is clearly evident that there is no optical
radiation hazard at the point of entry and if the necessary
protective devices are being worn by the entering personnel.
Exceptions to these requirements may be approved by the
Radiation Safety Committee provided alternate engineering and
administrative controls are used to prevent unexpected entry of
personnel into a hazardous area during laser operations.
5.2.3 Exceptions for Lasers Utilizing Beam
In applications of laser or laser systems where the entire
beam path is enclosed, certain access restrictions are not
needed. See section 5.8 and 5.9. 5.3 Training of
Operators and Personnel Working on or near Lasers
- Fundamentals of laser operation (physical principles,
- Bio effects of laser radiation on the eye and skin.
- Relations of specular and diffuse reflections.
- Non radiation hazards of lasers (electrical, chemical,
reaction by products, etc.).
- Laser and laser system classifications.
- Control measures.
- Overall management and employee responsibilities.
- Medical Surveillance.
5.4 Posting and Labeling of Rooms and Equipment
5.4.1 Equipment Labels
5.5 Protective Eye wear and
All classes of lasers or laser systems (except Class I) are
required to contain warning labels by the Federal Laser Product
Performance Standard. Manufacturers place these labels on laser
equipment. These labels must not be removed. Equipment modified
or constructed at ASU shall be provided with labels that are
clearly visible during operation and affixed to the laser
housing or control panel. Labels must be placed on both laser
housing and control panel when these are separated by more than
2 meters. Label design and verbiage are provided by the LSO.
5.4.2 Posting of Rooms
Areas containing Class IIIb or IV lasers must be posted with
appropriate signs. The design and verbiage of the sign must be
approved by the LSO.
5.5.1 Eye Protection Devices.
5.6 Engineering Controls
Eye protection devices specially designed for protection
against radiation from lasers must be used by all personnel
working with or near lasers during laser operation unless
engineering, procedural, or administrative controls are used to
eliminate likely exposure.
All protective eye wear must be clearly labeled with the
optical density and wavelength for which protection is afforded.
In addition, eye wear must be marked with a unique
identifying label that will assist in maintaining inspection and
inventory records required by ARRA regulations.
Eye wear will be inspected by ORS staff during semi annual
laser inspections. Protective eye wear will be removed from
service if damaged or otherwise unable to provide protection
adequate for laser equipment in use. For laser eye wear, the ORS
has a list of vendors and registrants inventory. 5.5.2
Where personnel may be exposed to levels of radiation that
may damage the skin, protective clothing is required. The LSO
determines the need for protective clothing and the type of
clothing to be used.
5.6.1 Beam Enclosures
Beam enclosures should be used whenever practical. Use of
enclosures will significantly reduce the need for other
engineering or administrative controls (see Sections 5.8 and
5.7 Administrative Controls
5.6.2 Activation Warning Systems
Inside the laser control area, an alarm (for example, an
audible sound such as a bell or chime), a warning light (visible
through protective eye wear), or a verbal "countdown" command
must be used with Class IIIb and Class IV lasers or laser
systems during activation or startup.
Distinctive and clearly identifiable sounds which arise from
auxiliary equipment (such as a vacuum pump or fan) and which are
uniquely associated with the emission of laser radiation are
acceptable as an audible warning.
A warning light outside the control area must be used with
Class IIIb and IV lasers. (The ORS has a list of suitable light
5.6.3 Emission Delay
For operation of Class IIIb or IV lasers or laser systems,
the warning system must be activated a sufficient time prior to
emission of laser radiation to allow appropriate action to be
taken to avoid exposure to the laser. 5.6.4 Window and
All windows, doorways, open portals, etc., must be either
controlled or restricted in such a manner as to prevent escape
of potentially hazardous radiation. Typically curtains at door
ways are required for Class IIIb and IV lasers in open beam
configurations to prevent escape of potentially hazardous
radiation. (The ORS has a list of suitable barrier and curtain
5.7.1 Standard Operating Procedures
Written procedures should be established for operation,
alignment, and maintenance of lasers at ASU. The LSO may require
these procedures as part of the approved control measures.
5.7.2 Alignment Procedures
Alignment of laser optical systems (mirrors, lenses, beam
deflectors, etc.) must be performed in such a manner that the
primary beam, or a specular or diffuse reflection of a beam,
does not expose the eye to dangerous levels of radiation.
Written procedures outlining alignment methods may be
required. The use of low power (Class I or Class II) visible
lasers for path simulation of higher power lasers is recommended
for alignment of higher power Class IIIb and Class IV visible or
invisible lasers and laser systems.
Experience has shown that a significant ocular hazard may
exist during alignment procedures. (The ORS can assist in
developing a record of alignment procedures.) 5.7.3
Visitors and Spectators
Spectators shall not be permitted within a laser area during
operation of a Class IIIb or Class IV laser or laser system
can help registrants ensure visitors obtain the adequate
5.7.4 Servicing of Lasers
- Specific protective measures for visitors and spectators
have been approved by the LSO.
- The degree of hazard and avoidance procedure has been
explained to spectators.
- Appropriate protective measures are taken.
Personnel who require access to Class IIIb or Class IV lasers
or laser systems contained within protective housing or
protected area enclosure for the purpose of service must comply
with the appropriate control measures of the enclosed or
embedded laser or laser system. The service personnel shall have
the education and training commensurate with the class of the
laser or laser system contained within the protective housing.
5.7.5 Modifications of Lasers or Laser Systems
The registrant must notify the LSO of any
modifications that could change a laser's class and affects its
output power or operator characteristics so as to make it
potentially more hazardous. The LSO must review the control
measures to determine if additional requirements are needed.
5.8 Exceptions for Lasers with Fully Enclosed and
Interlocked Beam Paths
In applications of lasers or laser systems where the entire
beam path is enclosed, the requirements for Class I laser
systems are met and none of the other control measures of this
chapter are required, provided:
- Interlocks are designed to prevent access to laser
radiation. The interlock may be electrically or mechanically
interfaced to a shutter, or to power supply in such a way that
the beam is interrupted when the protective beam enclosure is
opened or removed. These interlocks must be of fail safe
- The protective housing interlocks must not be defeated
- Adjustments or procedures during service must not cause
the interlocks to be inoperative when equipment is returned to
normal operating conditions.
- When requirements 5.1.1. through 5.1.3. are temporarily
relaxed, such as during service, LSO approved control measures
must be applied. These may include temporary area control, and
administrative and procedural controls.
5.9 Exceptions for Lasers with Fully Enclosed Beam Paths
In application of lasers or laser systems where the entire
beam path is enclosed, but the enclosure does not meet the
requirements specified in 5.8., the laser is exempt from
controls described in Sections 5.2.2, 5.5.1., 5.5.2., and 5.6.4.
- Beam enclosures prevent access to laser radiation.
- Beam enclosures are not removed during normal operation.
- When conditions of a and b are relaxed such as during
service, LSO approved control measures are applied.