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Definition
and Properties of Laser Light
How
a Laser Works
Laser
Types and Classifications
Laser Biological Hazards
Eyes
Skin
Non-Beam Laser Hazards
Protective Measures - Laser Safety
Protective Equipment
Path to Laser Operation
Test
Laser Links
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Engineering - Administrative - Personal
Protective Measures
Protective measures are devised to reduce the
possibility of exposure of the eye and skin to hazardous levels of laser
radiation and the individual to other hazards associated with laser
devices during operation and maintenance.
Before we discuss the protective measures, let's
examine the types of laser incidents that have been reported so we can
better understand why we require controls and protective measures in the
first place.
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From ANSI Z136.1 (2000): "A review of
reported incidents has demonstrated that accidental eye and skin
exposures to laser radiation and accidents related to ancillary hazards
of a laser or laser system are most often associated with personnel
involved with the use of these systems under the following conditions:
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Unanticipated eye exposure during alignment
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Misaligned optics and upwardly directed beams
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Available eye protection not used
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Equipment malfunction
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Improper methods for handling high voltage
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Intentional exposure of unprotected personnel
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Operators unfamiliar with laser equipment
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Lack of protection for ancillary hazards
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Improper restoration of equipment following
service
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Eyewear worn not appropriate for laser in use
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Unanticipated eye/skin exposure during laser
usage
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Inhalation of laser-generated air contaminants
and/or viewing of laser-generated plasmas
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Ignition of fires of both a facility or personal
nature
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Eye or skin injury of photochemical nature
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Failure to follow standard operating procedures
(SOPs)
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Engineering controls will be the "first line of
defense" when it comes to protection from laser radiation and its
ancillary hazards.
Enclosure of the beam path is the preferred method of
control since the enclosure will isolate or minimize the hazard.
If engineering controls are impractical or inadequate,
administrative and procedural controls and personal protective equipment
will be used.
Engineering Controls
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Engineering controls
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protective housing shall be provided
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if enclosed Class 3b or 4 laser, interlocks shall
be provided on any removable parts of the housing, or the
laser shall have a service access panel that is either
interlocked or requires a tool for removal
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if the MPE is exceeded, a temporary laser controlled area shall
be devised
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Engineering controls
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protective housing shall be provided
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warning labels shall be conspicuous
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the area should be posted with the appropriate
warning sign
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if the MPE is exceeded, viewing portals and/or display
screens shall be designed such that MPE is not exceeded
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if enclosed Class 3b or 4 laser, interlocks shall
be provided on any removable parts of the housing, or the
laser shall have a service access panel that is either
interlocked or requires a tool for removal
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if the MPE is exceeded, a temporary laser controlled area shall
be devised
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Engineering controls
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protective housing shall be provided
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warning labels shall be conspicuous
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interlocks shall be provided on removable parts of
the housing
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a permanent beam stop or attenuator should be
provided
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the area should be posted with the appropriate
warning sign
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if the laser has a service access panel, it shall
be interlocked or require a tool for removal
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if the MPE is exceeded, a temporary laser controlled area shall
be devised
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if the MPE is exceeded, viewing portals and/or display
screens shall be designed such that MPE is not exceeded
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Engineering controls
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protective housing shall be provided
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interlocks shall be provided on removable parts of
the housing
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if the entire beam in not enclosed, a NHZ determination shall
be made by the laser safety officer; a controlled area shall
be established and control measures shall be
implemented
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if there exists a limited open beam path, a NHZ
determination shall be made by the laser safety officer
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the appropriate warning signs shall be posted
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the controlled area shall only be occupied by trained
and authorized personnel
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if the NHZ leaves an indoor controlled area, the
controlled area shall have a limited beam path
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a key-controlled master switch should be provided
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a remote interlock connector should be provided
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a permanently attached beam stop or attenuator should
be provided
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an alarm, warning light, or verbal countdown should
be used during use or start-up of the laser
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if an imbedded Class 4 laser, service access panels shall
be interlocked or require a tool for removal
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if the MPE is exceeded:
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viewing portals and/or display screens shall be
designed such that the MPE is not exceeded
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collecting optics shall be designed such that
the MPE is not exceeded
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the controlled area should:
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be supervised by an individual with knowledge of laser
safety
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have limited access to spectators
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have beam stops to terminate potentially dangerous
laser beams
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be designed to reduce diffuse and specular reflections
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have eye protection for personnel
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not have a laser beam at eye level with people
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have restrictions on windows and doorways to reduce
exposure to levels below the MPE
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require storage or disabling of the laser when it is
not being used
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if used outdoors, a Class 3b laser shall:
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have an established NHZ
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have restrictions on unauthorized persons in areas
where the MPE is exceeded
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have appropriate controls if personnel are within the
NHZ
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be designed such that a beam path is not near eye
level of a sitting or standing person
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be terminated with a beam stop when possible
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be disabled when not in used
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only be operated by qualified and authorized personnel
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bear appropriate warning labels in a conspicuous place
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have appropriate warning signs posted in the area
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Engineering controls
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protective housing shall be provided
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interlocks shall be provided on removable parts of
the housing
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service access panels shall be interlocked or
require a tool for removal
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a key-controlled master switch shall be provided
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when the entire beam in not enclosed, a NHZ shall
be established
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when there exists a partially limited beam path, a NHZ shall
be established
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a permanent beam stop or attenuator shall be
provided
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an alarm, warning light, or verbal countdown shall
be used during use or start-up of the laser
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the controlled area shall:
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be restricted to authorized personnel only
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be designed to allow for rapid emergency egress
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be equipped with a device that allows for deactivation
of the laser or reduction of output to below the MPE
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be designed to fulfill Class 3b controlled area
requirements
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be designed with entry safety controls
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the laser should be monitored and fired from a
remote location
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if used outdoors, a Class 4 laser shall:
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have an established NHZ
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be restricted from the presence of unauthorized
personnel if the MPE is exceeded
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have appropriate controls if personnel are permitted
in the NHZ
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have a beam path that is not at eye level with sitting
or standing persons
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be terminated by a beam stop, if possible
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be disabled when not in use
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be operated only by authorized personnel
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be evaluated for necessary personnel protective
equipment in inclement conditions
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have warning labels in a conspicuous place
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have a warning system which activates prior to
emergence of the beam
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if the MPE is exceeded:
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viewing portals and/or display screens shall be
designed so as not to exceed the MPE
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collecting optics shall be designed so as not
to exceed the MPE
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Administrative and Procedural Controls
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Administrative and procedural controls
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if embedded Class 3b or 4 laser and the MPE
is exceeded, service personnel shall comply with the
control measures appropriate for the class of the embedded
laser
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Administrative and procedural controls
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if embedded Class 3b or 4 laser and the MPE is exceeded,
service personnel shall comply with the control
measures appropriate for the class of the embedded laser
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alignment procedures shall ensure that the MPE is
exceeded
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Class 3a
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Administrative and procedural controls
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education and training shall be offered to
operators, maintenance and service personnel
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alignment procedures shall ensure that the MPE is
not exceeded
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if embedded Class 3b or 4 laser and the MPE is exceeded,
service personnel shall comply with the control
measures appropriate for the class of the embedded laser
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Class 3b
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Administrative and procedural controls
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Class 3b laser operations require
approval by the Non-Ionizing Radiation Safety Committee (NIRSC)
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education and training shall be provided for laser
operators, maintenance and service personnel
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only authorized personnel shall service the laser
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alignment procedures shall ensure that the MPE to
the eye is not exceeded
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control procedures shall be followed by service
personnel
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the laser safety officer shall implement controls
necessary to reduce exposure if the laser safety officer
considers exposures to be excessive
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approved, written standard operating, maintenance, and
service procedures should be developed
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appropriate eye protection should be required
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unauthorized persons should not be permitted within
the controlled area
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Class 4
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As the last line of defense, personal protective
equipment (PPE) will vary on how well the engineering, administrative,
and procedural controls have mitigated the hazard. Some of the
possible PPE required are:
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Laser Protective Eyewear
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Chemical Protective Gloves (for dyes and
solvents)
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Thermal Protective Clothing
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UV Protective Clothing and Lotion
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Hard Hats and Safety Shoes
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Welding Cloth
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Viewing Filters
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