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6410 Appendix T2: Laser Hazard Evaluation and
Controls |
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Described
within is the laser hazard evaluation process and establishment of required
control measures. Explanations and examples are further provided.
After a laser hazard evaluation, the Laser Safety Officer (LSO) and
appropriate Laser System Supervisor (LSS) will determine which control measures
are required in order to mitigate specific laser hazards.
This
program satisfies applicable federal, state, and local requirements as outlined
in Chapter 2410, Appendix T1: Hazard
Issues List.
This
appendix applies to Classes 3B and 4 lasers that are used at Jefferson Lab. This procedure is
performed in conjunction with Chapter 6410,
Laser Safety Program.
Note: Management
authority may be delegated to a task-qualified TJNAF employee at the discretion
of the responsible manager.
3.1
Qualified Laser Worker
(QLW)
·
use laser controls as required per Laser Operational Safety
Procedure (LOSP)
·
if alteration of a laser safety control is needed, contact LSS
·
notify LSS when a laser control fails
·
report near misses to LSS
3.2
Laser System Supervisor (LSS)
·
document required laser safety controls in LOSP; include non-beam
hazards
·
document visitor requirements in LOSP
·
contact LSO if laser control is altered
·
notify LSO in cases of near miss or failure in hazard controls
3.3
Laser Safety Officer (LSO)
·
review and approve laser safety controls, including non-beam
hazards
·
recommend and approve controls such as laser protective eyewear
(LPE), material of construction for enclosure, warning signs, etc.
·
seek
assistance from other subject matter experts (SMEs) as applicable (e.g., Fire
Marshal for Class 4 lasers, Industrial Safety Group for hazardous energy control
or working at heights)
3.4
Fire Marshal
·
review and approve fire detection devices for Class 4 lasers
·
provide fire detection devices as necessary
·
support LSS during 6-month laser inspections for areas with fire
detection devices
3.5
Environment, Safety,
and Health Subject Matter Experts (SMEs) review and approve LOSPs, as needed, for assigned subject area(s)
3.6
Division Safety Officers (DSO)
·
ensure work planning and control process is being followed
·
review and approve LOSPs
Unless otherwise stated, the procedure outlined below is
performed by qualified LSS’ and LSOs trained in laser safety.
Evaluation is performed by the LSS and LSO for new or modified
laser systems, laser-controlled areas (LCAs), and laser operations. The
evaluation considers:
·
Type of laser or lasing system including but not limited to:
o
wavelength
o
output power
o
laser class
·
Beam path including optics (e.g., lenses, mirrors), amplifiers,
configuration (open beam, fiber optics, enclosure)
·
Nominal Hazard Zone (NHZ) of all possible beam paths
·
MPE for all laser within an LCA
·
The extent of hazardous diffuse reflections
·
The likelihood for operation or maintenance personnel to be within
the NHZ during laser operation
·
The presence of collecting optics such as hand magnifiers*
·
Potential for fire
·
Potential laser generated air contaminants (LGAC)
·
Non-beam hazards
·
Enclosure materials of construction (e.g. attenuation of laser)
·
Hazardous energy control
*Viewing the main beam
or a specular laser target with an optical instrument is potentially hazardous
due to the instrument's light-gathering capability. Therefore, use of such
optical systems may effectively increase the NHZ boundaries and shall be
considered in the overall hazard evaluation.
4.2
Evaluation of Non-beam Hazards (NBHs)
The LSS and LSO
evaluate non-beam hazards result
from factors other than direct human exposure to a laser beam, but are
associated with laser equipment or laser operations. NBH controls will
be documented in the LOSP for the laser/LCA.
NBH include physical,
chemical, and human factors.
4.2.1
Physical agents
·
electrical hazards, electrical shock, electrical spark ignition of
flammable materials
·
resistive heating
·
arc flash
·
non-laser radiation, optical radiation, microwave, radiofrequency,
extremely low frequency, static electromagnetic fields
·
at very high irradiance - ionizing radiation
·
plasma radiation
·
fire hazard, combustion of flammable materials
·
explosion hazards from high-pressure arc lamps, filament lamps,
capacitor banks
·
mechanical hazard associated with robotics
·
noise
·
fiber-optic fragment hazard
·
nanoparticles
4.2.2
Chemical agents
·
laser-generated air contaminants (LGAC)
·
compressed gases, cryogenics
·
laser dyes and solvents
4.2.3
Human
factors
·
ergonomics
·
limited work space
·
work patterns
Note: Due
to the diversity of NBHs, the LSO will assist in identifying common types of
non-beam hazards. The LSO or LSS may
consult the appropriate safety professionals and other subject matter experts
as needed.
4.3
Control Measures
Controls are divided
into three groups: engineering, administrative, and personal protective
equipment (PPE). The hierarchy of controls should be used as follows:
·
Engineering controls dedicated to protecting personnel – first
line of defense
Example: Enclosure of
the laser equipment or beam path
·
Administrative controls used by personnel
Example: Training, LOSP
·
Personal Protective Equipment (PPE) worn by personnel – last line
of defense
4.3.1
Minimum Hazard Controls for Class
3B and Class 4 lasers
4.3.1.1
Engineering Controls
·
Interlock(s)
required on laser housings/LCA:
o
a
laser room used as the laser housing may have defeatable
interlocks for room access
o
laser
housing may have service access panels with non-defeatable
interlocks or tooled housing enclosure
o
each
laser room or laser enclosure must have a signed off schematic of the interlock
system filed with TJNAFs Document Control
o
Class
1 walk-in enclosures must be equipped with devices to interlock with laser
power supply or shutter to prevent laser exposure above the MPE
·
An
emergency crash button (e.g. kill switch) must be located outside the LCA.
o
Crash
buttons may also be located inside the LCA.
·
A
laser warning device shall be illuminated at least 30 seconds before the laser
system is enabled. This device shall be
mounted at the entrance to the LCA and within the LCA. The warning device must visible through laser
protective eyewear (LPE).
o
Audible
warning device may also be required to warn individuals in a greater space than
the immediate laser area about startup or activation of a laser system. Consult with LSO to determine need for
audible warning devices.
·
A
laser emission indicator is be located on the laser power supply or housing.
·
Class
4 lasers require a smoke detector or other fire detection device interlocked to
the laser power supply.
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Figure
1: Examples of acceptable LCA laser
warning devices |
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4.3.2
Administrative Controls
·
Access
restricted to only QLWs.
·
Hazard
warning sign posted outside of LCA warning of laser hazard. Appropriate sign determined by the LSO.
·
The
interlock system functionality shall be tested at least every six months and
after significant changes to the system.
·
Approved
LOSP.
4.3.3
Personal
Protective Equipment (PPE)
·
Laser
Protective Eyewear (LPE)
Laser
protective eyewear (LPE) must reduce exposure below the Maximum Permissible
Exposure (MPE) when the laser system is enabled (ready to lase).
The MPE values are below known hazardous levels. The LSO will
evaluate the laser setup and will determine the MPE and the needed optical
density (OD) for laser eyewear.
LPE may include goggles, face shields, spectacles, or prescription
eyewear using special absorptive filter material or reflective coating (or a
combination of both) to reduce the potential ocular exposure.
The following factors shall be considered
when selecting the appropriate LPE to be used: laser power and/or pulse energy,
wavelength(s) of laser output, potential for multi-wavelength operation, need
for prescription glasses, comfort, and fit.
o LPE
must be worn at all times within the LCA, when required per the LOSP and the
laser system is enabled.
o The LPE is labeled with
the optical density (OD) and wavelength for which protection is afforded. In
addition, the laser user may choose to use distinctive identification of LPE in
a multi-laser environment to aid users in the selection of approved
eyewear.
o The visible luminous
(light) transmission (VLT) of the protective filter as well as the comfort,
fit, and need for prescription glasses must be considered in the choice of
eyewear. When VLT is less than 20%, there may be insufficient light to perform
the intended task.
o The eyewear must be
stored in such a manner as to protect its physical integrity.
o The LPE shall be
inspected prior to each use and cleaned periodically per manufacturer recommendations. Remove eyewear in suspicious condition from
service.
o
There must be sufficient number of laser protective eyewear on
hand for users and expected visitors, and be available for inspection by the
LSO during periodic visits.
Laser protective
eyewear is ordered by the LSO who inspects the LPE prior to distribution to
LSSs.
·
Skin
Protection
Skin protection can be best achieved through engineering controls.
In some cases, a face shield, gloves, laboratory jacket, or coat with long
sleeves may fulfill the requirement, although tightly woven, flame-retardant
fabrics (e.g., welder’s gloves) provide the best protection for Class 4
lasers.
o For wavelengths greater
than 1400 nm, “large area” exposures can cause heat loading, causing skin
dryness, and with excessive exposures, may lead to heat stress. In these cases,
personnel exposures shall be minimized.
o Particular care shall
be taken when using UV lasers or laser systems. Exposure to UV radiation shall
be minimized by using beam shields, and perimeter guards along with face
shields and long-sleeve clothing that attenuate the specific UV wavelengths to
levels below the applicable MPE. Most gloves (e.g., nitrile and latex) will
provide some protection against laser UV radiation. Do not use vinyl gloves for
UV protection. Skin covers and /or "sunscreen" creams are
recommended.
4.4 Non-beam
Hazard Control Measures
Non-beam
hazard controls will be determined per specific laser operations. Any required controls such as electrical
safety, LOTO, ODH, high noise, fall protection, etc. will be documented in the
LOSP along with any additional training requirements necessary.
4.5 Substitution
of Control Measures
When the primary
control measures are not feasible or practical, the LSO will recommend or
approve substitute or alternate control measures that provide equivalent
protection. The approval of substitute or alternate controls must be
incorporated and documented into the LOSP. Examples would include the use of a
curtain maze or use of administrative control such as warning signs in
place of an entrance interlock. If an alternate control measure is used, all
personnel shall be provided with appropriate laser safety and operational
training.
4.6 Manufacturer
Control Measures
All laser products
sold, imported, or otherwise distributed in the United States must comply with
the Federal Laser Product Performance Standard (FLPPS). These laser products
are certified by their manufacturers, and are reported to the U.S. Food and
Drug Administration (FDA) Center for Devices and Radiological Health (CDRH).
Those who use these laser products as intended by their manufacturers may rely
to some extent on the built-in manufacturer control measures.
4.7 Lasers
and Laser Systems Built or Modified at Jefferson Lab (non-CDRH lasers)
Lasers or laser systems
assembled in-house as well as certified Class 3B or 4 laser products may need
additional engineering controls or additional labels to be applied.
User-developed or
user-modified laser products shall have their engineering controls reviewed and
approved by the LSO to determine the adequacy of their protection.
All laser products
developed and built at Jefferson Lab with the intention to be distributed to
users outside Jefferson Lab shall comply with the FLPPS. When distributing to users
outside Jefferson Lab, Jefferson Lab is considered to be a “manufacturer” by
federal regulations if one or more conditions below are met by TJNAF workers:
·
assembled a laser from parts
·
modified a commercially available laser or
laser system so that the output or safety characteristics have been changed
·
embedded or incorporated a commercially
available or Lab-built laser or laser system into some type of a Lab-built
laser system
The LSS must notify the
LSO when a manufactured laser is to be sent off site. If the LSO’s written
evaluation determines that any of the conditions above apply, the system must
either be:
·
Certified by the FDA/CDRH and shown to comply with 21 CFR 1040,
“Performance Standards for Light Emitting Products”
OR
·
Exempted from the compliance process (21 CFR 1010.5) by the
Director of FDA/CDRH, who has the authority to grant an exemption from the
federal product regulations if the laser system is to be used for government
purposes (i.e., research, investigations, studies, demonstration, training, or
reasons of national security)
4.8
Lasers or laser systems taken
off-site
Occasionally, JSA lends
lasers and laser systems to off-site organizations or individuals, or a laser
user takes them for research at different institution. It is a responsibility
of the LSS to notify the LSO and use the TJNAF shipping authorization form to
send the laser offsite. The LSO will verify that the off-site organization
receiving a Class 3B or 4 laser(s) has an established laser safety program with
an appointed LSO.
Exceptions
to the required LSO evaluation include unmodified commercially available
consumer products, such as laser pointers, laser printers, compact disc
players, and barcode scanners, or units being returned to the original
manufacturer or qualified service company for repair, maintenance, warranty
work, modification, or similar circumstances.
4.9
Lasers or Laser Systems Returning to Jefferson Lab
It is expected that DOE/TJNAF
property will be returned for future use. Upon the laser’s return, the LSS must
notify the LSO.
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summary |
date |
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0 |
- new
content to align with TJNAF programs and activities - original
T2 became new T1 |
01.02.2024 |
