Arrangements for the Safe Use of
Laser Devices in UCL
Author: Mr B Kavanagh, Safety Officer
Legal requirements
The Health and Safety at Work Act (1974) requires that all tasks are performed in such
a manner that “so far as is reasonably practicable” there is no risk of injury to: workers,
bystanders or member of the public.
The Control of Artificial Optical Radiation at Work Regulations 2010 (AOR regs) made
under the Health and Safety at Work Act governs the safe use of laser devices. The
AOR regs specify that the BS EN 60825:series of standards are the minimum safety
standard that must be applied to the use of lasers.
Some activities associated with the use of lasers may be specifically legislated for by
other regulations also made under the Act: e.g. the Electricity at Work regulations and
the Provision and Use of Work Equipment Regulations (1992).
UCL Laser Safety Provision
Safety Services will provide advice to Departments, and obtain expert advice as
necessary.
Departmental Laser Safety Provision
Organisation
Head of Department
It is the responsibility of the Head of the Department to ensure that there are
arrangements for the safe use of lasers for their department.
To assist with the organisation planning and administration of its arrangements for safe
use of laser devices, departments should appoint Laser Safety Supervisors.
Departmental Laser Safety Supervisor
The Departmental Laser Safety Supervisor for a department provides competent
advice and administrative assistance to the Head of Department on matters pertaining
to the control of the use of laser devices. In particular, the Departmental Laser Safety
Supervisor assists the Head of Department to write and implement the Departmental
Local Rules for Laser Safety.
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Organising for the Safe Use of Lasers
Departmental Laser Safety Supervisors
Class 3 and above Laser Devices
Departments using class 3 or above must appoint a Departmental Laser Safety
Supervisor.
Any person using a class 3 or above lasers must be authorised by the Laser Safety
Supervisor.
All purchasers of laser equipment must be with the approval of the departmental Laser
Safety Supervisor.
All Class 3 and above lasers should be used in a designated laser area.
Precautions should be taken to ensure the security of the laser equipment.
Class 1 and 2 Laser devices
Department using laser equipment of class 1 or 2 may choose to appoint a Laser
Safety Supervisor, or else allow laser safety to be dealt with by research group
supervisors and/or the Departmental Safety Officer.
Risk Assessment
A risk assessment must be prepared to ensure that risks are reduced to an acceptable
level.
The risk assessment should be conducted by the project supervisor in consultation with
the users of the equipment, and if necessary the Departmental Laser Safety Supervisor
and the equipment manufacturer or supplier.
The user should be aware of the:
•
hazards associated with the equipment they are to use
•
systems of work and precautions in place as a result of risk assessment
•
emergency action to take in case of an accident.
The Laser User
The users of laser equipment are primarily responsible for the safety of both
themselves and of any other persons who may be affected by their actions.
Before starting any work the users must be familiar with the:
Hazards associated with the use of Laser Equipment
Safety requirements and local rules
Equipment and the particular work environment they will be
working in.
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Laser Controlled Areas
A Laser Controlled Area is a location, usually a laboratory, designated by the
Departmental Laser Supervisor, specifically equipped and adapted for the safe laser
use. The area is classified as being that relevant to the highest class of laser apparatus
to be used in the area.
A Laser Controlled Area must have specific laser local rules to cover the use of the
specific equipment in that area.
Entry to a controlled area should be by a door with a special key or unique door entry
code.
Each Laser Controlled Area must have a designated responsible person (Laser
Controlled Area manager).
Personal access to a Laser Controlled Area is restricted to those authorised to work
within that particular controlled area. Such personnel must be trained operators and
must be aware of and understand all the laser hazards that may be encountered within
the Laser Controlled Area. Any person using a controlled area must be given a copy of
the laser local rules.
Training
Operation of Class (3A) 3R, 3B and Class 4 laser systems can represent a hazard not
only to the user but also to other people over a considerable distance.
Because of this hazard potential, only persons who receive training to an appropriate
level should be placed in control of such systems. The training should include, but is
not limited to:
™ familiarisation with systems operating procedures;
™ the proper use of hazard control procedures, warning signs etc.;
™ the need for personal protection;
™ accident reporting procedures;
™ bioeffects of the laser upon the eye and skin.
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Appendix 1 Basic Laboratory Rules for use of Lasers
Do not look into a laser beam.
Don’t look down specular reflections (e.g. from reflective surfaces).
Don’t stare at diffuse reflections
If it looks bright - don’t stare at it!
Keep room lights on brightly if possible.
The brighter the ambient lighting level, the smaller the eye’s pupil will become and the
less chance of a laser beam hitting it.
Remove all personal jewellery.
Watches and rings etc. act as reflectors. Remove anything which may pose a
reflection hazard when entering a laser laboratory; this is to protect you and your coworkers.
Do this for even low power lasers so that you get into good habits when using higher
power lasers.
Locate and terminate all stray beams.
Make sure all stray beams are terminated with a matt, diffuse beam dump which can
handle the power of the laser beam, e.g. a power transistor heat sink.
Clamp all components securely.
Double clamp optical components - this helps prevent your experiment from becoming
misaligned and reduces the chances of a component moving and sweeping a laser
beam over you.
Keep beams horizontal.
Horizontal beams are usually easier to work with and more predictable. Avoid vertical
and skew beams if possible.
Change beam height with a periscope and be careful when aligning it.
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Don’t bend down below beam height.
If you drop something, block the laser beam at the laser before picking the object up.
If you can’t stop the beam exposure, kick the object out of the way so that you don’t trip
over it.
If you must sit down in the lab, make sure that the chair is high enough, so that your
head is above beam height.
Remember optical components reflect, transmit and absorb light.
Often a transmitting component will also reflect light, a reflecting component will also
transmit light. This can lead to stray beams.
Be aware that optical components can change their optical characteristics when used
with high power lasers; e.g. neutral density filters can bleach or even crack/explode.
Don’t forget none optical hazards.
Don’t:
o
o
o
o
o
trip over (especially as a result of aversion response),
electrocute yourself,
spill chemicals,
start a fire,
burn yourself on cryogenic liquids.
Wear laser safety eye-wear.
If goggles are provided, wear them. If you think goggles should be provided, see your
supervisor, or the Departmental Laser Safety Supervisor, or the Departmental Safety
Officer.
If in doubt - find out
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Appendix 2 Entertainment and public performance
Prior to the public use of any display laser product the operator of the laser system
should provide UCL Safety Services with sufficient information, sketches, calculations,
radiometric measurement data, etc., to demonstrate that the system can be used safely
and without risks to health.
The operator should also, similarly, provide written information regarding his security
arrangements and define conditions that, should they arise, would require the laser
operation to be shut down.
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Appendix 3 Laboratory use of Lasers
Class 1 lasers
Description of Class 1 lasers from EN 60825-1: 2001
“Lasers which are safe under reasonably foreseeable conditions of operations.” This is
not the same as absolutely safe.
Description of class 1 M lasers from EN 60825-1: 2001
“Lasers which are safe provided optical instruments are not used”
Class 1 lasers may be divided into types
Lasers whose outputs are so low that the relevant MPE cannot be exceeded under any
viewing conditions.
Laser systems where the relevant MPE cannot be exceeded due to engineering
design.
Radiation from these devices may exceed the MPE if the device is operated with
the enclosure opened.
There are no special requirements for the use of class 1 lasers.
Class 2 lasers
Description of a class 2 laser from EN 60825-1: 2001
Lasers emitting visible Radiation in the wavelength from 400 nm to 700 nm (ie visible),
which are of a power that eye protection is normally afforded by aversion responses
including the blink reflex.
Description of a class 2M laser EN 60825-1: 2001
As above provided optical instruments are not used.
Control measures.
The use of class 2 lasers should be confined to laboratory or demonstration areas.
The laser beam should be terminated at the end of its useful path by a suitable beam
stop.
Open laser beam paths at eye level should be avoided.
Do not stare into a laser or at its (specular) reflections.
Do not point class 2 lasers at people or animals.
Class 3 lasers
The description of Class 3A lasers from EN 60825-1: 1994::
Lasers which are safe for viewing with the unaided eye. For lasers emitting in the
wavelength from 400 nm to 700 nm protection is afforded by aversion responses
including the blink reflex. For other wavelengths the hazard to the unaided eye is no
greater than for class 1. Direct intrabeam viewing of Class 3A lasers with optical aids
(e.g. binoculars, telescope, and microscopes) may be hazardous.
The description of Class 3R laser from EN 60825-1: 2001
Low risk lasers with less than five times the AEL for class 1.
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Control measures.
The use of class 3A and 3R lasers should be confined to laboratory or demonstration
areas.
The laser beam should be terminated at the end of its useful path by a suitable beam
stop.
Open beam paths at eye level should be avoided and should be enclosed (e.g. within a
tube) where practicable.
Open laser beam paths at eye level should be avoided.
Do not stare into a laser or at its (specular) reflections.
Do not point class 3A or 3R lasers at people or animals.
Avoid using optical aids, such as telescopes, to view beams as such devices will
readily collect all the light from the laser and cause physical damage to the eye.
All class 3A and 3R lasers should be stored securely when not in use
Laser warning signs must be displayed at the entrance to areas were class 3A lasers
are used.
Only trained personnel may use class 3A and 3R lasers
Class 3B lasers
The current description of Class 3B lasers from EN 60825-1: 2001
Direct intrabeam viewing of these lasers is always hazardous. Viewing diffuse
reflections is normally safe.
Control measures.
The use of class 3B lasers should be confined to Controlled areas.
Care should be exercised to prevent unintentional specular reflections.
The laser beam should be terminated at the end of its useful path by a material that is
diffuse and of such a colour and reflectivity as to make beam positioning possible while
still minimising the reflection hazards.
Open beam paths at eye level should be avoided and should be enclosed (e.g. within a
tube) where practicable.
Open laser beam paths at eye level should be avoided.
Do not stare into a laser or at its reflections.
Do not point class 3B lasers at people or animals.
Avoid using optical aids, such a telescopes to view beams; as such devices will readily
collect all the light from the laser and cause physical damage to the eye.
All class 3B lasers should be stored securely when not in use
Laser warning signs must be displayed at the entrance to areas were class 3A lasers
are used.
Only trained personnel may use class 3B lasers
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Class 4 lasers
The current description lasers class IV from EN 60825-1: 2001
Lasers which are also capable of producing hazardous defuse reflections. They may
cause skin injuries and could also constitute a fire hazard. Their use requires extreme
caution
Control Measures
Beam paths
Beam paths should be enclosed whenever practicable.
Access to the laser
environment during laser operation should be limited to persons wearing proper laser
protective eyewear and protective clothing.
Beam paths should avoid work areas where possible, and long sections of tubes
should be mounted so that thermal expansion, vibration and other sources of
movement in them do not significantly affect the alignment of beam forming
components.
Remote control
Class 4 lasers should be operated by remote control whenever practicable, thus
eliminating the need for personnel to be physically present in the laser environment.
Room illumination
Good room illumination is important in areas where laser eye protection is worn. Light
coloured diffuse wall surfaces help achieve this condition.
Fire
Fire, thermally induced aberrations in optical components and the melting or
vaporisation of the solid targets designed to contain the laser beam, are all potential
hazards induced by the radiation from class 4 lasers. A suitable beam stop should be
provided, preferably in the form of an adequately cooled metal or graphite target. Very
high power densities can be handled by absorbing the radiation over several
reflections, each reflection being inclined at such as angle to the incident radiation as to
spread the laser power over a wide area.
Invisible reflections
Special precautions may be required to prevent unwanted reflections in the invisible
spectrum from far infra red laser radiation and the laser target area should be
surrounded by a material opaque to the laser wavelength. (Even dull metal surfaces
may become highly specular at the CO2 wavelength of 10.6 μm).
Local screening should be used wherever practicable to reduce the extent of reflected
radiation.
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Appendix 4 Hazards incidental to laser operation
Atmospheric contamination
a) Vaporised target material and reaction products from laser cutting, drilling and
welding operations. These materials may well include asbestos, carbon monoxide,
carbon dioxide, ozone, lead, mercury, other metals, and biological material.
b) Gases from the flowing gas laser systems or from the by products of laser reactions,
such as bromine, chlorine, and hydrogen cyanide.
c) Gases or vapours from cryogenic coolers
d) Gases used to assist laser-target interactions, such as oxygen.
Collateral radiation hazards
Ultra-violet collateral radiation
There is considerable hazard from ultra-violet radiation associated with flash-lamps and
CW laser discharge tubes, especially when ultra-violet transmitting tubing or mirrors
(such as quartz) are used.
Visible and infra-red collateral radiation
The visible and near infra-red radiation emitted from flash tubes and pump sources and
target re-radiation may be of sufficient radiance to produce potential hazard.
Electrical hazards
Most lasers make use of high voltages (>1 kV) and pulsed lasers are especially
dangerous because of the stored energy in the capacitor banks.
Unless properly shielded, circuit components such as electronic tubes working at
anode voltages greater than 5 kV may emit X-rays.
Cryogenic coolants
Cryogenic liquids may cause burns and require special handling precautions.
Materials Processing
Specifications for laser products used to process materials may vary according to their
intended use. If the users wish to process materials other than those recommended by
the manufacturers, the users must make themselves aware of the different degree of
risk associated with the processing of such materials and take appropriate precautions
to prevent, for example, the emission of toxic fume, fire, explosion or reflection of laser
radiation from the work piece.
Other Hazards
There is potential for explosions at the capacitor bank or optical pump systems during
the operation of some high-powered laser systems. There is a possibility of flying
particles from the target area in the laser cutting, drilling and welding operations.
Explosive reactions of chemical laser reagents or other gases used within the
laboratory are also possible.
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Appendix 5 Personal Protective Clothing
Eye protection
Eye protection must be “suitable and sufficient” for the particular laser device and purpose for
which it is used.
The following should be considered when specifying suitable protective eyewear:
Do risk assessment specific eyewear for the application
The wavelength(s) of operation
The radiant exposure or irradiance
The maximum permissible exposure (MPE)
The optical density of the eyewear at laser output wavelength;
The visible light transmission requirements; specific to the
application the eyewear is intended for
The radiant exposure or irradiance at which damage to eyewear
occurs
The need for prescription glasses; specific to individual users
The requirement comfort and ventilation
Any degradation or modification of absorbing media, even if
temporary or transient
The strength of materials (resistance to shock, thermal or
physical)
Peripheral vision requirements
Relevant national regulations, i.e. PPE regulations: 1992 and the
requirements that eyewear be CE marked
Eye protection which is designed to provide adequate protection against specific laser
radiations should be used in all hazard areas where Class 3B or Class 4 lasers are in
use. Exceptions are:
a) when engineering and administrative controls are such as to
eliminate potential exposure in excess of the MPE.
b) when, due to the unusual operating requirements, the use of
eye protection is not practicable. Such operating procedures
should only be undertaken with the approval of the laser safety
officer.
Note
Protective eyewear should be comfortable to wear , provide as wide a field of view as
possible, maintain a close fit while still providing adequate ventilation to avoid problems
of misting up and provide adequate visual transmittance. Care should be taken to
avoid, as far as is possible, the use of flat reflecting surfaces which might cause
hazardous specular reflections. It is important that the frame and any side pieces
should give equivalent protection to that afforded by the lens (es).
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Protective Clothing
Where personnel may be exposed to levels of radiation that exceed the MPE for the
skin, suitable clothing should be provided. Class 4 lasers especially are a potential fire
hazard and protective clothing should be made from a suitable flame and heat resisting
material.
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Appendix 6 Laser Classification
Old
Current
Description
Safe time base 2-30,000s
Class 1
Class 1
Safe under foreseeable conditions.
Class 1M
Safe provided optical instruments are not used.
Safe for 0.25s
Class 2
Class 2
Safe provided blink and aversion responses operate.
Class 2M
As above; provided optical instruments are not used.
Low Risk
Class 3A
Safe provided optical instruments are not used.
Class 3R
Low risk lasers with less then 5 times AEL for class 1.
Injurious lasers
Class 3B
Class 3B
Can cause injury.
Class 4
Class 4
Exposure to direct or diffusely scattered radiation can be dangerous. May
cause fires.
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Appendix 7 Medical use of lasers
Introduction
The use of lasers in treatment differs fundamentally from the majority of laser use, in
that medical treatment using lasers may involve the deliberate irradiation of parts of
people or animals, something usually studiously avoided.
But the normal precautions must be adhered to prevent unintentional exposure to the
patient or operator.
Specific requirements for Medical Laser Products
Each medical laser product shall comply with all of the applicable requirements for
laser products of its class. In addition the manufacturers shall:
a) For Class 3B or Class 4 laser products, incorporate in each
medical laser product a means for the measurement of the level
of that laser radiation intended for irradiation of the human body
with an error in measurement of no more than ±20%. Indication
of the measurement shall be in SI units.
b) Supply with each medical laser product instructions specifying
a procedure and schedule for the calibration of the measurement
system
c) Provide a target-indicating device for Class 3B and Class 4
laser products
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Appendix 8 Use of lasers outside laboratory/workshop
environment
Laser pointers
Laser pointers should be of class 1 or 2 wherever reasonably practicable.
Persons issued with the pointers should be instructed in there use, preferably by some
member of the issuing department with suitable competence.
The pointer should be switched off when it is not actually being used.
Care should be taken never to direct the laser pointer, at an audience or any other
persons, whether it is switched on or not.
Surveying equipment
(Based on EN60825:1994)
Class 2 and Class 2M laser products
Outdoor and construction laser installations
Wherever reasonably practicable the beam should be terminated at the end of its
useful path, and the laser should not be aimed at personnel (at head height).
Class 3R laser products used for surveying, alignment and levelling
a) Only qualified and trained employees approved by the laser
safety supervisor should be assigned to install, adjust and
operate the laser equipment.
b) Areas in which these lasers are used should be posted with a
standard laser warning sign.
c) Wherever practicable, mechanical or electronic means should
be used to assist in the alignment of the laser.
d) Precautions should be taken to ensure that persons do not
look directly into the beam (prolonged intrabeam viewing is
hazardous). Direct viewing of the beam through optical
instruments (theodolite, etc.) may be hazardous and should not
be permitted unless specifically approved by a laser safety
officer.
e) The laser beam should be terminated at the end of its useful
beam path and should in all cases be terminated if the
hazardous beam path (to NOHD) extends beyond the controlled
area.
f) The laser beam path should be located well above or below
eye level wherever practicable.
g) Precautions should be taken to ensure that the laser beam is
not unintentionally directed at mirror-like (specular surfaces
(most importantly, at flat mirror-like surfaces).
h) When not in use the laser should be stored in a location where
unauthorised personnel cannot gain access.
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Class 3B and Class 4 laser products
Class 3 B and Class 4 lasers in outdoor and similar environments should only be
operated by personnel adequately trained in their use and approved by the laser safety
officer. To minimise possible hazards, the following precautions should be employed in
addition to those given in (EN60825:1994,12.6.2).
a) Personnel should be excluded from the beam path at all
points where the beam irradiance or radiant exposures exceed
the MPE's unless they are wearing appropriate protective eye
shields and clothing. Engineering controls such as physical
barriers, interlocks limiting the beam traverse and elevation, etc.
should be used wherever practicable to augment administrative
controls.
b) The intentional tracking on non-target vehicular traffic or
aircraft, should be prohibited within the nominal ocular hazard
distance.
c) The beam path should, whenever practicable, be cleared of all
surfaces capable of producing unintended reflections that are
potentially hazardous, or the hazard area should be extended
appropriately.
d) Although direct intra-beam viewing of Class 3B lasers is
usually hazardous, a beam may in all cases be safely viewed via
a diffuse reflector under the following conditions:
1) minimum viewing distance between screen and cornea
of 13 cm;
2) maximum viewing time of 10 s
If ether of these conditions is not satisfied, a careful
evaluation of the hazard necessary.
Lasers for surveying, alignment, and levelling
Lasers of Class 1 or Class 2 should be used for surveying, alignment, and levelling
applications whenever practicable. There may be situations, however, where high
ambient light levels require the use of lasers of higher output power. If Class 3A lasers
are used, the requirements of sub-clause (EN60825:1994, 12.6.2) should be followed.
In addition human access should not be permitted to laser radiation in the wavelength
range 400 nm to 700 nm with a radiant power that exceeds 5×10-3 W for any emission
exceeding 3.8 × 10-4 s, nor should human access be permitted to laser radiation in
excess of AEL for Class 1 for any other combination of emission duration and
wavelength range.
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LEGAL REQUIREMENTS .................................................................................................................. 1
UCL LASER SAFETY PROVISION .................................................................................................. 1
DEPARTMENTAL LASER SAFETY PROVISION ......................................................................... 1
ORGANISATION ....................................................................................................................................... 1
ORGANISING FOR THE SAFE USE OF LASERS........................................................................ 2
DEPARTMENTAL LASER SAFETY SUPERVISORS .................................................................................. 2
RISK ASSESSMENT................................................................................................................................. 2
THE LASER USER ................................................................................................................................... 2
LASER CONTROLLED AREAS ................................................................................................................ 3
TRAINING.............................................................................................................................................. 3
APPENDIX 1 BASIC LABORATORY RULES FOR USE OF LASERS................................... 4
APPENDIX 2 ENTERTAINMENT AND PUBLIC PERFORMANCE.......................................... 6
APPENDIX 3 LABORATORY USE OF LASERS ........................................................................ 7
CLASS 1 LASERS .................................................................................................................................... 7
CLASS 2 LASERS .................................................................................................................................... 7
CLASS 3 LASERS .................................................................................................................................... 7
CLASS 3B LASERS ................................................................................................................................. 8
CLASS 4 LASERS .................................................................................................................................... 9
APPENDIX 4 HAZARDS INCIDENTAL TO LASER OPERATION ........................................... 10
ATMOSPHERIC CONTAMINATION.......................................................................................................... 10
COLLATERAL RADIATION HAZARDS .................................................................................................... 10
ELECTRICAL HAZARDS ......................................................................................................................... 10
CRYOGENIC COOLANTS ....................................................................................................................... 10
MATERIALS PROCESSING .................................................................................................................... 10
OTHER HAZARDS ................................................................................................................................. 10
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APPENDIX 5 PERSONAL PROTECTIVE CLOTHING ............................................................. 11
EYE PROTECTION.................................................................................................................................. 11
PROTECTIVE CLOTHING ....................................................................................................................... 12
APPENDIX 6 LASER CLASSIFICATION ...................................................................................... 13
APPENDIX 7 MEDICAL USE OF LASERS................................................................................... 14
INTRODUCTION...................................................................................................................................... 14
SPECIFIC REQUIREMENTS FOR MEDICAL LASER PRODUCTS ............................................................ 14
APPENDIX 8 USE OF LASERS OUTSIDE LABORATORY/WORKSHOP ENVIRONMENT
............................................................................................................................................................... 15
LASER POINTERS .................................................................................................................................. 15
SURVEYING EQUIPMENT ....................................................................................................................... 15
Safety Services Reference(s):
Safe Use of Laser Devices
First Published
Reviewed
July 02
July 03
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