Guidance Notes Concerning
THE USE OF LASERS
HEALTH AND SAFETY UNIT
AUTUMN TERM 2007
CONTENTS
INTRODUCTION ................................................................................. 4
ADMINISTRATIVE ARRANGEMENTS ............................................................ 5
Laser Users/Operators ...................................................................... 5
Supervisor/principal investigator ......................................................... 5
Departmental Laser Safety Officer ....................................................... 6
University Laser Safety Adviser ........................................................... 7
HAZARD CLASSIFICATION FOR LASERS ....................................................... 7
Example AELs ................................................................................ 9
Maximum Permissible Exposure (MPE) ................................................... 9
GENERAL SAFETY PROCEDURES .............................................................. 9
Laser Inventory .............................................................................. 9
Registration of Laser Users................................................................. 9
Training ....................................................................................... 9
Undergraduate work ....................................................................... 10
Designation of Laser Areas ................................................................ 10
Labelling of Lasers ......................................................................... 10
Experimental design ....................................................................... 10
Laboratory design .......................................................................... 11
BIOLOGICAL EFFECTS OF LASER RADIATION ............................................... 12
Laser damage to the eye .................................................................. 12
Ultraviolet wavelengths ................................................................ 12
Visible and near Infra-red wavelengths .............................................. 12
Infra-red wavelengths ................................................................... 12
Penetration of laser radiation into the eye .......................................... 13
Laser damage to the skin ................................................................. 13
Penetration of radiation into the skin ................................................ 14
Summary of laser radiation hazards .................................................. 15
SAFETY PROCEDURES FOR SPECIFIC CLASSES OF LASER ................................. 15
RISK ASSESSMENT AND SYSTEM OF WORK .................................................. 18
Optical hazards ............................................................................. 18
Non-optical hazards ........................................................................ 18
Assessing Risk ............................................................................... 19
Risk control measures ..................................................................... 19
Record of Assessment ...................................................................... 20
Review ....................................................................................... 20
PERSONAL PROTECTIVE EQUIPMENT ........................................................ 20
Protective eyewear ........................................................................ 20
Other protective equipment .............................................................. 21
ACCIDENTAL EXPOSURES AND EMERGENCY EYE EXAMINATIONS ........................ 21
LASER POINTERS ............................................................................... 22
CONCLUSIONS .................................................................................. 23
LASERS FOR DISPLAY PURPOSES ............................................................. 24
LASER SIGNS AND LABELS .................................................................... 25
Designated Laser Areas .................................................................... 25
Laser Labels ................................................................................. 25
Aperture Labels for Class 3R, Class 3B & Class 4 lasers ............................... 28
Radiation Output and Standards Information .......................................... 29
FORMS........................................................................................... 30
SUMMARY OF WARNINGS & PROTECTIVE CONTROL MEASURES ....................... 30
LASER SURVEY FORM ....................................................................... 31
LASER INVENTORY .......................................................................... 33
REGISTRATION FORM FOR LASER USERS ................................................. 34
USE OF CLASS 1M, 2M,2 AND 3R LASERS – HAZARD & RISK ASSESSMENT ............ 35
USE OF CLASS 3B & 4 LASERS – HAZARD & RISK SSESSMENT .......................... 37
SYSTEM OF WORK FOR LASERS ............................................................ 41
EMERGENCY PROCEDURE FOR EXPOSURE TO CLASS 3B OR 4 LASER ................. 47
TRAINING RECORD FORM .................................................................. 48
3
INTRODUCTION
This Guidance is intended to be used as a reference document for all users of
lasers within Manchester Metropolitan University and applies to both
employees and students. The guidance draws from a number of reference
documents including the relevant British Standard series of documents BS EN
60825 and associated amendments, and the AURPO Guidance on the safe
use of lasers in education and research.
This document forms the basis of Laser Safety Management in the University
and is a general guidance to good practice and assistance in the identification
of hazards, risk assessment and appropriate control measures associated
with the use of lasers as required by the Health and Safety at Work Act.
The current classification for lasers (implemented in 2001) is used which is
based on seven classes of laser (1, 1M, 2, 2M, 3R, 3B and 4). The Safety of
laser products is covered by British Standards BS EN 60825 which is based
upon the corresponding International Electrotechnical Commission’s 60825
document. Of particular importance to laser users is the Technical Report PD
IEC TR 60825-14 a detailed user’s guide.
4
ADMINISTRATIVE ARRANGEMENTS
The responsibilities of those working with or involved with laser activities in
the University are as follows:
Laser Users/Operators
Laser Users/Operators have the following responsibilities:
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to observe Local Rules and Systems of Work applicable to the lasers
that will be used and follow the guidance of supervisors and the
Departmental Laser Safety Officer.
to keep the supervisor fully informed of any proposal to depart from
established safety procedure.
not to leave a laser experiment running unattended unless a risk
assessment has established that it is safe to do so.
for their own safety and that of others who may be affected by their
acts or omissions.
When working with Class 3B and Class 4 lasers where there is a
possibility of stray laser beams that could damage eyesight, the
appropriate laser eyewear must be worn.
Supervisor/principal investigator
Research Supervisors have duty delegated to them from the Head of
Department, to provide “such supervision as is necessary” to ensure the
safety of all the students for whom they responsible. This includes all
postgraduate and undergraduate students working with lasers. Supervisors
also have responsibility for the following:
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All work involving hazardous lasers must be covered by risk
assessments and where appropriate written Systems of Work and
protocols.
There should be procedures in place to ensure lasers and any
associated hazardous materials are disposed of properly.
The Supervisor should ensure that their laser users/operators are
adequately trained and supervised.
New lasers must be registered with the University Laser Safety
Adviser (using the Laser Inventory form) with the exception of laser
pointers and embedded lasers e.g. CD/DVD players and laser printers.
Users of Class 3R, 3B, 4 and modified 1M and 2M lasers must be
registered with the University Laser Safety Adviser (using the
Registration Form For Laser Users).
Notifying the University Laser Safety Adviser of any accident involving
lasers.
5
Departmental Laser Safety Officer
The Departmental Laser Safety Officer plays a fundamental role in supporting
that the University complies with the requirements of the Health and Safety at
Work Act and the Management of Health and Safety at Work Regulations. He
or she should be directly involved with the Department’s work with lasers in
order to allow them to exercise sufficient supervisory authority. It is
recognised that in some departments the DLSA may not be the immediate
supervisor overseeing the work with lasers. In these cases the
Supervisor/principal investigator takes on these duties.
The functions of the DLSO will include:

The promotion of awareness by all persons who use Lasers within the
Department to which the DLSO is assigned of any potential hazards.

Drafting and reviewing of Local Rules/Systems of work and observing
that they are applied in the appropriate areas.

Drafting and reviewing Risk Assessments for work being carried out
with lasers.
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To monitor that all users have attended or are booked to attend an
appropriate Laser Safety training course.

To restrict or stop any laser activity that does not comply with the local
rules/System of Work.

To keep a record of all users working with lasers. Users of Class 3R,
3B, 4 and modified 1M and 2M lasers must be registered with the
University Laser Safety Adviser (using the Registration Form For Laser
Users).

To inform the University Laser Safety Adviser (ULSA) of details of any
new lasers. New lasers must be registered with the University Laser
Safety Adviser (using the Laser Inventory form) with the exception of
laser pointers and embedded lasers e.g. CD/DVD players and laser
printers.

To inform the Laser Safety Adviser of any new or significantly different
activities involving lasers.
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The bringing to the immediate attention of the Health and Safety Unit of
any ‘incident’ involving lasers
In addition to the above the DLSO will undertake to attend appropriate training
in order to carry the above duties effectively.
6
University Laser Safety Adviser
The University Laser Safety Adviser has responsibility for the administration
and auditing of systems of control relating to Laser Safety in order to ensure
compliance with the Health and Safety at W ork Act and provide advice and
assistance in order to implement the requirements of BS EN 60825.
The University Laser Safety Adviser will conduct routine inspections of
laboratories in which laser work is undertaken and provide information and
advice. In addition the ULSA has the following responsibilities:
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To provide assistance in evaluating and controlling hazards
To maintain a register of lasers and users
To co-ordinate laser safety training of laser users, supervisors/principal
investigators and Departmental Laser Safety Officers.
To participate in any accident investigations involving lasers.
To restrict or stop any laser activity that does not comply with the
Health and Safety at Work Act and BS EN 60825
To inform all Departmental Laser Safety Officers of any change in
existing or new legislation applicable to the use of lasers.
To provide guidance on the safe use of lasers.
HAZARD CLASSIFICATION FOR LASERS
Lasers produce electromagnetic radiation in the wavelength range 100nm
(ultraviolet) to 1mm (infrared) which includes the visible range 400nm-700nm.
The output from a laser may be continuous (CW) or pulsed which produce
short bursts of radiation. Because of the wide ranges of wavelength, energy
and pulse characteristics of laser beams, the hazards arising from their use
varies widely.
Lasers are grouped into seven categories depending on the potential to cause
harm. Accessible Emission Levels (AELs) have been determined for each
class of laser. The AEL depends on the wavelength, exposure duration and
the viewing conditions and specifies the maximum output within each laser
class.
Laser classes are as follows:
Class 1: Lasers that are safe under reasonably foreseeable conditions either
because of the laser’s low emission or because of engineering design such
that it is totally enclosed and access to higher levels is not possible during
normal operation e.g. CD/DVD player or a laser printer. NB If access panels
on a totally enclosed system are removed then the laser product is no longer
a Class 1 laser product and the precautions applicable to the embedded laser
must be applied.
7
Class 1M:
Laser products emitting in the wavelength range between
302.5nm and 4000nm whose total output is in excess of a Class 1 laser but,
because of their diverging beams or low power density, do not pose a hazard
under reasonably foreseeable conditions. However, they may be hazardous to
the eyes under the following conditions:
a) With a diverging beam if optics are placed within 100mm of the source to
collimate/concentrate the beam.
b) With a large diameter collimated beam where optics are used to increase
the proportion of the beam entering the eye e.g. binoculars or telescope.
Class 2: Lasers emitting in the visible wavelength region between 400nm
and 700nm and whose output is less than the appropriate AEL. Safe for
accidental viewing as protection of the eyes is provided by the aversion
response (blinking and/or moving the head).
Class 2M: Laser products emitting in the visible wavelength region between
400nm and 700nm whose total output is in excess of a Class 2 laser but,
because of their diverging beams or low power density, are safe for accidental
viewing under reasonably foreseeable conditions. However, they may be
hazardous to the eyes under the following conditions:
a) With a diverging beam if optics are placed within 100mm of the source to
collimate/concentrate the beam.
b) With a large diameter collimated beam where optics are used to increase
the proportion of the beam entering the eye e.g. binoculars or telescope.
Class 3R: Lasers emitting in the wavelength range 302.5nm to 1mm where
direct intrabeam viewing is potentially hazardous but the risk is lower than for
Class 3B lasers. The AEL is below five times the Class 2 AEL in the visible
region (400nm-700nm) and below five times the Class 1 AEL for all other
wavelengths.
Class 3B: Lasers in both the visible and invisible range of wavelengths.
Direct intrabeam viewing near (i.e. within the Nominal Ocular Hazard Distance
where the radiant exposure will exceed the Maximum Permitted Exposure
limit) is always hazardous. Viewing diffuse reflections is normally safe
provided the eye is no closer than 13cm from the diffusing surface and the
exposure duration is less than 10 seconds. Output levels must be less than
the appropriate AEL for Class 3B devices.
Class 4:
High power lasers from which direct beam or reflected beam
viewing is always hazardous. Likely to cause both eye and skin injury.
Environmental damage (fire and hazardous fumes) is also a serious
possibility. Class 4 laser use requires extreme caution.
8
Example AELs
The AELs for Helium-Neon lasers emitting a continuous narrow beam at
633nm are as follows:
Class 1 and 1M
0.39 mW
Class 2 and 2M
1.00 mW
Class 3R
5.00 mW
Class 4
500.00 mW
The above limits will also apply to other narrow beam visible CW lasers
except for Class 1 and 1M devices where there further restrictions apply to
wavelengths below 500nm. For full details of restrictions see BS EN 60825-1.
Maximum Permissible Exposure (MPE)
The Maximum Permissible Exposure (MPE) is the level of radiation below
which no adverse effects to the eye and skin should occur. There is a safety
factor incorporated into the MPEs to take account of individual variations in
sensitivity to laser radiation. MPE levels are specified in BS EN 60825-1 and
in particular in – Safety of Laser Products – Part 14: A user’s guide, PD IEC
TR 60825-14:2004. Planned ocular exposure to lasers should not exceed the
MPE.
GENERAL SAFETY PROCEDURES
Laser Inventory
All Class 3R, 3B and Class 4 lasers should be identified and recorded on the
Laser Inventory Form, a copy of which should be sent to the University Laser
Safety Adviser. In addition Class 1M, 2M and Class 2 lasers should also be
recorded except for laser pointers and embedded lasers in products such as
laser printers and CD/DVD players. It is not necessary to register low powered
Class 1 devices.
Registration of Laser Users
All persons intending to work with lasers except for inherently safe Class 1
and Class 2 devices or embedded lasers in products such as laser printers
and CD/DVD players, should register with the University Laser Safety Adviser
using the Registration form for Laser Users.
Training
Persons intending to use Class 3R, 3B and Class 4 lasers should attend
training before commencing any laser work and should also be familiar with
System of Work for the lasers they intend to use. Training in the use of
individual lasers is the responsibility of the Student/Research Supervisor and
a record of this training should be made. The Training Record for Authorised
9
Laser Users must be filled in and a copy sent to the University Laser Safety
Adviser. Laser Safety Training Sessions can be arranged by contacting the
University Laser Safety Adviser.
Undergraduate work
Wherever possible undergraduate work should be restricted to Class 1, 1M, 2,
2M or visible 3R lasers. For class experiments it is important to introduce
students to good safety practice and a written system of work/local rules
should be drawn up and posted in the laboratory. In addition, clear written
instructions should be provided for each student experiment.
Students involved in project work with Class 3B and Class 4 lasers will be
treated as laser workers and must register with the University Laser Safety
Adviser using the Registration for Laser Users. In addition they must receive
appropriate Laser Safety Training. Laser Safety Training Sessions can be
arranged by contacting the University Laser Safety Adviser. These students
must work under close supervision if working with high-powered lasers.
Designation of Laser Areas
Points of access to areas in which Class 3B and Class 4 lasers are used must
have appropriate warning signs (see section on Laser signs and labels).
Areas in which open beam work with modified Class 1M,2M or 3R lasers are
used will also require appropriate warning signs.
Labelling of Lasers
All lasers must be labelled correctly in accordance with BS EN 60825-1 (see
section on Laser Signs and Labels). Where lasers and laser systems are not
adequately labelled e.g. imported lasers, they must be relabelled.
NB For mains powered equipment the labelling of lasers must comply with
European Standards and any institution obtaining a laser directly from the US
will assume the responsibilities of the importer and supplier.
Experimental design
Before using a laser the following points should be considered:
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Is it possible to use a lower powered laser?
Can the laser output power be restricted?
Can the laser be used in a screened off area?
Can work be carried in a total enclosure?
Can intrabeam viewing be avoided by engineering design?
Are beam paths as short as possible?
Have optical reflections been minimized? Use of anti-reflective coated
components or shrouds.
The beam should be terminated with an energy absorbing, nonreflective beam stop
10
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Lasers should be securely fixed.
Keep beam paths above or below eye level
Make sure laser is facing away from laboratory entrance
Keep optical benches free from clutter
Remove jewellery, wristwatches etc.
Alignment of lasers should be at lowest possible power, if practicable
use low-power lasers for alignment or introduce neutral density filters.
Alternatively remote viewing techniques can be considered.
Laboratory design
The following relates to Class 3B and Class 4 lasers:
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If practicable the laboratory should have a high level of illumination that
will minimize pupil size and reduce the risk of stray laser light reaching
the retina.
Windows may need to be covered or protected with blinds. These
should be non-reflective and may need to be fireproof if high powered
lasers are used.
Walls, ceilings, and fittings should be painted with a light coloured matt
paint to enhance illumination and minimize specular reflections.
Reflecting surfaces should be avoided.
Ventilation is an important factor particularly if cryogens are used or
toxic fumes produced. Extraction of toxic fumes will need to be close to
the source.
Some dye lasers are associated with toxic chemicals which will require
appropriate facilities for handling and storage.
Appropriate fire fighting equipment should be available
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Electrical supplies, switch and control gear should be sited to:
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o Allow shut down by a person standing next to the laser
o Prevent accidental firing of the laser
o Provide an indication of the state of readiness of the laser
o Enable persons to stand in a safe place
o Enable the laser to be made safe in an emergency from outside
the laser area if reasonably practicable
o Provide sufficient and adequate power supplies so that the use
of trailing cables is kept to a minimum
11
BIOLOGICAL EFFECTS OF LASER RADIATION
When the body is exposed to laser radiation some of the radiation is absorbed
by the body tissues. The parts of the body most susceptible to injury are the
eyes and skin. The amount of radiation absorbed by the eyes and skin will
vary with wavelength, type of tissue, energy or power of the incident beam,
size of the irradiated area and duration of exposure.
Laser damage to the eye
Tissue damage will only occur when energy is absorbed by it. Different
wavelengths affect different parts of the eye because of the specific
characteristics of the particular tissues involved:
Ultraviolet wavelengths
UVC and UVB (180nm-315nm) are primarily absorbed in the cornea resulting
in keratitis. This is a painful condition feeling like grit in the eye accompanied
by excessive tear flow and an aversion to bright light. The eye usually
recovers from this within 48 hours. When UVC and UVB wavelengths are
absorbed by deeper layers of the cornea a photochemical reaction may cause
the cornea to turn milky usually between 6 and 12 hours after exposure.
UVA (315nm-400nm) is primarily absorbed by the lens of they eye and can
result in yellowing of the lens and cataract formation.
Visible and near Infra-red wavelengths
Visible and IR-A (400-1400nm) wavelengths are transmitted by the eye and
focussed on the retina. Short pulsed high peak power lasers are particularly
hazardous as they deliver a lot of energy in a short period of time. IR-A beams
are also particularly hazardous as they are invisible and will be focussed on
the retina without the person being aware of it until damage has been caused.
Infra-red wavelengths
IR-B (1400nm-3000nm) and IR-C (3000nm-1mm) wavelengths are absorbed
by the cornea which can cause infrared cataracts and above 2000nm flash
burns. If the IR radiation is great enough to damage the cornea, the pain
associated with it will be enough to trigger the aversion response which could
help to minimize the tissue damage.
12
Penetration of laser radiation into the eye
Laser damage to the skin
Damage to the skin by laser radiation is usually considered less significant
than damage to the eye since skin injuries will usually heal even following
penetrating damage leading to infection. Skin damage may lead to scarring.
All laser wavelengths with sufficient power density can cause surface burns
and particularly with high powered Class 4 laser where there may be no
warning of this occurring. Near infrared lasers are also of particular concern
as they can penetrate the subcutaneous layers of the skin. Chronic exposure
to lasers in the Ultraviolet region can increase the long term risk of skin
cancer.
13
Penetration of radiation into the skin
UV
Visible
IR-A
IR-B/C
14
Summary of laser radiation hazards
More information on biological hazards can be found in Annex B to BS-EN
60825-1:1994 or Annex C to PD IEC TR 60825-14:2004.
SAFETY PROCEDURES FOR SPECIFIC CLASSES OF LASER
The following gives the minimum safety requirements for using lasers of
different classes within the University:
Class 1
1)
The laser must be labelled correctly (see section on laser signs and
labels).
2)
Class 1 lasers, laser products and systems do not require any special
safety controls.
NB
If the laser system is class 1 due to engineering controls and contains
a laser of a higher class than 2M then significant hazards may occur
during servicing, alignment etc. In this case, it should be included in the
laser inventory and there should be a system of work for that activity.
This does not apply to laser printers, CD/DVD players or other devices
not serviced by the user. If in doubt contact the University Laser Safety
Adviser for advice.
15
Class 1M
1)
The laser must be labelled correctly (see section on laser signs and
labels).
2)
Avoid intrabeam viewing with condensing optics such as telescopes,
binoculars, microscopes or other lens based systems. Modifications
need to be carefully assessed and reclassified if necessary.
Class 2
1)
The laser must be labelled correctly (see section on laser signs and
labels).
2)
Beam should be terminated at the end of its useful path.
3)
Keep beam paths above or below eye level.
Class 2M
1)
The laser must be labelled correctly (see section on laser signs and
labels).
2)
Avoid intrabeam viewing with condensing optics such as telescopes,
binoculars, microscopes or other lens based systems. Modifications
need to be carefully assessed and reclassified if necessary
3)
Beam should be terminated at the end of its useful path.
4)
Keep beam paths above or below eye level.
Class 3R
1)
The laser must be labelled correctly (see section on laser signs and
labels).
2)
Beam should be terminated at the end of its useful path.
3)
Keep beam paths above or below eye level.
4)
Avoid open beam paths and where practicable enclose the beam.
5)
Safety interlocks required on access panels.
6)
Where non-visible wavelengths are used an emission indicator is
required to indicate the laser is energised.
7)
Training to an appropriate level. (If required Laser Safety Training
Session can be arranged by University Laser Safety Adviser).
16
8)
Provide appropriate PPE if necessary. See section on Personal
Protection)
9)
Register laser using with University Laser Safety Adviser using Laser
Inventory form.
10)
Register users with University Laser Safety Adviser using Registration
form for Laser Users.
Class 3B and 4
1)
The laser must be labelled correctly (see section on laser signs and
labels).
2)
Beam should be terminated at the end of its useful path.
3)
Keep beam paths above or below eye level.
4)
Prepare risk assessment (see Use of 3B & 4 Lasers – Hazard & Risk
Assessment form)
5)
Prepare scheme of work following risk assessment (see System of
Work for Lasers form. In grey text on this form are the considerations
which should be taken into account, exact detail will vary between
different laser systems). The scheme of work should be displayed in a
prominent position or readily available within a laboratory folder) along
with an Emergency Procedure for Exposure to Class 3B or 4 Lasers
form, an example of which is in these Guidance Notes for the All Saints
site.
6)
Avoid open beam paths and where practicable enclose the beam.
7)
Provide appropriate PPE if necessary. (See section on Personal
Protection).
8)
Safety interlocks required on access panels.
9)
Remote interlock for door or enclosure.
10)
Emission indicator is required to indicate the laser is energised.
11)
Beam stop or attenuator/shutter
12)
Users must attend Laser Safety Training Session (Laser Safety
Training Session can be arranged by University Laser Safety Adviser).
13)
Areas need to be defined and warning signs used.
14)
Register laser with University Laser Safety Adviser using Laser
Inventory form.
17
15)
Register users with University Laser Safety Adviser using Registration
form for Laser Users.
16)
Local Laser Safety Officer to be appointed.
RISK ASSESSMENT AND SYSTEM OF WORK
The main areas at risk from laser radiation are the eye and the skin. When
carrying out a risk assessment it is important to know the effects of laser
radiation on biological tissue (See section Biological Effects of Laser
Radiation). Before the appropriate controls can be selected and applied, laser
hazards must be identified and evaluated along with any other hazards
associated with the laser system.
Special considerations apply to the use of lasers for medical and dental
purposes as well as lasers used for display purposes (see section on The use
of Lasers for Display Purposes).
To assist in assessing hazards and risk control methods see the following
forms:

Use of Class 1M,2M,2 and 3R lasers – Hazard and Risk Assessment

Use of Class 3B and 4 Lasers – Hazard and Risk Assessment
Optical hazards
Class 3B and Class 4 lasers can cause significant eye injury to anyone
looking directly into the beam or its specular reflections. Diffuse reflections
from a high powered laser can also cause permanent eye damage. High
powered laser beams can also cause skin burns, ignite flammable materials
and heat materials causing hazardous fumes.
Non-optical hazards
Electrical Hazards (Most lasers contain high voltage power supplies and often
large capacitors that store lethal amounts of electrical energy)
Laser Dyes (Laser dyes are often hazardous dissolved in flammable solvents)
Compressed and Toxic Gases (Hazardous gases may be used in laser
applications (e.g. excimer lasers (fluorine, hydrogen chloride)
Cryogenic liquids (Cryogenic liquids may create a hazard. Adequate
ventilation must be provided)
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Laser generated fumes, vapours and air contaminants (High energy laser
beams may vapourise a target creating hazardous fumes or vapours that may
need to be captured or exhausted)
UV and visible Radiation/plasma emissions (UV and visible radiation may be
generated by laser discharge tubes , pump lamps or plasmas which may
create an eye and skin hazard)
Explosion hazards (High pressure arc lamps, filament lamps, and capacitors
may explode if they fail during operation. Laser targets and some optical
components may shatter if heat is not dissipated quickly enough)
Ionising Radiation (X-rays can be produced from high voltage vacuum tubes
of laser power supplies such as rectifiers, thyratrons and electric discharge
lasers. Any power supply that requires more than 15kV may produce x-rays)
Additional hazards may also a arise from the environment in which the laser is
used – temperature and humidity, low level lighting, mechanical shock or
vibration, interruptions to power supply, computer software problems,
ergonomic problems created by design and laboratory layout. Issues such as
cleaners and maintenance staff inadvertently disturbing equipment and
unsupervised access must also be taken into account.
Assessing Risk
Identify people at risk in addition to the laser user/s. Consider other people
such as cleaning, maintenance personnel, contractors, visitors and the public.
Risk from the laser can be assessed by using quantitative measures that
combine the likelihood of occurrence with the severity of the injury, however,
in laser safety it is usually more important to eliminate the risk of injury by
adopting appropriate control measures in all situations where the Maximum
Permissible Exposures (MPEs) are likely to be exceeded (MPE levels are
specified in BS EN 60825 in particular in Safety of Laser Products – Part 14:
A user’s guide, PD IEC TR 60825-14:2004.
Risk from non-optical hazards need to be evaluated for each hazard taking
into account existing controls.
Risk control measures
The simplest rule to follow to avoid eye injury is not to look directly into a laser
beam or any specular reflections from it, regardless of the Laser’s power,
classification or eyewear being worn. Maximum Permissible Exposure, MPE
calculations are based on the radiated wavelength(s), output power(s) or
energy(ies) and if appropriate, the pulse duration and repetition rate. MPE’s
will apply to a specific combination of these parameters and will usually
change if any of the parameters changes.
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Engineering and administrative controls should be used to keep exposures
below the MPE whenever practicable. Skin and eyewear should be used
where engineering and administrative controls are not practical.
All open beam work must have an appropriate protocol/operating
procedure/system of work. To assist in drawing up a system of work see the
System of Work for Lasers form. The grey text on the form is an indication of
the points that should be considered and will vary between different laser
systems. All users must read and sign the system of work.
Record of Assessment
The following forms should be used to record your assessment and a copy
sent to the University Laser Safety Adviser along with a copy of the System of
Work for each laser system.
Use of Class 1M,2M,2 and 3R lasers – Hazard and Risk Assessment
Use of Class 3B and 4 Lasers – Hazard and Risk Assessment
Review
Risk assessments and systems of work should be routinely reviewed and
particularly whenever there is a significant change in the activity.
PERSONAL PROTECTIVE EQUIPMENT
Personal Protective Equipment is an important element of personal laser
protection, however, reliance upon PPE should be avoided through
engineering and administrative controls and should not be regarded as a
convenient alternative to a thorough safety evaluation. Situations in which
protective goggles or gloves are necessary do arise and selecting the correct
PPE is crucial to ensuring safety.
Protective eyewear
Safety eyewear should never be relied on to provide protection against
deliberate exposure to a laser beam but should be regarded as a means of
providing some protection against accidental exposure. Information on
specifying eye protection is given in PD IEC TR 60825-14: A user’s guide.
Protection by safety eyewear is afforded by incorporating optical filters to
reduce the level of transmitted laser radiation such that the eye is not exposed
to laser radiation above the Maximum permissible exposure. As maximum
permissible exposures are wavelength dependent the eye protection supplied
must provide adequate attenuation at the appropriate wavelength and comply
20
with the requirements of BS EN 207 – Filters and equipment used for
personal eye protection against laser radiation and BS EN 208 – Personal
eye-protection used for adjustment work on lasers and laser systems.
BS EN 207 applies to filters and equipment designed to provide protection
against laser radiation in the wavelength range 180nm to 1mm.
BS EN 208 applies to eye protectors for use in adjustment work on laser or
laser systems in the wavelength range 400nm to 700nm i.e. visible. The
protective eyewear which meets the requirements of the standard reduces the
level of incident radiation upon the eye to the MPE level for a Class 2 laser
and is therefore still reliant upon the aversion response (blink reflex).
The required optical filter must have a sufficient optical density (OD) at the
laser wavelength(s) to reduce the incident radiation to a level below the MPE.
The optical density is a numerical quantity which indicates how much of the
laser radiation will be transmitted through the filter. As the transmission
properties of materials vary with wavelength, the optical density should be
quoted for the given wavelength(s). In addition the protective filter must also
withstand the intensity of radiation for a sufficient time to allow the user to
respond and take appropriate avoiding action. Whilst the filter should have a
low transmittance at the laser wavelength the percentage of the visible
spectrum that is not filtered by the eyewear should be as high as possible in
order to minimise vision impairment.
Other protective equipment
Class 4 lasers present a fire hazard and protective clothing made from
suitable flame retardant and heat resistant material may be required.
When working with Class 4 and some Class 3B devices emitting in the
ultraviolet region skin protection may be required.
Gloves should be worn when preparing chemicals for dye lasers, optics
cleaning chemicals, handling cryogenic materials and filters fromextraction
systems used for materials processing.
Face masks/respirators may be needed where fume and dusts are a hazard.
Personal protective equipment should be personal, i.e. it should be
appropriately cleaned between users, or each user has their own.
ACCIDENTAL EXPOSURES AND EMERGENCY EYE EXAMINATIONS
Eye examinations for laser users are not recommended as part of a safety
programme. The value of routine examinations for laser users has been
reviewed and it is generally accepted that routine examinations are of little
value.
21
It is important, however, to have procedures in place in the event of suspected
ocular exposure. In the event of an accident or incident involving suspected
injury to the eye, and emergency examination by a qualified specialist should
be carried out as soon as possible and within 24 hours.
All persons working with Class 3B and Class 4 lasers need to be aware of the
action to take in the event of an accident/incident. The form Emergency
Procedure for Exposure to Class 3B or Class 4 Laser should be available for
each laser to take with the casualty to the Hospital. (Please note the form is
designed for use on the All Saints Campus, for other areas the form should be
modified appropriately to include the nearest Accident and Emergency
Department).
Where an emergency eye examination is required, the University Laser Safety
Adviser and School/Departmental Laser Safety Officer will carry out a detailed
investigation of the accident/incident.
All accidents and incidents, whether involving emergency examination or not,
must be reported to the Health and Safety Unit using the appropriate Accident
Report Form.
LASER POINTERS
Laser pointers are small battery operated devices which emit a thin powerful
beam of light for distances of about 100 meters or more, and are intended for
use by teachers and lecturers as hand held pointers. The beams themselves
are invisible but appear as brilliant spots when they hit a screen or other
surface. When considering the safety implications of the laser beam an
important parameter is the amount of power in the beam divided by the crosssectional area of the beam. This is called the irradiance and is usually quoted
in watts per square metre or W/m2. The pointers are cheap and readily
available from certain shops and market stalls.
Although there have been no reported incidents of permanent injury in the UK,
there have been reports of incidents concerning the misuse of pointers by
persons deliberately targeting people such as footballers, bus, taxi drivers and
fire fighters. There have also been reports of people using the pointers in
discos and night-clubs. The laser beams have caused temporary eye
irritation or blurring of sight. In addition, there have been several instances of
MMU Security staff being targeted whilst on patrol and in one case from a car
on Oxford Road. Misuse of laser pointers can lead to prosecution for
common assault and more serious charges if this leads to serious injury to
eyesight or a motoring accident.
The degree of adverse effect on the eyes depends on the power of the beam
and the duration of exposure. By law all laser devices have to carry a label
with a warning symbol and power classification. This can range from the
weakest class 1 such as those used as bar code readers at supermarket
22
checkouts to class 4 which can cut through metal and require very stringent
regulation.
Laser pointers sold in the UK should be classified in accordance with the
current British Standard (BS EN 60825) on laser safety. This document
specifies requirements for the manufacturers of laser products to ensure that
the risk of accidental exposure is minimised through the use of engineering
control features and product labelling, and by specifying minimum
requirements for the supply of product information to allow for its safe use.
The British Standard also provides advice on the use of lasers for
demonstrations, displays and exhibition and states that only Class 1 or Class
2 devices should be used in unsupervised areas unless under the control of
experienced well-trained operators.
The Health Protection Agency has examined several laser pointers currently
available to the general public in order to assess their laser class and many
laser pointers which are either unlabelled or labelled as class 2 lasers have
been found to be Class 3R or class 3B devices when measured.
Green laser pointers have given a particular cause for concern and many of
these cause afterimages in people viewing the beam on a projection screen.
Because of the way the green beam is generated, there may also be
additional invisible laser beams emitted.
Direct ocular exposure close to a class 3b lasers is always hazardous
and will cause damage to the eye.
The risk of a permanent eye injury from a laser pointer is small; however, a
transient eye exposure from a laser will cause a bright flash, a dazzling effect,
which is likely to cause distraction and temporary loss of vision in the affected
eye and possible after-images. Recovery from these effects will vary for
different individuals. Medical attention should only be sought if after-images
persist for hours, or if a disturbance in reading vision is suddenly apparent.
CONCLUSIONS
1. The Health Protection Agency considers the professional use of a Class 1
or Class 2 laser pointer as a training aid in the workplace to be justified and
regards these Classes of laser product as being generally adequate for such
use.
2. Only members of staff and postgraduate students undertaking teaching or
presentations should be permitted to use laser pointers. They should be
aware of the hazards and exercise caution insuring that they do not direct
pointers towards any person within the range of the beam.
3. Staff and students who do not meet the above criteria must not be
permitted to use laser pointers on University premises.
23
4.
It is not possible to recommend particular laser pointers since even
pointers from reputable sources may be incorrectly labelled according to
European standards. When purchasing a laser pointer, however, the following
points should be considered:
a) The pointer should be classified either Class 1 or Class 2 in
accordance With the requirements of the current British Standard (BS
EN 60825).
b) It should carry with it sufficient accompanying information to enable the
user to operate the product in a safe manner.
c) The pointer should be labelled as either a Class 1 Laser Product or a
Class 2 Laser Product and in the latter case should also state “Do not
stare into beam”.
5. Anyone who suspects that he/she has been assaulted by a laser pointer
should report it and arrange to seek prompt medical attention if it is suspected
that the eyes have been affected. If possible the device involved should be
confiscated, both to prevent further misuse, and to find the label to ascertain
its classification.
This information may assist medical staff. An incident report form should be
completed and forwarded to the Health and Safety Unit in Minshull.
LASERS FOR DISPLAY PURPOSES
Guidance on laser displays and shows can be found in IEC 60825 Part 3 and
the Health and Safety Executive Guidance Note HS(G)95 The Radiation
Safety of Lasers used for Display Purposes.
Organisers of events at which lasers are used for display should:
1) Carry out a general risk assessment to identify relevant hazards
and appropriate control measures are in place, in advance of any
display.
2) Contact the University Laser Safety Adviser with details of the
intended display
3) Comply with the requirements of HS(G)95 and ensure that any
statutory notifications are made.
Where the relevant precautions above are not implemented for a particular
class of laser, a justification needs to made in the appropriate
documentation/protocol for the display.
Deliberate scanning of an audience with laser beams will not be permitted
unless a rigorous assessment of the likely exposure, and any foreseeable
fault conditions show that the applicable Maximum Permitted Exposure limit
will not be exceeded.
24
LASER SIGNS AND LABELS
Designated Laser Areas
The points of access to areas in which Class 3B or Class 4 laser products are
used must be marked with warning signs complying with BS 5378 and the
Health & Safety (Safety Signs and Signals) Regulations 1996.
The signs shall incorporate the following information:
1) hazard warning symbol
2) highest class of laser in the area
3) responsible person with contact details
For the area signs the specifications are quite simple -50% of the area should
be yellow and the width of the black border is 0.06 x the length of the side.
A more detailed specification is given for the symbol used in labels, see spec
on p65 of BS EN 60825-1
Laser Labels
Laser labels are required for all laser products except for low power Class 1
devices. They are designed to give a warning of laser radiation, the class of
laser, basic precautions and the laser's characteristics.
The laser warning uses the same symbol as for the door sign in an
appropriate size for the laser to be labelled and should be clearly visible.
Supplementary information should be black text on a yellow background in
accordance with BS EN 60825-1.
Where the size of the laser product does not permit the affixing of a
reasonably sized label, a sign should be displayed in close proximity to the
laser with all appropriate information on.
Information over and above that specified by BS EN 60825-1 is required for
25
Class 1 products that are Class 1 by engineering design.
For these types of laser product we specify that they are totally enclosed
systems and give details of the laser enclosed. The BS requirement is just to
describe them on the outside as a Class 1 laser product.
Details of wording required on explanatory labels are given below:
Class 1 (by engineering design)
No hazard warning label.
Explanatory label bearing the words:
CLASS 1 LASER PRODUCT
A TOTALLY ENCLOSED LASER SYSTEM
CONTAINING A CLASS ..... LASER
In addition each access panel or protective housing shall bear the words:
CAUTION - CLASS ....... LASER RADIATION WHEN OPEN
with the appropriate class inserted and then followed by the hazard warning
associated with that class of laser (see warning statements in following
labels).
Class 1M
No hazard warning label.
Explanatory label bearing the words:
LASER RADIATION
DO NOT VIEW DIRECTLY
WITH OPTICAL INSTRUMENTS
CLASS 1M LASER PRODUCT
NB-'Optical Instruments' can be supplemented with either 'Binoculars or
Telescopes' (for a large diameter collimated beam) or 'Magnifiers' (for a highly
diverging beam).
Class 2
Label with hazard warning symbol.
26
Explanatory label bearing the words:
LASER RADIATION
DO NOT STARE INTO BEAM
CLASS 2 LASER PRODUCT
Class 2M
Label with hazard warning symbol.
Explanatory label bearing the words:
LASER RADIATION
DO NOT STARE INTO BEAM OR VIEW
DIRECTLY WITH OPTICAL
INSTRUMENTS
CLASS 2M LASER PRODUCT
NB-'Optical Instruments' can be supplemented with either 'Binoculars or
Telescopes' (for a large diameter collimated beam) or 'Magnifiers' (for a highly
diverging beam).
Class 3R
Label with hazard warning symbol.
Explanatory label bearing the words:
For wavelengths 400nm-1400nm ONLY.
LASER RADIATION
AVOID DIRECT EYE EXPOSURE
CLASS 3R LASER PRODUCT
NB - For other wavelengths replace 'AVOID DIRECT EYE EXPOSURE' with
'AVOID EXPOSURE TO BEAM'
27
Class 3B
Label with hazard warning symbol.
Explanatory label bearing the words:
LASER RADIATION
AVOID EXPOSURE TO BEAM
CLASS 3B LASER PRODUCT
Class 4
Label with hazard warning symbol.
Explanatory label bearing the words:
LASER RADIATION
AVOID EYE OR SKIN EXPOSURE TO
DIRECT OR SCATTERED RADIATION
CLASS 4 LASER PRODUCT
Aperture Labels for Class 3R, Class 3B & Class 4 lasers
Each Class 3R, Class 3B and Class 4 laser product shall display a label close
to where the beam is emitted bearing the words 'LASER APERTURE' or
'AVOID EXPOSURE - LASER RADIATION IS EMITTED FROM THIS
APERTURE'. This label can take the form of an arrow if this displays more
meaning:
LASER
APERTURE
28
Radiation Output and Standards Information
All laser products, except for low power Class 1 devices, shall be described
on an explanatory label with details of :• maximum output
• emitted wavelength
• whether laser beam is visible, invisible or both
• pulse duration (if appropriate)
• name and publication date of classification standard
It may be found useful to also put on the labels details of the type of laser and
the lasing medium, although this is not a BS requirement.
Information put on explanatory labels may be combined and LED shall be
used to replace the word 'laser' when appropriate.
A selection of labels is available from the Laser Safety Adviser in the Health
and Safety Unit.
29
FORMS
SUMMARY OF WARNINGS & PROTECTIVE CONTROL MEASURES
CLASS
PROTECTIVE CONTROL MEASURES
1
No protective control measures for normal use (NB special precautions
may be needed for service work on embedded laser products.)
1M
Prevent direct viewing with magnifying optics. (NB fitting external optics
that decrease beam divergence may affect classification) + see footnote
2
Do not stare into beam.
Do not direct the beam at other people or into public areas.
2M
Do not stare into beam
Do not direct the beam at other people or into public areas.
Terminate beam at end of useful path with a non-specular beam stop.
Prevent direct viewing with magnifying optics. (NB fitting external optics
that decrease beam divergence may affect classification) + see footnote
3R
Prevent direct eye exposure to the beam.
Do not direct the beam at other people or into public areas. + see footnote
3B and 4
Class 3B and Class 4 laser products should not be used without first
carrying out a risk assessment to determine the protective control
measures necessary to ensure safe operation. Where reasonably
practicable engineering means should be used reduce the laser class to a
totally enclosed Class 1 laser product.
The use of any Class 3B or Class 4 laser without an interlocked enclosure
will require a written scheme of work. Even with an enclosure written
procedures will be necessary if the user is involved in any alignment
procedures that require over-riding of interlocks.
Class 3B and Class 4 laser products require the control of access to the
area where the laser is operated by the use of a remote interlock, the use
of key control, emission indicators, beam shutters, removal of reflecting
surfaces that could be struck by an errant beam, beam enclosures
wherever practical, the use of eye protection and protective clothing as
appropriate, training of staff and the appointment of a Laser Safety Officer.
+ Classes 1M, 2M and 3R may also require training of staff, care with beam paths and
specular reflections - see BS EN 60825 -1 and PD IEC TR 60825-14:2004 for more
details.
Special attention should also be given to other non-optical hazards such as risk of
electric shock, hazardous chemicals, cryogenic liquids and flying debris from targets to
name but a few. It is often the non-optical hazards that pose the greatest risk - one
could be blinded in one eye from a powerful laser but electrocution could be fatal.
Some non-optical hazards may be present with even Class 1 laser products.
30
LASER SURVEY FORM
Date:
Dept:
Lab:
Make:
Type:
Model:
Continuous/Pulsed
Serial No.
Wavelength
Max. Power:
Precautions
Remote
Interlock
Key Control
Class Class Class Class Class Class
1 (E)
1
1M
2
2M
3R
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Safety Interlocks
N/A
N/A
N/A
N/A
Emission
Indicator
Beam
Stop/Shutter
Beam terminator
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Beam level
N/A
N/A
N/A
N/A
N/A
N/A
Beam enclosure
Class
4
N/A
N/A
Eye protection
N/A
N/A
N/A
N/A
N/A
Protective
clothing
Training
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Class
3B
N/A
Laser labels
Door signs/Area
signs
N/A
N/A
N/A
N/A
N/A
N/A
Eye
Examinations
N/A
N/A
N/A
N/A
N/A
N/A
Class 1(E) refers to a Class 1 totally enclosed system
31
Administrative controls
Recommendations
1
Remote interlock -
connection provided by the manufacturer for door or enclosure
interlock for Class 3B and Class 4 lasers
2
Safety interlocks -
required for access panels on Class3R, 3B and 4 laser systems
3
Key control
a key or similar device is required to control unauthorised
operation of Class 3B and Class 4 lasers
4
Emission indicator -
an audible or visible indicator should be provided by the
manufacturer for each Class 3R laser ( except wavelengths 400700nm) and each Class 3B and Class 4 laser system
5
Beam stop or
attenuator/shutter -
should be provided by the manufacturer for each Class 3B or
Class 4 laser system
6
Beam termination -
the user should ensure that all beam paths are terminated at the
end of their useful path. (Does not apply to Class 1 devices)
7
Beam level -
avoid eye level
8
Beam enclosure -
to guard against specular reflections from Class 3R, Class 3B
and Class 4 lasers - can mean anything from screening the
experimental area or piping the beam up to a total enclosure.
9
Eye protection -
required for open beam work with invisible beam Class 3R and
all Class 3B and Class 4 devices.
10 Protective clothing
mainly required for Class 4 lasers but be careful with Class 3B
UV lasers as well, may need fire resistant material for some
lasers
11 Eye examinations -
only required after an accident but may be important to people
with poor eyesight working with Class 3B or Class 4 lasers
12 Training -
required for people working with any Class 3 or Class 4 laser
and any modified Class 1M or Class 2M devices.
13 Laser labels -
required for all lasers except low power Class 1 ( though need
not be directly affixed if the size of the laser product does not
permit this)
14 Door/Area signs -
required for Class 3B and Class 4 lasers indoors and also for
Class 1M, 2M and 3R if used outdoors
32
LASER INVENTORY
Manufacturer and
Model
Type
Location Wavelength Power Output (for CW) or
Pulse Power, duration and
repetition rate
Laser
Class
Note: Do not include office based Class 1 laser products or equipment
containing them i.e. Compact Disc/DVD players, laser printers etc.
School/Department:
Laser Supervisor/Officer:
Date:
33
REGISTRATION FORM FOR LASER USERS
Surname:
Forename(s):
Title (Mr, Ms, Dr etc)
Status (Lecturer, Student, Technician,
Research student etc)
email:
Supervisor:
Department:
Lasers to be used:
Laboratory to be used:
34
USE OF CLASS 1M, 2M,2 AND 3R LASERS – HAZARD & RISK ASSESSMENT
Class 1M, 2M and class 2 devices do not create an eye hazard as long as a person does not stare
into the beam as eye protection is normally afforded by the aversion response. Exposure hazard to
the eye is possible if:
a) Exposure is in excess of 0.25 seconds from class 2/2M lasers
b) Class 1M/2M lasers are modified. Modified devices may need to be reassessed to a higher
classification
c) A Class 3R laser is viewed directly
There is no skin or fire hazard.
FACULTY
SCHOOL/DEPARTMENT
LOCATION OF ACTIVITY
DESCRIPTION OF ACTIVITY
Brief description of Laser set up and purpose
LASER SPECIFICATION
Complete the following table
Type (e.g. He-Ne,
NdYAG)
Model
Max Power
Wavelength
LASER CLASS
35
1) HAZARDS
Non-optical and Optical (1M/2M)
Hazard
Control measure
Detail the significant risks
and control measures
necessary for any nonoptical hazard identified and
any optical hazard from
1M/2M devices
2) PERSONS AT RISK
Staff, students, visitors
3) RISK CONTROL METHODS
1. Avoid eye level and do not point beam at other persons
2. Follow the manufacturers safety instructions
3. Keep the laser on only when necessary
4. Terminate the beam at the end of its useful path
5. Do not point at highly reflective surfaces
6. Do not look directly into the laser aperture or stare into the beam
7. Do not use direct optical viewing aids
8. Restrict unauthorized use
4) CONTACT
Report Accident/Incident to Health and Safety Office ext 3317
NAME AND TITLE OF ASSESSOR
SIGNATURE
DATE
REVIEW DATE
36
USE OF CLASS 3B & 4 LASERS – HAZARD & RISK SSESSMENT
FACULTY
SCHOOL/DEPARTMENT
LOCATION OF ACTIVITY
DESCRIPTION OF ACTIVITY
Brief description of laser set up and purpose
LASER SPECIFICATION
Complete the following table including all lasers such as low power alignment lasers
Laser 1
Laser 2
Laser 3
Laser 4
Type (e.g. He-Ne,
NdYAG)
Manufacturer
Model
Serial Number
Maximum Power
Maximum pulse energy
Wavelength range
Wavelength used
Power used
Pulse energy used
Pulse length
Pulse repetition rate
Beam diameters (x,y)
Beam shape (e.g.
ellipse, circular)
Beam divergence (x,y)
LASER CLASS
37
1) HAZARDS
Identification of non-beam hazards
Electrical hazards (Most lasers contain high voltage power supplies and often large capacitors that store lethal
amounts of electrical energy)
Are any special precautions/procedures required?
Yes
No
Laser Dyes (Laser dyes are often hazardous dissolved in flammable solvents)
Are laser dyes used?
Yes
No
If yes, give details
Compressed and Toxic Gases (Hazardous gases may be used in laser applications (e.g. excimer lasers (fluorine,
hydrogen chloride)
Are compressed and/or toxic gases used?
Yes
No
If yes, give details
Cryogenic liquids (Cryogenic liquids may create a hazard. Adequate ventilation must be provided)
Are cryogenic liquids used?
Yes
No
If yes, give details
Laser generated fumes, vapours and air contaminants (High energy laser beams may vapourise a target
creating hazardous fumes or vapours that may need to be captured or exhausted)
Are there likely to be laser generated fumes, vapours or air contaminants?
Yes
No
If yes, give details
UV and visible Radiation/plasma emissions (UV and visible radiation may be generated by laser discharge tubes ,
pump lamps or plasmas which may create an eye and skin hazard)
Is there likely to be significant UV/visible radiation produced
Yes
No
If yes, give details
38
Explosion hazards (High pressure arc lamps, filament lamps, and capacitors may explode if they fail during operation.
Laser targets and some optical components may shatter if heat is not dissipated quickly enough)
Is there an explosion hazard?
Yes
No
If yes give details
Ionising Radiation (X-rays can be produced from high voltage vacuum tubes of laser power supplies such as rectifiers,
thyratrons and electric discharge lasers. Any power supply that requires more than 15kV may produce x-rays)
Is there an ionizing radiation hazard?
Yes
No
If yes give details
Other hazards not specified above (Please give details)
2) PERSONS AT RISK
Authorized laser users
Project supervisors
Staff and students in the immediate vicinity
3) RISK CONTROL METHODS
Reduction of Laser beam risk
Are open or partially enclosed
beams used
During initial setting up and
beam alignment
During the addition of new
optical elements/lasers
During maintenance
Yes
No
Are there protocols, procedures
or systems of work to control
risks from eye and skin
hazards
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
List operating protocols/procedures/systems of work
ALL OPEN BEAM WORK MUST HAVE AN APPROPRIATE
PROTOCOL/OPERATINGPROCEDURE/SYSTEM OF WORK
39
Protective Eyewear
Please give details of optical eyewear:
Location
Optical Density
Wavelength
Number available
Reduction of risk of associated hazards (as identified in Secion 1)
Detail the significant risks and the control measures necessary (i.e. by reference to protocols/procedures/systems of work)
For hazardous substances specify the location of the appropriate COSHH assessments
Training
Authorised laser users must receive appropriate training and instruction.
Specify the instruction and training arrangements.
Instructions
All users must read and sign System of Work.
Audit Methods
It is the responsibility of the individual laser operator to follow the guidelines on laser safety. Where control measures have
failed or have been suspect then laser users should report these. Supervisors should monitor that users are complying with
procedures. Departmental Laser Safety Officers and the University Laser Safety Officer will carry out periodic checks.
Review arrangements
If the laser system or work deviates from standard procedures described in the system of work.
During University Laser Safety Officer visit.
4) CONTINGENCY ARRANGEMENTS
Suspected Malfunction – See System of work
Suspected Overexposure – See System of work
Faculty fire evacuation procedures will apply and the EM Plan for the Faculty.
NAME AND TITLE OF ASSESSOR
SIGNATURE
DATE
REVIEW DATE
40
SYSTEM OF WORK FOR LASERS
System of work for the safe operation of Please enter type of a laser located in
Dept:
, Room
, and building
Departmental Laser Safety Officer:
University Laser Safety Officer:
Date:
Description of Activity
Description of activity/expermient and its purpose
Description of Laser
Class:
Please enter class of laser
Model
Serial Number
Name and type of laser
(e.g. Nd;YAG, He/Ne, etc. )
Wavelength
Pulsed or continuous
Length and energy of pulse
Maximum power
Beam delivery system
Open or enclosed beam, Mirrors?, How is output terminated? e.g. photo-multiplier
tube, beam dump, beam stop.
Laser process
High voltages, chemicals, gases involved
41
Calculations
Maximum Permissible Exposure (MPE) and Nominal Ocular Hazard
Distance calculations.
Description of safety eyewear i.e. Optical density at appropriate
wavelength.
Authorised users
Only persons who are adequately trained state howand authorised may
work with the laser/carry out user maintenance Authorised users of the above
laser(s) are:
Student
Other, please specify:
Laser controlled area
Describe extent of laser controlled area and conditions under which one
exists. Access, interlocks, illuminated signs and how they operate.
Protection measures
A Risk Assessment must be completed prior to carrying out the
laser activity.
Identify safety critical operations e.g.
Setting up and alignment of the beam
Describe control measures which need to be carried out for each
operation (for guidance and examples please refer to Appendix 1 of the
this form)
Maintenance
Maintenance applies to adjustments and procedures specified in the
information supplied by the manufacturer of the laser product which
are carried out by the user to order to assure the intended
performance of the product. This may require access within the laser
enclosure which may lead to an increased risk to the laser worker to
higher energy laser beams, high voltages and toxic chemicals. These
42
activities will vary depending on the laser product and specific
protocols will need to be prepared for each laser.
Servicing carried out by the manufacturer is outside the scope of this
document.
 Before commencing maintenance procedures the manual for the
laser system should be consulted for recommended methods.
 If the laser manual does not give a method or in the case of nonroutine maintenance, the advice of an experienced laser technician
should be sought. Some procedures should only be carried out by
an experienced laser technician.
 A written risk assessment of the procedure should be carried out.
In the case some routine procedure e.g. changing the dye in a dye
laser reference to an existing protocol may be sufficient.
 Maintenance procedures involving beam alignment inside an
enclosure can lead to an increased risk of exposure to high power
laser beams which are normally enclosed. The protocol in the
previous section for setting up and alignment should be consulted.
Contingency plan
In the event of an accident
Report accident to Health and Safety Ext 3317 office during normal office
hours. All accidents and incidents must be reported to the Health &
Safety office using the current Accident Report Form
In the case of accidents involving exposure to Class 3B and Class 4
lasers the casualty should be taken to:
Accident & Emergency
Royal Eye Hospital
Nelson Street, M13.
Tel: 0161-276 1234
(NB the above applies to the All Saints site. In the case of other sites please fill in
appropriate information)
The form ‘The Emergency Procedure for Exposure to Class 3B or 4’
Laser should be filled in and taken with the casualty.
In the case of serious injury dial 999 for an ambulance.
Laser Safety Officer
Date
43
Declaration
Declaration that authorised users sign to say that they have understood
and agree to work to the local rules.
Name (in block capitals)
Signature
Date
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Appendix 1
Setting up and alignment of the beam
In grey text are the principal risk control measures which should be taken into
account, exact detail will vary between different laser systems.
 Discuss installation/changes with a supervisor prior to operation
of Class 3B/4 laser systems
 When new work is being carried out the Departmental Laser
Safety Officer and/or University Laser Safety Adviser must be
consulted and invited to visit the lab.
 Laser beam paths and optics should be arranged so as to
minimise stray reflections
 Laser beam paths should be arranged so that the eyes are well
above the level of laser beams
 Termination of the beam should be planned e.g. using beam
stops or beam dumps where necessary.
 Suitable laser safety eyewear should be provided.
 Keys and key switches – where and how to get them
 Before starting work beam paths should be inspected for items
that should not be there.
 Laser warning signs should be on, barriers and beam covers in
place, unauthorised persons excluded and doors closed.
 Class 3B and Class 4 lasers require the control of access to the
area where the laser is operated by the use of remote interlock.
 Reflective jewellery and wristwatches should be removed.
 Turning water on/off
 High voltages on/off
 Appropriate safety eyewear should be worn if practicable. If this
is not possible e.g. when the beam cannot be seen on a card
when eyewear is worn, then extra caution needs to be taken.
 Initial laser beam alignment should be carried out with a Class 2
or Class 1 laser e.g. He-Ne or small CW diode laser.
 Flight tubes should be used to enclose long runs of laser beam;
these should be designed to allow limited access to the beam
for alignment checking without having to remove them.
 Secondary alignment may be carried out using a Class 3B/4
laser beam at low power. This should be done using the lowest
possible laser energy. Visualisation is dependent on the
wavelength e.g. UV or visible beams can be viewed on
fluorescent card infrared beams may be viewed on LCD heat
sensitive paper or possibly burn paper or a laser power meter.
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 In the case of UV or IR beams appropriate eyewear should be
worn during alignment at all times when the laser energy
exceeds the MPE.
 In the case of visible or multi-wavelength beams, alignment may
have to be carried out without laser safety eyewear in order to
visualize the beam on a card. If possible the laser should be
operated below the MPE and in any case at the lowest
practicable pulse energy. The blocking of stray reflections
should be double checked before alignment. Alignment of each
laser beam to variable diameter apertures (iris diaphragms)
should be employed where possible to minimise the necessity
for multi-wavelength alignment.
 Under no circumstances must direct viewing of the laser beam
be attempted even if the beam has been attenuated.
 Remote viewing using a video camera should be considered.
 All optics should be checked for damage, and the stability of the
optical mounts checked prior to operating the laser.
 Minor re-alignment may sometimes be necessary during the
experimental activity when the beam is at full power. In this
event extra caution should be exercised. If possible minor
alignment should be carried out using the experimental signal as
a guide so that visualizing the beam is not necessary.
 Attention should also be given to any other hazards such as
chemicals, gases, hot surfaces, electricity, cryogenic liquids and
flying debris from targets.
Adding new elements
 Initial laser beam alignment should be carried out with a Class 2
or Class 1 laser e.g. He-Ne or small CW diode laser.
 All optical elements in the beam path must be analysed for stray
reflections. This can be done by predicting the likely path of
specular (non-diffuse) reflections and from the actual reflections
from the Class 1/2 alignment laser. Suitable beam blocks which
are opaque to the appropriate wavelengths should then be
installed where necessary to block stray reflections.
 All optics should be checked for damage, and the stability of the
optical mounts checked prior to operating the laser.
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EMERGENCY PROCEDURE FOR EXPOSURE TO CLASS 3B OR 4 LASER
REPORT TO: Accident & Emergency, Royal Eye Hospital, Nelson Street, M13
Tel: 0161-276 1234
IF OTHER A&E please specify: Enter address details
As soon as possible and within 24 hours of the incident. Do not drive yourself, get a friend or
colleague to take you.
Out of hours: Contact local Security or Emergency Services
i. State Building and Department
ii. Location and nature of incident/accident
iii. Request ambulance to take the casualty to the Royal Eye Hospital (as above)
iv. Take the information below to the Hospital
EMERGENCY OPHTHALMIC EXAMINATION LASER EXPOSURE
LASER DETAILS:
Type: e.g. NdYAG, He-Ne
Continuous Wave / Pulsed
Wavelength (nm):
Power Output (CW): or Pulse Energy,
Duration, and Rate (pulsed):
Laser Classification:
EXPOSURE DETAILS:
Circumstances of accident/injury:
Time of Injury
Eye affected:
Was protective eyewear being worn?
Date of injury
Left/Right/Both
Yes
No
REPORT ACCIDENT/INCIDENT TO:
Health and Safety Office Ext 3317 during normal hours. Fill in Accident Report Form.
All accidents and incidents, whether involving an emergency examination or not, must be reported promptly to the Health
and Safety Office using the current Accident/Incident Report Form. The Laser Safety Adviser and School/Departmental
Laser Supervisor/Officer must also carry out a detailed investigation of the accident/incident. Any serious injury or 3 days
absence from work has to be reported to the Health and Safety Executive under 'The Reporting of Injuries, Diseases and
Dangerous Occurrences Regulations 1995’
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TRAINING RECORD FORM
Researcher
Room number
Lasers used
Registered as University laser user
Familiar with hazards and risk assessments within the laboratory
Familiar with laser System of Work
Trained in use of lasers named above
Attended Laser Safety Training Session
Read University Laser Safety Guidance Notes
Signed …………………………………………………………….
Researcher
Date
Supervisor
Date
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