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School of Chemistry Safety Protocol – Use of Lasers
PROTOCOL FOR USE OF LASER EQUIPMENT
Main Hazards
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Permanent Eye Damage
Premature aging of eye and cataract formation
Electric shock from laser components
Chemical Hazards from Chemical Components
Key Safety Procedures
Use by trained operators only
Wear suitable eye protection
General Comments
When used properly a laser presents no more risk than other research instrumentation. However,
almost all lasers should be regarded as potentially hazardous. Direct viewing of the beam from Class
3B and Class 4 lasers is almost certain to result in permanent damage to the eye, and there is also a
significant risk from specular reflections.
Harm from laser radiation results from photochemical or thermal damage to the irradiated tissue.
Obviously the eye is particularly vulnerable. Because of the eye's ability to focus the incident
radiation the power density at the retina can be extremely high even for low power lasers. Exposure
can cause denaturing of the proteins responsible for vision which causes irreversible damage and
general impairment of vision. Long-term exposure to bright light, particularly in the ultraviolet,
might also lead to “premature ageing” of the eye and cataract formation.
Lasers also pose significant conventional hazards: Electrical risks from laser power supplies and
associated equipment: Toxic chemical hazard, e.g. excimer gases, dye lasers, specialised optics, laser
vaporisation products: Fire hazard from solvents, e.g. dye lasers: X-ray generation by high voltage
rectifiers and focussed laser radiation: Photochemical hazard, e.g. zone production.
Detailed Instructions for Use
New users:
1. New users must register with the School and University Laser Protection Officer before starting
any work with lasers in Class 3 or above.
2. New users must read and discuss with the School Laser Protection Officer a copy of the local
guidance notes. A signed copy of the notes should be kept with the users’ laboratory notebook.
The School of Chemistry Safety Committee have approved this protocol for the named School operation or procedure.
This task must be carried out in line with this protocol. If you believe that this protocol is unsuitable for the
circumstances in your laboratory or area of work discuss this procedure with your supervisor or line manager and the
appropriate Safety Advisor. Any modified operating procedures must be documented, approved and signed by your
supervisor or line manager before they are undertaken
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School of Chemistry Safety Protocol – Use of Lasers
3. New users must attend the Safety course given by the University Laser Protection Officer the first
available opportunity.
General:
All laser users should be familiar with the contents of the following documents:
1. CVCP document “Safety in Universities: Part 2.1 Lasers” (1992 revised Code of Practice)
2. BS 7192 “Radiation Safety for Laser Products” and BS EN 60825
Copies of these documents are available from the School Laser Protection Officer.
You may only operate Class 3B and Class 4 laser systems in designated areas. All Class3B and Class 4
lasers must be registered with the School Laser Protection Officer and must be labelled in
accordance with the guidelines given in the CVCP Code of Practice. Only registered laser workers are
allowed to enter designated laser laboratories when a laser is in operation.
In designated laser laboratories you should:
1. If practicable wear suitable safety glasses when operating a laser. Always wear suitable eye
protection when making alignment adjustments in the laser head itself. Suitable means of the
appropriate wavelength for the particular laser and conforming to European Standard EN207
2. Be aware of the conventional hazards associated with a laser. For example, many laser power
supplies operate at high voltage (ca. 10-20 kV) and are water cooled! All metal optical tables and
benches must be connected to a suitable electrical earth. COSHH forms must be completed for
the correct handling and disposal of laser dyes and gases if appropriate. You should be aware
that the materials in some optical components is toxic, e.g. ZnSe
3. Avoid wearing jewellery, such as rings and wrist-watches etc., when working with lasers.
4. Make alignment adjustments at the lowest energy/power consistent with the purpose of the
experiment.
5. Avoid exposure to specular reflections as much as possible placing the laser and associated
experiment in an enclosure or by the use of light pipes, screens, beam dumps etc.
6. Never remove or add an optical component into a laser or its output beam while the laser is
working.
New Experiments:
Before changing an existing experimental arrangement or when setting up a new experiment you
should:
1. Assess the potential risk of stray beams and ensure that adequate beam blocks are installed
before allowing the laser beam into the experiment. Remember that there may be a fire hazard
from the laser radiation so ensure that any beam blocks will withstand the exposure to the stray
radiation when the laser is operating at full power.
2. You must document your risk assessment (a simple sketch of the proposed new experimental
arrangement will often suffice) and discuss it with your supervisor or the School Laser Protection
The School of Chemistry Safety Committee have approved this protocol for the named School operation or procedure.
This task must be carried out in line with this protocol. If you believe that this protocol is unsuitable for the
circumstances in your laboratory or area of work discuss this procedure with your supervisor or line manager and the
appropriate Safety Advisor. Any modified operating procedures must be documented, approved and signed by your
supervisor or line manager before they are undertaken
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School of Chemistry Safety Protocol – Use of Lasers
3.
4.
5.
6.
7.
Officer before proceeding with the new set up. A copy of your risk assessment must be kept with
your laboratory notebook or in the laboratory.
Warn other users in the laboratory what you are about to do before allowing the beam into the
experiment.
Make sure that the laser is operating at low energy/power before allowing the laser beam to
enter the experiment.
Ensure that all beam steering optical elements and beam dumps are firmly fixed into their
mounts and that the mounts are firmly fixed to the optical table or bench.
Make all alignment adjustments of the optical path at the lowest possible laser energy/power
Check again that there are no stray reflections before increasing the laser energy/power to its
operating value. Always work at the lowest possible energy/power consistent with the purpose
of the experiment.
Existing Experiments:
A risk assessment of the experimental set up (including a simple sketch of the optical path) must
exist and should be available for inspection.
Each time the laser apparatus is used you should:
1. Check that all beam blocks are correctly positioned, that no beam steering components have
been moved and that they are still firmly fixed into their mounts and that the mounts are firmly
fixed to the optical table/bench since the last time you used the equipment before turning on
the laser.
2. Warn other users in the laboratory that you are about to turn on the laser.
3. Ensure that the laser is operating at low energy/power before admitting the laser beam into the
experiment.
4. Check that there are no stray reflections before increasing the laser energy/power to its working
value.
Dealing with breakdowns and faults:
It is impossible to give a detailed protocol for fault-finding and repair of lasers, since each is
different; however, there are some general guidance points, which you should note. There are
many conventional hazards associated with lasers. Power supplies and the high voltage
components with the laser head are particularly dangerous. In the event of a fault developing
with the system do not attempt to rectify the fault yourself unless you have received instruction
from your supervisor, a service engineer, or other technically competent person. Never carry out
work involving high voltage components on your own (even if the unit is switched off and
disconnected from the mains power supply). Lethal high voltages can build up on capacitor banks
even when they are disconnected, so they must be properly earthed before attempting any work
inside a laser power supply.
The School of Chemistry Safety Committee have approved this protocol for the named School operation or procedure.
This task must be carried out in line with this protocol. If you believe that this protocol is unsuitable for the
circumstances in your laboratory or area of work discuss this procedure with your supervisor or line manager and the
appropriate Safety Advisor. Any modified operating procedures must be documented, approved and signed by your
supervisor or line manager before they are undertaken
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School of Chemistry Safety Protocol – Use of Lasers
After instruction, proceed with extreme care.
1. Always read the manual carefully before attempting any repair or fault-finding procedure.
2. Discuss anything you do not understand with a technically competent person.
3. Assess the risk of any procedure before attempting it.
Emergency Procedures
Eye injuries should be treated immediately at the LGI.
Protocol written by:
Approved by the Safety Committee:
Last Review by:
Last Review Date:
B. Whitaker
5. 2001
R. Fox
7. 2015
The School of Chemistry Safety Committee have approved this protocol for the named School operation or procedure.
This task must be carried out in line with this protocol. If you believe that this protocol is unsuitable for the
circumstances in your laboratory or area of work discuss this procedure with your supervisor or line manager and the
appropriate Safety Advisor. Any modified operating procedures must be documented, approved and signed by your
supervisor or line manager before they are undertaken
Page 4 of 4