Resource Person
Laser equipment should only be used or manipulated by someone who has
followed a specific training concerning the safety conditions, the
instructions and specific procedures required for its use. Before any
utilisation, identify the person in charge of laser equipment and/or
contact the ACMO, they will inform you on the specific instructions
that must be followed.
The effects and risks of lasers
Effects on the eyes
depend on the wavelength, the power and the duration of exposure as
well as how the exposure is made over time (continuous or pulsed
exposure, duration and frequency of the pulses).
The consequences may be:
- burns and irreversible lesions of the retina (visible or near IR lasers), permanent visual loss
- irritation or inflammation of the conjunctiva
- inflammation or serious burns of the cornea (e.g., UV or IR lasers)
- damage of the crystalline lens or formation of a cataract through repeated or prolonged exposure
The thermal effects
effects of laser radiation are dangerous for the skin. For an
accidental exposure, depending on the conditions of exposure
(wavelength, duration of exposure, power, different skin damages may be
observed from red spots to blisters or burns.
Other potential risks may also be introduced by laser equipment, in particular:
Chemical risks:
Some lasers use toxic substances, either carcinogenic or toxic gases
that must be manipulated with precautions (ventilated enclosures,
gloves...).
Electrical risks: Some lasers use high voltages and stock significant amounts of power in condensers (risks during equipment maintenance...).
Fire risks:
Some lasers develop enough power to cause the combustion of inflammable
materials (e.g. wood, plastics...). Precautions must be taken to
confine the beam and dissipate the power.
Classification
Lasers are classified according to the risks they generate :
CLASS 1 |
Lasers considered without danger in all conditions of reasonable use. |
CLASS 1M |
Lasers for which direct vision into the beam, especially through optical instruments, can be dangerous. |
CLASS 2 |
Lasers which emit visible radiations in the wavelength range from 400 to 700 nm. The winking reflex normally protects the eye. |
CLASS 2M |
Lasers which emit visible radiations in the wavelength range from 400
to 700 nm and for which direct vision into the beam, especially through
optical instruments, can be dangerous. |
CLASS 3R |
Lasers for which direct vision into the beam is potentially dangerous
but the level of risk is less than that of class 3B lasers. |
CLASS 3B |
Lasers for which direct vision into the beam is always dangerous. Normally the vision of diffuse reflections is not dangerous. |
CLASS 4 |
Lasers
for which both direct vision into the beam and diffuse reflections are
always dangerous. They can cause skin lesions and be a fire hazard.
Their use requires extreme precautions. |
Labelling laser equipment
All laser equipment should be have:
- a plate indicating the class of the laser as well as complementary information according to the class.
- the laser icon (except for class 1):
General precautions
A risk analysis will already have been done by the ACMO and/or the
person in charge of laser equipment. They will give you all the
information necessary for laser use.
The main recommendations are the following:
- Concerning the use of laser equipment: :
- the orientation of a laser should not be modified while it is being used
- install the laser at a height different from that of your eyes and avoid sitting zones in the laser area
- make sure that the optical elements in the beam path are firmly fixed
- make sure you have a laser hood
- take into account that the elements of the optical path may be sources of beam reflection
- when possible, tag the laser path with clear and explicit posters
- the access must be forbidden during periods of laser emission
- avoid the presence of reflecting objects in the room, on people or on their clothes
- make
sure there is absolutely no possible parasitic reflexion (reflecting
surfaces) or reflexions due to objects like rings, watches, tools or
glossy paper struck by the beam
- never start the laser if all the elements (source, optical elements, target) has not been properly stabilised
- do not direct the laser beam towards the room entrance or position it at eye-height for the users
- hood the beam as much as possible and locate the beam path clearly
- do not forget that the targets are also potential sources of reflexions
- disposer d’écrans absorbeurs d’énergie, d’obturateur de sécurité
- régler et aligner en atténuant le faisceau au maximum ou avec un laser secondaire de classe 1 ou 2
- always respect restricted access indications
- inform medical staff of laser use in your professional activities and indicate any incident or accident
- Concerning individual protection (ask the ACMO for instructions) :
- skin protection
- wear non flammable gloves (for lasers up to a few dozens of watts)
- • eye protection:
- porter
des lunettes de protection-laser adaptées à la longueur d'onde, à la
puissance et au mode d'émission du laser, et en bon état
- porter
des lunettes de réglage-laser adaptées à la longueur d'onde, à la
puissance et au mode d'émission du laser, et en bon état
