For classes 2 to 4 - Helmholtz

Transcription

Helmholtz-Zentrum Berlin
für Materialien und Energie
Instruction about
hazards in laser areas
and the
required precautions
(UVV Laserstrahlung VBG 93)
Laserschutzunterweisung für BENSC
1
I. Laser hazards
a) physical background:
laser properties:
● monochromatic
● coherent
● directional !
i.e. extremly shaped emission characteristic
Concentration
High intensity
of the
⇓
radiation
by a
Interaction with
factor of 106!
human tissue
2
3
b)
effect of laser radiation on the eye
Wavelength [nm]
100
no free propagation through air!
UV-C 180
Lens (incl.)
280 UV-B
315
UV-A
380
400
Focusing
VIS
Photochem. processes
Effect of heat (tolerable: some K)
40°C - 45°C: Enzyme induct., oedema
> 60°C: Coagulation, Necrosis Shock waves
500
Retina
effect!
780
IR-A
Retina + Vitreous
Vitreous, Lens,
1400
Aqueous
1000
1200
> 80°C: Collagen denaturation, membrane effects
> 100°C: Dehydration
> 150°C: Carbonation
Avalanche
breakdown!
Photoconjunctivitis (pinkeye)
Photokeratitis
Promotes cataract formation
Cornea
Promotes cataract formation
IR-B 2000
Effect of heat
Cornea
3000
Penetration depth
2
10
5
10
9
10 Intensity
[W m-2]
4
Eye injuries
due to laser radiation
are
in general irreparable!
Risk of
permanent loss of vision!
5
c) other hazard due to laser radiation
1. Irradiation of skin:
Wavelength [nm]
UV-C
180
280
315
UV-A
380
UV-B
VIS
Erythema formation
(reddened skin, sunburn),
subsequent pigmentation;
maximun at λ ~ 300 nm
enhanced
risk of
skin cancer !
Burns
2. Secondary hazards:
Hazard of fire or explosion:
Chemical und toxic hazards:
Solvents
Gas mixtures
Flammable plastics (synthetic fibre!!)
Paper!
due to: Gases
Smokes
Dusts
Formation: as combustion
product due to
laser-matter
interaction
6
II. Laser classes and their
risk potential
visible
invisible
Class 1
Safe
Safe
Class 2
Eye lid reflex
Class 3a
No collecting
optics!
Class 3b
Eye hazards!
In the upper power range also
for skin.
Diffuse reflections harmless.
Possibly hazard of fire or
explosion.
Class 4
High-power laser
– Very hazardous! –
Any exposure (eyes, skin)
may result in laser injuries,
even diffuse reflections!
Hazard of fire or explosion!
Safe
(as class 1)
7
Every laser system has to be classified!
8
III. Control measures and safety devices
a) administrative controls:
For classes 2 to 4 (i.e. in general)
Additionally for classes 3B and 4
•
•
•
Keep laser area* small
•
Warn all attendants before turning-on
Restricted number of attendants
•
Restricted access (to avoid entering
of unauthorised personnel).
First aid must be possible!
•
Labelling of each laser area*
•
Hazard evaluation, duty to give notice
•
Prohibition to employ minors
•
Appointment of a laser safety officer
•
Don‘t work alone
Training
*) Definition laser area:
entire (!) area which can be reached by laser radiation
9
b) warning signs and labels, warning light:
For classes 2 to 4:
To be posted with warning signs:
(clearly visible, permanent)
• at each entry to the laser area
• at the laser (system)
For class 4:
Warning light at the entry to
the laser area:
LASERSTRAHLUNG
NICHT DEM STRAHL AUSSETZEN
LASER KLASSE 3B
UNSICHTBARE LASERSTRAHLUNG
BESTRAHLUNG VON AUGE ODER HAUT DURCH
DIREKTE ODER STREUSTRAHLUNG VERMEIDEN
LASER KLASSE 4
NACH EN 60 825-1:94
Po =
W
λ =
nm
NACH EN 60 825-1:94
Po
PP
t
F
λ
=
=
=
=
=
100 W
≤ 5,5 kW
0,1-20 ms
Einzelimpuls bis 300 Hz
1064 nm
10
c) engineering controls:
General:
• Laser class as low as possible
• Avoidance of unintended reflections
• Appropriate enclosures / barriers
• Attention to other radiation
(x-ray, RF, UV)
For classes 1 to 3A:
Design of the laser (system) must not
allow an upgrade to a higher laser class
by means of an adapter optical unit!
For classes 2 to 4:
• Avoidance of unintentional emission
• Optical axis must not point at a window
• Termination of the beam path (beam stop)
• Beam path below or above eye level
Additionally for classes 3B and 4:
•
•
•
•
•
•
Don‘t use for basic alignment!
Secure optical components properly to
assure beam control!
Remove /cover all reflective surfaces
(e.g. tools, watch(!), jewellery)
Non-combustible housing, if possible
(label with warning signs!)
Interlocks ( e.g. emergency stop switch,
door interlock, etc.)
Key switch
11
d) personal protective equipment:
1. Laser protective eyewear:
DIN EN 207
Always needed, if any exposure of the eyes to laser radiation can not be excluded!
Requirement to label:
mode of operation
Caution:
⇒ important:
D/I
1060 nm
wavelength
range
L5
X
DIN
optical density
+ CE mark
manufacturer
In general narrow-band filters.
Protection only for the labeled wavelengths
Prevent mix-up!
(e.g. indication of the room number)
Laser protective eyewear must not show obvious defects!
(e.g. cracks, colour changes, remarkable defects of the frame, etc.)
For the visible range there exists also adjustment eyewear (DIN EN 208)
12
2. Skin protection:
In case of skin hazard
● Gloves (cotton)
● Clothing (no synthetic fibre!)
13
IV. Non- beam hazards:
a) electrical :
● High voltage
● High currents
● Capacitor banks
b) chemical:
● from operating agents
( - gases like halogens, CO, …
- dyes
- solvents)
c) other radiation:
● UV radiation (flash- / arc lamps)
● x-rays (electron tubes, HV)
● RF fields
14
V. Emergency procedures, in particular in case of eye damage
symptoms:
● Strong glare, flash blindness
● Afterimage
● Visual field loss
what to do:
■ Switch off power supply
■ First aid (?)
■ If suspecting eye injury
⇒ immediate ophthalmologic examination
(fluorescence angiography)
caused by: employer, supervisor, laser safety officer,
safety engineer
■ Notify supervisor/laser safety officer/dept. of occupational safety
of the incident
15
VI. Main guidelines for the handling of laser systems
■ Warn ALL attendants shortly before turning-on, in particular inexpert persons!
DON‘T allow any noninvolved persons to stay in the laser area!
■ Don‘t work alone!
■ Pay attention to the warning signal! Enter the room only after express request!
■ NEVER leave an activated laser unattended!
■ DO STRICTLY AVOID intrabeam viewing as long as the laser is activated!
■ Wear your laser protective eyewear!
■ NEVER handle with reflecting surfaces (mirrors, jewellery, watch) in the beam path
as long as the laser is activated!
■ Don‘t darken the laser area completely!
■ Pay attention to abnormal occurrences (sounds, smells)!
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VII. Laser safety officer
■ Laser safety training
■ Advice on questions of laser safety
■ Assistance in choosing protective equipment
■ Control of the protective measures and precautions
● Use of protective eyewear
● Access restrictions / labeling of each laser area
■ Participation in case of an accident (in collaboration with dept. of
occupational safety)
● Notification
● Investigation
● Causing of medical examination
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For classes 2 to 4 - Helmholtz

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