Laser Safety Instructions - Laser Pointers EN 207 Tab. B1. TOP – Personal safety precautions ... If you drop something, block the laser beam at the laser before picking the object

Laser Safety Instructions

April, 15th 2010

Alexander Podlipensky (MPL)

Stefan Malzer (IOIP)

MPL IOIP

Hazard of unenclosed laser beam (wavelength range: 1 mm - 100 nm)

Thermal damage of skin by a CO2 laser

Damage by photochemical, thermal or opto-mechanical effects. by harmful gases and vapors by flammable materials und explosive gas mixtures (solvents, paper, plastics, ...)

Why laser safety instructions?

Sun: ~2x105 W/m2

Hazard of the laser radiation

(1 mW laser causes 100 x sun irradiance)

Penetration depth in the eyePhotochemical cataract

Kindling of the

cornea Photochemical injury of the cornea

Burning of the retina

Thermal injury of the retina Burning of the cornea

cornea lens retina lensretina

cornealens

Damaged structure

UV cornea damage

Retina damage

Cornea thermal damage

Thermal damage of skin

Penetration depth in skin

MPE- maximum permissible exposure (MZB-Werte – maximale zulässige Bestrahlung)EN 60825-1, Table 6BGV B2 Tables 6a, 6b, 7 (pp. 57-59)

Laser categories (EN 60825-1)



MPE as power density versus exposure time for various wavelengths.

MPE as energy density versus exposure time for various wavelengths.

AELs– accessable emission limits(GZS – Grenzwerte der zugänglichen Strahlung)



MPE as power density versus exposure time for various wavelengths.

MPE as energy density versus exposure time for various wavelengths.

MPE

Laser categories (EN 60825-1)Laser Class

Concept λ , nm AELs Risk

1 The radiation emitted by this laser is not dangerous

all Depends on wavelength (µW)

No need for protection equipment

1M not harmful for the eye as long as no focusing elements reduce the beam profile.

302,5-4000

Depends on wavelength

No need for protection equipment, if used without optical instruments

2 Eye safe by aversion responses including the blink reflex (< 0.25 s)

400 - 700

<1 mW No need for protection equipment

2M Eye safe by aversion responses (<0.25 s) as long as no optical instruments reduce the beam profile

400 - 700

< 1mW No need for protection equipment, if used without optical instruments

3R The radiation exceeds the MPE values. The radiation is max. 5xAELs of class 1 (invisible) or 5x of class 2 (visible).

302,5 - 106

<5 mW Dangerous to the eye, safety glasses are recommended

3B The view into the laser is dangerous. Diffuse reflection are not considered as dangerous.

all 500 mW Dangerous to the eye, safety glasses are obligatory

4 Even scattered radiation can be dangerous, danger of fire, danger to the skin

all >500 mW Personal safety equipment is necessary (glasses, screens)

Risk – a combination of the likelihood of harm occurring and the severity of the harm that could be caused

Equipment - poorly designed, difficult to use or operate.

Potential faults or system failures resulting in additional hazards

Risk factors in work with lasers (how harm could occur?)



Process - experimental or investigative nature.

There might be a need to readjust the beam, to rearrange configuration of the equipment introducing additional risks



Location in which the work is being carried out.

Not adequately enclosed or screened area, vibration and other environmental factors might disturb the safe operation.






People might not be fully aware of all the hazards or understand how the risk should be controlled.

Location in which the work is being carried out.



Decrease of the riskusing T.O.P. principle

TOP -principle

T Technical safety precautions, safety instruments

O Organization of the safe conditions on the working place

P Personal safety precautions – what everybody has to take into account

TOP - Technical safety precautions Enclose the laser and the beam path Keep open beam paths to a minimum

Use curtains to protect the entrance area in the laser laboratory

Use the beam damps to block the laser beam- before optics rearrangement- if the laser is not in use

Enclose your setup from the sides by screens or curtains

Key switches for the class 3 B and 4. Interlocks and note switches

Laser areas have to be clearly labeled.

Make them as small as possible.

No „visitors“!

Regular cleaning.

Wear safety goggles!

Safety of the laser area

TOP – Organization

Labeling of the laser area


1 - warning lamp2 - curtains protecting the entrance area3 - depot for the laser goggles

Schematic image of a laser laboratory


From class 3R, laser safety engineers have to be appointed and lasers have to be notified by the LUK(federal accident insurance carrier).

Annual laser safety instruction is due

Regular control of safety instruments and equipment


Safety precautions in work with class 3B and 4 lasers:

at least two persons have to operate the laser;

wear the laser protection glasses;

don‘t leave the key in the key switch, if the laser is out of the use to avoid access to the laser for not-authorized personal (every lab must have a key box);

the laser should not be used out of regular working time and on weekends to avoid accidences caused by overwork.


TOP – Personal safety precautions

Full protection (EN 207)After the glasses the laser radiation corresponds to the class 1

Alignment protection (EN 208)After the glasses the laser radiation corresponds to the class 2

Never look into the beam!!!

According the EN207/208 standards the laser safety eye wear is tested for direct 10 s (100 pulses) laser exposure.

How to choose the laser safety glasses?

TOP – Personal safety precautionsHow to choose the laser safety glasses?

MPE values 60825-1, Tab. 6BGV B2, Tab. 6a, 6b, 7

Laser parametersspectral range, intensity, fluence, repetition rate

Protection levelOptical density of the filterIncrease of the working distanceProtection boxes and tubes


Full protection (EN 207)

Reference: EN 207 Tab. B1


Alignment protection (EN 208)

Reference: EN 208

TOP – Personal safety precautionsLabeling of the laser safety glasses

532 D L5 LV DIN CE S

Wavelength, nm

Laser typeD cwI pulsedR giant pulsedM modelocked

Protection level

Manufacturer

Indicator for DIN GS program(Geprüfte Sichercheit – tested safety)

EC type approval

Increased mechanical robustness


Adjustment

block the laser beam before optics rearrangementdecrease the power of the laser or use an additional low power VIS laser source

use pinholes and beam stops

Laser Laser

safe design of the experimental set up

place the laser beam below the eye level

design the setup properly to keep the incident and reflected beams in the plane parallel to the table (constant beam hight)

Avoid propagation of beams in vertical direction!!!

Enclose your setup

Control the reflecting and refracting beams and use the beam stops


The 10 golden rules of laser safety

Do not look into a laser beam.Don't look down specular reflections (eg: from mirrors or other reflective surfaces). Don't stare at diffuse reflections.If it looks bright-don't stare at it.

Keep room lights on brightly if possible.

The brighter the ambient lighting level,the smaller the eye's pupil will become, and the chance of a laser beamentering the eye will be lessened.

Remove personal jewellery.

Watches, rings etc act as reflectors. When entering a laser lab, remove anything which may pose a reflection hazard. This is to protect you and your co-workers.

Locate and terminate all stray laser beams.

Make sure that all stray beams are terminated with a matt, diffusing beam dump which is capable of handling the power of the laser beam.

Clamp all optical components securely.

Clamp, and where possible double clamp all optical components; this helps prevent your experiment from becoming misaligned and reduces the chances of a component moving and sweeping a laser beam over you.

Keep beams horizontal.

Horizontal beams are easier to work with and are predictable. Avoid vertical and skew beams if possible. Change beam height with a periscope, and be careful when aligning it.

Don't bend down below beam height.

If you drop something, block the laser beam at the laser before picking the object up. If you can't stop the beam (for instance, if you are in the middle of an experimental run), kick the object out of the way so that you don't trip over it. If you must sit down in a lab,make sure that the chair is high enough that your head is above beam height. If, for one reason or an other, you have to bend down, close your eyes when doing so or protect them with your hands.

Remember, optical components reflect, transmit and absorb light.

Often, a transmitting component will also reflect light, a reflecting component will transmit light etc.. This can lead to stray beams. Beware that optical components may change their characteristics when used with high power lasers i.e: neutral density filters can bleach, crack or even explode.

Don't forget non-optical hazards.

Don't trip over, electrocute yourself, spill solvents,burn yourself on liquid nitrogen etc..

Wear laser safety eyewear.

If eyewear is provided, ensure that it is suitable and wear it.

And again….

Keep your working space clean and tidy

No food and drinks in the lab area!!!

In emergency • „See“ the doctor

(ophthalmic clinic,

phone 85-33001)

immediately!

• Inform your boss

and the safety officer.

Laser safety video

available at

optikshare://For All Divisions/lasersafety video divx6

Guide to laser safety (Laservision)

BGV B2

BGI 5092

Thank you for your attention!

Documents

Laser Safety Instructions - Laser Pointers EN 207 Tab. B1. TOP – Personal safety precautions ... If you drop something, block the laser beam at the laser before picking the object