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Laser saftey

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LAN_403

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Tue Aug 08 2006, 07:48PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Ok guys, this has really been bugging me.

Any site on laser safety tell you to wear goggles that reduce the intensity of the light to a safe level. But I have yet to be able to find what a safe level is.

I am guessing that for CW visible beams, 5mw is 'safe' because you blink fast enough that it can't do any damage.

But I can't find any information on the other types of lasers I like... Mainly how many joules of q-switched YAG and non q-switched YAG is considered safe. I have been using OD5 goggles, which reduces the .2J output of my ssy-1 to about 2uJ, which seems safe enough...

Also what is 'safe' for near ir (ie 780/880nm) when you aren't going to blink. I am leaning tords about 1mw, but that seems a little high for continuous staring into the beam...

So, where in the hell am I supposed to find the safe exposure levels for different laser radiation?

Madgyver

Tue Aug 08 2006, 09:34PM

Registered Member #177 Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214

The safty level of the goggle has to be matched with the laser system.

As I understand it, the phrase isn't meant to be understood literaly.

A google only makes handling safer. Normaly, a goggle designed for a specific band, will reduce a stated maximum intensity to an unharmful level. In most cases however, the laser beam itelf is much much stronger then that. So with a goggle you can't safely watch into the beam or stuff. It only hinders scattering from making blind.

I worked with collimated class 4 IR Laser systems before and actually only a b/w camera is realy considered safe here.

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Tue Aug 08 2006, 11:37PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

There has to be a standard that the manuactures use to decide what googles are correct, right

They don't just throw in a pair of od5 googles and hope for the best do they

I know that most googles are not designed for you to be able to stare into the beam with, I just want to know what is safe so that I don't fry myself.

muciek man

Wed Aug 09 2006, 12:25AM

Registered Member #163 Joined: Mon Feb 13 2006, 01:55PM
Location: caledonia ohio
Posts: 22

i recently bought a laset from a surplus store and not having any information on intensity just used my welding hood (#10 shade) and a spot light to see what i was doing and that worked really well for me reduced the laser to a glow similer to a very low power led after 3 hours the only problem i had was getting used to daylight again

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Wed Aug 09 2006, 01:27AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Well the types of lasers I am asking about are all invisible (or at least you should never see them, as at that point there is too much power to be safe) which is why I am asking about what type of protection is needed. For visible wavelengths (I certainly hope that laser you had was visible) it is easier as you can see them and know when it is too bright. That isn't the story of nanosecond pulses of invisible light

Madgyver

Wed Aug 09 2006, 09:53AM

Registered Member #177 Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214

Well as I tried to imply, the safty level greatly depends on the power your laser has. If you are working with 1mw IR Laserdiodes any goggle should be ok.
If you are realy working with YAG Lasers in the watt area or Joule area you obviously have to use one with high absorbance. I wouldn't bother reading DIN or other norms, but directly ask vendors, what they would suggest. They have to stick to the norms anyway.

HV Enthusiast

Wed Aug 09 2006, 12:47PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

A quick one second search on GOOGLE . . .

http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_6.html

lists the allowable maximum limits for various lasers (per OSHA)

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Wed Aug 09 2006, 03:31PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Thanks EVR, I had been searching for a standard from the ANSI, never thought to check OHSA

Looks like my od5 googles are perfect for my laser

muciek man

Wed Aug 09 2006, 08:09PM

Registered Member #163 Joined: Mon Feb 13 2006, 01:55PM
Location: caledonia ohio
Posts: 22

my laser is visible but i have a slight tan mark from the reflecting mirror so i will play it safe though i just found out it was used for visible laser croshairs on an x-ray machine im now thinking about using it for a targeting for a potato cannon

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