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Question about safety class for an IR laser






Benm

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You should definitely get some eye protection if messing around with those.

Technically it would be class 3B, but far more dangerous to handle compared to a well visible laser of the same power rating. The 3B rating covers a very wide area of lasers, basicsally anything visible or IR under 500 mW beyond which i would be class 4.

This looks like a line producing module, greatly reducing the chance of injury for a distance, but it would still be 3B unless you were mechanically obstructed from viewing it up close.

Class does not equate to likely safe use though. For example, a 400 mW 1064 nm laser is nearly or completely invisible, whereas a 400 mW 445 nm laser is so bright you would not even think of looking directly into it. The are, however, both class 3B devices, but the former is far more likely to injure someone now knowing what they are doing.
 
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You should definitely get some eye protection if messing around with those.

Technically it would be class 3B, but far more dangerous to handle compared to a well visible laser of the same power rating. The 3B rating covers a very wide area of lasers, basicsally anything visible or IR under 500 mW beyond which i would be class 4.

This looks like a line producing module, greatly reducing the chance of injury for a distance, but it would still be 3B unless you were mechanically obstructed from viewing it up close.

Class does not equate to likely safe use though. For example, a 400 mW 1064 nm laser is nearly or completely invisible, whereas a 400 mW 445 nm laser is so bright you would not even think of looking directly into it. The are, however, both class 3B devices, but the former is far more likely to injure someone now knowing what they are doing.

Thanks for the reply! Just another curious question, how do you guys typically determine the safety class? Do you actually do the power distribution calculations or estimate based on wavelength and power?
 
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There are some more extensive maximum permissible exposure (MPE) calculations you can go through taking into account surface reflection, power, duration of exposure, wavelength, pulse length, etc. Here's a site you can go to to read about them.

For the wavelengths and systems you'll likely encounter, the standard laser class system will probably suffice. They're essentially the same for major safety/standards organizations (ANSI, IEC, etc.); some with extra stipulations.

Basically, for the lasers you'll work with:
  • Class 1: Safe for viewing (barcode scanners, etc.)
  • Class 2 (< 1mW) : safe enough that your blink reflex will avoid eye damage
  • Class 3a/3r (< 5mW): Eye hazardous, but non-sustained blink reflex (0.1sec exposure) avoidance will usually prevent eye damage. Highest rating a laser "pointer" can be.
  • Class 3b (< 500mW): Eye hazardous. Blink reflex won't help, though exposure time less than that time may avoid damage. Note how large the range is. Lasers cannot be designated "pointers" but instead "modules."
  • Class 4 (> 500mW): As above but also an environment hazard, i.e. can cause things to burn if not managed.

The MPE calculations are useful if you're using a moving laser beam, such as in a scanner, where exposure time can play a factor in whether the laser is actually dangerous. Unless you are trained/certified in laser safety and have done all the math, you should avoid exposing people to a high powered laser beam (e.g. audience scanning).
 
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Benm

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MPE calculations absoutly matter when looking at laser shows where the audience is scanned. If the show is predermined you can check every possible spot audience could be in and measure how much exposure they would get throughout the whole show in worst case conditions.

For a handheld laser this is not really an option since you cannot control circumstances that much. As a ballpark figure class 3B and up require using eye protection since there is no mechanism present to exclude eye damage otherwise.

Class 3B really is broad though, including fairly safe line generating lasers for levels as well has projector diodes that'd fry your eyes in an single glance. Sadly there is no subdivision here, which is the point where it really matters.
 
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its pretty much all been said above. 50 mW of IR is pretty much a major hazard only to your eyes, and if focused may cause minor burns on dark surfaces. generally a OD3+ pair of glasses is sufficient for protection for your eyes, assuming that its power is as it is labeled and not higher. Just be careful as to where you're aiming it and manage the beam so people dont interact with it in a way that is dangerous.

invisible lasers follow slightly different rules than visible lasers, and have a seperate 'safety' class system than that of visible ones. most all are considered class 3B simply for the fact that they are a potentially higher hazard, due to your eye not reacting to them in the same way. there are no Class 2 and class 3a/3R classes of invisible lasers. only 1 (enclosed completely), and 3B, and 4.
 

Benm

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Class 1 does not require complete enclosure, but it should be safe to directly look into the laser for an indefinite period of time without any eye hazard. Something that would meet that criterium would be 0.1 mW laser, regardless if it is 650 or 940 nm wavelength.

Here you also cross paths with non-laser products that actually do produce potentially dangerous amounts of IR light. You can think of IR LEDs in remote controllers here that can have an output power of 50 mW or so. If they were laser devices they'd probably b e in class 1M or potentially even 3B as remote controls are often designed in a way that allow you to put the LED right in front of your eye.

Classes 2, 2M and 3A are not possible for invisible lasers, so its either 1, 3B or 4. Some practical lasers may actually be in class 1 due to low power. Think of low power IR lasers used to see if a person or vehicle passes through a road and applications like that.
 
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Well sort of...The class 1 definition is -no access to the radiation under normal operation- a good example would be a CD player. Any exposure at all is generally considered class 2. It was changed when it was revised last I checked, though the <0.1mW is a suggestion regarding the -no harm- description and is given just to give it a numerical value for the sake of defining class 2 which is no harm for viewing for up to 100 seconds iirc as well as to incorporate other light sources in references and allowable side scatter, etc. Then 3R which is 1-4.99mW which is no damage for brief exposure without additional elements/optics. I'll double check later though. LEDs generally are classified under their own CFRs last I checked though they do make references back and forth.
 

Benm

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Not really, the class-1 definition just defines it as being impossible to sustain eye damage regardless of the duration of exposure, even if that was 24/7. A fully enclosed laser product such as a cd/dvd player would fall into that category, but so would a 0.1 mW visible or IR exposed beam. You could literally stare into that the whole day, every day, without injury.

Classes 2 and 3A rely on the blink reflex which is absent for IR lasers, so that would push them straight from 1 into 3B if staring into them forever would be dangerous.

The 3B to 4 transistion is fairly arbitrary at 0.5 watts output power, but is basically designed to show the difference between lasers that are only dangerous to your eyes and lasers that are dangerous causing burns, setting things on fire and such. In addition reflections on matte surfaces from 3B devices are considered not dangerous, but that's not overly practical as it doesnt even state how far away from the dot you need to be.
 
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Ok not that I want to get technical, but the table I have says the following:

Class1: (400-1400 nm) not to exceed 0.00000039W per 10,000 seconds duration. (So no more than 3.9mW of total exposure over not quite 3 hours-ish. Assuming I did my math right, but I did it at work on the fly do correct if I'm wrong)

Class2a: (400-710nm) not to exceed 0.0000039W per 1000 sec.

Class2: (400-710nm) not to exceed 0.001W per 1000 sec.

Either way it's a moot point. It's a class 3b laser. We answered his question.
 
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Benm

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I think you may be off 3 of orders of magnitude there really, but the conclusion that the linked product should be classed 3B is spot on.

Most importantly i'd like to stress that an invisble laser of this power level is FAR more dangerous than a visible on in practical use, despite being in the same safety class. 808 nm is particularly nastly as it looks so dim, so innocent, until it sets something on fire with a brightness that seems insufficient to entertain a cat at arms length at first glance.
 





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