Talk:Laser safety
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Laser safety was a good article candidate, but did not meet the good article criteria at the time. Once the objections listed below are addressed, the article can be renominated. You may also seek a review of the decision if you feel there was a mistake.
Date of review: 2007-03-03 |
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[edit] What is safe?
There seems to be considerable disagreement on reasonable safety guidelines. The initial version of this article seemed to justify (or try to justify) practices which include systematic breaching of laser safety regulations. In particular, it was considered safe to routinely work without safety glasses, even when dealing with class-IV lasers, provided that some guidelines are followed. Surely such practices would be allowed by safety regulations if it could be convincingly shown that they are safe. However, for many reasons (some of which are now given in the modified article), they are not safe. A former colleague of mine worked exactly in this style (no glasses, but keep out of the experimental plane) with a 500-mW Nd:YAG laser. He was later told by a doctor that peripheral regions of both his retinas are burned. He had not noticed that, but with somewhat less luck it could have hit the central portion of the retina, blinding him for ever. He then changed his style; at earlier times, I had been unable to convince him to use his glasses.
Even though most laser operators have probably at least sometimes breached some safety regulations, there is an important difference between occassionally breaching a rule oneself and publicly recommending such breaches to others as allegedly reasonable practices. The latter can hardly be considered responsible. Therefore, I strongly recommend not to return to a relaxed version before laser safety experts can be convinced to include such practices into official rules and guidelines.
RPaschotta 13:38, 30 Oct 2004 (UTC)
I think that after your edit, the article is reasonably NPOV, discussing both common practice and objections against it. (As opposed to earlier versions that could be read as promoting dangerous behaviour and then as moralizing).
By the way, I think most operators are actually more careful with class 4 lasers. I haven't found a table that lists the exact tresholds for the different classes at various wavelengths, but the treshold for class 4 seems to be around 500 mW. Diffuse reflections from pieces of paper with 500 mW visible light are definitely unpleasant to have within your field of view -- and likely harmful as well, so people tend to be more careful with those.
More philosophically, one could wonder where one should put the boundary between acceptable and unacceptable risks. The chance of dying from head injury is about the same for an hour of car driving as for an hour of cycling (quite low compared to other risks in either case). However, few find it reasonable to recommend helmets to car drivers. Laser accidents happen, but are not very common, and I have not heard about anyone who actually completely lost sight in an eye. The worst I know of is someone who damaged 30% of the central view area of one eye due to a reflection from a mixing crystal.
Han-Kwang (talk) 15:54, 30 Oct 2004 (UTC)
It appears to me that the recommendations made in 2004 have not been implemented. The text still appears to condone unsafe behavior. Eyewear must be worn when engineering or other controls are inadequate to eliminate the potential exposure in excess of the applicable MPE. There have been dramatic improvements in eyewear coatings in the past few years. Eyewear can now be tailored to block only the harmful wavelengths produced by a given laser. The eyewear is also lightweight and comfortable, so the old excuses no longer apply. In the US, your employer is mandated by law to provide you with the safety equipment mandated by the ANSI Z136.1-2000 standard. In the case of Class 4 lasers, this applies to the purchase of eyewear, signage, viewing aids and laser access control systems.
1sciguy 18:25, 6 April 2007 (UTC)
- It's an open encyclopedia: go ahead and edit it. However, if you update it, make sure that it's NPOV - something that already lacks now. The article is really not supposed to tell the reader what to do and what not to do - but rather explain what are common practices and what official regulations are. Han-Kwang 19:23, 6 April 2007 (UTC)
[edit] disputed
It says most laser pointers are class II. Where's the evidence for this? They're class IIIa or IIIb. Class II lasers have minimal output intensity, like that from an LED. Also see my counterclaims at Talk:Laser. lysdexia 21:25, 21 Dec 2004 (UTC)
[edit] Laser proof curtain is necessary
Blink reflex does not work when you look at sun behind a curtain. It also applies when we exposed to a laser behind a curtain however, it is still dangerous it will burn points where the picture of light holes focus in the retina. All fabric curtains have these direct holes. --Mahdig 31 October 2006 (UTC)
- I'm not sure what you mean. Of course, a laser curtain should be made of a material that doesn't transmit any light, but not for the reason you mention. The images of the holes on your retina are too low in intensity to cause harm (For the record, I regularly hold pieces of tissue paper into multi-watt beams and watch them without any harmful effects). However, typically part of the beam will propagate into the same direction after going through the tissue or open fabric. If your eye is in that beam path, it will of course be very unhealthy, since that beam will be focused onto a single spot on the retina. Han-Kwang 23:59, 31 October 2006 (UTC)
- You said, "The images of the holes on your retina are too low in intensity to cause harm". It will be true only when the harm of light is thermal. However, in visible light region, the harm of laser to retina is photochemical and the size of picture in retina does not change harm effect. about the test you have done that I think you mean that when you look at a lamp behind a tissue the flash blindness does not occur however it occurs but in the points with distance to each other so it is not so noticeable. The problem exists with ordinary plastic curtain, too. Because you can see bright light behind them that it means that, it has holes. --Mahdig 14:06, 1 November 2006 (UTC)
I still have no clue what you are talking about. I see that you created an article Cutains and The blinking reflex containing the above comment. I strongly suggest that you add a diagram, remove the two spelling errors in the article, and add some context. As the new article is now it is non-encyclopedic and a very likely candidate for WP:AFD. Also please remember WP:NOR. Han-Kwang 14:42, 1 November 2006 (UTC)
- May be you understand what I am saying if you use a cloth instead of a tissue (tissue holes is very small) and with dark color and put it in front of your eye when looking to a lamp. Mahdig 18:52, 26 November 2006 (UTC)
- OK, you mean that a laser-shielding curtain should be absolutely light-tight. Agreed. But that doesn't have anything to do with the blinking reflex. Han-Kwang 19:36, 26 November 2006 (UTC)
[edit] Assenment scale
I'd say that this article definately needs an A-class or at least a GA-class rating on the assesment scale. I have nominated it for one of these ratings. G man yo 09:55, 28 February 2007 (UTC)
- What do these classes mean? Pzavon 15:24, 28 February 2007 (UTC)
[edit] Reasons for GA Failure
Unfortunately I have failed this article as there are a few areas in which I would like to bring to attention to the editors of this article in order to hepefully bring it up to standaeds in the future.
- The name of the article (Laser safety) is not mentioned in the introduction and not emboldened as mentioned in WP:MOS
- Secondly, there are very few interwikis is the second half of the article, therefore once again it is not up to the standards of WP:MOS.
- The different classes for the old system and the revised system should be in subcategories instead of just emboldened as mentioned in WP:MOS.
- There are only 2 categories, I'm sure they could be a few more added.
If this article was improved in the ways mentioned above and any other areas in which editors bring to attention then it may pass in future months/weeks.Tellyaddict 13:00, 3 March 2007 (UTC)
[edit] Leakage of high-power IR pump beam from DPSS laser pointers?
Anything authoritative on this issue?
