Laser Safety Classification
For laser safety, lasers have been classified internationally on the basis of how safe they are to use. There are also Australian standards in the use of lasers in the construction industry, here I will outline the basics and clear up some misunderstandings.
The latest International IEC Standard for Laser Safety and classifications 60825-1 Ed. 3.0 was released in 2014 and provided some revisions on the previous releases. The classes them self have stayed pretty much unchanged since a big shake up in 2004. These international standards have been adopted pretty much globally
Class1 are extremely safe as they have very low power output insufficient to cause damage under “reasonably foreseeable conditions”.
Class2 are also extremely safe, they have a greater power output but the human blink reflex will prevent any damage to eye sight under most circumstances.
Class 3R (formally 3A pre-2004) emits greater power again and there are potential hazards particularly if viewed through a telescope or similar. Finally, class 4 which are potentially strong enough to burn objects.
In the Australia construction industry only Class1, Class2 and Class3R (formally class3A) can be used. This is covered in the Australian Standard AS 2397 (1993). Note this standard was written prior to the change in the classification so references to class3A can be read as class3R. However, some larger work sites take issue in allowing 3R as they are not specifically mentioned in the AS 2397.
In the US/Canada and Europe again Class1, 2 and 3r(3A) are suitable for construction laser levels.
Class1 laser levels are few and far between due to the very limited range that the power output can produce. In fact, I am not aware of any available on the market at present. The last one I saw was an old spectra precision and it had a very limited range of 60m in one axis and 100m in the other. Thus making it very limited for larger construction jobs. There are no real special safety precautions for this class of laser.
The majority of laser levels on the market are class2 and are mainly red visible beams. These lasers are in a variety of formats such as; rotating lasers, line lasers and dot lasers. The Australian standard for this class state very basic safety precautions such as “don’t stare into the beam”. Display warning signs where access to the beam is possible (setting the beam out of reach of eye height negates this requirement). Nominating a Laser Safety Officer (no certification required) to determine the lasers are being used in a safe manner. Finally, line or dot beams are terminated (as most line and dot lasers are used indoors they are automatically terminated) so as not to shine out of the work site.
For the US, Canada and Europe safety requirement you will need to check the relevant standards although I believe they are broadly similar.
Class3R (3A) has the same requirements as class2 plus the need to terminate rotating beams (prevent shining off-site). Prevent shining laser onto mirrored surfaces, set up so that operators of optical devices such as theodolites or dumpy levels cannot see the beam (set up above or below the level of view). Plus a couple of other points such as prevent unauthorised use by removing batteries etc.
In conclusion, all lasers levels with class1,2 and 3R(3A) are approved for use on Australian construction sites. This is as long as the appropriate precautions as outlined are followed.