BASICS: Know your laser class

Laser, fascinating, entertaining, and dangerous at the same time, so everything a man needs to have fun. But to ensure that no one gets hurt, today we will focus on the basics of laser classes.

Lasers are classified in Europe according to the standard EN 60825-1. Americans use a different standard, but they are almost the same in content. Laser products are generally divided into five different classes. In the visible light range, there is an additional Class 2, which is not found in the non-visible ranges. But what do these classes mean?

• Class 1: Safe laser devices. These are either safe because their power is so low, or because they have a protective housing that completely shields the laser radiation to the outside during normal operation. Laser products of Class 1 therefore have no danger zone. Theoretically, you could even look into the beam all the time, but we do not recommend it.
• Class 2 (formerly Class 3A): Eye protection is ensured at low powers through natural avoidance reactions (e.g. blinking reflex). For point sources, such as most laser pointers, the maximum permissible power for Class 2 is 1 mW. Laser Class 2 are safe as long as the natural avoidance reaction is not suppressed (intentionally staring into the beam) or affected by medications, drugs, etc. Laser products of Class 2 therefore have no danger zone.
• Class 3R (formerly Class 3B): Class 3R could be seen as a transition between the (practically safe) Class 2 and the "dangerous" Class 3B in terms of the risk of eye damage. Realistically, the probability of damage only occurs with irradiation lasting several seconds, as well as corresponding studies and accident reports show. However, a danger zone can be defined for Class 3R products.
  With some pulsed systems, there is also a risk for short-term exposure. It is important with Class 3R lasers that only people who have been trained about the residual risk use them. Wearing safety goggles is only unnecessary if it can be assumed that there will be no eye exposure within the danger zone.
• Class 3B: From here it becomes dangerous. There is a risk to the eye within the danger zone and in exceptional cases to the skin. Eye damage can occur after a very short duration of irradiation, which also applies to non-visible radiation. In general, there is no danger to the skin or eyes when looking at a diffuse reflection.
• Class 4: The really dangerous lasers. Applies to laser devices with powers over 0.5 W. There is a danger to the eye and skin within the respective danger zones, where not only the direct laser beam, but also diffuse scatter radiation poses a danger and has its own danger zone. Should the laser beam hit flammable materials, there is even a risk of fire!

Here again, the laser hazard classes summarized in a table. In short, the higher the laser class, the more dangerous it becomes.

Most military laser aiming devices such as AN/PEQ 15 etc. fall into laser classes 2 to 3B. For lasers in the infrared range, the classification into classes depends on the wavelength. This results from the calculation defined in the standard. The relevant IR lasers for us are found in the range around 800 nm and are classified as Class 3R at a power above 0.5 milliwatts. Users of such lasers must be trained about the residual risk as mentioned before.

So be careful if you want to get a laser box or a laser pointer, because once you are blind, you will remain so. And please do not shine on airplanes or helicopters, as this can have serious consequences.

We have introduced the new SPARTANAT BASICS category for you. With this, we present you the basics that you have always wanted to know how they work.