Lasers that fall under the class 4 category are among the most dangerous. They can burn your skin and cause severe, permanent damages to your eyes. So, you definitely want to be properly prepared before you use them.
Let’s overview the main characteristics of the class 4 lasers and their safety requirements.
How lasers are classified
Lasers are categorized in different classes from 1 to 4. The IEC 60825-1 (International Electrotechnical Commission) standard defined the different laser classes.
The IEC introduced a system for the classification of lasers and other products emitting laser radiation in the wavelength range from 180 nm to 1 mm. They are classified according to the hazard they represent for humans. The norm also aims to aid with hazard evaluation and the determination of user control measures.
What is the class 4 laser exactly?
As a guideline, under the old class system, lasers were considered class 4 when their optical power was over 500 mW. There are in fact many applications that use class 4 lasers; laser engraving, 3D printing, and material cutting, just to name a few.
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The higher the class, the more harmful the laser could be, and appropriate safety measures should be followed. Typically, all lasers manufacturers must indicate the class of their lasers, so the end user can then conform to the safety requirements from the governing bodies in his/her country.
What makes class 4 lasers so dangerous?
One can easily conceive that lasers can be very harmful. What people don’t fully realize, however, is that a lot of lasers are not in the visible range, and even low power lasers can cause injury to the eyes or the skin.
A study done by the LIA reports that 71% of incidents when using lasers were related to eyes injuries resulting mainly in blind spot in the field of vision. Most accidents happen in research and development laboratories with unconfined beams either during alignment or through a manipulation in the optical setup while the laser is active.
Also, worth to know, many accidents result from an unexpected upward reflection. Not using eyewear or using an incorrect selection or improper fit was identified as the main cause.
Typically, in the United States, safety guidance is coming from ANSI Z136 standards (American Standard Institute). The LIA (Laser Institute of America) being the publisher of those standards. Class 4 is currently the most dangerous class, with lasers in this category being able to cause severe injuries for the skin and eyes.
So, what are the class 4 laser safety requirements?
In a nutshell, class 4 laser safety requirements are as follow:
- First, classifying the laser and laser systems according to their relative hazards and then specifying the appropriate control measures based on their conditions of use as well. Hazard evaluation includes the capability of the beam path, the process interactions between the laser and the surrounding materials, the location of the laser itself, etc. Then a nominal hazard zone needs to be identified which means that a zone where the laser beam may exceed the maximum permissible exposure (MPE) needs to be defined so it can be confined to a limited space so the latter can act as protection to the nearby people.
- The institution management has the fundamental responsibility to ensure the safety of the lasers used in the facilities under its control.
- The institution must provide a safety and training program for Class 3B and 4 lasers. An individual designated as the Laser Safety Officer (LSO) with the authority and responsibility to evaluate and implement safety measures. Specific duties are listed under Appendix A of the ANSI Z136,1. A laser safety program must be put in place and documented to ensure that laser users have a detailed understanding of the laser risks and hazards so they are enable to use the safety measure in place and also evaluate the required control measure to be selected.
Whenever possible, class 4 laser should be controlled and monitored at a position as far as possible from the beam path to mitigate the risk and hazard.
It may be necessary for the Laser Safety Officer (LSO) to measure the lasers in order to establish the maximum permissible exposure (MPE) values. In this case, you will need to get a high-precision laser beam measurement that you can obtain with an industrial-grade laser power meter in order to get accurate values.
This blog does not pretend to replace the standards listed above. It is up to the user to verify what class 4 laser safety requirements are enforced in your country. There is usually an institution controlling those guidelines in each nation.
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FAQs
One of the key requirements for working with Class 4 lasers is the use of appropriate personal protective equipment (PPE), such as laser safety glasses or goggles. These PPE must be specifically designed for the wavelength and power of the laser being used, and must be worn at all times when working with the laser.
What are the rules for Class 4 laser safety? ›
One of the key requirements for working with Class 4 lasers is the use of appropriate personal protective equipment (PPE), such as laser safety glasses or goggles. These PPE must be specifically designed for the wavelength and power of the laser being used, and must be worn at all times when working with the laser.
What are some potential hazards of Class 4 lasers? ›
Class 4 lasers cause immediate injury to eye and skin if a worker is exposed to the beam or the reflection of the beam from either a shiny or dull surface. They also pose “non-beam” hazards, such as the possibility of: fire. exposure to high voltage.
What are the guidelines for laser safety? ›
Never direct the beam toward other people. Operate lasers only in the area designed for their use and make sure that the beam is terminated at the end of its use path. Never allow a laser beam to escape its designated area of use. Position the laser so that the beam is well above or below eye level.
What happens if you look at a Class 4 laser? ›
Lasers that fall under the class 4 category are among the most dangerous. They can burn your skin and cause severe, permanent damages to your eyes.
Are Class 4 lasers illegal in US? ›
Are Class 4 lasers illegal? A. Therapeutic Class 4 lasers are NOT illegal. However, there have been some Class 4 laser pointers which have been sold illegally, can cause severe eye damage and are not permitted for sale in the US.
What does a class 4 laser do? ›
Class 4 laser therapy stimulates the production of ATP (adenosine triphosphate) which drives many of the processes within our cells. This increased production of ATP helps speed up the healing process within cells.
What is the biggest safety issue with lasers? ›
The human body is vulnerable to the output of certain lasers, and under certain circ*mstances, exposure can result in damage to the eye and skin. Research relating to injury thresholds of the eye and skin has been carried out in order to understand the biological hazards of laser radiation.
Can Class 4 laser cause fire? ›
Class 4 laser products are capable of causing injury to both the eye and skin from direct exposure and reflections also may be hazardous. Class 4 laser beams also present a fire hazard.
What is an example of a Class 4 hazard? ›
Commonly Transported Flammable Solids; Spontaneous Combustibles and 'Dangerous When Wet' Materials
- Alkali metals.
- Metal powders.
- Aluminium phosphide.
- Sodium batteries.
- Sodium cells.
- Firelighters.
- Matches.
- Calcium carbide.
The fundamental or guiding principle of laser safety is to make sure any exposure to a person's eyes or skin is at or below the threshold to cause injury.
Does OSHA require a laser safety officer? ›
The recognized industry standard for the safe use of lasers, American National Standard for Laser Safety [ANSI Z136. 1-2007], requires a Laser Safety Officer (LSO) when workers use Class IIIB or Class IV lasers – unless the lasers are enclosed in a Class I enclosure so they don't expose workers to damaging radiation.
What are the major safety needed for laser machine? ›
Keep interior of the laser cutter clean and free of debris. Visually inspect the interior between uses and clean tray if debris or residue are present. DO NOT modify or disable any safety features of the laser system. DO NOT operate the laser unless all covers are in place and interlocks are working properly.
What are the precautions for Class 4 laser? ›
Prevent all eye exposure to beams from Class 4 lasers.
This includes accidental exposures -- be careful to keep the beam away from eyes and faces. Also, remember that reflections off mirrors, glass, and shiny surfaces can be just as hazardous as the direct beam.
Are Class 4 laser products safe? ›
laser wavelength and power. Class 4 lasers can damage tissue and skin and so opaque gloves (e.g. latex) must be worn and even so, hands (or fingers etc) should not be placed in the beam path as a method of locating the beam.
Do Class 4 lasers damage tissue all the time? ›
However, Class IV Deep Tissue Therapy Lasers do not and should not cause any damage, when used properly. With that said, improper use of any of a number of household or vocational tools can be dangerous.
Who has primary responsibility for laser safety any time a Class 3B or Class 4 laser is operated? ›
ANSI Z136. 1 specifies that any facility using Class 3b or Class 4 lasers or laser systems should designate a Laser Safety Officer to oversee safety for all operational, maintenance, and servicing situations. This person should have the authority and responsibility to monitor and enforce the control of laser hazards.
What are the safety requirements for laser welding? ›
It is necessary to wear laser safety glasses or goggles that meet the applicable standards, like BS EN 207:2017. These goggles block the particular frequencies of the laser in operation. To avoid laser radiation reaching the skin, it is important to wear complete protective clothing and gloves.
What are the hazards of Type IV infrared lasers? ›
Class 4 - high power, high risk
Also, systems whose diffuse reflections may be eye hazards and direct exposure may cause serious skin burns. Class 4 lasers normally require restrictive warning labels and even more restrictive control measures (e.g., safety goggles, interlocks, warning signs, etc).
What control measures for class 3B and 4 lasers are designed to ensure? ›
MPED. NHZ. 6 Control measures for Class 3 B and 4 lasers are designed to ensure that eye and skin exposures do not exceed the applicable limit .
